Lead Your Boss The Subtle Art of Managing Up

CERN Document Server

Baldoni, John

2009-01-01

Every manager on the move wants to have influence at the top in order to get his or her ideas heard and ultimately acted upon. In Lead Your Boss, recognized leadership guru John Baldoni gives managers new—as well as tried-and-true— methods for influencing both their bosses and their peers, and giving senior leaders reasons to follow their lead. Featuring instructive stories based on real-life experiences from leaders at all levels, Lead Your Boss reveals proven strategies for: • Developing spheres of influence • Handling tough issues • Asserting oneself diplomatically • Putting the team first

Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

Science.gov (United States)

Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

2018-06-01

Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

Science.gov (United States)

Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

2018-04-01

Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

Dream Catchers: "Margin Call," "Boss," and Climbing the Beanstalk

Science.gov (United States)

Beck, Bernard

2012-01-01

Two recent popular entertainments, "Margin Call" (Barnum, Dodson, Jenckes, Moosa, Quinto & Chandor, 2011) and "Boss" (Safinia, 2011), depict powerful and successful groups of bosses confronting sudden, extreme threats. They are forced to react quickly and sacrifice important values to achieve survival of their organizations. In these emergencies,…

Low-waste electrochemical decontamination of stainless-steel surface

International Nuclear Information System (INIS)

Babain, V.A.; Smirnov, I.V.; Shadrin, A.Yu.; Firsin, N.G.; Zakharchuk, G.A.; Pavlov, A.B.; Shilov, V.V.

2002-01-01

An electrochemical decontamination method using a formic acid-based recycling electrolyte was proposed to remove firmly fixed contaminants from stainless-steel surfaces. The following provisions make for minimisation of the amounts of waste: (i) use of specially designed electrodes with vacuum removal of spent electrolyte; (ii) inter-cycle removal of radionuclides from the electrolyte by using an inorganic sorbent; (iii) periodic regeneration of the spent electrolyte. the dissolved metals (Fe, Cr, Ni) being transformed into acidic phosphates; (iv) solidification of residues arising from the regeneration of the electrolyte and spent sorbent into iron-phosphate ceramics. The technology and equipment developed were used for decontamination of a plutonium glove-box. The level of surface contamination was reduced 100-fold in two decontamination cycles. The depth of metal skimming was 1.5 μ for the ceiling and walls and 4.5 μ for the table top. Each square meter of stainless-steel surface provides about 100 g of solid radioactive waste in the form of iron-phosphate ceramic blocks

Spreading of lithium on a stainless steel surface at room temperature

Energy Technology Data Exchange (ETDEWEB)

Skinner, C.H., E-mail: cskinner@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Capece, A.M. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Roszell, J.P.; Koel, B.E. [Department of Chemical and Biological Engineering, Princeton University, NJ 08540 (United States)

2016-01-15

Lithium conditioned plasma facing surfaces have lowered recycling and enhanced plasma performance on many fusion devices and liquid lithium plasma facing components are under consideration for future machines. A key factor in the performance of liquid lithium components is the wetting by lithium of its container. We have observed the surface spreading of lithium from a mm-scale particle to adjacent stainless steel surfaces using a scanning Auger microprobe that has elemental discrimination. The spreading of lithium occurred at room temperature (when lithium is a solid) from one location at a speed of 0.62 μm/day under ultrahigh vacuum conditions. Separate experiments using temperature programmed desorption (TPD) investigated bonding energetics between monolayer-scale films of lithium and stainless steel. While multilayer lithium desorption from stainless steel begins to occur just above 500 K (E{sub des} = 1.54 eV), sub-monolayer Li desorption occurred in a TPD peak at 942 K (E{sub des} = 2.52 eV) indicating more energetically favorable lithium-stainless steel bonding (in the absence of an oxidation layer) than lithium–lithium bonding.

PITTING CORROSION OF STAINLESS STEEL AT THE VARIOUS SURFACE TREATMENT

Directory of Open Access Journals (Sweden)

Viera Zatkalíková

2011-09-01

Full Text Available The stainless steel surface treatment is very important with regard to its pitting corrosion susceptibility. An effect of various types surfacing on pitting corrosion resistance of AISI 304stainless steel is investigated in this work. The samples of the tested material are turned, blasted, peened, grinded and a half of them are pickled to achieve higher purity of surfaces and better quality of passive film. Eight types of different finished surfaces are tested by electrochemical and immersion tests to determine corrosion behaviour in conditions where pitting is evoked by controlled potential and second by solution with high redox potential. By this way the effect of mechanical and chemical surface treatment on the resistance to pitting corrosion, character, size and shape of pits are compared in the conditions of different mechanisms of corrosion process.

Radiation-heterogeneous processes on the surface of stainless steel in contact with water

International Nuclear Information System (INIS)

Garibov, A.; Agayev, T.N.; Velibekova, G.Z.; Ismayilov, Sh.S.; Aliyev, A.G.

2003-01-01

Full text: Stainless steels are one of prevailing materials of nuclear power engineering. Under operating conditions in real systems they are exposed to influence of ionizing radiation in contact with various environments. Therefore in the processes of corrosion and destruction of stainless steels special significance takes on surface processes and subsequent heterogeneous processes with their participation. In this report the results of research of nuclear-heterogeneous processes regularities in contact with stainless steel of nuclear reactors with water under influence of γ-quanta in the temperature range 300-573 K are given. Radiolytic processes in water are investigated comprehensively and therefore it was taken as modelling system for titration of surface defects and secondary electrons, emitted from metal. It was determined, that radiation processes in stainless steel give rise to the increasing of energy output of molecular hydrogen at water radiolysis from 0.45 molecule/100 eV at pure water radiolysis at 296 K up to 3.4 molecule/100 eV at the presence of stainless steel at 300 K. With increase of temperature the output of molecular hydrogen increases up to 8.2 molecule/100 eV at 573 K. Processes of lattice damage in samples of stainless steel under influence of γ-rays were investigated by electrophysical method. Influence of γ-radiation on stainless steel in contact with water at temperatures T ≤ 423 K and initial values of radiation dose D ≤ 200 kGy given rise to the reduction of electrical resistivity of samples. At doses D≥200 kGy electrical resistivity is increased. Increase of temperature from 333 K up to 423 K lead to the reduction of dose value, at which the transition to resistance increase, from 200 kGy up to 100 kGy occurs. At T≥523 K insoluble oxide phase is formed on a surface of metal which give rise to the increase of electrical resistivity of stainless steel samples. Surface oxide film formed in contact of stainless steel + H 2 O

Silver deposition on stainless steel container surfaces in contact with disinfectant silver aqueous solutions

International Nuclear Information System (INIS)

Petala, M.; Tsiridis, V.; Mintsouli, I.; Pliatsikas, N.; Spanos, Th.; Rebeyre, P.; Darakas, E.; Patsalas, P.; Vourlias, G.; Kostoglou, M.; Sotiropoulos, S.; Karapantsios, Th.

2017-01-01

Highlights: • Silver is one of the biocides of water consumed in the International Space Station. • Ionic silver is depleted from potable water when in contact with stainless steel (SS). • SEM and XPS analysis reveal a uniform silver deposition over the SS surface. • Silver deposits in its metallic form, in line with a galvanic deposition mechanism. • Evidence is provided that Cr and/ or Ni oxide builds-up on SS surfaces. - Abstract: Silver is the preservative used on the Russian segment of the International Space Station (ISS) to prevent microbial proliferation within potable water supplies. Yet, in the frame of the European Automated Transfer Vehicle (ATV) missions to ISS, silver depletion from water has been detected during ground transportation of this water to launch site, thereby indicating a degradation of water quality. This study investigates the silver loss from water when in contact with stainless steel surfaces. Experiments are conducted with several types of stainless steel surfaces being exposed to water containing 10 or 0.5 mg/L silver ions. Results show that silver deposits on stainless steel surfaces even when a passivation layer protects the metallic surface. The highest protection to silver deposition is offered by acid passivated and electropolished SS 316L. SEM and XPS experiments were carried out at several locations of the sample area that was in contact with the Ag solution and found similar morphological (SEM) and compositional (sputter-etch XPS) results. The results reveal that silver deposits uniformly across the wetted surface to a thickness larger than 3 nm. Moreover, evidence is provided that silver deposits in its metallic form on all stainless steel surfaces, in line with a galvanic deposition mechanism. Combination of ICP-MS and XPS results suggests a mechanism for Ag deposition/reduction with simultaneous substrate oxidation resulting in oxide growth at the exposed stainless steel surface.

Silver deposition on stainless steel container surfaces in contact with disinfectant silver aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Petala, M., E-mail: petala@civil.auth.gr [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Tsiridis, V. [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Mintsouli, I. [Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Pliatsikas, N. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Spanos, Th. [Department of Petroleum and Mechanical Engineering Sciences, Eastern Macedonia and Thrace Institute of Technology, Kavala, 65404 (Greece); Rebeyre, P. [ESA/ESTEC, P.O.Box 299, 2200 AG, Noordwijk (Netherlands); Darakas, E. [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Patsalas, P.; Vourlias, G. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Kostoglou, M.; Sotiropoulos, S.; Karapantsios, Th. [Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece)

2017-02-28

Highlights: • Silver is one of the biocides of water consumed in the International Space Station. • Ionic silver is depleted from potable water when in contact with stainless steel (SS). • SEM and XPS analysis reveal a uniform silver deposition over the SS surface. • Silver deposits in its metallic form, in line with a galvanic deposition mechanism. • Evidence is provided that Cr and/ or Ni oxide builds-up on SS surfaces. - Abstract: Silver is the preservative used on the Russian segment of the International Space Station (ISS) to prevent microbial proliferation within potable water supplies. Yet, in the frame of the European Automated Transfer Vehicle (ATV) missions to ISS, silver depletion from water has been detected during ground transportation of this water to launch site, thereby indicating a degradation of water quality. This study investigates the silver loss from water when in contact with stainless steel surfaces. Experiments are conducted with several types of stainless steel surfaces being exposed to water containing 10 or 0.5 mg/L silver ions. Results show that silver deposits on stainless steel surfaces even when a passivation layer protects the metallic surface. The highest protection to silver deposition is offered by acid passivated and electropolished SS 316L. SEM and XPS experiments were carried out at several locations of the sample area that was in contact with the Ag solution and found similar morphological (SEM) and compositional (sputter-etch XPS) results. The results reveal that silver deposits uniformly across the wetted surface to a thickness larger than 3 nm. Moreover, evidence is provided that silver deposits in its metallic form on all stainless steel surfaces, in line with a galvanic deposition mechanism. Combination of ICP-MS and XPS results suggests a mechanism for Ag deposition/reduction with simultaneous substrate oxidation resulting in oxide growth at the exposed stainless steel surface.

Image BOSS: a biomedical object storage system

Science.gov (United States)

Stacy, Mahlon C.; Augustine, Kurt E.; Robb, Richard A.

1997-05-01

Researchers using biomedical images have data management needs which are oriented perpendicular to clinical PACS. The image BOSS system is designed to permit researchers to organize and select images based on research topic, image metadata, and a thumbnail of the image. Image information is captured from existing images in a Unix based filesystem, stored in an object oriented database, and presented to the user in a familiar laboratory notebook metaphor. In addition, the ImageBOSS is designed to provide an extensible infrastructure for future content-based queries directly on the images.

X-ray impact induced desorption of gases from stainless steel surfaces

International Nuclear Information System (INIS)

Brumbach, S.; Kaminsky, M.

1975-01-01

During the operation of plasma devices the interaction of energetic photons with surfaces can cause gas release by photodesorption, and thereby contribute to plasma contamination. Measurements of gases released from stainless steel surfaces were made in an ultrahigh vacuum environment using x-rays characteristic for a tungsten target bremsstrahlung spectrum for electron energies varying from 15 to 50 keV. The predominant gas species observed mass spectrometically are CO 2 (m/e = 44), CO (m/e = 28), and O 2 (m/e = 32). Mean quantum yields for the release of these species from stainless steel were determined. For example, for fresh stainless steel surfaces irradiated by x-rays produced by 50 keV electrons, a mean quantum yield for molecular CO 2 release of 3 x 10 -4 molecules per photons in a bremsstrahlung spectrum at 50 keV electron energy was observed. Based on such a quantum yield an outgassing rate was determined

Bank of Standardized Stimuli (BOSS phase II: 930 new normative photos.

Directory of Open Access Journals (Sweden)

Mathieu B Brodeur

Full Text Available Researchers have only recently started to take advantage of the developments in technology and communication for sharing data and documents. However, the exchange of experimental material has not taken advantage of this progress yet. In order to facilitate access to experimental material, the Bank of Standardized Stimuli (BOSS project was created as a free standardized set of visual stimuli accessible to all researchers, through a normative database. The BOSS is currently the largest existing photo bank providing norms for more than 15 dimensions (e.g. familiarity, visual complexity, manipulability, etc., making the BOSS an extremely useful research tool and a mean to homogenize scientific data worldwide. The first phase of the BOSS was completed in 2010, and contained 538 normative photos. The second phase of the BOSS project presented in this article, builds on the previous phase by adding 930 new normative photo stimuli. New categories of concepts were introduced, including animals, building infrastructures, body parts, and vehicles and the number of photos in other categories was increased. All new photos of the BOSS were normalized relative to their name, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. The availability of these norms is a precious asset that should be considered for characterizing the stimuli as a function of the requirements of research and for controlling for potential confounding effects.

Gaseous surface hardening of martensitic stainless steels

DEFF Research Database (Denmark)

Tibollo, Chiara; Villa, Matteo; Christiansen, Thomas L.

The present work addresses heat and surface treatments of martensitic stainless steel EN 1.4028. Different combinations of heat treatments and surface treatments were performed: conventional austenitisation, cryogenic treatment and in particular high temperature solution nitriding (HTSN) and low...... that cubic lath martensite in conventionally austenitised EN 1.4028 dissolves nitrogen and develops expanded martensite (ferrite) during LTSH. HTSN leads to a microstructure of tetragonal plate martensite and retained austenite. The content of retained austenite can be reduced by a cryo...

Simultaneous surface engineering and bulk hardening of precipitation hardening stainless steel

DEFF Research Database (Denmark)

Frandsen, Rasmus Berg; Christiansen, Thomas; Somers, Marcel A. J.

2006-01-01

This article addresses simultaneous bulk precipitation hardening and low temperature surface engineering of two commercial precipitation hardening stainless steels: Sandvik Nanoflex® and Uddeholm Corrax®. Surface engineering comprised gaseous nitriding or gaseous carburising. Microstructural....... The duration and temperature of the nitriding/carburising surface hardening treatment can be chosen in agreement with the thermal treatment for obtaining optimal bulk hardness in the precipitation hardening stainless steel....... characterisation of the cases developed included X-ray diffraction analysis, reflected light microscopy and micro-hardness testing. It was found that the incorporation of nitrogen or carbon resulted in a hardened case consisting of a combination of (tetragonal) martensite and expanded (cubic) austenite...

Influence of surface roughness of stainless steel on microbial adhesion and corrosion resistance

DEFF Research Database (Denmark)

Hilbert, Lisbeth Rischel; Bagge-Ravn, Dorthe; Kold, John

2003-01-01

Abstract The aim of this study was to evaluate if hygienic characteristics of stainless steel used in the food industry could be improved by smoothing surface roughness from an Ra of 0.9 to 0.01 ƒÝm. The adherence of Pseudomonas sp., Listeria monocytogenes and Candida lipolytica to stainless steel...... was not affected by surface roughness (Ra) ranging from grit 4000 polished stainless steel (Ra steel (Ra 0.9). Neither adhesion of Ps. aeruginosa nor its removal by an alkaline commercial cleaner in a flow system was affected by surface roughness. Pitting corrosion resistance...... was evaluated in a commercial disinfectant and in 1 M NaCl. Electropolished and grit 4000 polished steel proved more corrosion resistant as opposed to grit 80 and 120 polished surfaces. In conclusion, the surface finish did not influence bacterial attachment, colonisation, or removal, but is an important...

Iodine susceptibility of pseudomonads grown attached to stainless steel surfaces

Science.gov (United States)

Pyle, B. H.; McFeters, G. A.

1990-01-01

Pseudomonads were adapted to grow in phosphate-buffered water and on stainless steel surfaces to study the iodine sensitivity of attached and planktonic cells. Cultures adapted to low nutrient growth were incubated at room temperature in a circulating reactor system with stainless steel coupons to allow biofilm formation on the metal surfaces. In some experiments, the reactor was partially emptied and refilled with buffer at each sampling time to simulate a "fill-and-draw" water system. Biofilms of attached bacteria, resuspended biofilm bacteria, and reactor suspension, were exposed to 1 mg l-1 iodine for 2 min. Attached bacterial populations which established on coupons within 3 to 5 days displayed a significant increase in resistance to iodine. Increased resistance was also observed for resuspended cells from the biofilm and planktonic bacteria in the system suspension. Generally, intact biofilms and resuspended biofilm cells were most resistant, followed by planktonic bacteria and phosphate buffer cultures. Thus, biofilm formation on stainless steel surfaces within water systems can result in significantly increased disinfection resistance of commonly-occurring water-borne bacteria that may enhance their ability to colonise water treatment and distribution systems.

Characteristics of modified martensitic stainless steel surfaces under tribocorrosion conditions

International Nuclear Information System (INIS)

Rozing, Goran; Marusic, Vlatko; Alar, Vesna

2017-01-01

Stainless steel samples were tested in the laboratory and under real conditions of tribocorrosion wear. Electrochemical tests were also carried out to verify the corrosion resistance of modified steel surfaces. Metallographic analysis and hardness testing were conducted on stainless steel samples X20Cr13 and X17CrNi16 2. The possibilities of applications of modified surfaces of the selected steels were investigated by testing the samples under real wear conditions. The results have shown that the induction hardened and subsequently nitrided martensitic steels achieved an average wear resistance of up to three orders of magnitude higher as compared to the delivered condition.

Characteristics of modified martensitic stainless steel surfaces under tribocorrosion conditions

Energy Technology Data Exchange (ETDEWEB)

Rozing, Goran [Osijek Univ. (Croatia). Chair of Mechanical Engineering; Marusic, Vlatko [Osijek Univ. (Croatia). Dept. of Engineering Materials; Alar, Vesna [Zagreb Univ. (Croatia). Dept. Materials

2017-04-01

Stainless steel samples were tested in the laboratory and under real conditions of tribocorrosion wear. Electrochemical tests were also carried out to verify the corrosion resistance of modified steel surfaces. Metallographic analysis and hardness testing were conducted on stainless steel samples X20Cr13 and X17CrNi16 2. The possibilities of applications of modified surfaces of the selected steels were investigated by testing the samples under real wear conditions. The results have shown that the induction hardened and subsequently nitrided martensitic steels achieved an average wear resistance of up to three orders of magnitude higher as compared to the delivered condition.

Micro/nano engineering on stainless steel substrates to produce superhydrophobic surfaces

Energy Technology Data Exchange (ETDEWEB)

Beckford, Samuel; Zou Min, E-mail: mzou@uark.edu

2011-12-30

Creating micro-/nano-scale topography on material surfaces to change their wetting properties has been a subject of much interest in recent years. Wenzel in 1936 and Cassie and Baxter in 1944 proposed that by microscopically increasing the surface roughness of a substrate, it is possible to increase its hydrophobicity. This paper reports the fabrication of micro-textured surfaces and nano-textured surfaces, and the combination of both on stainless steel substrates by sandblasting, thermal evaporation of aluminum, and aluminum-induced crystallization (AIC) of amorphous silicon (a-Si). Meanwhile, fluorinated carbon films were used to change the chemical composition of the surfaces to render the surfaces more hydrophobic. These surface modifications were investigated to create superhydrophobic surfaces on stainless steel substrates. The topography resulting from these surface modifications was analyzed by scanning electron microscopy and surface profilometry. The wetting properties of these surfaces were characterized by water contact angle measurement. The results of this study show that superhydrophobic surfaces can be produced by either micro-scale surface texturing or nano-scale surface texturing, or the combination of both, after fluorinated carbon film deposition.

Surface interactions of cesium and boric acid with stainless steel

International Nuclear Information System (INIS)

Grossman-Canfield, N.

1995-08-01

In this report, the effects of cesium hydroxide and boric acid on oxidized stainless steel surfaces at high temperatures and near one atmosphere of pressure are investigated. This is the first experimental investigation of this chemical system. The experimental investigations were performed using a mass spectrometer and a mass electrobalance. Surfaces from the different experiments were examined using a scanning electron microscope to identify the presence of deposited species, and electron spectroscopy for chemical analysis to identify the species deposited on the surface. A better understanding of the equilibrium thermodynamics, the kinetics of the steam-accelerated volatilizations, and the release kinetics are gained by these experiments. The release rate is characterized by bulk vaporization/gas-phase mass transfer data. The analysis couples vaporization, deposition, and desorption of the compounds formed by cesium hydroxide and boric acid under conditions similar to what is expected during certain nuclear reactor accidents. This study shows that cesium deposits on an oxidized stainless steel surface at temperatures between 1000 and 1200 Kelvin. Cesium also deposits on stainless steel surfaces coated with boric oxide in the same temperature ranges. The mechanism for cesium deposition onto the oxide layer was found to involve the chemical reaction between cesium and chromate. Some revaporization in the cesium hydroxide-boric acid system was observed. It has been found that under the conditions given, boric acid will react with cesium hydroxide to form cesium metaborate. A model is proposed for this chemical reaction

Surface characterization and wear behaviour of laser surface melted AISI 316L stainless steel

CSIR Research Space (South Africa)

Kumar, A

2010-01-01

Full Text Available The present study concerns an in depth investigation of the influence of laser surface melting of AISI 316L stainless steel using Ar and N2 as shrouding atmosphere. Laser surface melting has been carried out using a 5 kW continuous wave (CW) fibre...

Portable hyperspectral fluorescence imaging system for detection of biofilms on stainless steel surfaces

Science.gov (United States)

Jun, Won; Lee, Kangjin; Millner, Patricia; Sharma, Manan; Chao, Kuanglin; Kim, Moon S.

2008-04-01

A rapid nondestructive technology is needed to detect bacterial contamination on the surfaces of food processing equipment to reduce public health risks. A portable hyperspectral fluorescence imaging system was used to evaluate potential detection of microbial biofilm on stainless steel typically used in the manufacture of food processing equipment. Stainless steel coupons were immersed in bacterium cultures, such as E. coli, Pseudomonas pertucinogena, Erwinia chrysanthemi, and Listeria innocula. Following a 1-week exposure, biofilm formations were assessed using fluorescence imaging. In addition, the effects on biofilm formation from both tryptic soy broth (TSB) and M9 medium with casamino acids (M9C) were examined. TSB grown cells enhance biofilm production compared with M9C-grown cells. Hyperspectral fluorescence images of the biofilm samples, in response to ultraviolet-A (320 to 400 nm) excitation, were acquired from approximately 416 to 700 nm. Visual evaluation of individual images at emission peak wavelengths in the blue revealed the most contrast between biofilms and stainless steel coupons. Two-band ratios compared with the single-band images increased the contrast between the biofilm forming area and stainless steel coupon surfaces. The 444/588 nm ratio images exhibited the greatest contrast between the biofilm formations and stainless coupon surfaces.

Comparison of adhesion of the food spoilage bacterium Shewanella putrefaciens to stainless steel and silver surfaces

DEFF Research Database (Denmark)

Hjelm, Mette; Hilbert, Lisbeth Rischel; Møller, Per

2002-01-01

The aim of this study is to compare the number of attached bacteria, Shewanella putrefaciens, on stainless steel with different silver surfaces. Thus evaluating if silver surfaces could contribute to a higher hygienic status in the food industry. Bacterial adhesion to three types of silver surfaces...... (new silver, tarnished silver and sulphide treated silver) was compared to adhesion to stainless steel (AISI 316). Numbers of attached bacteria (cfu cm-2) were estimated using the Malthus indirect conductance method. A lower number of attached bacteria were measured on new silver surfaces compared...... to stainless steel for samples taken after 24 hours. However this was not significant (P > 0.05). The numbers of attached bacteria were consistently lower when tarnished silver surfaces were compared to stainless steel and some, but not all, experiments showed statistically significant. A difference of more...

Surface analysis of 316 stainless steel treated with cold atmospheric plasma

Energy Technology Data Exchange (ETDEWEB)

Williams, David F., E-mail: david.williams@surrey.ac.uk [Department of Mechanical Engineering Sciences, University Of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); TWI Ltd Granta Park Great Abington, Cambridge CB21 6AL (United Kingdom); Kellar, Ewen J.C. [TWI Ltd Granta Park Great Abington, Cambridge CB21 6AL (United Kingdom); Jesson, David A.; Watts, John F. [Department of Mechanical Engineering Sciences, University Of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

2017-05-01

Highlights: • Reduction in carbon contamination from ∼80 at.% to 40 at.% after 15 s treatment. • Associated carbon thickness reduction from 4.5 nm to 0.5 nm. • Area treated by torch has a diameter of 11 mm measured using imaging XPS. - Abstract: The surface of 316 stainless steel has been modified using cold atmospheric plasma (CAP) to increase the surface free energy (by cleaning the and chemically activating the surface)IN preparation for subsequent processes such as painting, coating or adhesive bonding. The analyses carried out, on CAP treated 316 stainless steel surfaces, includes X-ray photoelectron spectroscopy (XPS), imaging XPS (iXPS), and surface free energy (SFE) analysis using contact angle measurements. The CAP treatment is shown to increase the SFE of as-received 316 stainless steel from ∼39 mJ m{sup −1} to >72 mJ m{sup −1} after a short exposure to the plasma torch. This was found to correlate to a reduction in adventitious carbon, as determined by XPS analysis of the surface. The reduction from ∼90 at% to ∼30% and ∼39 at%, after being plasma treated for 5 min and 15 s respectively, shows that the process is relatively quick at changing the surface. It is suggested that the mechanism that causes the increase in surface free energy is chain scission of the hydrocarbon contamination triggered by free electrons in the plasma plume followed by chemical functionalisation of the metal oxide surface and some of the remaining carbon contamination layer.

Surface composition effect of nitriding Ni-free stainless steel as bipolar plate of polymer electrolyte fuel cell

Energy Technology Data Exchange (ETDEWEB)

Yu, Yang; Shironita, Sayoko [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Nakatsuyama, Kunio [Nakatsuyama Heat Treatment Co., Ltd., 1-1089-10, Nanyou, Nagaoka, Niigata 940-1164 (Japan); Souma, Kenichi [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Hitachi Industrial Equipment Systems Co., Ltd., 3 Kanda Neribei, Chiyoda, Tokyo 101-0022 (Japan); Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

2016-12-01

Graphical abstract: The anodic current densities in the passive region of nitrided SUS445-N stainless steel are lower than those of a non heat-treated SUS445 stainless steel and heat-treated SUS445-Ar stainless steel under an Ar atmosphere. It shows a better corrosion resistance for the SUS445 stainless steel after the nitriding heat treatment. - Highlights: • The nitriding heat treatment was carried out using Ni-free SUS445 stainless steel. • The corrosion resistance of the nitrided SUS445-N stainless steel was improved. • The structure of the nitrided SUS445-N stainless steel changed from α-Fe to γ-Fe. • The surface elemental components present in the steels affect the corrosion resistance. - Abstract: In order to increase the corrosion resistance of low cost Ni-free SUS445 stainless steel as the bipolar plate of a polymer electrolyte fuel cell, a nitriding surface treatment experiment was carried out in a nitrogen atmosphere under vacuum conditions, while an Ar atmosphere was used for comparison. The electrochemical performance, microstructure, surface chemical composition and morphology of the sample before and after the electrochemical measurements were investigated using linear sweep voltammetry (LSV), X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDS) and laser scanning microscopy (LSM) measurements. The results confirmed that the nitriding heat treatment not only increased the corrosion resistance, but also improved the surface conductivity of the Ni-free SUS445 stainless steel. In contrast, the corrosion resistance of the SUS445 stainless steel decreased after heat treatment in an Ar atmosphere. These results could be explained by the different surface compositions between these samples.

Surface nanocrystallization of stainless steel for reduced biofilm adherence

International Nuclear Information System (INIS)

Yu Bin; Li, D Y; Davis, Elisabeth M; Irvin, Randall T; Hodges, Robert S

2008-01-01

Stainless steel is one of the most common metallic biomedical materials. For medical applications, its resistance to the adherence of biofilms is of importance to the elimination or minimization of bacterial infections. In this study, we demonstrate the effectiveness of a process combining surface nanocrystallization and thermal oxidation (or a recovery heat treatment in air) for reducing the biofilm's adherence to stainless steel. During this treatment, a target surface was sandblasted and the resultant dislocation cells in the surface layer were turned into nanosized grains by a subsequent recovery treatment in air. This process generated a more protective oxide film that blocked the electron exchange or reduced the surface activity more effectively. As a result, the biofilm's adherence to the treated surface was markedly minimized. A synthetic peptide was utilized as a substitute of biofilms to evaluate the adhesion between a treated steel surface and biofilms using an atomic force microscope (AFM) through measuring the adhesive force between the target surface and a peptide-coated AFM tip. It was shown that the adhesive force decreased with a decrease in the grain size of the steel. The corresponding surface electron work function (EWF) of the steel was also measured, which showed a trend of variation in EWF with the grain size, consistent with corresponding changes in the adhesive force

New Stainless Steel Alloys for Low Temperature Surface Hardening?

DEFF Research Database (Denmark)

Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.

2015-01-01

The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE presen...

Desensitization of stainless steels by laser surface heat-treatment

Energy Technology Data Exchange (ETDEWEB)

Nakao, Yoshikuni; Nishimoto, Kazutoshi

1987-11-01

Laser heating was applied for the desensitization heat-treatment of the surface layer in the sensitized HAZ of Type 304 stainless steel. The degree of sensitization was examined by EPR technique and the 10 % oxalic acid electrolytic etch test. The CO/sub 2/ laser with maximum power of 1.5 kW was used for heat-treatment. Time-Temperature-Desensitization diagram (TTDS diagram) for sensitized Type 304 stainless steels were developed by calculation assuming the chromium diffusion control for desensitization which might occur when the chromium depleted zone was healed up due to dissolution of chromium carbide and chromium diffusion from the matrix being heated at the solution annealing temperatures. TTDS diagrams calculated agree fairly well with ones determined by corrosion tests. Laser irradiation conditions (e.g., Laser power, beam diameter and traveling velocity) required for desensitization of sensitized Type 304 stainless steels were calculated using additivity rule from the TTDS diagram calculated and theoretical thermal curve of laser heating derived from the heat conduction theory. After laser beam irradiated under an optimum condition predicted by calculation, the sensitized HAZ of Type 304 stainless steel restored complete resistance to intergranular corrosion.

Effect of surface treatment on mechanical properties of glass fiber/stainless steel wire mesh reinforced epoxy hybrid composites

Energy Technology Data Exchange (ETDEWEB)

N, Karunagaran [S.K.P Engineering College, Tiruvannamalai (India); A, Rajadurai [Anna University, Chennai (India)

2016-06-15

This paper investigates the effect of surface treatment for glass fiber, stainless steel wire mesh on tensile, flexural, inter-laminar shear and impact properties of glass fiber/stainless steel wire mesh reinforced epoxy hybrid composites. The glass fiber fabric is surface treated either by 1 N solution of sulfuric acid or 1 N solution of sodium hydroxide. The stainless steel wire mesh is also surface treated by either electro dissolution or sand blasting. The hybrid composites are fabricated using epoxy resin reinforced with glass fiber and fine stainless steel wire mesh by hand lay-up technique at room temperature. The hybrid composite consisting of acid treated glass fiber and sand blasted stainless steel wire mesh exhibits a good combination of tensile, flexural, inter-laminar shear and impact behavior in comparison with the composites made without any surface treatment. The fine morphological modifications made on the surface of the glass fiber and stainless steel wire mesh enhances the bonding between the resin and reinforcement which inturn improved the tensile, flexural, inter-laminar shear and impact properties.

Laser surface modification of stainless steels for cavitation erosion resistance

Science.gov (United States)

Kwok, Chi Tat

1999-12-01

Austenitic stainless steel UNS S31603 (Fe -17.6Cr -11.2Ni -2.5Mo -1.4Mn -0.4Si -0.03C) has higher pitting corrosion resistance but lower cavitation erosion resistance than that of UNS S30400. This is because of its lower tendency for strain induced martensitic transformation and higher stacking fault energy as compared with those of UNS S30400. In order to improve its cavitation erosion resistance, surface modification of S31603 was performed by laser surface melting and laser surface alloying using a 2-kW CW Nd-YAG laser and a 3-kW CW CO2 laser. For laser surface melting, austenitic stainless steel UNS S30400, super duplex stainless steel UNS S32760 and martensitic stainless steel UNS S42000 were also investigated for comparison purpose. For laser surface alloying, alloying materials including various elements (Co, Cr, Ni, Mo, Mn, Si & C), alloys (AlSiFe & NiCrSiB), ceramics (Si3N 4, SiC, Cr3C2, TiC, CrB & Cr2O 3) and alloys-ceramics (Co-WC, Ni-WC, Ni-Al2O3, Ni-Cr2C3) were used to modify the surface of S31603. The alloyed surface was achieved first by flame spraying or pre-placing of the alloy powder on the S31603 surface and then followed by laser surface remelting. The cavitation erosion characteristics of laser surface modified specimens in 3.5% NaCl solution at 23°C were studied by means of a 20-kHz ultrasonic vibrator at a peak-to-peak amplitude of 30 mum. In addition, their pitting corrosion behaviour was evaluated by electrochemical techniques. The microstructures, compositions, phase changes and damage mechanisms under cavitation erosion were investigated by optical microscopy, SEM, EDAX and X-ray diffractometry. Mechanical properties such as microhardness profile were also examined. The cavitation erosion resistance Re (reciprocal of the mean depth of penetration rate) of laser surface melted S31603 was found to be improved by 22% and was attributed to the existence of tensile residual stress. Improvement on the Re of S42000 was found to be 8.5 times

Improved surface bioactivity of stainless steel substrates using osteocalcin mimetic peptide

International Nuclear Information System (INIS)

Hosseini, Samaneh; Naderi-Manesh, Hossein; Vali, Hojatollah; Faghihi, Shahab

2014-01-01

Although stainless steel has a good biocompatibility for most clinical cases, the higher tissue response (bone bonding property) is required in orthopedic field. In this study, to improve bone-bonding ability of stainless steel substrates, a specific sequence of osteocalcin mimetic peptide is used as bioactive coating material to biochemically modify the surface of metallic samples. This sequence consists of thirteen amino acids present in the first helix of osteocalcin is synthesized in amidic form and physically adsorbed on the surface of 316LS (316 low carbon surgical grade) stainless steel substrates. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to characterize the surface of peptide coated and uncoated substrates. The bioactivity and bone bonding ability of coated and uncoated substrates are assessed by level of hydroxyapatite formation, using transmission electron microscopy (TEM), energy-dispersive x-ray (EDS), and scanning electron microscopy (SEM). The pre-osteoblast cell attachment and proliferation are also evaluated by MTT assay. The results show that the surface of coated sample is homogenously covered by the peptide and display a rougher surface relative to uncoated sample. TEM images reveal the formation of plate-like hydroxyapatite crystals in the presence of the peptide and an amorphous calcium phosphate phase without the peptide. Pre-osteoblast cells proliferation is significantly higher on the surface of peptide coated substrate, while cell attachment remains unaffected by the peptide coatings. Pre-osteoblast cells also demonstrate a higher degree of spreading on the surface of coated sample. It is believed that osteocalcin mimetic peptide improve surface bioactivity and promote hydroxyapatite crystal formation may lead to increased mineralization and bone formation on the surface of metallic biomedical devices. - Graphical abstract: A peptide sequence located in the first helix of OC is selected based on its

Improved surface bioactivity of stainless steel substrates using osteocalcin mimetic peptide

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Samaneh [Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161 (Iran, Islamic Republic of); Naderi-Manesh, Hossein, E-mail: naderman@modares.ac.ir [Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Vali, Hojatollah [Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7 (Canada); Faghihi, Shahab, E-mail: sfaghihi@nigeb.ac.ir [Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161 (Iran, Islamic Republic of)

2014-02-14

Although stainless steel has a good biocompatibility for most clinical cases, the higher tissue response (bone bonding property) is required in orthopedic field. In this study, to improve bone-bonding ability of stainless steel substrates, a specific sequence of osteocalcin mimetic peptide is used as bioactive coating material to biochemically modify the surface of metallic samples. This sequence consists of thirteen amino acids present in the first helix of osteocalcin is synthesized in amidic form and physically adsorbed on the surface of 316LS (316 low carbon surgical grade) stainless steel substrates. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to characterize the surface of peptide coated and uncoated substrates. The bioactivity and bone bonding ability of coated and uncoated substrates are assessed by level of hydroxyapatite formation, using transmission electron microscopy (TEM), energy-dispersive x-ray (EDS), and scanning electron microscopy (SEM). The pre-osteoblast cell attachment and proliferation are also evaluated by MTT assay. The results show that the surface of coated sample is homogenously covered by the peptide and display a rougher surface relative to uncoated sample. TEM images reveal the formation of plate-like hydroxyapatite crystals in the presence of the peptide and an amorphous calcium phosphate phase without the peptide. Pre-osteoblast cells proliferation is significantly higher on the surface of peptide coated substrate, while cell attachment remains unaffected by the peptide coatings. Pre-osteoblast cells also demonstrate a higher degree of spreading on the surface of coated sample. It is believed that osteocalcin mimetic peptide improve surface bioactivity and promote hydroxyapatite crystal formation may lead to increased mineralization and bone formation on the surface of metallic biomedical devices. - Graphical abstract: A peptide sequence located in the first helix of OC is selected based on its

Recrystallization and modification of the stainless-steel surface relief under photonic heat load in powerful plasma discharges

Energy Technology Data Exchange (ETDEWEB)

Budaev, V. P., E-mail: budaev@mail.ru; Martynenko, Yu. V. [National Research Centre Kurchatov Institute (Russian Federation); Khimchenko, L. N. [Project Center ITER (Russian Federation); Zhitlukhin, A. M.; Klimov, N. S. [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Pitts, R. A. [ITER Organization (France); Linke, J. [EURATOM Association, Forschungszentrum Jülich GmbH (Germany); Bazylev, B. [IHM, Karlsruhe Institute of Technology (Germany); Belova, N. E.; Karpov, A. V. [National Research Centre Kurchatov Institute (Russian Federation); Kovalenko, D. V.; Podkovyrov, V. L.; Yaroshevskaya, A. D. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2013-11-15

Targets made of ITER-grade 316L(N)-IG stainless steel and Russian-grade 12Cr18Ni10Ti stainless steel with a close composition were exposed at the QSPA-T plasma gun to plasma photonic radiation pulses simulating conditions of disruption mitigation in ITER. After a large number of pulses, modification of the stainless-steel surface was observed, such as the formation of a wavy structure, irregular roughness, and cracks on the target surface. X-ray and optic microscopic analyses of targets revealed changes in the orientation and dimensions of crystallites (grains) over a depth of up to 20 μm for 316L(N)-IG stainless steel after 200 pulses and up to 40 μm for 12Cr18Ni10Ti stainless steel after 50 pulses, which is significantly larger than the depth of the layer melted in one pulse (∼10 μm). In a series of 200 tests of ITER-grade 316L(N)-IG ITER stainless steel, a linear increase in the height of irregularity (roughness) with increasing number of pulses at a rate of up to ∼1 μm per pulse was observed. No alteration in the chemical composition of the stainless-steel surface in the series of tests was revealed. A model is developed that describes the formation of wavy irregularities on the melted metal surface with allowance for the nonlinear stage of instability of the melted layer with a vapor/plasma flow above it. A decisive factor in this case is the viscous flow of the melted metal from the troughs to tops of the wavy structure. The model predicts saturation of the growth of the wavy structure when its amplitude becomes comparable with its wavelength. Approaches to describing the observed stochastic relief and roughness of the stainless-steel surface formed in the series of tests are considered. The recurrence of the melting-solidification process in which mechanisms of the hill growth compete with the spreading of the material from the hills can result in the formation of a stochastic relief.

Antibacterial isoeugenol coating on stainless steel and polyethylene surfaces prevents biofilm growth.

Science.gov (United States)

Nielsen, C K; Subbiahdoss, G; Zeng, G; Salmi, Z; Kjems, J; Mygind, T; Snabe, T; Meyer, R L

2018-01-01

Pathogenic bacteria can spread between individuals or between food items via the surfaces they share. Limiting the survival of pathogens on surfaces, therefore, presents an opportunity to limit at least one route of how pathogens spread. In this study, we propose that a simple coating with the essential oil isoeugenol can be used to circumvent the problem of bacterial transfer via surfaces. Two commonly used materials, stainless steel and polyethylene, were coated by physical adsorption, and the coatings were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurements. We quantified and visualized the colonization of coated and uncoated surfaces by three bacteria: Staphylococcus aureus, Listeria monocytogenes and Pseudomonas fluorescens. No viable cells were detected on surfaces coated with isoeugenol. The isoeugenol coating prepared with simple adsorption proved effective in preventing biofilm formation on stainless steel and polyethylene surfaces. The result was caused by the antibacterial effect of isoeugenol, as the coating did not diminish the adhesive properties of the surface. Our study demonstrates that a simple isoeugenol coating can prevent biofilm formation of S. aureus, L. monocytogenes and P. fluorescens on two commonly used surfaces. © 2017 The Society for Applied Microbiology.

Characterization of a Laser Surface-Treated Martensitic Stainless Steel

OpenAIRE

S.R. Al-Sayed; A.A. Hussein; A.A. Nofal; S.I. Hassab Elnaby; H. Elgazzar

2017-01-01

Laser surface treatment was carried out on AISI 416 machinable martensitic stainless steel containing 0.225 wt.% sulfur. Nd:YAG laser with a 2.2-KW continuous wave was used. The aim was to compare the physical and chemical properties achieved by this type of selective surface treatment with those achieved by the conventional treatment. Laser power of different values (700 and 1000 W) with four corresponding different laser scanning speeds (0.5, 1, 2, and 3 m?min?1) was adopted to reach the op...

Effect of Spreading Time on Contact Angle of Nanofluid on the Surface of Stainless Steel AISI 316 and Zircalloy 4

Science.gov (United States)

Prajitno, D. H.; Trisnawan, V.; Syarif, D. G.

2017-05-01

The solid surface tension plays an important role in the heat and mass transfer system for heat exchanger equipment. In the nuclear power plant industry, the stainless steel AISI 316 and Zircalloy 4 have been used for long time as structure materials. The purpose of the experimental is to study solid state surface tension behavior by measure contact angle Nano fluid contain nano particle alumina on metal surface of stainless steel AISI 316 and Zircalloy 4 by sessile drop method. The experiment is to measure the static contact angle and drop nano fluid contains nano particle alumina on stainless steel 316 and zircalloy 4 with different spreading time from 1 to 30 minute. It was observed that stainless steel 316 and zircalloy 4 lose their hydrophobic properties with increasing elapsed time during drop of nano fluid on the surface of alloy. As a result the contact angle of nano fluid on surface of metal is decrease with increasing elapsed time. While the magnitude diameter of drop nano fluid and wetting surface is increase with increasing elapsed time on the surface of the stainless steel SS 316 and Zircalloy 4.

Preparation and High-temperature Anti-adhesion Behavior of a Slippery Surface on Stainless Steel.

Science.gov (United States)

Zhang, Pengfei; Huawei, Chen; Liu, Guang; Zhang, Liwen; Zhang, Deyuan

2018-03-29

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A typical anti-wetting superhydrophobic surface easily fails when exposed to a high-temperature liquid. Recently, Nepenthes-inspired slippery surfaces demonstrated a new way to solve the adhesion problem. A lubricant layer on the slippery surface can act as a barrier between the repelled materials and the surface structure. However, the slippery surfaces in previous studies rarely showed high-temperature resistance. Here, we describe a protocol for the preparation of slippery surfaces with high-temperature resistance. A photolithography-assisted method was used to fabricate pillar structures on stainless steel. By functionalizing the surface with saline, a slippery surface was prepared by adding silicone oil. The prepared slippery surface maintained the anti-wetting property for water, even when the surface was heated to 300 °C. Also, the slippery surface exhibited great anti-adhesion effects on soft tissues at high temperatures. This type of slippery surface on stainless steel has applications in medical devices, mechanical equipment, etc.

Effect of SUS316L stainless steel surface conditions on the wetting of molten multi-component oxides ceramic

Energy Technology Data Exchange (ETDEWEB)

Wang, Jin, E-mail: wangjinustb@gmail.com [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196 (Japan); Matsuda, Nozomu [Bar and Wire Product Unit, Nippon steel and Sumitomo Metal Corporation, Fukuoka, 802-8686 (Japan); Shinozaki, Nobuya [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196 (Japan); Miyoshi, Noriko [The Center for Instrumental Analysis, Kyushu Institute of Technology, Fukuoka, 804-8550 (Japan); Shiraishi, Takanobu [Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8588 (Japan)

2015-02-01

Highlights: • Multi-component oxides had a good wetting on stainless substrates with pretreatments. • Various substrates surface roughness caused the difference of final contact angles. • The wetting rate was slow on polished substrate due to the slow surface oxidation. - Abstract: A study on the effect of SUS316L stainless steel surface conditions on the wetting behavior of molten multi-component oxides ceramic was performed and aimed to contribute to the further understanding of the application of oxides ceramic in penetration treatment of stainless steel coatings and the deposition of stainless steel cermet coatings. The results show that at 1273 K, different surface pre-treatments (polishing and heating) had an important effect on the wetting behavior. The molten multi-component oxides showed good wettability on both stainless steel substrates, however, the wetting process on the polished substrate was significantly slower than that on the heated substrates. The mechanism of the interfacial reactions was discussed based on the microscopic and thermodynamic analysis, the substrates reacted with oxygen generated from the decomposition of the molten multi-component oxides and oxygen contained in the argon atmosphere, and the oxide film caused the molten multi-component oxides ceramic to spread on the substrates surfaces. For the polished substrate, more time was required for the surface oxidation to reach the surface composition of Heated-S, which resulted in relatively slow spreading and wetting rates. Moreover, the variance of the surface roughness drove the final contact angles to slightly different values following the sequence Polished-S > Heated-S.

Investigation of Selected Surface Integrity Features of Duplex Stainless Steel (DSS) after Turning

Czech Academy of Sciences Publication Activity Database

Krolczyk, G.; Nieslony, P.; Legutko, S.; Hloch, Sergej; Samardžić, I.

2015-01-01

Roč. 54, č. 1 (2015), s. 91-94 ISSN 0543-5846 Institutional support: RVO:68145535 Keywords : duplex stainless steel * machining * turning * surface integrity * surface roughness Subject RIV: JQ - Machines ; Tools Impact factor: 0.959, year: 2014 http://hrcak.srce.hr/126702

Honeywell starts energy-management service: savings guaranteed; BOSS replaced

Energy Technology Data Exchange (ETDEWEB)

Schwartz, R.

1983-01-24

Honeywell Inc. guarantees that its new Honeywell Service Link Operation (HSLO), a time-sharing service, will produce greater energy savings than its monthly fees. There are no front-end costs because the central computer is located at the supplier's Atlanta site, making energy management cost-affordable for facilities as small as 25,000 square feet. HSLO replaces Honeywell's Building Operations Service System (BOSS) that has a minimum-size requirement of 100,000 square feet. BOSS customers will be automatically changed to HSLO at no charge. All 21 regional computer centers will be available to users. Johnson Controls, Inc. also operates a time-sharing operation called Total Automated Building Services (TABS). (DCK)

Ombud’s Corner: Boss, where are you?

CERN Multimedia

Sudeshna Datta-Cockerill

2015-01-01

Sometimes bosses seem to wear Harry Potter’s invisibility cloak: always caught in meetings, away on duty travel, overwhelmed with technical duties… the time they have left to spend with their teams can drop down to almost zero. But their people need them…   “Oh no, he is too busy.” “I can’t go and disturb my supervisor, she has no time.” “No, my supervisor doesn’t want to deal with this type of interpersonal problem.” “I have been struggling to get a final decision on this for ages now...” Having to deal with an invisible boss is often a very worrying source of frustration for the supervisee: no one to share their professional concerns with, no one to make decisions that are perhaps vital to a project, no one to resolve an ongoing conflict between colleagues and a flow of information that is not as regular or structured as...

Controlling the stainless steel surface wettability by nanosecond direct laser texturing at high fluences

Science.gov (United States)

Gregorčič, P.; Šetina-Batič, B.; Hočevar, M.

2017-12-01

This work investigates the influence of the direct laser texturing at high fluences (DLT-HF) on surface morphology, chemistry, and wettability. We use a Nd:YAG laser ( λ = 1064 nm) with pulse duration of 95 ns to process stainless steel surface. The surface morphology and chemistry after the texturing is examined by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD), while the surface wettability is evaluated by measuring the static contact angle. Immediately after the texturing, the surface is superhydrophilic in a saturated Wenzel regime. However, this state is not stable and the superhydrophilic-to-superhydrophobic transition happens if the sample is kept in atmospheric air for 30 days. After this period, the laser-textured stainless steel surface expresses lotus-leaf-like behavior. By using a high-speed camera at 10,000 fps, we measured that the water droplet completely rebound from this superhydrophobic surface after the contact time of 12 ms.

Effect of metal surface composition on deposition behavior of stainless steel component dissolved in liquid sodium

International Nuclear Information System (INIS)

Yokota, Norikatsu; Shimoyashiki, Shigehiro

1988-01-01

Deposition behavior of corrosion products has been investigated to clarify the effect of metal surface composition on the deposition process in liquid sodium. For the study a sodium loop made of Type 304 stainless steel was employed. Deposition test pieces, which were Type 304 stainless steel, iron, nickel or Inconel 718, were immersed in the sodium pool of the test pot. Corrosion test pieces, which were Type 304 stainless steel, 50 at% Fe-50 at%Mn and Inconel 718, were set in a heater pin assembly along the axial direction of the heater pin surface. Sodium temperatures at the outlet and inlet of the heater pin assembly were controlled at 943 and 833 K, respectively. Sodium was purified at a cold trap temperature of 393 K and the deposition test was carried out for 4.3 x 10 2 - 2.9 x 10 4 ks. Several crystallized particles were observed on the surface of the deposition test pieces. The particles had compositions and crystal structures which depended on both the composition of deposition test pieces and the concentration of iron and manganese in sodium. Only iron-rich particles having a polyhedral shape deposited on the iron surface. Two types of particles, iron-rich α-phase and γ-phase with nearly the same composition as stainless steel, were deposited on Type 304 stainless steel. A Ni-Mn alloy was deposited on the nickel surface in the case of a higher concentration of manganese in sodium. On the other hand, for a lower manganese concentration, a Fe-Ni alloy was precipitated on the nickel surface. Particles deposited on nickel had a γ-phase crystal structure similar to the deposition test piece of nickel. Hence, the deposition process can be explained as follows: Corrosion products in liquid sodium were deposited on the metal surface by forming a metal alloy selectively with elements of the metal surface. (author)

Tips and tricks for antegrade recanalization of chronic total occlusions using the CrossBoss catheter.

Science.gov (United States)

Kwan, Tak W; Diwan, Ravi; Ratcliffe, Justin A; Huang, Yili; Patri, Rahul; James, David; Liou, Michael; Fallahi, Arzhang; Young, Bruce; Nanjundappa, Aravinda; Daggubati, Ramesh

2015-02-01

To provide new strategies and techniques for the successful recanalization of chronic total occlusions (CTOs) with the sole use of the CrossBoss catheter. In addition, some common CTO scenarios are illustrated in detail. CTOs are one of the most challenging complex coronary lesion subsets to intervene upon. Even with the innovation of specialized catheters, the success rate of antegrade recanalization remains low. Between June and December 2013, a retrospective analysis of 50 consecutive patients who presented with a planned percutaneous intervention (PCI) of a CTO was performed. In all patients, the CrossBoss catheter was used. No additional reentry devices were necessary. Procedural success was defined as failure. The average fluoroscopy time was 45.9 minutes and the average amount of contrast use was 273.8 mL. No patient suffered a coronary perforation from the CrossBoss catheter. With increased experience using the CrossBoss catheter, the antegrade success rate of CTOs can be improved. Some tips include identifying the likely course of the artery with the aid of retrograde injection, proper guidewire selection and manipulation, and redirecting the CrossBoss catheter if there is substantial deviation from the original path.

Surface characterization of adsorbed asphaltene on a stainless steel surface

International Nuclear Information System (INIS)

Abdallah, W.A.; Taylor, S.D.

2007-01-01

X-ray photoelectron spectroscopy was used to characterize a single layer of adsorbed asphaltene on a metallic surface. The deposits were created by immersing a stainless steel disc into a dilute asphaltene solution with either toluene or dichloromethane as the solvent, although the toluene solution allowed for better control of the adsorbed asphaltene layer and less atmospheric oxygen contamination. The analyses for C 1s, S 2p 3/2 , N 1s and O 1s photoemission peaks indicated that different functional groups are present in the asphaltene layer including carboxylic, pyrrolic, pyridininc, thiophenic and sulfite, with slight differences in their binding energies

Study of the interaction of liquid with the surface of mass standards of high accuracy stainless steel

International Nuclear Information System (INIS)

Ramirez Varas, Lautaro; Castro, Claudio S.C.; Cacais, Fabio L.; Pires, Manoel J. M.; Loayza Mendoza, Victor M.

2011-01-01

The long term stability of mass standards depends on the interaction between the surface and environment molecules. From this point of view, a study was investigated of the effect on stainless steel surfaces by liquids frequently used in hydrostatic weighing (FC40) and in cleaning procedures of mass standards (isopropyl alcohol). Firstly, mass weighing difference was measured as function of time with a gravimetric method. Additionally, stainless steel samples were analyzed by X-ray Photoelectron Spectroscopy (XPS). The standard used for the gravimetric mass difference determination was immersed in FC40. The samples analyzed by XPS were previously immersed in both FC40 and isopropyl alcohol. Mass differences were obtained with an uncertainty of 1 μg when FC40 was used. Preliminary results have suggested that FC40 is not chemically bound to stainless steel surfaces and the mass gain was due to physisorbed molecules on the surface. (author) [es

Modification and characterization of the AISI 410 martensitic stainless steels surface

International Nuclear Information System (INIS)

Bincoleto, A.V.L.; Nascente, P.A.P.

2010-01-01

Steam turbines are used in the generation of more than half the electric energy produced in the world nowadays. It is important the study which aims to improve the efficiency by means of the optimization of leaks and of the aerodynamic profiles, as well as to maintain the integrity of the components. The martensitic stainless steels are widely employed due to the combination of their good mechanical properties with higher corrosion resistance. However, their lower wear resistance and their poor tribological behavior limit their use, since they decrease the component life time. In order to evaluate the improvement in the performance of the AISI 410 stainless steel, several process of surface modification were employed. Five samples were produced: the first one was not treated, the second one received liquid nitriding, the third, gas nitriding, the forth, thermal aspersion of tungsten carbide, and the fifth, boronizing. The samples were characterized by optical microscopy, surface microhardness, and X-ray diffractometry. (author)

Comparing modelling techniques when designing VPH gratings for BigBOSS

Science.gov (United States)

Poppett, Claire; Edelstein, Jerry; Lampton, Michael; Jelinsky, Patrick; Arns, James

2012-09-01

BigBOSS is a Stage IV Dark Energy instrument based on the Baryon Acoustic Oscillations (BAO) and Red Shift Distortions (RSD) techniques using spectroscopic data of 20 million ELG and LRG galaxies at 0.5VPH) gratings have been identified as a key technology which will enable the efficiency requirement to be met, however it is important to be able to accurately predict their performance. In this paper we quantitatively compare different modelling techniques in order to assess the parameter space over which they are more capable of accurately predicting measured performance. Finally we present baseline parameters for grating designs that are most suitable for the BigBOSS instrument.

BOSS: Borehole Disposal of Disused Sealed Sources. A Technical Manual

International Nuclear Information System (INIS)

2011-01-01

The management of disused radioactive sources is the responsibility of individual Member States. Accordingly, interest in technologies to allow the safe, secure and sustainable management of disused sealed radioactive sources is growing. This publication is a technical summary on preparing and planning predisposal and disposal activities with regard to the BOSS (borehole disposal of disused sealed sources) system, a safe, simple and cost effective solution for the management of disused sealed radioactive sources. It advises potential implementers and decision makers on the implementation of BOSS, which is expected to provide Member States with a successful tool to contribute to the safety and security of current and future generations.

Effect of Ultrasonic Nano-Crystal Surface Modification (UNSM) on the Passivation Behavior of Aged 316L Stainless Steel.

Science.gov (United States)

Kim, Ki-Tae; Lee, Jung-Hee; Kim, Young-Sik

2017-06-27

Stainless steels have good corrosion resistance in many environments but welding or aging can decrease their resistance. This work focused on the effect of aging time and ultrasonic nano-crystal surface modification on the passivation behavior of 316L stainless steel. In the case of slightly sensitized 316L stainless steel, increasing the aging time drastically decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film, even though aging did not form chromium carbide and a chromium depletion zone. This behavior is due to the micro-galvanic corrosion between the matrix and carbon segregated area, and this shows the importance of carbon segregation in grain boundaries to the pitting corrosion resistance of stainless steel, in addition to the formation of the chromium depletion zone. UNSM (Ultrasonic Nano Crystal Surface Modification)-treatment to the slightly sensitized 316L stainless steel increased the pitting potential, decreased the passive current density, and increased the resistance of the passive film. However, in the case of heavily sensitized 316L stainless steel, UNSM-treatment decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film. This behavior is due to the dual effects of the UNSM-treatment. That is, the UNSM-treatment reduced the carbon segregation, regardless of whether the stainless steel 316L was slightly or heavily sensitized. However, since this treatment made mechanical flaws in the outer surface in the case of the heavily sensitized stainless steel, UNSM-treatment may eliminate chromium carbide, and this flaw can be a pitting initiation site, and therefore decrease the pitting corrosion resistance.

DOUBLE BOSS SCULPTURED DIAPHRAGM EMPLOYED PIEZORESISTIVE MEMS PRESSURE SENSOR WITH SILICON-ON-INSULATOR (SOI

Directory of Open Access Journals (Sweden)

D. SINDHANAISELVI

2017-07-01

Full Text Available This paper presents the detailed study on the measurement of low pressure sensor using double boss sculptured diaphragm of piezoresistive type with MEMS technology in flash flood level measurement. The MEMS based very thin diaphragms to sense the low pressure is analyzed by introducing supports to achieve linearity. The simulation results obtained from Intellisuite MEMS CAD design tool show that very thin diaphragms with rigid centre or boss give acceptable linearity. Further investigations on very thin diaphragms embedded with piezoresistor for low pressure measurement show that it is essential to analyse the piezoresistor placement and size of piezoresistor to achieve good sensitivity. A modified analytical modelling developed in this study for double boss sculptured diaphragm results were compared with simulated results. Further the enhancement of sensitivity is analyzed using non uniform thickness diaphragm and Silicon-On-Insulator (SOI technique. The simulation results indicate that the double boss square sculptured diaphragm with SOI layer using 0.85μm thickness yields the higher voltage sensitivity, acceptable linearity with Small Scale Deflection.

Who's afraid of the boss: cultural differences in social hierarchies modulate self-face recognition in Chinese and Americans.

Science.gov (United States)

Liew, Sook-Lei; Ma, Yina; Han, Shihui; Aziz-Zadeh, Lisa

2011-02-16

Human adults typically respond faster to their own face than to the faces of others. However, in Chinese participants, this self-face advantage is lost in the presence of one's supervisor, and they respond faster to their supervisor's face than to their own. While this "boss effect" suggests a strong modulation of self-processing in the presence of influential social superiors, the current study examined whether this effect was true across cultures. Given the wealth of literature on cultural differences between collectivist, interdependent versus individualistic, independent self-construals, we hypothesized that the boss effect might be weaker in independent than interdependent cultures. Twenty European American college students were asked to identify orientations of their own face or their supervisors' face. We found that European Americans, unlike Chinese participants, did not show a "boss effect" and maintained the self-face advantage even in the presence of their supervisor's face. Interestingly, however, their self-face advantage decreased as their ratings of their boss's perceived social status increased, suggesting that self-processing in Americans is influenced more by one's social status than by one's hierarchical position as a social superior. In addition, when their boss's face was presented with a labmate's face, American participants responded faster to the boss's face, indicating that the boss may represent general social dominance rather than a direct negative threat to oneself, in more independent cultures. Altogether, these results demonstrate a strong cultural modulation of self-processing in social contexts and suggest that the very concept of social positions, such as a boss, may hold markedly different meanings to the self across Western and East Asian cultures.

Low temperature gaseous surface hardening of stainless steel

DEFF Research Database (Denmark)

Christiansen, Thomas; Somers, Marcel A. J.

2010-01-01

The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular......, the morphology, microstructure and characteristics of so-called expanite “layers” on stainless steel are addressed....

Resistance of pathogenic bacteria on the surface of stainless steel depending on attachment form and efficacy of chemical sanitizers.

Science.gov (United States)

Bae, Young-Min; Baek, Seung-Youb; Lee, Sun-Young

2012-02-15

Various bacteria including food spoilage bacteria and pathogens can form biofilms on different food processing surfaces, leading to potential food contamination or spoilage. Therefore, the survival of foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, Cronobacter sakazakii) in different forms (adhered cells, biofilm producing in TSB, biofilm producing at RH 100%) on the surface of stainless steel and stored at various relative humidities (RH 23%, 43%, 68%, 85%, and 100%) at room temperature for 5 days was investigated in this study. Additionally, the efficacy of chemical sanitizers (chlorine-based and alcohol-based commercial sanitizers) on inhibiting various types of biofilms of E. coli O157:H7 and S. aureus on the surface of stainless steel was investigated. The number of pathogens on the surface of stainless steel in TSB stored at 25°C for 7 days or RH 100% at 25°C for 7 days was significantly increased and resulted in the increase of 3 log(10) CFU/coupon after 1 day, and these levels were maintained for 7 days. When stainless steel coupons were stored at 25°C for 5 days, the number of pathogens on the surface of stainless steel was significantly reduced after storage at RH 23%, 43%, 68%, and 85%, but not at 100%. When the bacteria formed biofilms on the surface of stainless steel in TSB after 6 days, the results were similar to those of the attached form. However, levels of S. aureus and C. sakazakii biofilms were more slowly reduced after storage at RH 23%, 43%, 68%, and 85% for 5 days than were those of the other pathogens. Formation of biofilms stored at RH 100% for 5 days displayed the highest levels of resistance to inactivation. Treatment with the alcohol sanitizer was very effective at inactivating attached pathogens or biofilms on the surface of stainless steel. Reduction levels of alcohol sanitizer treatment ranged from 1.91 to 4.77 log and from 4.35 to 5.35 log CFU/coupon in E. coli

Changes of surface layer of nitrogen-implanted AISI316L stainless steel

International Nuclear Information System (INIS)

Budzynski, P.; Polanski, K.; Kobzev, A.P.

2007-01-01

The effects of nitrogen ion implantation into AISI316L stainless steel on friction, wear, and microhardness have been investigated at an energy level of 125 keV at a fluence of 1·10 17 - 1·10 18 N/cm 2 . The composition of the surface layer was investigated by RBS, XRD (GXRD), SEM and EDX. The friction coefficient and abrasive wear rate of the stainless steel were measured in the atmospheres of air, oxygen, argon, and in vacuum. As follows from the investigations, there is an increase in resistance to frictional wear in the studied samples after implantation; however, these changes are of different characters in various atmospheres. The largest decrease in wear was observed during tests in the air, and the largest reduction in the value of the friction coefficient for all implanted samples was obtained during tests in the argon atmosphere. Tribological tests revealed larger contents of nitrogen, carbon, and oxygen in the products of surface layer wear than in the surface layer itself of the sample directly after implantation

Chemical nanocavitation of surfaces to enhance the utility of stainless steel as a medical material.

Science.gov (United States)

Rodriguez-Contreras, Alejandra; Guadarrama Bello, Dainelys; Flynn, Sam; Variola, Fabio; Wuest, James D; Nanci, Antonio

2018-01-01

While stainless steel is a broadly used alloy with interesting mechanical properties, its applications in medicine suffers from inherent biocompatibility limitations. An attractive opportunity to improve its performance is to alter its surface, but this has proven challenging. We now show how high range anodization conditions using H 2 SO 4 /H 2 O 2 as an atypical electrolyte can efficiently nanocavitate the surface of both stainless steel SS304 and SS316 and create a topography with advantageous biomedical characteristics. We describe the structural and chemical features of the resulting surfaces, and propose a nanocorrosion/transpassivation/repassivation mechanism for its creation. Our approach creates a thin mesoporous layer of crystalline oxide that selectively promotes mammalian cell activity and limits bacterial adhesion. The modified surfaces favor the formation and maturation of focal adhesion plaques and environment-sensing filopodia with abundant extra small lateral membrane protrusions, suggesting an increase in membrane fluidity. These protrusions represent a yet undescribed cellular response. Such surfaces promise to facilitate the integration of implantable SS devices, in general. In addition, our strategy simultaneously provides a simple, commercially attractive way to control the adhesion of microorganisms, making nanostructured stainless steel broadly useful in hospital environments, in manufacturing medical devices, as well as offering possibilities for non-medical applications. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Development of stress corrosion cracking resistant welds of 321 stainless steel by simple surface engineering

Science.gov (United States)

Mankari, Kamal; Acharyya, Swati Ghosh

2017-12-01

We hereby report a simple surface engineering technique to make AISI grade 321 stainless steel (SS) welds resistant to stress corrosion cracking (SCC) in chloride environment. Heat exchanger tubes of AISI 321 SS, welded either by (a) laser beam welding (LBW) or by (b) metal inert gas welding (MIG) were used for the study. The welds had high magnitude of tensile residual stresses and had undergone SCC in chloride environment while in service. The welds were characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Subsequently, the welded surfaces were subjected to buffing operation followed by determination of residual stress distribution and surface roughness by XRD and surface profilometer measurements respectively. The susceptibility of the welds to SCC was tested in buffed and un-buffed condition as per ASTM G-36 in boiling MgCl2 for 5 h and 10 h, followed by microstructural characterization by using optical microscope and FESEM. The results showed that the buffed surfaces (both welds and base material) were resistant to SCC even after 10 h of exposure to boiling MgCl2 whereas the un-buffed surfaces underwent severe SCC for the same exposure time. Buffing imparted high magnitude of compressive stresses on the surface of stainless steel together with reduction in its surface roughness and reduction in plastic strain on the surface which made the welded surface, resistant to chloride assisted SCC. Buffing being a very simple, portable and economic technique can be easily adapted by the designers as the last step of component fabrication to make 321 stainless steel welds resistant to chloride assisted SCC.

Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel

Energy Technology Data Exchange (ETDEWEB)

Lin Yimin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: linyimin_2001@yahoo.com.cn; Lu Jian [LASMIS, University of Technology of Troyes, 10000 Troyes (France); Wang Liping [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Tao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China)]. E-mail: qjxue@ns.lzb.ac.cn

2006-12-15

A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Vickers hardness tester and UMT-2MT tribometer. The results show that the plasma nitriding of AISI 321 steel can be enhanced considerably by means of SMAT process before nitriding, and a much thicker nitrogen diffusion layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples. In addition, the wear resistance and load capacity of the nitrided layers on the SMAT samples was much higher than that of the un-SMAT samples due to the thicker S phase case and the gradient nitrogen diffusion layer.

Pit formation on stainless steel surfaces pre-treated with biosurfactants produced by Pseudomonas fluorescens

International Nuclear Information System (INIS)

Dagbert, Catherine; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noelle

2008-01-01

Today, it is widely established that the surface tension of water can be reduced by some microorganisms capable of synthesizing surface-active compounds called biosurfactants (BS). BS characteristics depend on the microorganism that produces them and therefore, on the microorganism culture conditions. Some studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; indeed they are used as a good corrosion inhibition tool. The purpose of this study was first, to estimate the importance and behavior of the stainless steels passive film on the adsorption of BS, produced by the Gram negative bacteria Pseudomonas fluorescens, and secondly, to study the impact of these treatments on the pitting corrosion. In this paper, the galvanostatic polarization technique, used as accelerated method for determining the characteristic pit potentials on stainless steels, is examined. Pit growth, shape and cover formation were also observed. The surface topography of the corroded specimens was investigated using field emission scanning electron microscopy (FESEM)

Pit formation on stainless steel surfaces pre-treated with biosurfactants produced by Pseudomonas fluorescens

Energy Technology Data Exchange (ETDEWEB)

Dagbert, Catherine [ECP-LGPM, Grande Voie des Vignes, 92295 Chatenay-Malabry (France)], E-mail: catherine.dagbert@ecp.fr; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noelle [INRA, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France); AGROPARISTECH, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France)

2008-12-01

Today, it is widely established that the surface tension of water can be reduced by some microorganisms capable of synthesizing surface-active compounds called biosurfactants (BS). BS characteristics depend on the microorganism that produces them and therefore, on the microorganism culture conditions. Some studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; indeed they are used as a good corrosion inhibition tool. The purpose of this study was first, to estimate the importance and behavior of the stainless steels passive film on the adsorption of BS, produced by the Gram negative bacteria Pseudomonas fluorescens, and secondly, to study the impact of these treatments on the pitting corrosion. In this paper, the galvanostatic polarization technique, used as accelerated method for determining the characteristic pit potentials on stainless steels, is examined. Pit growth, shape and cover formation were also observed. The surface topography of the corroded specimens was investigated using field emission scanning electron microscopy (FESEM)

Private Political Violence and Boss-Rule in the Philippines

Directory of Open Access Journals (Sweden)

Peter Kreuzer

2009-04-01

Full Text Available Despite its rather strong and venerable democratic credentials the Philippines is still marred by political violence. Targeted killings and physical harassment by vigilantes, death squads, private armed groups, para-military militias, the police or members of the armed forces as well as violent competition for political jobs cost hundreds of lives every year. One central anchor point of this broad range of violent actors and forms are the locally embedded political bosses. (Defective democracy provides an ideal frame for the continuing competition between various segments of the highly fragmented elite. The paper shows how the bosses succeeded in controlling most means of political violence employed and were thereby able to advance their interests to an extraordinary extent. Upholding private control over means of violence furthered their interests as a political class even though it weakened the state

Cranial Bosses of Choerosaurus dejageri (Therapsida, Therocephalia): Earliest Evidence of Cranial Display Structures in Eutheriodonts.

Science.gov (United States)

Benoit, Julien; Manger, Paul R; Fernandez, Vincent; Rubidge, Bruce S

2016-01-01

Choerosaurus dejageri, a non-mammalian eutheriodont therapsid from the South African late Permian (~259 Ma), has conspicuous hemispheric cranial bosses on the maxilla and the mandible. These bosses, the earliest of this nature in a eutheriodont, potentially make C. dejageri a key species for understanding the evolutionary origins of sexually selective behaviours (intraspecific competition, ritualized sexual and intimidation displays) associated with cranial outgrowths at the root of the clade that eventually led to extant mammals. Comparison with the tapinocephalid dinocephalian Moschops capensis, a therapsid in which head butting is strongly supported, shows that the delicate structure of the cranial bosses and the gracile structure of the skull of Choerosaurus would be more suitable for display and low energy combat than vigorous head butting. Thus, despite the fact that Choerosaurus is represented by only one skull (which makes it impossible to address the question of sexual dimorphism), its cranial bosses are better interpreted as structures involved in intraspecific selection, i.e. low-energy fighting or display. Display structures, such as enlarged canines and cranial bosses, are widespread among basal therapsid clades and are also present in the putative basal therapsid Tetraceratops insignis. This suggests that sexual selection may have played a more important role in the distant origin and evolution of mammals earlier than previously thought. Sexual selection may explain the subsequent independent evolution of cranial outgrowths and pachyostosis in different therapsid lineages (Biarmosuchia, Dinocephalia, Gorgonopsia and Dicynodontia).

Cranial Bosses of Choerosaurus dejageri (Therapsida, Therocephalia: Earliest Evidence of Cranial Display Structures in Eutheriodonts.

Directory of Open Access Journals (Sweden)

Julien Benoit

Full Text Available Choerosaurus dejageri, a non-mammalian eutheriodont therapsid from the South African late Permian (~259 Ma, has conspicuous hemispheric cranial bosses on the maxilla and the mandible. These bosses, the earliest of this nature in a eutheriodont, potentially make C. dejageri a key species for understanding the evolutionary origins of sexually selective behaviours (intraspecific competition, ritualized sexual and intimidation displays associated with cranial outgrowths at the root of the clade that eventually led to extant mammals. Comparison with the tapinocephalid dinocephalian Moschops capensis, a therapsid in which head butting is strongly supported, shows that the delicate structure of the cranial bosses and the gracile structure of the skull of Choerosaurus would be more suitable for display and low energy combat than vigorous head butting. Thus, despite the fact that Choerosaurus is represented by only one skull (which makes it impossible to address the question of sexual dimorphism, its cranial bosses are better interpreted as structures involved in intraspecific selection, i.e. low-energy fighting or display. Display structures, such as enlarged canines and cranial bosses, are widespread among basal therapsid clades and are also present in the putative basal therapsid Tetraceratops insignis. This suggests that sexual selection may have played a more important role in the distant origin and evolution of mammals earlier than previously thought. Sexual selection may explain the subsequent independent evolution of cranial outgrowths and pachyostosis in different therapsid lineages (Biarmosuchia, Dinocephalia, Gorgonopsia and Dicynodontia.

Surface modification of superaustenitic and maraging stainless steels by low-temperature gas-phase carburization

Science.gov (United States)

Gentil, Johannes

Low-temperature gas-phase carburization of 316L austenitic stainless steel was developed in recent years by the Swagelok company. This process generates great mechanical and electrochemical surface properties. Hardness, wear resistance, fatigue behavior, and corrosion resistance are dramatically improved, while the formation of carbides is effectively suppressed. This new technique is of technical, economical, but especially of scientific interest because the surface properties of common stainless steel can be enhanced to a level of more sophisticated and more expensive superalloys. The consequential continuation of previous research is the application of the carburization process to other steel grades. Differences in chemical composition, microstructure, and passivity between the various alloys may cause technical problems and it is expected that the initial process needs to be optimized for every specific material. This study presents results of low-temperature carburization of AL-6XN (superaustenitic stainless steel) and PH13-8Mo (precipitation-hardened martensitic stainless steel). Both alloys have been treated successfully in terms of creating a hardened surface by introducing high amounts of interstitially dissolved carbon. The surface hardness of AL-6XN was increased to 12GPa and is correlated with a colossal carbon supersaturation at the surface of up to 20 at.%. The hardened case develops a carburization time-dependent thickness between 10mum after one carburization cycle and up to 35mum after four treatments and remains highly ductile. Substantial broadening of X-ray diffraction peaks in low-temperature carburized superaustenitic stainless steels are attributed to the generation of very large compressive biaxial residual stresses. Those large stresses presumably cause relaxations of the surface, so-called undulations. Heavily expanded regions of carburized AL-6XN turn ferromagnetic. Non-carburized AL-6XN is known for its outstanding corrosion resistance

Cavitation erosion resistance of AISI 316L stainless steel laser surface-modified with NiTi

International Nuclear Information System (INIS)

Chiu, K.Y.; Cheng, F.T.; Man, H.C.

2005-01-01

The present study is part of a project on the surface modification of AISI 316 stainless steel using various forms of NiTi for enhancing cavitation erosion resistance. In this study, NiTi powder was preplaced on the AISI 316L substrate and melted with a high-power CW Nd:YAG laser. With appropriate laser processing parameters, an alloyed layer of a few hundred micrometers thick was formed and fusion bonded to the substrate without the formation of a brittle interface. EDS analysis showed that the layer contained Fe as the major constituent element while the XRD patterns of the surface showed an austenitic structure, similar to that of 316 stainless steel. The cavitation erosion resistance of the modified layer (316-NiTi-Laser) could reach about 29 times that of AISI 316L stainless steel. The improvement could be attributed to a much higher surface hardness and elasticity as revealed by instrumented nanoindentation tests. Among various types of samples, the cavitation erosion resistance was ranked in descending order as: NiTi plate > 316-NiTi-Laser > 316-NiTi-TIG > AISI 316L, where 316-NiTi-TIG stands for samples surfaced with the tungsten inert gas (TIG) process using NiTi wire. Though the laser-surfaced samples and the TIG-surfaced samples had similar indentation properties, the former exhibited a higher erosion resistance mainly because of a more homogeneous alloyed layer with much less defects. In both the laser-surfaced and TIG-surfaced samples, the superelastic behavior typical of austenitic NiTi was only partially retained and the superior cavitation erosion resistance was thus still not fully attained

The surface cleanliness of 316 L + N stainless steel studied by SIMS and AES

CERN Document Server

Mathewson, A G

1974-01-01

Some cleaning methods for 316 L+N stainless steel including solvent cleaning, high temperature treatment in vacuo and gas discharge cleaning have been studied by SIMS and AES with a view to providing a clean vacuum chamber surface with low gas desorption under ion bombardment. After solvent cleaning the main surface contaminant was found to be C and its associated compounds. Laboratory investigations on small samples of stainless steel showed that clean surfaces could be obtained by heating in vacuo to 800 degrees C followed by exposure to air and by argon or argon/10% oxygen discharge cleaning. Due to a cross contamination within the vacuum system, the 800 degrees C treated chamber gave positive desorption coefficients under ion bombardment. The pure argon discharge cleaned chambers proved stable giving negative desorption coefficients up to 2200 eV ion energy even after several weeks storage discharge treatment and installation. (10 refs).

Influence of the chemical composition, heat and surface treatment in the biofouling of austenitic stainless steels

International Nuclear Information System (INIS)

Sarro, M. I.; Aleman, O.; Moreno, D. A.; Roso, M.; Ranninger, C.

2004-01-01

The main objective of this study was to analyse the biofouling processes in the kinds of stainless steels used normally in industry (UNS S30400, UNS S30403 and UNS S31600), with different surface treatments after grinding and polishing. The study was developed using two microscopy techniques. Scanning Electron Microscopy (SEM was used to evaluate the microorganisms distribution in the materials, and Epi fluorescence Microscopy was used to evaluate the viability of cells in the biofilm. The results revealed the influence of the material, heat treatment, surface treatment and roughness in the biofouling processes in the stainless steel assays. (Author) 33 refs

Plasma surface oxidation of 316L stainless steel for improving adhesion strength of silicone rubber coating to metal substrate

Energy Technology Data Exchange (ETDEWEB)

Latifi, Afrooz, E-mail: afroozlatifi@yahoo.com [Department of Biomaterials, Biomedical Engineering Faculty, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Imani, Mohammad [Novel Drug Delivery Systems Dept., Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of); Khorasani, Mohammad Taghi [Biomaterials Dept., Iran Polymer and Petrochemical Institute, P.O. Box 14965/159, Tehran (Iran, Islamic Republic of); Daliri Joupari, Morteza [Animal and Marine Biotechnology Dept., National Institute of Genetic Engineering and Biotechnology, P.O. Box 14965/161, Tehran (Iran, Islamic Republic of)

2014-11-30

Highlights: • Stainless steel 316L was surface modified by plasma surface oxidation (PSO) and silicone rubber (SR) coating. • On the PSO substrates, concentration of oxide species was increased ca. 2.5 times comparing to non-PSO substrates. • The surface wettability was improved to 12.5°, in terms of water contact angle, after PSO. • Adhesion strength of SR coating on the PSO substrates was improved by more than two times comparing to non-PSO ones. • After pull-off test, the fractured area patterns for SR coating were dependent on the type of surface modifications received. - Abstract: Stainless steel 316L is one of the most widely used materials for fabricating of biomedical devices hence, improving its surface properties is still of great interest and challenging in biomaterial sciences. Plasma oxidation, in comparison to the conventional chemical or mechanical methods, is one of the most efficient methods recently used for surface treatment of biomaterials. Here, stainless steel specimens were surface oxidized by radio-frequency plasma irradiation operating at 34 MHz under pure oxygen atmosphere. Surface chemical composition of the samples was significantly changed after plasma oxidation by appearance of the chromium and iron oxides on the plasma-oxidized surface. A wettable surface, possessing high surface energy (83.19 mN m{sup −1}), was observed after plasma oxidation. Upon completion of the surface modification process, silicone rubber was spray coated on the plasma-treated stainless steel surface. Morphology of the silicone rubber coating was investigated by scanning electron microscopy (SEM). A uniform coating was formed on the oxidized surface with no delamination at polymer–metal interface. Pull-off tests showed the lowest adhesion strength of coating to substrate (0.12 MPa) for untreated specimens and the highest (0.89 MPa) for plasma-oxidized ones.

Effect of surface finishing on the oxidation behaviour of a ferritic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Ardigo-Besnard, M.R., E-mail: maria-rosa.ardigo-besnard@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS—Université de Bourgogne Franche-Comté, BP 47870, 21078 Dijon Cedex (France); Popa, I.; Heintz, O.; Chassagnon, R. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS—Université de Bourgogne Franche-Comté, BP 47870, 21078 Dijon Cedex (France); Vilasi, M. [Institut Jean Lamour, UMR 7198 CNRS—Université de Lorraine, Parc de Saurupt, 54011 Nancy (France); Herbst, F. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS—Université de Bourgogne Franche-Comté, BP 47870, 21078 Dijon Cedex (France); Girardon, P. [APERAM, Centre de Recherche, BP15, 62330 Isbergues (France); Chevalier, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS—Université de Bourgogne Franche-Comté, BP 47870, 21078 Dijon Cedex (France)

2017-08-01

Highlights: • Study of surface finishing effect on the corrosion behaviour of a stainless steel. • Mirror polished samples were compared to as-rolled material. • Two oxidation mechanisms were identified depending on the surface finishing. • Before oxidation, native chemical phases are identical for both samples. • Subsurface dislocations generated by the polishing process promote Cr{sub 2}O{sub 3} formation. - Abstract: The corrosion behaviour and the oxidation mechanism of a ferritic stainless steel, K41X (AISI 441), were evaluated at 800 °C in water vapour hydrogen enriched atmosphere. Mirror polished samples were compared to as-rolled K41X material. Two different oxidation behaviours were observed depending on the surface finishing: a protective double (Cr,Mn){sub 3}O{sub 4}/Cr{sub 2}O{sub 3} scale formed on the polished samples whereas external Fe{sub 3}O{sub 4} and (Cr,Fe){sub 2}O{sub 3} oxides grew on the raw steel. Moreover, isotopic marker experiments combined with SIMS analyses revealed different growth mechanisms. The influence of surface finishing on the corrosion products and growth mechanisms was apprehended by means of X-ray photoelectron spectroscopy (XPS) and residual stress analyses using XRD at the sample surfaces before ageing.

Inhibitory activity of Paenibacillus polymyxa on the biofilm formation of Cronobacter spp. on stainless steel surfaces.

Science.gov (United States)

Yang, Soonwook; Kim, Seonhwa; Ryu, Jee-Hoon; Kim, Hoikyung

2013-07-01

The objective of this study was to control the survival or biofilm formation of Cronobacter spp. on stainless steel surfaces using Paenibacillus polymyxa. The antibacterial activity of a cell-free culture supernatant (CFCS) of P. polymyxa against Cronobacter spp. was found to vary with P. polymyxa incubation time. Maximum activity occurred when P. polymyxa was incubated at 25 or 30 °C for 96 h. When the CFCS was introduced to Cronobacter spp. adhered to stainless steel strips at 25 °C for up to 72 h, the CFCS successfully inhibited Cronobacter biofilm formation. Additionally, stainless steel surfaces with a preformed P. polymyxa biofilm were exposed to Cronobacter spp. suspensions in PBS or 0.1% peptone water at 3, 5, or 7 log CFU/mL to facilitate its attachment. The Cronobacter population significantly decreased on this surface, regardless of inoculum level or carrier, when the P. polymyxa biofilm was present. However, the microbial population decreased within 6 h and remained unchanged thereafter when the surface was immersed in an inoculum suspended in 0.1% peptone water at 5 or 7 log CFU/mL. These results indicate that P. polymyxa is able to use a promising candidate competitive-exclusion microorganism to control Cronobacter spp. © 2013 Institute of Food Technologists®

Duplex stainless steel surface bay laser cladding

International Nuclear Information System (INIS)

Amigo, V.; Pineda, Y.; Segovia, F.; Vicente, A.

2004-01-01

Laser cladding is one of the most promising techniques to restore damaged surfaces and achieve properties similar to those of the base metal. In this work, duplex stainless steels have been cladded by a nickel alloy under different processing conditions. The influence of the beam speed and defocusing variables ha been evaluated in the microstructure both of the cladding and heat affected zone, HAZ. These results have been correlated to mechanical properties by means of microhardness measurements from cladding area to base metal through the interface. This technique has shown to be very appropriate to obtain controlled mechanical properties as they are determined by the solidification microstructure, originated by the transfer of mass and heat in the system. (Author) 21 refs

Plasma-induced surface degradation in 304 stainless steel used for TRIAM-1M limiter

International Nuclear Information System (INIS)

Tsukuda, N.; Kuramoto, E.; Tokunaga, K.; Muroga, T.; Yoshida, N.; Itoh, S.

1994-01-01

Surface degradation in a 304 stainless steel limiter of TRIAM-1M by long-pulse discharge during long period operation has been examined by means of X-ray diffraction, scanning electron microscopy and dynamical microindentation tests. Particular exfoliation and hardening of the surface of the electron drift side were observed. These result from the formation of α prime martensite induced by hydrogen in the plasma. The stability of the martensitic phase has been studied by annealing experiments on the cathodically hydrogen charged 316 stainless steel by X-ray diffraction. Both ε and α prime martensites were formed by 22 h cathodic charging. The former reverts to γ-phase and/or converts to α prime martensite below 723 K and the latter reverts to γ-phase below 923 K, repectively. ((orig.))

Short communication: Evaluation of a sol-gel-based stainless steel surface modification to reduce fouling and biofilm formation during pasteurization of milk.

Science.gov (United States)

Liu, Dylan Zhe; Jindal, Shivali; Amamcharla, Jayendra; Anand, Sanjeev; Metzger, Lloyd

2017-04-01

Milk fouling and biofilms are common problems in the dairy industry across many types of processing equipment. One way to reduce milk fouling and biofilms is to modify the characteristics of milk contact surfaces. This study examines the viability of using Thermolon (Porcelain Industries Inc., Dickson, TN), a sol-gel-based surface modification of stainless steel, during thermal processing of milk. We used stainless steel 316L (control) and sol-gel-modified coupons in this study to evaluate fouling behavior and bacterial adhesion. The surface roughness as measured by an optical profiler indicated that the control coupons had a slightly smoother finish. Contact angle measurements showed that the modified surface led to a higher water contact angle, suggesting a more hydrophobic surface. The modified surface also had a lower surface energy (32.4 ± 1.4 mN/m) than the control surface (41.36 ± 2.7 mN/m). We evaluated the susceptibility of control and modified stainless steel coupons to fouling in a benchtop plate heat exchanger. We observed a significant reduction in the amount of fouled layer on modified surfaces. We found an average fouling weight of 19.21 mg/cm 2 and 0.37 mg/cm 2 on the control and modified stainless steel coupons, respectively. We also examined the adhesion of Bacillus and biofilm formation, and observed that the modified stainless steel surface offered greater resistance to biofilm formation. Overall, the Thermolon-modified surface showed potential in the thermal processing of milk, offering significantly lower fouling and bacterial attachment than the control surface. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Characterization of the thrombogenic potential of surface oxides on stainless steel for implant purposes

International Nuclear Information System (INIS)

Shih, C.-C.; Shih, C.-M.; Su, Y.-Y.; Chang, M.-S.; Lin, S.-J.

2003-01-01

Marketed stents are manufactured from various metals and passivated with different degrees of surface oxidation. The functional surface oxides on the degree of antithrombotic potential were explored through a canine femoral extracorporeal circuit model. Related properties of these oxide films were studied by open-circuit potential, current density detected at open-circuit potential, the electrochemical impedance spectroscopy, transmission electron microscopy, Auger spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. Experimental evidences showed that blood clot weight after a 30-min follow-up was significantly lower for the stainless steel wire passivated with amorphous oxide (AO) compared to the wire passivated with polycrystalline oxide (PO) or commercial as-received wire coils (AS). Surface characterizations showed that a stable negative current density at open-circuit potential and a significant lower potential were found for the wire surface passivated with AO than for the surface passivated with PO. Time constant of AO is about 25 times larger than that of polycrystalline oxide. Significant difference in oxide grain sizes was found between PO and AO. Surface chemistries revealed by the AES and XPS spectra indicated the presence of a Cr- and oxygen-rich surface oxide for AO, and a Fe-rich and oxygen-lean surface oxide for PO. These remarkable characteristics of AO surface film might have a potential to provide for excellent antithrombotic characteristics for the 316L stainless steel stents

Nanosecond laser surface modification of AISI 304L stainless steel: Influence the beam overlap on pitting corrosion resistance

International Nuclear Information System (INIS)

Pacquentin, Wilfried; Caron, Nadège; Oltra, Roland

2014-01-01

Surface modifications of AISI 304L stainless steel by laser surface melting (LSM) were investigated using a nanosecond pulsed laser-fibre doped by ytterbium at different overlaps. The objective was to study the change in the corrosion properties induced by the treatment of the outer-surface of the stainless steel without modification of the bulk material. Different analytical techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and glow discharge optical emission spectrometry (GDOES) were used to characterize the laser-melted surface. The corrosion resistance was evaluated in a chloride solution at room temperature by electrochemical tests. The results showed that the crystallographic structure, the chemical composition, the properties of the induced oxide layer and consequently the pitting corrosion resistance strongly depend on the overlap rate. The most efficient laser parameters led to an increase of the pitting potential by more than 300 mV, corresponding to a quite important improvement of the corrosion resistance. This latter was correlated to chromium enrichment (47 wt.%) at the surface of the stainless steel and the induced absence of martensite and ferrite phases. However, these structural and chemical modifications were not sufficient to explain the change in corrosion behaviour: defects and adhesion of the surface oxide layer must have been taken into consideration.

Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062

Science.gov (United States)

Rosemann, P.; Müller, C.; Baumann, O.; Modersohn, W.; Halle, T.

2017-03-01

The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments.

Influence of growth conditions on adhesion of yeast Candida spp. and Pichia spp. to stainless steel surfaces.

Science.gov (United States)

Tomičić, Ružica; Raspor, Peter

2017-08-01

An understanding of adhesion behavior of Candida and Pichia yeast under different environmental conditions is key to the development of effective preventive measures against biofilm-associated infection. Hence in this study we investigated the impact of growth medium and temperature on Candida and Pichia adherence using stainless steel (AISI 304) discs with different degrees of surface roughness (Ra = 25.20-961.9 nm), material typical for the food processing industry as well as medical devices. The adhesion of the yeast strains to stainless steel surfaces grown in Malt Extract broth (MEB) or YPD broth at three temperatures (7 °C, 37 °C, 43 °C for Candida strains and 7 °C, 27 °C, 32 °C for Pichia strains) was assessed by crystal violet staining. The results showed that the nutrient content of medium significantly influenced the quantity of adhered cells by the tested yeasts. Adhesion of C. albicans and C. glabrata on stainless steel surfaces were significantly higher in MEB, whereas for C. parapsilosis and C. krusei it was YPD broth. In the case with P. pijperi and P. membranifaciens, YPD broth was more effective in promoting adhesion than MEB. On the other hand, our data indicated that temperature is a very important factor which considerably affects the adhesion of these yeast. There was also significant difference in cell adhesion on all types of stainless steel surfaces for all tested yeast. Copyright © 2017 Elsevier Ltd. All rights reserved.

OPTIMIZATION OF SURFACE ROUGHNESS OF AISI 304 AUSTENITIC STAINLESS STEEL IN DRY TURNING OPERATION USING TAGUCHI DESIGN METHOD

Directory of Open Access Journals (Sweden)

D. PHILIP SELVARAJ

2010-09-01

Full Text Available The present work is concentrated with the dry turning of AISI 304 Austenitic Stainless Steel (ASS. This paper presents the influence of cutting parameters like cutting speed, feed rate and depth of cut on the surface roughness of austenitic stainless steel during dry turning. A plan of experiments based on Taguchi’s technique has been used to acquire the data. An orthogonal array, the signal to noise (S/N ratio and the analysis of variance (ANOVA are employed to investigate the cutting characteristics of AISI 304 austenitic stainless steel bars using TiC and TiCN coated tungsten carbide cutting tool. Finally the confirmation tests that have been carried out to compare the predicted values with the experimental values confirm its effectiveness in the analysis of surface roughness.

The effects of parametric changes in electropolishing process on surface properties of 316L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Rahman, Zia ur [School of Engineering and Technology, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Science of Advanced Materials, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Deen, K.M. [Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Department of Metallurgy and Materials Engineering, CEET, University of the Punjab, Lahore, 54590 (Pakistan); Cano, Lawrence [Department of Mechanical Engineering, The University of Texas Rio Grande Valley, Edinburg, TX 78539 (United States); Haider, Waseem, E-mail: haide1w@cmich.edu [School of Engineering and Technology, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Science of Advanced Materials, Central Michigan University, Mt. Pleasant, MI 48859 (United States)

2017-07-15

Highlights: • 316L stainless steel was electropolished at the oxygen evolution (EPO) and below the oxygen evolution (EPBO) potentials. • EPBO samples displayed low fractional polarity and surface roughness when compared to EPO. • Both electropolished samples (EPO and EPBO) showed higher resistance to corrosion when compared to mechanically polished samples. • EPO and EPBO samples showed enhanced cell proliferation and stellar morphology after 24 h. - Abstract: Corrosion resistance and biocompatibility of 316L stainless steel implants depend on the surface features and the nature of the passive film. The influence of electropolishing on the surface topography, surface free energy and surface chemistry was determined by atomic force microscopy, contact angle meter and X-ray photoelectron spectroscopy, respectively. The electropolishing of 316L stainless steel was conducted at the oxygen evolution potential (EPO) and below the oxygen evolution potential (EPBO). Compared to mechanically polished (MP) and EPO, the EPBO sample depicted lower surface roughness (Ra = 6.07 nm) and smaller surface free energy (44.21 mJ/m{sup 2}). The relatively lower corrosion rate (0.484 mpy) and smaller passive current density (0.619 μA/cm{sup 2}) as determined from cyclic polarization scans was found to be related with the presence of OH, Cr(III), Fe(0), Fe(II) and Fe(III) species at the surface. These species assured the existence of relatively uniform passive oxide film over EPBO surface. Moreover, the relatively large charge transfer (R{sub ct}) and passive film resistance (R{sub f}) registered by EPBO sample from impedance spectroscopy analysis confirmed its better electrochemical performance. The in vitro response of these polished samples toward MC3T3 pre-osteoblast cell proliferation was determined to be directly related with their surface and electrochemical properties.

Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

Directory of Open Access Journals (Sweden)

David Keinan

2010-01-01

Full Text Available Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ, was analyzed. An energy dispersive X-ray spectrometer (EDS was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (<.001. Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

Chemical decontamination of stainless steel

International Nuclear Information System (INIS)

Onuma, Tsutomu; Akimoto, Hidetoshi

1991-01-01

The present invention concerns a method for chemical decontamination of radioactive metal waste materials contaminated with radioactive materials on the surface, generated in radioactive materials-handling facilities. The invention is comprised of a method of chemical decontamination of stainless steel, characterized by comprising a first process of immersing a stainless steel-based metal waste material contaminated by radioactive materials on the surface in a sulfuric acid solution and second process of immersing in an aqueous solution of sulfuric acid and oxidizing metal salt, in which a portion of the surface of the stainless steel to be decontaminated is polished mechanically to expose a portion of the base material before the above first and second processes. 1 figs., 2 tabs

Surface collisions of formic acid cations HCOOH+ and DCOOD+ with a hydrocarbon-covered stainless steel surface

Science.gov (United States)

Tepnual, Thawatchai; Feketeová, Linda; Grill, Verena; Scheier, Paul; Herman, Zdenek; Märk, Tilmann D.

2005-07-01

Interaction of the formic acid cation HCOOH+ with a stainless steel surface covered with hydrocarbons has been studied as a function of the collision energy from a few eV up to 40 eV. Mass spectra of the product ions showed ions produced by surface-induced dissociation of the projectile and formation of HCO2H2+ in interaction with the surface material. The fragmentation of the projectile led to product ions HCOO+ and CHO+. The product ion HCO2H2+ fragmented to give only CHO+, indicating that its structure was HC(OH)2+ as suggested earlier by others. The results were confirmed by studies using the deuterated formic acid cation DCOOD+.

Facile fabrication of superhydrophobic surfaces from austenitic stainless steel (AISI 304) by chemical etching

Science.gov (United States)

Kim, Jae-Hun; Mirzaei, Ali; Kim, Hyoun Woo; Kim, Sang Sub

2018-05-01

Stainless steels are among the most common engineering materials and are used extensively in humid areas. Therefore, it is important that these materials must be robust to humidity and corrosion. This paper reports the fabrication of superhydrophobic surfaces from austenitic stainless steel (type AISI 304) using a facile two-step chemical etching method. In the first step, the stainless steel plates were etched in a HF solution, followed by a fluorination process, where they showed a water contact angle (WCA) of 166° and a sliding angle of 5° under the optimal conditions. To further enhance the superhydrophobicity, in the second step, they were dipped in a 0.1 wt.% NaCl solution at 100 °C, where the WCA was increased to 168° and the sliding angle was decreased to ∼2°. The long-term durability of the fabricated superhydrophobic samples for 1 month storage in air and water was investigated. The potential applicability of the fabricated samples was demonstrated by the excellent superhydrophobicity after 1 month. In addition, the self-cleaning properties of the fabricated superhydrophobic surface were also demonstrated. This paper outlines a facile, low-cost and scalable chemical etching method that can be adopted easily for large-scale purposes.

Tritiated Water Interaction with Stainless Steel

International Nuclear Information System (INIS)

Glen R. Longhurst

2007-01-01

Experiments conducted to study tritium permeation of stainless steel at ambient and elevated temperatures revealed that HT converts relatively quickly to HTO. Further, the HTO partial pressure contributes essentially equally with elemental tritium gas in driving permeation through the stainless steel. Such permeation appears to be due to dissociation of the water molecule on the hot stainless steel surface. There is an equilibrium concentration of HTO vapor above adsorbed gas on the walls of the experimental apparatus evident from freezing transients. The uptake process of tritium from the carrier gas involves both surface adsorption and isotopic exchange with surface bound water

Laser surface modification of 316 L stainless steel with bioactive hydroxyapatite.

Science.gov (United States)

Balla, Vamsi Krishna; Das, Mitun; Bose, Sreyashree; Ram, G D Janaki; Manna, Indranil

2013-12-01

Laser-engineered net shaping (LENS™), a commercial additive manufacturing process, was used to modify the surfaces of 316 L stainless steel with bioactive hydroxyapatite (HAP). The modified surfaces were characterized in terms of their microstructure, hardness and apatite forming ability. The results showed that with increase in laser energy input from 32 J/mm(2) to 59 J/mm(2) the thickness of the modified surface increased from 222±12 μm to 355±6 μm, while the average surface hardness decreased marginally from 403±18 HV0.3 to 372±8 HV0.3. Microstructural studies showed that the modified surface consisted of austenite dendrites with HAP and some reaction products primarily occurring in the inter-dendritic regions. Finally, the surface-modified 316 L samples immersed in simulated body fluids showed significantly higher apatite precipitation compared to unmodified 316 L samples. © 2013.

Investigation of surface residual stress profile on martensitic stainless steel weldment with X-ray diffraction

Directory of Open Access Journals (Sweden)

I.I. Ahmed

2018-04-01

Full Text Available The development of residual stresses during fabrication is inevitable and often neglected with dire consequences during the service life of the fabricated components. In this work, the surface residual stress profile following the martensitic stainless steel (MSS pipe welding was investigated with X-ray diffraction technique. The results revealed the presence of residual stresses equilibrated across the weldment zones. Tensile residual stress observed in weld metal was balanced by compressive residual stresses in the parent material on the opposing sides of weld metal. Keywords: Residual stress, Weld, Stainless steel, X-ray, HAZ

Effect of surface roughness and stainless steel finish on Listeria monocytogenes attachment and biofilm formation.

Science.gov (United States)

Rodriguez, Andres; Autio, Wesley R; McLandsborough, Lynne A

2008-01-01

The purpose of this study was to evaluate the effect of surface roughness (Ra) and finish of mechanically polished stainless steel (Ra = 0.26 +/- 0.05, 0.49 +/- 0.10, and 0.69 +/- 0.05 microm) and electropolished stainless steel (Ra = 0.16 +/- 0.06, 0.40 +/- 0.003, and 0.67 +/- 0.02 microm) on Listeria adhesion and biofilm formation. A four-strain cocktail of Listeria monocytogenes was used. Each strain (0.1%) was added to 200 ml of tryptic soy broth (TSB), and coupons were inserted to the mixture for 5 min. For biofilm formation, coupons with adhesive cells were incubated in 1:20 diluted TSB at 32 degrees C for 48 h. The experiment was performed by a randomized block design. Our results show that the level of Listeria present after 48 h of incubation (mean = 7 log CFU/cm2) was significantly higher than after 5 min (mean = 6.0 log CFU/cm2) (P stainless steel (mean = 6.7 log CFU/cm2) (P > 0.05). Listeria initial adhesion (values ranged from 5.9 to 6.1 log CFU/cm2) or biofilm formation (values ranged from 6.9 to 7.2 log CFU/cm2) was not significantly correlated with Ra values (P > 0.05). Image analysis with an atomic force microscope showed that bacteria did not colonize the complete surface after 48 h but were individual cells or grouped in microcolonies that ranged from 5 to 10 microm in diameter and one to three cell layers in thickness. Exopolymeric substances were observed to be associated with the colonies. According to our results, electropolishing stainless steel does not pose a significant advantage for food sanitation over mechanically finished stainless steel.

Method for decontaminating stainless cladding tubes

International Nuclear Information System (INIS)

Komatsu, Fumiaki.

1986-01-01

Purpose: To form an oxide film over the surface of stainless cladding tubes and to efficiently remove radioactive materials from the steel surface together with the oxide layer by the use of an acid water solution. Method: After the removal of water from cladding tubes that have passed through the re-processing process, an oxide film is formed on the surface of the cladding tubes by heating over 400 deg C in an oxidizing atmosphere and thereafter washed again in an acid water solution. When the cladding tubes are thus oxidized once, the stainless base metal itself is oxidized, an oxide layer of several 10 μm or more being formed thereon. In consequence, since the oxide layer is far inferior in corrosion resistance to stainless metals, a pickling liquid easily penetrates into the stainless metal through the oxide layer, thereby remarkably promoting the peeling of the layer from the base metal surface and also improving the residual radioactive material removing efficiency together. (Takahashi, M.)

Effect of microbial treatment on the prevention and removal of paraffin deposits on stainless steel surfaces.

Science.gov (United States)

Xiao, Meng; Li, Wen-Hong; Lu, Mang; Zhang, Zhong-Zhi; Luo, Yi-Jing; Qiao, Wei; Sun, Shan-Shan; Zhong, Wei-Zhang; Zhang, Min

2012-11-01

In this study, biosurfactant-producing strain N2 and non-biosurfactant producing stain KB18 were used to investigate the effects of microbial treatment on the prevention and removal of paraffin deposits on stainless steel surfaces. Strain N2, with a biosurfactant production capacity, reduced the contact angle of stainless steel to 40.04°, and the corresponding adhesion work of aqueous phase was decreased by 26.5 mJ/m(2). By contrast, KB18 could only reduce the contact angle to 50.83°, with a corresponding 7.6 mJ/m(2) decrease in the aqueous phase work adhesion. The paraffin removal test showed that the paraffin removal efficiencies of strain N2 and KB18 were 79.0% and 61.2%, respectively. Interestingly, the N2 cells could attach on the surface of the oil droplets to inhibit droplets coalescence. These results indicate that biosurfactant-producing strains can alter the wettability of stainless steel and thus eliminate paraffin deposition. Copyright © 2012 Elsevier Ltd. All rights reserved.

Current status of stainless steel industry and development of stainless steel

International Nuclear Information System (INIS)

Lee, Yong Deuk; Lee, Chan Soo; Kim Kwang Tae

2000-01-01

Stainless steel is not only clean and smooth in its surface, but also it is superior in quality in terms of corrosion resistance and strength. So that, it is widely in use in the field of construction, chemical installations, and other industries. Growth of stainless steel industry started since the steel technology was developed for mass production in 1960s. Since then stainless steel industry grew rapidly on account of diversified development in this field and growth rate went up to 5.8% per year comparable to 2.3% of steel growth. The rapid growth is attributed to significant industry developments in Europe and Japan in the years of 1970s and 1980s. In addition to these the expansion of stainless steel industry in Korea and Taiwan. Presently Korea produces about 120,000 tons of stainless steel and occupies about 8% of international market. This means Korea become the second largest single country in world in stainless steel production. Moreover Korea is to reinforce its domestic production line by affiliating production companies, increasing of production capability, and specializing in types of stainless steel. This paper is to describe activity of material development, and types of stainless steel for industry use. (Hong, J. S.)

Modulation of dry tribological property of stainless steel by femtosecond laser surface texturing

Science.gov (United States)

Wang, Zhuo; Zhao, Quanzhong; Wang, Chengwei; Zhang, Yang

2015-06-01

We reported on the modification of tribological properties of stainless steel by femtosecond laser surface microstructuring. Regular arranged micro-grooved textures with different spacing were produced on the AISI 304L steel surfaces by an 800-nm femtosecond laser. The tribological properties of smooth surface and textured surface were investigated by carrying out reciprocating ball-on-flat tests against Al2O3 ceramic balls under dry friction. Results show that the spacing of micro-grooves had a significant impact on friction coefficient of textured surfaces. Furthermore, the wear behaviors of smooth and textured surface were also investigated. Femtosecond laser surface texturing had a marked potential for modulating friction and wear properties if the micro-grooves were distributed in an appropriate manner.

Bering-Okhotsk Seal Survey (BOSS) On-Effort Flight Tracks (2012-13)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Aerial surveys were flown during the spring of 2012 and 2013 as part of the Bering Okhotsk Seal Surveys (BOSS) project to gather data on distribution and abundance...

Investigation of selected surface integrity features of duplex stainless steel (DSS after turning

Directory of Open Access Journals (Sweden)

G. Krolczyk

2015-01-01

Full Text Available The article presents surface roughness profiles and Abbott - Firestone curves with vertical and amplitude parameters of surface roughness after turning by means of a coated sintered carbide wedge with a coating with ceramic intermediate layer. The investigation comprised the influence of cutting speed on the selected features of surface integrity in dry machining. The material under investigation was duplex stainless steel with two-phase ferritic-austenitic structure. The tests have been performed under production conditions during machining of parts for electric motors and deep-well pumps. The obtained results allow to draw conclusions about the characteristics of surface properties of the machined parts.

Characterization of a Laser Surface-Treated Martensitic Stainless Steel.

Science.gov (United States)

Al-Sayed, S R; Hussein, A A; Nofal, A A; Hassab Elnaby, S I; Elgazzar, H

2017-05-29

Laser surface treatment was carried out on AISI 416 machinable martensitic stainless steel containing 0.225 wt.% sulfur. Nd:YAG laser with a 2.2-KW continuous wave was used. The aim was to compare the physical and chemical properties achieved by this type of selective surface treatment with those achieved by the conventional treatment. Laser power of different values (700 and 1000 W) with four corresponding different laser scanning speeds (0.5, 1, 2, and 3 m•min-1) was adopted to reach the optimum conditions for impact toughness, wear, and corrosion resistance for laser heat treated (LHT) samples. The 0 °C impact energy of LHT samples indicated higher values compared to the conventionally heat treated (CHT) samples. This was accompanied by the formation of a hard surface layer and a soft interior base metal. Microhardness was studied to determine the variation of hardness values with respect to the depth under the treated surface. The wear resistance at the surface was enhanced considerably. Microstructure examination was characterized using optical and scanning electron microscopes. The corrosion behavior of the LHT samples was also studied and its correlation with the microstructures was determined. The corrosion data was obtained in 3.5% NaCl solution at room temperature by means of a potentiodynamic polarization technique.

The precipitation behavior of titanium carbide on the surface of SUS 321 stainless steel

International Nuclear Information System (INIS)

Yoshihara, Kazuhiro; Nii, Kazuyoshi

1982-01-01

The surface composition of SUS 321 stainless steel at high temperatures was observed in vacuum with Auger electron spectroscopy. The precipitation of titanium carbide was found on the surface of SUS 321. The thickness of precipitated titanium carbide layer increased in proportion to the square root of annealing time and became about 0.05 μm after heated at 1100 K for 432 ks. The precipitated titanium carbide was not replaced by the most surface active element sulfur, and remained stable on the surface. The precipitated layer, however, was not even and had many holes about 1 μm in diameter. The bottom of a hole was SUS 321, on which phosphorus, oxygen and sulfur segregated. As the annealing time was prolonged, these segregants were replaced one by one in the order of the surface activity, and finally the most surface active element, sulfur, remained on the bottom of the hole. Moreover, sulfur diffused over the outside of the hole. The precipitation of titanium carbide on the surface occurred according to the following processes: (1) The titanium and carbon which had been dissolved in the bulk diffused onto the surface of the stainless steel. (2) The titanium carbide which had been precipitated in the bulk dissolved because the concentration of titanum and carbon fell under their solubility limits in the bulk. (3) The titanium and carbon diffused onto the surface which was exposed to vacuum. (4) The titanium and carbon recombined into titanium carbide and precipitated on the surface. The growth rate of the thickness of the precipitated layer was controlled by the diffusion of titanium and carbon in the precipitated titanium carbide. (J.P.N.)

A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

Science.gov (United States)

Curtis, Colin K; Marek, Antonin; Smirnov, Alex I

2017-01-01

This article reports a comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively (hydroxylated) or negatively (carboxylated) charged nanodiamonds (ND). Immersion in −ND suspensions resulted in a decrease in the macroscopic friction coefficients to values in the range 0.05–0.1 for both stainless steel and alumina, while +ND suspensions yielded an increase in friction for stainless steel contacts but little to no increase for alumina contacts. Quartz crystal microbalance (QCM), atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements were employed to assess nanoparticle uptake, surface polishing, and resistance to solid–liquid interfacial shear motion. The QCM studies revealed abrupt changes to the surfaces of both alumina and stainless steel upon injection of –ND into the surrounding water environment that are consistent with strong attachment of NDs and/or chemical changes to the surfaces. AFM images of the surfaces indicated slight increases in the surface roughness upon an exposure to both +ND and −ND suspensions. A suggested mechanism for these observations is that carboxylated −NDs from aqueous suspensions are forming robust lubricious deposits on stainless and alumina surfaces that enable gliding of the surfaces through the −ND suspensions with relatively low resistance to shear. In contrast, +ND suspensions are failing to improve tribological performance for either of the surfaces and may have abraded existing protective boundary layers in the case of stainless steel contacts. This study therefore reveals atomic scale details associated with systems that exhibit starkly different macroscale tribological properties, enabling future efforts to predict and design complex lubricant interfaces. PMID:29046852

A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

Directory of Open Access Journals (Sweden)

Colin K. Curtis

2017-09-01

Full Text Available This article reports a comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively (hydroxylated or negatively (carboxylated charged nanodiamonds (ND. Immersion in −ND suspensions resulted in a decrease in the macroscopic friction coefficients to values in the range 0.05–0.1 for both stainless steel and alumina, while +ND suspensions yielded an increase in friction for stainless steel contacts but little to no increase for alumina contacts. Quartz crystal microbalance (QCM, atomic force microscopy (AFM and scanning electron microscopy (SEM measurements were employed to assess nanoparticle uptake, surface polishing, and resistance to solid–liquid interfacial shear motion. The QCM studies revealed abrupt changes to the surfaces of both alumina and stainless steel upon injection of –ND into the surrounding water environment that are consistent with strong attachment of NDs and/or chemical changes to the surfaces. AFM images of the surfaces indicated slight increases in the surface roughness upon an exposure to both +ND and −ND suspensions. A suggested mechanism for these observations is that carboxylated −NDs from aqueous suspensions are forming robust lubricious deposits on stainless and alumina surfaces that enable gliding of the surfaces through the −ND suspensions with relatively low resistance to shear. In contrast, +ND suspensions are failing to improve tribological performance for either of the surfaces and may have abraded existing protective boundary layers in the case of stainless steel contacts. This study therefore reveals atomic scale details associated with systems that exhibit starkly different macroscale tribological properties, enabling future efforts to predict and design complex lubricant interfaces.

Synergistic effect of wire bending and salivary pH on surface properties and mechanical properties of orthodontic stainless steel archwires.

Science.gov (United States)

Hobbelink, Marieke G; He, Yan; Xu, Jia; Xie, Huixu; Stoll, Richard; Ye, Qingsong

2015-01-01

The aim of this study was to investigate the corrosive behaviour of stainless steel archwires in a more clinically relevant way by bending and exposing to various pH. One hundred and twenty pieces of rectangular stainless steel wires (0.43 × 0.64 mm) were randomly assigned into four groups. In each group, there were 15 pieces of bent wires and 15 straight ones. Prior to measurements of the wires, as individual experimental groups (group 1, 2, and 3), the wires were exposed to artificial saliva for 4 weeks at pH 5.6, 6.6, and 7.6, respectively. A control group of wires (group 4) remained in air for the same period of time before sent for measurements. Surface roughness (Ra-value) was measured by a profilometer. Young's modulus and maximum force were determined by a four-point flexural test apparatus. Scanning electron microscopy was used to observe the surface morphology of straight wire. Differences between groups were examined using a two-way analysis of variance (ANOVA). Mean surface roughness values, flexural Young's moduli, and maximum force values of bent wires are significantly different from those of the straight wires, which was the main effect of wire bending, ignoring the influence of pH. A significant effect was found between Ra-values regarding the main effect of pH, ignoring the influence of shape. There was a significant interaction effect of bending and pH on flexural Young's moduli of stainless steel archwires, while pH did not show much impact on the maximum force values of those stainless steel wires. Bigger surface irregularities were seen on SEM images of straight wires immersed in artificial saliva at pH 5.6 compared to artificial saliva at other pH values. Surface depth (Rz) was more sensitive than Ra in revealing surface roughness, both measured from 3D reconstructed SEM images. Ra showed a comparable result of surface roughness to Ra-value measured by the profilometer. Bending has a significant influence on surface roughness and mechanical

Some preliminary notes on the Algae collection Weber-van Bosse

NARCIS (Netherlands)

Koster, Joséphine Th.

1936-01-01

This extensive collection, famous among algologists both of the Old and the New World, forms part of the collections of the National Herbarium (Rijksherbarium) Leiden since 1934. About fifty years ago it was started by Mrs. Dr. A. A. WEBER-VAN BOSSE (1852—hodie), an enthusiastic pupil of HUGO DE

Homogenous photocatalytic decontamination of prion infected stainless steel and titanium surfaces.

Science.gov (United States)

Berberidou, Chrysanthi; Xanthopoulos, Konstantinos; Paspaltsis, Ioannis; Lourbopoulos, Athanasios; Polyzoidou, Eleni; Sklaviadis, Theodoros; Poulios, Ioannis

2013-01-01

Prions are notorious for their extraordinary resistance to traditional methods of decontamination, rendering their transmission a public health risk. Iatrogenic Creutzfeldt-Jakob disease (iCJD) via contaminated surgical instruments and medical devices has been verified both experimentally and clinically. Standard methods for prion inactivation by sodium hydroxide or sodium hypochlorite have failed, in some cases, to fully remove prion infectivity, while they are often impractical for routine applications. Prion accumulation in peripheral tissues and indications of human-to-human bloodborne prion transmission, highlight the need for novel, efficient, yet user-friendly methods of prion inactivation. Here we show both in vitro and in vivo that homogenous photocatalytic oxidation, mediated by the photo-Fenton reagent, has the potential to inactivate the pathological prion isoform adsorbed on metal substrates. Photocatalytic oxidation with 224 μg mL(-1) Fe (3+), 500 μg mL(-1) h(-1) H 2O 2, UV-A for 480 min lead to 100% survival in golden Syrian hamsters after intracranial implantation of stainless steel wires infected with the 263K prion strain. Interestingly, photocatalytic treatment of 263K infected titanium wires, under the same experimental conditions, prolonged the survival interval significantly, but failed to eliminate infectivity, a result that we correlate with the increased adsorption of PrP(Sc) on titanium, in comparison to stainless steel. Our findings strongly indicate that our, user--and environmentally--friendly protocol can be safely applied to the decontamination of prion infected stainless steel surfaces.

Influence of the surface finishing on electrochemical corrosion characteristics of AISI 316L stainless steel

Czech Academy of Sciences Publication Activity Database

Dundeková, S.; Hadzima, B.; Fintová, Stanislava

2015-01-01

Roč. 22, č. 2 (2015), s. 77-84 ISSN 1335-0803 Institutional support: RVO:68081723 Keywords : AISI 316L stainless steel * EIS * Corrosion Subject RIV: JK - Corrosion ; Surface Treatment of Materials http://ojs.mateng.sk/index.php/Mateng/article/view/167/278

What BOSS has taught us about Quasars.

Science.gov (United States)

Ross, Nicholas; SDSS-III BOSS Quasar Science Working Group

2015-01-01

This talk presents science highlights from the SDSS-III BOSS Quasar Survey, which has obtained spectra for over 300,000 quasars, 200,000 of which are at redshift z>2. Using this dataset, new measurements of the luminosity function have been made, with the faint end of the luminosity function now measured to z~5. New clustering results from DR12 are presented, and the weak luminosity dependence of quasar clustering at z~0.5 is also discussed.New studies of the broad absorption line (BAL) quasar population have also been performed, with a sample of BAL quasars from the original SDSS being re-observed. These new data have shown the disappearance of CIV BAL troughs and indeed the transformation of BAL QSOs to non-BAL QSOs. BAL disappearance, and emergence, events appear to be extremes of general BAL variability, and have shed light on accretion-disk wind models.We highlight the discovery of new classes of quasars including: a population of broad-line Mg II emitters found in a passive galaxy sample; objects with extremely red optical-to-mid infrared colors; objects with very curious UV line (LyA:NV) ratios and potentially the long-sought after high-redshift Type 2 Quasar population.Finally, we describe two new dedicated programs, one focusing on reverberation mapping, the other on X-ray selected quasars.A full list of papers connected to the BOSS Quasar Survey is given at: http://www.sdss3.org/science/publications.php

Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

Science.gov (United States)

Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

2010-01-01

The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

Hydrophilic property of 316L stainless steel after treatment by atmospheric pressure corona streamer plasma using surface-sensitive analyses

Energy Technology Data Exchange (ETDEWEB)

Al-Hamarneh, Ibrahim, E-mail: hamarnehibrahim@yahoo.com [Department of Physics, Faculty of Science, Al-Balqa Applied University, Salt 19117 (Jordan); Pedrow, Patrick [School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA 99164 (United States); Eskhan, Asma; Abu-Lail, Nehal [Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164 (United States)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Surface hydrophilic property of surgical-grade 316L stainless steel was enhanced by Ar-O{sub 2} corona streamer plasma treatment. Black-Right-Pointing-Pointer Hydrophilicity, surface morphology, roughness, and chemical composition before and after plasma treatment were evaluated. Black-Right-Pointing-Pointer Contact angle measurements and surface-sensitive analyses techniques, including XPS and AFM, were carried out. Black-Right-Pointing-Pointer Optimum plasma treatment conditions of the SS 316L surface were determined. - Abstract: Surgical-grade 316L stainless steel (SS 316L) had its surface hydrophilic property enhanced by processing in a corona streamer plasma reactor using O{sub 2} gas mixed with Ar at atmospheric pressure. Reactor excitation was 60 Hz ac high-voltage (0-10 kV{sub RMS}) applied to a multi-needle-to-grounded screen electrode configuration. The treated surface was characterized with a contact angle tester. Surface free energy (SFE) for the treated stainless steel increased measurably compared to the untreated surface. The Ar-O{sub 2} plasma was more effective in enhancing the SFE than Ar-only plasma. Optimum conditions for the plasma treatment system used in this study were obtained. X-ray photoelectron spectroscopy (XPS) characterization of the chemical composition of the treated surfaces confirms the existence of new oxygen-containing functional groups contributing to the change in the hydrophilic nature of the surface. These new functional groups were generated by surface reactions caused by reactive oxidation of substrate species. Atomic force microscopy (AFM) images were generated to investigate morphological and roughness changes on the plasma treated surfaces. The aging effect in air after treatment was also studied.

Surface damage of 316 stainless steel irradiated with 4He+ to high doses

International Nuclear Information System (INIS)

Kaminsky, M.; Das, S.K.

1978-01-01

Surface blistering of niobium by implantation with helium ions in the 9 to 15 keV range was investigated. The apparent disappearance of blisters at sufficiently high doses was believed to be an equilibrium effect. To determine whether high temperature annealing causes the equilibrium condition, stainless steel-316 samples were irradiated at a constant 450 0 C. Results are presented

Corrosion behavior of 2205 duplex stainless steel.

Science.gov (United States)

Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

1997-07-01

The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

Decoration technique on surface of porous stainless steel for hydrogen purification

International Nuclear Information System (INIS)

Han Jun; Wang Heyi; Gu Mei

2006-01-01

The nano-meter stainless steel powder was first deposited on porous stainless steel by paste coating process, and a micro-porous membrane with an average pore size of 200 nm was obtained, its permeability for dry air was about 200 cm 3 ·cm -2 ·min -1 at room temperature and a pressure difference of 0.1 MPa. The micro-porous steel membrane was further coated with TiO 2 membrane by Sol-Gel method, and a composite membrane with pore size of 100 nm was achieved, its permeability for dry air was about 100 cm 3 ·cm -2 ·min -1 at room temperature and 0.1 MPa. Then this membrane was electroless-plated to deposit Pd-Ag alloy, and a membrane with smooth surface and better alloy formation was obtained. The permeability of H 2 for the Pd-Ag alloy membrane was about 35 cm 3 ·cm -2 ·min -1 under a normal condition of 0.1 MPa and 300 degree C, and the separation factor between H 2 and He was about 500. (authors)

X-ray analysis on the fatigue fracture surface of stainless steels

International Nuclear Information System (INIS)

Yoshioka, Yasuo; Guimard, B.

1986-01-01

Several X-ray diffraction parameters were observed on the fatigue fracture surface and its vicinity of both of SUS420J1 martensitic and SUS304 austenitic stainless steels and we discussed the relation between the stress intensity factor and these parameters. Monotonic plastic zone depth determined by the measurement of residual stress distribution proportionals to the squre of the maximum stress intensity factor as well as the case of ferritic steel. However, it is very difficult to find the relation between the stress intensity factor and residual stress or half value breadth of X-ray diffraction profile in the fracture surface for both materials. On the other hand, the amount of martensite induced by the transformation during fatigue process in SUS304 is related to the maximum stress intensity factor in the fracture surface regardless the stress ratio R. (author)

Detection of surface breaking cracks in centrifugally cast stainless steel with ultrasonic - Inspection from the cracked side

International Nuclear Information System (INIS)

Hoegberg, K.; Zetterwall, T.

1986-01-01

The ability of detecting surface breaking or near-surface cracks with ultrasonic techniques from the inside of centrifugally cast stainless steel pipes have been investigated by the Swedish Plant Inspectorate (SA) and AaF-Tekniska Roentgencentralen AB (AaF-TRC) on behalf of the Swedish Nuclear Power Inspectorate (SKI) and the Swedish State Power Board (SV). Fifteen specimens from the international Stainless Steel Round Robin Test (SSRRT) were used in this study. All specimens were examined from the cracked side with different ultrasonic probes. The data reported here indicate that a probe with dual elements, low frequency, longitudinal waves and short focus distance can detect almost all of the intended defects with a rather good signal-to-noise ratio. (author)

Anti-biofouling superhydrophobic surface fabricated by picosecond laser texturing of stainless steel

Science.gov (United States)

Sun, Ke; Yang, Huan; Xue, Wei; He, An; Zhu, Dehua; Liu, Wenwen; Adeyemi, Kenneth; Cao, Yu

2018-04-01

Anti-biofouling technology is based on specifically designed materials and coatings. This is an enduring goal in the maritime industries, such as shipping, offshore oil exploration, and aquaculture. Recently, research of the relationship between wettability and antifouling effectiveness has attracted considerable attention, due to the anti-biofouling properties of the lotus leaf and shark skin. In this study, super-hydrophobic surfaces (SHSs) with controllable periodic structures were fabricated on AISI304 stainless steel by a picosecond laser, and their anti-biofouling performance were investigated by seawater immersion for five weeks in summertime. The results showed that the specimens with SHS demonstrate significant anti-biofouling effect as compared with the bare stainless steel plate. We observed that nearly 50% decrease of the average microbe attachment area ratio (Avg. MAAR) could be obtained. The micro-groove SHS with more abundant hierarchical micro-nano structures showed better anti-biofouling performance than the micro-pit SHS.

Femtosecond laser fabrication of highly hydrophobic stainless steel surface with hierarchical structures fabricated by combining ordered microstructures and LIPSS

International Nuclear Information System (INIS)

Martínez-Calderon, M.; Rodríguez, A.; Dias-Ponte, A.; Morant-Miñana, M.C.; Gómez-Aranzadi, M.; Olaizola, S.M.

2016-01-01

Highlights: • Femtosecond laser treatment to achieve highly hydrophobic behavior on stainless steel. • Combination of micro-machined patterns with LIPSS into hierarchical structures. • Contact angles as high as 156° with only the femtosecond laser irradiation. - Abstract: In this work we have developed hierarchical structures that consist of micro-patterned surfaces covered by nanostructures with a femtosecond laser. The first part of this work is a study to determine the microscale modifications produced on a stainless steel alloy (AISI304) surface at high pulse energy, different velocities, and number of overscans in order to obtain microstructures with a selected depth of around 10 μm and line widths of 20 μm. The second part of the work is focused on finding the optimal irradiation parameters to obtain the nanostructure pattern. Nanostructures have been defined by means of Laser Induced Periodical Surface Structures (LIPSS) around 250 nm high and a period of 580 nm, which constitute the nanostructure pattern. Finally, dual scale gratings of 50 mm"2 were fabricated with different geometries and their effect on the measured contact angle. Combining the micro-pattern with the LIPSS nano-pattern, highly hydrophobic surfaces have been developed with measured static contact angles higher than 150° on a stainless steel alloy.

Femtosecond laser fabrication of highly hydrophobic stainless steel surface with hierarchical structures fabricated by combining ordered microstructures and LIPSS

Energy Technology Data Exchange (ETDEWEB)

Martínez-Calderon, M., E-mail: mmcalderon@ceit.es [CEIT-IK4 & Tecnun (University of Navarra), Paseo Manuel Lardizábal 15, 20018 San Sebastián (Spain); CIC microGUNE, Goiru Kalea 9 Polo Innovación Garaia, 20500 Arrasate-Mondragón (Spain); Rodríguez, A.; Dias-Ponte, A.; Morant-Miñana, M.C.; Gómez-Aranzadi, M.; Olaizola, S.M. [CEIT-IK4 & Tecnun (University of Navarra), Paseo Manuel Lardizábal 15, 20018 San Sebastián (Spain); CIC microGUNE, Goiru Kalea 9 Polo Innovación Garaia, 20500 Arrasate-Mondragón (Spain)

2016-06-30

Highlights: • Femtosecond laser treatment to achieve highly hydrophobic behavior on stainless steel. • Combination of micro-machined patterns with LIPSS into hierarchical structures. • Contact angles as high as 156° with only the femtosecond laser irradiation. - Abstract: In this work we have developed hierarchical structures that consist of micro-patterned surfaces covered by nanostructures with a femtosecond laser. The first part of this work is a study to determine the microscale modifications produced on a stainless steel alloy (AISI304) surface at high pulse energy, different velocities, and number of overscans in order to obtain microstructures with a selected depth of around 10 μm and line widths of 20 μm. The second part of the work is focused on finding the optimal irradiation parameters to obtain the nanostructure pattern. Nanostructures have been defined by means of Laser Induced Periodical Surface Structures (LIPSS) around 250 nm high and a period of 580 nm, which constitute the nanostructure pattern. Finally, dual scale gratings of 50 mm{sup 2} were fabricated with different geometries and their effect on the measured contact angle. Combining the micro-pattern with the LIPSS nano-pattern, highly hydrophobic surfaces have been developed with measured static contact angles higher than 150° on a stainless steel alloy.

Characterization of a Laser Surface-Treated Martensitic Stainless Steel

Directory of Open Access Journals (Sweden)

S.R. Al-Sayed

2017-05-01

Full Text Available Laser surface treatment was carried out on AISI 416 machinable martensitic stainless steel containing 0.225 wt.% sulfur. Nd:YAG laser with a 2.2-KW continuous wave was used. The aim was to compare the physical and chemical properties achieved by this type of selective surface treatment with those achieved by the conventional treatment. Laser power of different values (700 and 1000 W with four corresponding different laser scanning speeds (0.5, 1, 2, and 3 m•min−1 was adopted to reach the optimum conditions for impact toughness, wear, and corrosion resistance for laser heat treated (LHT samples. The 0 °C impact energy of LHT samples indicated higher values compared to the conventionally heat treated (CHT samples. This was accompanied by the formation of a hard surface layer and a soft interior base metal. Microhardness was studied to determine the variation of hardness values with respect to the depth under the treated surface. The wear resistance at the surface was enhanced considerably. Microstructure examination was characterized using optical and scanning electron microscopes. The corrosion behavior of the LHT samples was also studied and its correlation with the microstructures was determined. The corrosion data was obtained in 3.5% NaCl solution at room temperature by means of a potentiodynamic polarization technique.

Combined slurry and cavitation erosion resistance of surface modified SS410 stainless steel

Science.gov (United States)

Amarendra, H. J.; Pratap, M. S.; Karthik, S.; Punitha Kumara, M. S.; Rajath, H. C.; Ranjith, H.; Shubhatunga, S. V.

2018-03-01

Slurry erosion and combined slurry and cavitation erosion resistance of thermal spray coatings are studied and compared with the as-received martensitic stainless steel material. 70Ni-Cr coatings are deposited on SS 410 material through plasma thermal spray process. The synergy effect of the combined slurry and cavitation erosion resistance of plasma thermal spray coatings were investigated in a slurry pot tester in the presence of bluff bodies known as Cavitation Inducers. Results showed the combined slurry and cavitation erosion resistance of martensitic stainless steel - 410 can be improved by plasma thermal spray coating. It is observed that the plasma spray coated specimens are better erosion resistant than the as- received material, subjected to erosion test under similar conditions. As-received and the surface modified steels are mechanically characterized for its hardness, bending. Morphological studies are conducted through scanning electron microscope.

Microhardness changes gradient of the duplex stainless steel (DSS surface layer after dry turning

Directory of Open Access Journals (Sweden)

G. Krolczyk

2014-10-01

Full Text Available The article presents the gradient of microhardness changes as a function of the distance from the material surface after turning with a wedge provided with a coating with a ceramic intermediate layer. The investigation comprised the influence of cutting speed on surface integrity microhardness in dry machining. The tested material was duplex stainless steel (DSS with two-phase, ferritic-austenitic structure. The tests have been performed under production conditions during machining of parts for electric motors and deep-well pumps.

Constraint on neutrino masses from SDSS-III/BOSS Ly$\\alpha$ forest and other cosmological probes

CERN Document Server

Palanque-Delabrouille, Nathalie; Lesgourgues, Julien; Rossi, Graziano; Borde, Arnaud; Viel, Matteo; Aubourg, Eric; Kirkby, David; LeGoff, Jean-Marc; Rich, James; Roe, Natalie; Ross, Nicholas P.; Schneider, Donald P.; Weinberg, David

2015-02-27

We present constraints on the parameters of the $\\Lambda$CDM cosmological model in the presence of massive neutrinos, using the one-dimensional Ly$\\alpha$ forest power spectrum obtained with the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS) by Palanque-Delabrouille et al. (2013), complemented by additional cosmological probes. The interpretation of the measured Ly$\\alpha$ spectrum is done using a second-order Taylor expansion of the simulated power spectrum. BOSS Ly$\\alpha$ data alone provide better bounds than previous Ly$\\alpha$ results, but are still poorly constraining, especially for the sum of neutrino masses $\\sum m_\

THE BOSS EMISSION-LINE LENS SURVEY (BELLS). I. A LARGE SPECTROSCOPICALLY SELECTED SAMPLE OF LENS GALAXIES AT REDSHIFT {approx}0.5

Energy Technology Data Exchange (ETDEWEB)

Brownstein, Joel R.; Bolton, Adam S.; Pandey, Parul [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard College Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Seitz, Stella [University Observatory Munich, Scheinstrasse 1, 81679 Muenchen (Germany); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Wood-Vasey, W. Michael [Pittsburgh Center for Particle Physics, Astrophysics, and Cosmology (PITT-PACC), Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Brinkmann, Jon [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, PA 16802 (United States); Weaver, Benjamin A. [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

2012-01-01

We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with lens redshifts 0.4 {approx}< z {approx}< 0.7, discovered spectroscopically by the presence of higher-redshift emission lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST ACS image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The full five-year BOSS database should produce a sample of several hundred strong galaxy-galaxy lenses and in combination with SLACS lenses at lower redshift, strongly constrain the redshift evolution of the structure of elliptical, bulge-dominated galaxies as a function of luminosity, stellar mass, and rest-frame color, thereby providing a powerful test for competing theories of galaxy formation and evolution.

Stainless Steel Foil with Improved Creep-Resistance for Use in Primary Surface Recuperators for Gas Turbine Engines

International Nuclear Information System (INIS)

Browning, P.F.; Fitzpatrick, M.; Grubb, J.F.; Klug, R.C.; Maziasz, P.J.; Montague, J.P.; Painter, R.A.; Swindeman, R.W.

1998-01-01

Primary surface recuperators (PSRs) are compact heat-exchangers made from thin-foil type 347 austenitic stainless steel, which boost the efficiency of land-based gas turbine engines. Solar Turbines uses foil folded into a unique corrugated pattern to maximize the primary surface area for efficient heat transfer between hot exhaust gas on one side, and the compressor discharge air on the other side of the foil. Allegheny-Ludlum produces 0.003 - 0.0035 in. thick foil for a range of current turbine engines using PSRs that operate at up to 660 degrees C. Laboratory-scale processing modification experiments recently have demonstrated that dramatic improvements can be achieved in the creep resistance of such typical 347 stainless steel foils. The modified processing enables fine NbC carbide precipitates to develop during creep at 650-700 degrees C, which provides strength even with a fine grain size. Such improved creep-resistance is necessary for advanced turbine systems that will demand greater materials performance and reliability at higher operating conditions. The next challenges are to better understand the nature of the improved creep resistance in these 347 stainless steel foil, and to achieve similar improvements with scale-up to commercial foil production

Large deflection analysis of a pre-stressed annular plate with a rigid boss under axisymmetric loading

Science.gov (United States)

Su, Y. H.; Chen, K. S.; Roberts, D. C.; Spearing, S. M.

2001-11-01

The large deflection analysis of a pre-stressed annular plate with a central rigid boss subjected to axisymmetric loading is presented. The factors affecting the transition from plate behaviour to membrane behaviour (e.g. thickness, in-plane tension and material properties) are studied. The effect of boss size and pre-tension on the effective stiffness of the plate are investigated. The extent of the bending boundary layers at the edges of the plate are quantified. All results are presented in non-dimensional form. The design implications for microelectromechanical system components are assessed.

Surface melting technique of small diameter stainless steel pipe by means of yttrium aluminium garnet laser

International Nuclear Information System (INIS)

Katahira, Fujito; Hirano, Kenji; Tanaka, Yasuhiro; Yoshida, Kazuo; Kuribayashi, Munetaka; Umemoto, Tadahiro

1994-01-01

A new method of surface melting by using a high power yttrium aluminium garnet laser was developed. This method is applicable to a long distance and narrow space, because of the good accessibility of the laser beam through optical fibre.A desensitization of sensitized type 304 stainless steel pipe was demonstrated by using this technique. A melted layer of thickness approximately 200μm had a very finite solidification structure, which contained approximately 1.5% δ-ferrite. The average chemical composition of this layer was almost the same as that of type 304 stainless steel, and a band of 300μm thickness under the melted layer underwent solution heat treatment (SHT).As a result of such surface melting, the melted layer exhibited superior resistance to intergranular stress corrosion cracking (IGSCC). Since the SHT layer is highly resistant to IGSCC generally, it may be possible to improve the IGSCC resistance of base metal to a comparatively deep extent (500μm from the surface) by this technique. ((orig.))

Surface melting technique of small diameter stainless steel pipe by means of yttrium aluminium garnet laser

Energy Technology Data Exchange (ETDEWEB)

Katahira, Fujito (Ishikawajima-Harima Heavy Industries Co. Ltd., 1 Shin-Nakahara-Cho, Isogo-Ku, Yokohama 235 (Japan)); Hirano, Kenji (Ishikawajima-Harima Heavy Industries Co. Ltd., 1 Shin-Nakahara-Cho, Isogo-Ku, Yokohama 235 (Japan)); Tanaka, Yasuhiro (Ishikawajima-Harima Heavy Industries Co. Ltd., 1 Shin-Nakahara-Cho, Isogo-Ku, Yokohama 235 (Japan)); Yoshida, Kazuo (Ishikawajima-Harima Heavy Industries Co. Ltd., 1 Shin-Nakahara-Cho, Isogo-Ku, Yokohama 235 (Japan)); Kuribayashi, Munetaka (Ishikawajima-Harima Heavy Industries Co. Ltd., 1 Shin-Nakahara-Cho, Isogo-Ku, Yokohama 235 (Japan)); Umemoto, Tadahiro (Ishikawajima-Harima Heavy Industries Co. Ltd., 1 Shin-Nakahara-Cho, Isogo-Ku, Yokohama 235 (Japan))

1994-12-01

A new method of surface melting by using a high power yttrium aluminium garnet laser was developed. This method is applicable to a long distance and narrow space, because of the good accessibility of the laser beam through optical fibre.A desensitization of sensitized type 304 stainless steel pipe was demonstrated by using this technique. A melted layer of thickness approximately 200[mu]m had a very finite solidification structure, which contained approximately 1.5% [delta]-ferrite. The average chemical composition of this layer was almost the same as that of type 304 stainless steel, and a band of 300[mu]m thickness under the melted layer underwent solution heat treatment (SHT).As a result of such surface melting, the melted layer exhibited superior resistance to intergranular stress corrosion cracking (IGSCC). Since the SHT layer is highly resistant to IGSCC generally, it may be possible to improve the IGSCC resistance of base metal to a comparatively deep extent (500[mu]m from the surface) by this technique. ((orig.))

Martensitic Stainless Steels Low-temperature Nitriding: Dependence of Substrate Composition

OpenAIRE

Ferreira, Lauro Mariano; Brunatto, Silvio Francisco; Cardoso, Rodrigo Perito

2015-01-01

Low-temperature plasma assisted nitriding is a very promising technique to improve surface mechanical properties of stainless steels, keeping unaltered or even improving their surface corrosion resistance. During treatment, nitrogen diffuses into the steel surface, increasing its hardness and wear resistance. In the present work the nitriding process of different martensitic stainless steels was studied. As-quenched AISI 410, 410NiMo, 416 and 420 stainless steel samples were plasma nitrided a...

Controlling the synergetic effects in (3-aminopropyl) trimethoxysilane and (3-mercaptopropyl) trimethoxysilane coadsorption on stainless steel surfaces

International Nuclear Information System (INIS)

Vuori, Leena; Hannula, Markku; Lahtonen, Kimmo; Jussila, Petri; Ali-Löytty, Harri; Hirsimäki, Mika; Pärna, Rainer; Nõmmiste, Ergo; Valden, Mika

2014-01-01

Graphical abstract: - Highlights: • We studied the coadsorption of APS and MPS silanes on stainless steel. • Well-ordered monolayers of APS/MPS were fabricated with liquid phase deposition. • SR-PES enabled the determination of the APS and MPS orientation. • Inelastic electron background analysis was used to determine overlayer thicknesses. • The APS/MPS surface concentration is non-equal to the solution concentration. - Abstract: A versatile and economic method of preparing covalently-bound and uniform bifunctional silane monolayers on stainless steel is presented. Stainless steel is first electrochemically hydroxylated to enable the formation of a bifunctional overlayer via simultaneous liquid-phase deposition of two organofunctional silanes: (3-aminopropyl)trimethoxysilane (APS) and (3-mercaptopropyl)trimethoxysilane (MPS). The chemical composition, in-depth distribution, molecular orientation and chemical bonds in APS, MPS and APS/MPS layers over a range of APS/MPS mixing ratios are studied with synchrotron radiation mediated photoelectron spectroscopy (SR-PES), conventional X-ray photoelectron spectroscopy (XPS) and energy filtered X-ray photoemission electron microscopy (EF-XPEEM). Inelastic electron energy-loss background (IEEB) analysis is employed to determine the surface morphology of the silanized samples. Coadsorption is shown to produce a covalently-bound and highly ordered monolayer with a controllable MPS surface concentration within APS matrix. The results show evidence of strong synergistic effects during simultaneous adsorption of MPS and APS from liquid phase. While the uptake of MPS alone is low, the coadsorption of MPS and APS strongly enhances both the uptake of MPS and ordering in the APS/MPS overlayer. Results from PES, EF-XPEEM and IEEB analysis reveal that the surface is predominantly covered by a well-ordered APS/MPS monolayer with only slight degree of clustering. Clustering is attributed to different hydrolysis rates in

Hydrogen induced surface effects on the mechanical properties of type 304 stainless steel

International Nuclear Information System (INIS)

Silva, T.C.V. da; Pascual, R.; Miranda, P.E.V. de.

1983-01-01

The possibilities of modifying the mechanical properties of type 304 stainless steel by cathodic hydrogen charging were studied. The situations analysed included hydrogen embrittlement itself in tensile tests of hydrogen containing samples and the effects of delayed cracks in fatigue tests of hydrogenated and outgassed samples. SEM and TEM observations were also performed. It was found that hydrogen induced surface delayed cracks appear in great quantity during outgassing (of the order of several millions in a square centimeter). Hydrogen embrittlement was responsible for drastic losses in ductility in tension, while surface cracks severely reduced fatigue life. (author) [pt

Influence of surface texture on the galling characteristics of lean duplex and austenitic stainless steels

DEFF Research Database (Denmark)

Wadman, Boel; Eriksen, J.; Olsson, M.

2010-01-01

Two simulative test methods were used to study galling in sheet forming of two types of stainless steel sheet: austenitic (EN 1.4301) and lean duplex LDX 2101 (EN 1.4162) in different surface conditions. The pin-on-disc test was used to analyse the galling resistance of different combinations of ...

What If Your Boss Is a Woman? Work Organization, Work-Life Balance and Gender Discrimination at the Workplace

OpenAIRE

Lucifora, Claudio; Vigani, Daria

2016-01-01

In this paper, we investigate the association between female leadership, work organization practices and perceived gender discrimination within firms. Using data for 30 European countries for the period 1995-2010, we find that having a female "boss" is associated with lower overall gender discrimination at work. The female boss effect, however, differs across gender: it is associated with lower discrimination among female employees, but higher among male employees. We also investigate the und...

Immobilization of epidermal growth factor on titanium and stainless steel surfaces via dopamine treatment

Energy Technology Data Exchange (ETDEWEB)

Kang, Jeonghwa [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397 Japan (Japan); Sakuragi, Makoto; Shibata, Aya; Abe, Hiroshi; Kitajima, Takashi; Tada, Seiichi [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Mizutani, Masayoshi; Ohmori, Hitoshi [Material Fabrication Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Ayame, Hirohito [Diagnostic Biochip Laboratory, RIKEN Center for Intellectual Property Strategies, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Son, Tae Il [Bioscience and Biotechnology, Chung-Ang University, 40-1 San, Nae-Ri, Daeduck-myun, Ansung-si, Kyungki-do, 456-756 (Korea, Republic of); Aigaki, Toshiro [Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397 Japan (Japan); Ito, Yoshihiro, E-mail: y-ito@riken.jp [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397 Japan (Japan); Diagnostic Biochip Laboratory, RIKEN Center for Intellectual Property Strategies, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan)

2012-12-01

Titanium and stainless steel were modified with dopamine for the immobilization of biomolecules, epidermal growth factor (EGF). First, the treatment of metal surfaces with a dopamine solution under different pH conditions was investigated. At higher pH, the dopamine solution turned brown and formed precipitates. Treatment of the metals with dopamine at pH 8.5 also resulted in the development of brown color at the surface of the metals. The hydrophobicity of the surfaces increased after treatment with dopamine, independently of pH. X-ray photoelectron spectroscopy revealed the formation of a significant amount of an organic layer on both surfaces at pH 8.5. According to ellipsometry measurements, the organic layer formed at pH 8.5 was about 1000 times as thick as that formed at pH 4.5. The amount of amino groups in the layer formed at pH 8.5 was also higher than that observed in the layer formed at pH 4.5. EGF molecules were immobilized onto the dopamine-treated surfaces via a coupling reaction using carbodiimide. A greater amount of EGF was immobilized on surfaces treated at pH 8.5 compared with pH 4.5. Significantly higher growth of rat fibroblast cells was observed on the two EGF-immobilized surfaces compared with non-immobilized surfaces in the presence of EGF. The present study demonstrated that metals can become bioactive via the surface immobilization of a growth factor and that the effect of the immobilized growth factor on metals was greater than that of soluble growth factor. - Highlights: Black-Right-Pointing-Pointer Epidermal growth factor was covalently immobilized on titan or stainless steel surfaces. Black-Right-Pointing-Pointer Amino groups were formed on the surfaces by the treatment and the growth factor was immobilized through amide bonds. Black-Right-Pointing-Pointer The immobilized epidermal growth factor accelerated cell proliferation more than soluble ones on the surfaces.

Action of peracetic acid on Escherichia coli and Staphylococcus aureus in suspension or settled on stainless steel surfaces

Directory of Open Access Journals (Sweden)

Kunigk Leo

2001-01-01

Full Text Available The efficiency of a commercial peracetic acid sanitizer on destruction of Staphylococcus aureus and Escherichia coli was evaluated using two distinct methods. The first method is the AOAC suspension test and the second is a method proposed by one of the authors in which the microbial cells are settled on a stainless steel surface and then treated with the sanitizer. The results showed that when in suspension S. aureus was more resistant to the sanitizer than E. coli. When S. aureus was settled on the stainless steel surface, the contact time between the sanitizer and the microorganisms to attain a 6.5 log reduction in the number of viable cells was three times greater than when the cells were in suspension.

Microbiota formed on attached stainless steel coupons correlates with the natural biofilm of the sink surface in domestic kitchens.

Science.gov (United States)

Moen, Birgitte; Røssvoll, Elin; Måge, Ingrid; Møretrø, Trond; Langsrud, Solveig

2016-02-01

Stainless steel coupons are frequently used in biofilm studies in the laboratory, as this material is commonly used in the food industry. The coupons are attached to different surfaces to create a "natural" biofilm to be studied further in laboratory trials. However, little has been done to investigate how well the microbiota on such coupons represents the surrounding environment. The microbiota on sink wall surfaces and on new stainless steel coupons attached to the sink wall for 3 months in 8 domestic kitchen sinks was investigated by next-generation sequencing (MiSeq) of the 16S rRNA gene derived from DNA and RNA (cDNA), and by plating and identification of colonies. The mean number of colony-forming units was about 10-fold higher for coupons than sink surfaces, and more variation in bacterial counts between kitchens was seen on sink surfaces than coupons. The microbiota in the majority of biofilms was dominated by Moraxellaceae (genus Moraxella/Enhydrobacter) and Micrococcaceae (genus Kocuria). The results demonstrated that the variation in the microbiota was mainly due to differences between kitchens (38.2%), followed by the different nucleic acid template (DNA vs RNA) (10.8%), and that only 5.1% of the variation was a result of differences between coupons and sink surfaces. The microbiota variation between sink surfaces and coupons was smaller for samples based on their RNA than on their DNA. Overall, our results suggest that new stainless steel coupons are suited to model the dominating part of the natural microbiota of the surrounding environment and, furthermore, are suitable for different downstream studies.

The Effect of Surface Preparation on the Precipitation of Sigma During High Temperature Exposure of S32205 Duplex Stainless Steel

Science.gov (United States)

Jepson, Mark A. E.; Rowlett, Matthew; Higginson, Rebecca L.

2017-03-01

Although the formation of sigma phase in duplex stainless steels is reasonably well documented, the effect of surface finish on its formation rate in surface regions has not been previously noted. The growth of the sigma phase precipitated in the subsurface region (to a maximum depth of 120 μm) has been quantified after heat treatment of S32205 duplex stainless steel at 1073 K (800 °C) and 1173 K (900 °C) after preparation to two surface finishes. Here, results are presented that show that there is a change in the rate of sigma phase formation in the surface region of the material, with a coarser surface finish leading to a greater depth of precipitation at a given time and temperature of heat treatment. The growth rate and morphology of the precipitated sigma has been examined and explored in conjunction with thermodynamic equilibrium phase calculations.

Plasma decontamination of uranium oxide from stainless steel surfaces

International Nuclear Information System (INIS)

Veilleux, J.M.; El-Genk, M.S.; Chamberlin, E.P.

1997-01-01

The U.S. Department of Energy (DOE) is expected to have 845000 m 3 of transuranic (TRU) waste by the year 2000 that has accumulated during the development and assembly of the nation's nuclear stockpile. The TRU disposal costs alone range up to $28000/m 3 , which could be reduced to $1800/m 3 or less by treating and converting the material to low-level waste. Plasma-based processes have been shown to remove plutonium and uranium surface contaminants from metallic components and could be used to treat TRU with significant cost avoidance, estimated at over $1.0 billion. Martz and Hess conducted the initial work of plutonium etching in low-power radio-frequency (rf) plasma with etch rates ranging from 0.007 to 0.025 kg/m 2 ·h. Veilleux et al. reported that plasma decontamination of uranium from the interior of aluminum objects results in etch rates an order of magnitude greater. The current work reports on removal rates of uranium from stainless steel surfaces and includes estimates of the etch rates and characteristic times for removal

Reduction of Aeromonas hidrophyla biofilm on stainless stell surface by essential oils

Science.gov (United States)

Millezi, Alessandra Farias; Cardoso, Maria das Graças; Alves, Eduardo; Piccoli, Roberta Hilsdorf

2013-01-01

This study demonstrates the possibility of using sanitizing detergents based on natural products for the elimination and/or reduction of Aeromonas hydrophila biofilm formed on stainless steel surfaces. The goal of this work was to determine the reduction effect of sanitizing detergents containing essential oils of Thymus vulgaris (thyme) and Cymbopogon citratus (lemongrass) on biofilm formed by A. hydrophila on AISI 304 stainless steel coupons, using UHT skimmed milk as substratum. There was adhesion and biofilm formation by A. hydrophila at 28 °C, presenting 7.60 log cfu.cm−2 after the fourth day of cultivation. There was no significant difference between the lemongrass treatment and that of the thyme oil (p 0.05). The treatment with lemongrass solution reduced the biofilm by 4.51 log cfu cm−2 at 25 °C. The thyme detergent also reduced the number of cfu cm−2 by 3.84 log cycles at 25 °C. The use of the lemongrass and thyme solutions efficiently reduced the A. hydrophila biofilm. PMID:24159286

Reduction of Aeromonas hidrophyla biofilm on stainless stell surface by essential oils

Directory of Open Access Journals (Sweden)

Alessandra Farias Millezi

2013-01-01

Full Text Available This study demonstrates the possibility of using sanitizing detergents based on natural products for the elimination and/or reduction of Aeromonas hydrophila biofilm formed on stainless steel surfaces. The goal of this work was to determine the reduction effect of sanitizing detergents containing essential oils of Thymus vulgaris (thyme and Cymbopogon citratus (lemongrass on biofilm formed by A. hydrophila on AISI 304 stainless steel coupons, using UHT skimmed milk as substratum. There was adhesion and biofilm formation by A. hydrophila at 28 ºC, presenting 7.60 log cfu.cm-2 after the fourth day of cultivation. There was no significant difference between the lemongrass treatment and that of the thyme oil (p 0.05. The treatment with lemongrass solution reduced the biofilm by 4.51 log cfu cm-2 at 25 ºC. The thyme detergent also reduced the number of cfu cm-2 by 3.84 log cycles at 25 ºC. The use of the lemongrass and thyme solutions efficiently reduced the A. hydrophila biofilm.

Constraints on neutrino masses from Lyman-alpha forest power spectrum with BOSS and XQ-100

Energy Technology Data Exchange (ETDEWEB)

Yèche, Christophe; Palanque-Delabrouille, Nathalie; Baur, Julien; Bourboux, Hélion du Mas des, E-mail: christophe.yeche@cea.fr, E-mail: nathalie.palanque-delabrouille@cea.fr, E-mail: julien.baur@cea.fr, E-mail: helion.du-mas-des-bourboux@cea.fr [CEA, Centre de Saclay, IRFU/SPP, F-91191 Gif-sur-Yvette (France)

2017-06-01

We present constraints on masses of active and sterile neutrinos in the context of the ΛCDMν and ΛWDM models, respectively. We use the one-dimensional Lyα-forest power spectrum from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS-III) measured by Palanque-Delabrouille et al. [1], and from the VLT/XSHOOTER legacy survey (XQ-100). In this paper, we present our own measurement of the publicly released XQ-100 quasar spectra, focusing in particular on an improved determination of the spectrograph resolution that allows us to push to smaller scales than the public release and reach k -modes of 0.070 s km{sup −1}. We compare the obtained 1D Lyα flux power spectrum to the one measured by Irsic et al. [2] to k -modes of 0.057 s km{sup −1}. Fitting Lyα data alone leads to cosmological parameters in excellent agreement with the values derived independently from Planck 2015 Cosmic Microwave Background (CMB) data. Combining BOSS and XQ-100 Lyα power spectra, we constrain the sum of neutrino masses to ∑ m {sub ν} < 0.8 eV (95% C.L.) including all identified sources of systematic uncertainties. With the addition of CMB data, this bound is tightened to ∑ m {sub ν} < 0.14 eV (95% C.L.). With their sensitivity to small scales, Lyα data are ideal to constrain ΛWDM models. Using XQ-100 alone, we issue lower bounds on pure dark matter particles: m {sub X} ∼> 2.08 : keV (95% C.L.) for early decoupled thermal relics, and m {sub s} ∼> 10.2 : keV (95% C.L.) for non-resonantly produced right-handed neutrinos. Combining the 1D Lyα-forest power spectrum measured by BOSS and XQ-100, we improve the two bounds to m {sub X} ∼> 4.17 : keV and m {sub s} ∼> 25.0 : keV (95% C.L.), slightly more constraining than what was achieved in Baur et al. 2015 [3] with BOSS data alone. The 3 σ bound shows a more significant improvement, increasing from m {sub X} ∼> 2.74 : keV for BOSS alone to m {sub X} ∼> 3.10 : keV for the combined BOSS

Detergency of stainless steel surface soiled with human brain homogenate: an XPS study

International Nuclear Information System (INIS)

Richard, M.; Le Mogne, Th.; Perret-Liaudet, A.; Rauwel, G.; Criquelion, J.; De Barros, M.I.; Cetre, J.C.; Martin, J.M.

2005-01-01

In the detergency field of re-usable medical devices, a special attention is focused on the non conventional transmissible agent called prions which is a proteinaceous infectious agent. Few cleaning procedures are effective against prions and few techniques are available to study cleaning effectiveness with respect to proteins in general. In our study, X-ray photoelectron spectroscopy (XPS) has been used to evaluate the effectiveness of detergent formulations to remove proteins from stainless steel surface soiled with a brain homogenate (BH) from human origin. Our results showed that XPS is a reliable surface analysis technique to study chemical species remaining on surface and substrate properties after cleaning procedures. A semi-quantitative evaluation of the detergency effectiveness could also be performed

Detergency of stainless steel surface soiled with human brain homogenate: an XPS study

Energy Technology Data Exchange (ETDEWEB)

Richard, M. [Ecole Centrale de Lyon, UMR 5513 LTDS, 69 134 Ecully (France) and Laboratoires ANIOS, 59 260 Lille-Hellemmes (France)]. E-mail: marlene.richard@ec-lyon.fr; Le Mogne, Th. [Ecole Centrale de Lyon, UMR 5513 LTDS, 69 134 Ecully (France); Perret-Liaudet, A. [Hopital Neurologique de Lyon et INSERM U512, 69 394 Lyon (France); Rauwel, G. [Laboratoires ANIOS, 59 260 Lille-Hellemmes (France); Criquelion, J. [Laboratoires ANIOS, 59 260 Lille-Hellemmes (France); De Barros, M.I. [Ecole Centrale de Lyon, UMR 5513 LTDS, 69 134 Ecully (France); Cetre, J.C. [Unite d' Hygiene et d' Epidemiologie, Hopital de la Croix Rousse, 69 317 Lyon (France); Martin, J.M. [Ecole Centrale de Lyon, UMR 5513 LTDS, 69 134 Ecully (France)

2005-02-15

In the detergency field of re-usable medical devices, a special attention is focused on the non conventional transmissible agent called prions which is a proteinaceous infectious agent. Few cleaning procedures are effective against prions and few techniques are available to study cleaning effectiveness with respect to proteins in general. In our study, X-ray photoelectron spectroscopy (XPS) has been used to evaluate the effectiveness of detergent formulations to remove proteins from stainless steel surface soiled with a brain homogenate (BH) from human origin. Our results showed that XPS is a reliable surface analysis technique to study chemical species remaining on surface and substrate properties after cleaning procedures. A semi-quantitative evaluation of the detergency effectiveness could also be performed.

MC3T3-E1 cell response to stainless steel 316L with different surface treatments

International Nuclear Information System (INIS)

Zhang, Hongyu; Han, Jianmin; Sun, Yulong; Huang, Yongling; Zhou, Ming

2015-01-01

In the present study, stainless steel 316L samples with polishing, aluminum oxide blasting, and hydroxyapatite (HA) coating were prepared and characterized through a scanning electron microscope (SEM), optical interferometer (surface roughness, Sq), contact angle, surface composition and phase composition analyses. Osteoblast-like MC3T3-E1 cell adhesion on the samples was investigated by cell morphology using a SEM (4 h, 1 d, 3 d, 7 d), and cell proliferation was assessed by MTT method at 1 d, 3 d, and 7 d. In addition, adsorption of bovine serum albumin on the samples was evaluated at 1 h. The polished sample was smooth (Sq: 1.8 nm), and the blasted and HA coated samples were much rougher (Sq: 3.2 μm and 7.8 μm). Within 1 d of incubation, the HA coated samples showed the best cell morphology (e.g., flattened shape and complete spread), but there was no significant difference after 3 d and 7 d of incubation for all the samples. The absorbance value for the HA coated samples was the highest after 1 d and 3 d of incubation, indicating better cell viability. However, it reduced to the lowest value at 7 d. Protein adsorption on the HA coated samples was the highest at 1 h. The results indicate that rough stainless steel surface improves cell adhesion and morphology, and HA coating contributes to superior cell adhesion, but inhibits cell proliferation. - Highlights: • Rough stainless steel surface improves cell adhesion and proliferation. • HA coating results in superior cell morphology and cell attachment. • HA coating inhibits osteoblast cell proliferation after 7 d of incubation

MC3T3-E1 cell response to stainless steel 316L with different surface treatments

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hongyu [State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Han, Jianmin, E-mail: siyanghan@163.com [Dental Materials Laboratory, National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology, Beijing 100081 (China); Sun, Yulong [State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Huang, Yongling [Jinghang Biomedicine Engineering Division, Beijing Institute of Aeronautical Material, Beijing 100095 (China); Zhou, Ming [State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

2015-11-01

In the present study, stainless steel 316L samples with polishing, aluminum oxide blasting, and hydroxyapatite (HA) coating were prepared and characterized through a scanning electron microscope (SEM), optical interferometer (surface roughness, Sq), contact angle, surface composition and phase composition analyses. Osteoblast-like MC3T3-E1 cell adhesion on the samples was investigated by cell morphology using a SEM (4 h, 1 d, 3 d, 7 d), and cell proliferation was assessed by MTT method at 1 d, 3 d, and 7 d. In addition, adsorption of bovine serum albumin on the samples was evaluated at 1 h. The polished sample was smooth (Sq: 1.8 nm), and the blasted and HA coated samples were much rougher (Sq: 3.2 μm and 7.8 μm). Within 1 d of incubation, the HA coated samples showed the best cell morphology (e.g., flattened shape and complete spread), but there was no significant difference after 3 d and 7 d of incubation for all the samples. The absorbance value for the HA coated samples was the highest after 1 d and 3 d of incubation, indicating better cell viability. However, it reduced to the lowest value at 7 d. Protein adsorption on the HA coated samples was the highest at 1 h. The results indicate that rough stainless steel surface improves cell adhesion and morphology, and HA coating contributes to superior cell adhesion, but inhibits cell proliferation. - Highlights: • Rough stainless steel surface improves cell adhesion and proliferation. • HA coating results in superior cell morphology and cell attachment. • HA coating inhibits osteoblast cell proliferation after 7 d of incubation.

Recombination of chlorine atoms on plasma-conditioned stainless steel surfaces in the presence of adsorbed Cl{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Stafford, Luc; Poirier, Jean-Sebastien; Margot, Joelle [Departement de Physique, Universite de Montreal, Montreal, Quebec, H3C 3J7 (Canada); Khare, Rohit; Guha, Joydeep; Donnelly, Vincent M, E-mail: luc.stafford@umontreal.c, E-mail: vmdonnelly@uh.ed [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204 (United States)

2009-03-07

We investigated the interactions of atomic and molecular chlorine with plasma-conditioned stainless steel surfaces through both experiments and modelling. The recombination of Cl during adsorption and desorption of Cl{sub 2} was characterized using a rotating-substrate technique in which portions of the cylindrical substrate surface are periodically exposed to an inductively coupled chlorine plasma and then to an Auger electron spectrometer in separate, differentially pumped chambers. After several hours of exposure to the Cl{sub 2} plasma, the stainless steel substrate became coated with a Si-oxychloride-based layer (Fe : Si : O : Cl {approx} 1 : 13 : 13 : 3) due to chlorine adsorption and the erosion of the silica discharge tube. Desorption of Cl{sub 2} from this surface was monitored through measurements of pressure rises in the Auger chamber as a function of substrate rotation frequency. Significant adsorption and desorption of Cl{sub 2} was observed with the plasma off, similar to that observed previously on plasma-conditioned anodized aluminium surfaces, but with much faster desorption rates that are most likely attributable to the smoother and non-porous stainless steel surface morphology. When the plasma was turned on, a much larger pressure rise was observed due to Langmuir-Hinshelwood recombination of Cl atoms. Recombination coefficients, {gamma}{sub Cl}, ranged from 0.004 to 0.03 and increased with Cl-to-Cl{sub 2} number density ratio. This behaviour was observed previously for anodized aluminium surfaces, and was explained by the blocking of Cl recombination sites by adsorbed Cl{sub 2}. Application of this variable recombination coefficient to the modelling of high-density chlorine plasmas gives a much better agreement with measured Cl{sub 2} percent dissociations compared with predictions obtained with a recombination coefficient that is independent of plasma conditions.

The "Entrepreneurial Boss" Effect on Employees' Future Entrepreneurship Choices : A Role Model Story?

NARCIS (Netherlands)

Rocha, V.; van Praag, M.

Both organizational and sociological approaches in entrepreneurship research highlight the importance of social context in shaping individual preferences for entrepreneurship. An influential contextual factor that has not been studied in entrepreneurship research is one’s boss at work. Do

Influence of the surface finishing on the corrosion behaviour of AISI 316L stainless steel

Czech Academy of Sciences Publication Activity Database

Dundeková, S.; Zatkalíková, V.; Fintová, Stanislava; Hadzima, B.; Škorík, Viktor

2015-01-01

Roč. 22, č. 1 (2015), s. 48-53 ISSN 1335-0803 R&D Projects: GA MŠk(CZ) EE2.3.30.0063 Institutional support: RVO:68081723 Keywords : AISI 316L stainless steel * Corrosion * Immersion test * Corrosion rate Subject RIV: JK - Corrosion ; Surface Treatment of Materials http://ojs.mateng.sk/index.php/Mateng/article/view/166/251

Radiation blistering of stainless steel

International Nuclear Information System (INIS)

Yoshii, Naritsugu; Tanabe, Tetsuo; Imoto, Shosuke

1980-01-01

Surface blistering of stainless steels due to 20 keV He + ion bombardment has been investigated by examination of surface topography with a scanning electron microscope (SEM) and an optical microscope. Blisters of 0.1 to 2 μm in diameter are observed in all samples irradiated with fluence of about 1 x 10 18 He + /cm 2 at any temperature between -80 0 C and 500 0 C. With increasing the fluence blister covers are ruptured and exfoliated and finally the surface becomes rough surface without traces of blister formation. The surface effect is severer at 500 0 C than at 100 0 C irradiation. Also in double-phase stainless steel DP-3, similar surface topography to 316 SS is observed. But by the difference of the erosion rate by sputtering of the surface between α-phase and γ-phase, a striped pattern appears in DP-3 with heavy irradiation of about 2 x 10 19 He + /cm 2 . (author)

Effects on Machining on Surface Residual Stress of SA 508 and Austenitic Stainless Steel

International Nuclear Information System (INIS)

Lee, Kyoung Soo; Lee, Seong Ho; Park, Chi Yong; Yang, Jun Seok; Lee, Jeong Geun; Park, Jai Hak

2011-01-01

Primary water stress corrosion cracking has occurred in dissimilar weld areas in nuclear power plants. Residual stress is a driving force in the crack. Residual stress may be generated by weld or surface machining. Residual stress due to surface machining depends on the machining method, e.g., milling, grinding, or EDM. The stress is usually distributed on or near the surface of the material. We present the measured residual stress for machining on SA 508 and austenitic stainless steels such as TP304 and F316. The residual stress can be tensile or compressive depending on the machining method. The depth and the magnitude of the residual stress depend on the material and the machining method

High-power subnanosecond operation of a bistable optically controlled semiconductor switch (BOSS)

International Nuclear Information System (INIS)

Stoudt, D.C.; Richardson, M.A.; Demske, D.L.; Roush, R.A.; Eure, K.W.

1994-01-01

Recent high-power, subnanosecond-switching results of the Bistable Optically controlled Semiconductor Switch (BOSS) are presented. The process of persistent photoconductivity followed by photo-quenching have been demonstrated at megawatt power levels in copper-compensated, silicon-doped, semi-insulating gallium arsenide. These processes allow a switch to be developed that can be closed by the application of one laser pulse and opened by the application of a second laser pulse with a wavelength equal to twice that of the first laser. Switch closure is primarily achieved by elevating electrons from a deep copper center which has been diffused into the material. The opening phase is a two-step process which relies initially on the absorption of the 2-μm laser causing electrons to be elevated from the valance band back into the copper center, and finally on the recombination of electrons in the conduction band with boles in the valance band. The second step requires a sufficient concentration of recombination centers (RC) in the material for opening to occur in the subnanosecond regime. These RC's are generated in the bulk GaAs material by fast-neutron irradiation (∼ 1 MeV) at a fluence of about 3 x 10 15 cm -2 . High-power switching results which demonstrate that the BOSS switch can be opened in the subnanosecond regime are presented for the first time. Neutron-irradiated BOSS devices have been opened against a rising electric field of about 20 kV/cm (10 kV) in a time less than one nanosecond. Kilovolt electrical pulses have been generated with a FWHM of roughly 250 picoseconds

Correlation between Fatigue Crack Growth Behavior and Fracture Surface Roughness on Cold-Rolled Austenitic Stainless Steels in Gaseous Hydrogen

Directory of Open Access Journals (Sweden)

Tai-Cheng Chen

2018-03-01

Full Text Available Austenitic stainless steels are often considered candidate materials for use in hydrogen-containing environments because of their low hydrogen embrittlement susceptibility. In this study, the fatigue crack growth behavior of the solution-annealed and cold-rolled 301, 304L, and 310S austenitic stainless steels was characterized in 0.2 MPa gaseous hydrogen to evaluate the hydrogen-assisted fatigue crack growth and correlate the fatigue crack growth rates with the fracture feature or fracture surface roughness. Regardless of the testing conditions, higher fracture surface roughness could be obtained in a higher stress intensity factor (∆K range and for the counterpart cold-rolled specimen in hydrogen. The accelerated fatigue crack growth of 301 and 304L in hydrogen was accompanied by high fracture surface roughness and was associated with strain-induced martensitic transformation in the plastic zone ahead of the fatigue crack tip.

The surface topography of Inconel, stainless steel and copper after argon ion bombardment

International Nuclear Information System (INIS)

Vogelbruch, K.; Vietzke, E.

1983-01-01

Energetic particle bombardment of metals is known to change the surface topography. To simulate the behaviour of the first wall of a fusion device under real plasma conditions, we have investigated the surface topography of rotating targets after 30 keV argon ion bombardment at 70deg incident angle by electron scanning micrographs. Under these conditions Inconel 600, 601, 625, stainless steel, and copper showed no cones, pyramids or cliffs, but only etching figures and at higher ion doses relatively flat hills. Thus, it can be concluded, that the influence of energetic particles on the first wall of a fusion reactor is smaller than expected from the results of such sputtering experiments, which have dealt with the formation of surface structures under ion bombardment at constant incident direction. (author)

Oxidation Behavior of Surface-modified Stainless Steel 316LN in Supercritical-CO{sub 2} Environment

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hwan; Heo, Jin Woo; Kim, Hyunm Yung; Jang, Chang Heui [KAIST, Daejeon (Korea, Republic of)

2016-05-15

Compared to other working fluids such as helium or nitrogen, S-CO{sub 2} offers a higher efficiency at operating temperatures of advanced reactors above 550 .deg. C. Moreover, the S-CO{sub 2} cycle is expected to have a significantly smaller footprint compared to other power conversion cycles, resulting in a broader range of applications with lower capital costs. Currently, stainless steel 316 is considered as the candidate structural material for the SFR. In comparison, it is well known that alumina (Al{sub 2}O{sub 3}) have superior oxidation and carburization resistance specifically at higher temperatures where α-Al{sub 2}O{sub 3} may form. Thus, various surface modification techniques have been applied to mostly Ni-base alloys so that a protective and continuous Al-rich oxide layer forms on the surface, conferring superior oxidation and carburization resistance. In this study, SS 316LN was deposited with Al via physical vapor deposition (PVD) method followed by heat treatment processes to develop an Al-rich layer at the surface. The specimens are to be exposed to high temperature S-CO{sub 2} environment to evaluate the oxidation and carburization resistance. Stainless steel 316LN was surface-modified to develop an Al-rich layer for improvement of oxidation behavior in S-CO{sub 2} environment. As the test temperature of 600 .deg. C is not sufficiently high for the formation of protective α-Al{sub 2}O{sub 3} formation, pre-oxidation of surface modified SS 316LN was conducted.

Joining method for pressure tube and martensitic stainless steel tube

International Nuclear Information System (INIS)

Kimoto, Hiroshi; Koike, Hiromitsu.

1993-01-01

In a joining portion of zirconium alloy and a stainless steel, the surface of martensitic stainless steel being in contact with Zr and Zr alloy is applied with a laser quenching solidification treatment before expanding joining of them to improve the surface. This can provide the surface with refined coagulated cell tissues and make deposits and impurities homogeneous and solubilized. As a result, the surface of the martensitic stainless steel has highly corrosion resistance, to suppress contact corrosion with Zr and Zr alloy. Accordingly, even if it is exposed to high temperature water of 200 to 350degC, failures of Zr and Zr alloy can be suppressed. (T.M.)

Effect of residual stress and hardening on grain boundary sliding in welds of low-carbon stainless steels with surface machining

International Nuclear Information System (INIS)

Mori, Hiroaki; Mochizuki, Masahito; Nishimoto, Kazutoshi; Katsuyama, Jinya

2007-01-01

To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561K by the tensile test with the numerically simulated tensile residual stress due to welding and surface machining. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding accelerated by residual stress of multi pass welding and surface hardening. (author)

Effect of residual stress and hardening on grain boundary sliding in welds of low-carbon stainless steels with surface machining

International Nuclear Information System (INIS)

Mori, Hiroaki; Mochizuki, Masahito; Nishimoto, Kazutoshi; Katsuyama, Jinya

2008-01-01

To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561K by the tensile test with the numerically simulated tensile residual stress due to multi-pass welding and surface machining. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding induced by residual stress of multi pass welding and surface hardening. (author)

Modification of the surfaces of stainless steel during titanium nitride deposition by a dynamic mixing method

Science.gov (United States)

Yokota, Katsuhiro; Tamura, Susumu; Nakamura, Kazuhiro; Horiguchi, Motohiro; Nakaiwa, Hiroki; Sugimoto, Takashi; Akamatsu, Katsuya; Nakao, Kazuyoshi

2000-05-01

Surfaces of stainless steel SUS304 were coated with titanium nitride (TiN) at temperatures ranging from 400°C to 770°C using a dynamic mixing technique. The N+ ions were accelerated at energies of 0.5-2.0 keV, and were implanted into the stainless steel. The composition of the prepared TiN films was measured using Rutherford backscattering spectrometry with He ions at an energy of 2.0 MeV. Intermediate layers containing compounds such as FesNq, Cr2N, and CrFe were formed between the TiN films and substrates at substrate temperatures higher than 700°C. The thickness of the TiN films decreased significantly when the intermediate layers were formed.

Effect of electropulsing on surface mechanical properties and microstructure of AISI 304 stainless steel during ultrasonic surface rolling process

Energy Technology Data Exchange (ETDEWEB)

Wang, Haibo [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Song, Guolin [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Tang, Guoyi, E-mail: tanggy@mail.tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China)

2016-04-26

The present work integrates 3D digital optical microscopy (OM), nano-indentation, X-ray diffraction (XRD), scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) to systematically investigate the effect of electropulsing on the surface mechanical properties and microstructure of AISI 304 stainless steel during the ultrasonic surface rolling process (USRP). Compared with the original USRP, the introduction of electropulsing with optimal parameters can effectively facilitate surface crack healing and improve surface hardness and wear resistance dramatically, and the residual compressive stress is further enhanced. Meanwhile, more martensite phase and fewer deformation twins can be found in the strengthened layer. Rapid improvement of the surface mechanical properties should be attributed to the ultra-refined grains, accelerated martensitic phase transformation and suppressed deformation twining induced by the coupling effect of USRP and electropulsing. The high strain rate given by USRP, increased stacking fault energy and accelerated dislocation mobility caused by electropulsing are likely the primary intrinsic reasons for the observed phenomena.

Effect on stress-strain relations brought by surface carburization of 316 stainless steel

International Nuclear Information System (INIS)

Matsumoto, K.

1977-01-01

The effect of sodium. environment on austenitic stainless steels used as structural materials in Liquid Metal Cooled Fast Breeder Reactors (LMFBRs) has long been the subject of extensive studies in many countries. Recent developments tending toward stricter control of the oxygen content permitted to be present in the circulating sodium have come to allay the apprehensions formerly held on the possibility of general corrosion affecting the mechanical properties of structural materials expected to be used In LMFBR plants. Grain boundary corrosion and depletion of elements from the structure surface also have come to be considered to provide little cause of fear in this regard, though some uncertainty is still left concerning the influence that these phenomena might exert toward the end of plant life. What still remains essentially to be clarified relates to carbon mass transfer. Decarburization and/or carburization are phenomena that cannot be disregarded even in the primary heat transfer system of LMFBRs, on account of the temperature dependence of carbon activity in steels, which could cause the carbon to leak out from structural material into the circulating sodium in the higher temperature zones of a circuit, to deposit itself on the channel walls in the lower temperature parts. Recent reports on loop experiments point toward the possibility of carboneous matter leaching into flowing sodium and into the cover gas to produce significant carburization phenomena. Carburization, in particular, can bring about loss of ductility and deterioration of fatigue properties, and hence serious consideration of this aspect is called for in the design of components incorporating thin stainless steel plates. To represent the stress-strain behavior at 550 deg. C of 316 stainless steel affected by surface carburization, an empirical formula was adopted. It was proposed by Voce for relating true stress to true plastic strain: σ = Aexp(C ε p ) + B, where σ is the true stress, and

Immobilization of mesoporous silica particles on stainless steel plates

International Nuclear Information System (INIS)

Pasqua, Luigi; Morra, Marco

2017-01-01

A preliminary study aimed to the nano-engineering of stainless steel surface is presented. Aminopropyl-functionalized mesoporous silica is covalently and electrostatically anchored on the surface of stainless steel plates. The anchoring is carried out through the use of a nanometric spacer, and two different spacers are proposed (both below 2 nm in size). The first sample is obtained by anchoring to the stainless steel amino functionalized, a glutaryl dichloride spacer. This specie forms an amide linkage with the amino group while the unreacted acyl groups undergo hydrolysis giving a free carboxylic group. The so-obtained functionalized stainless steel plate is used as substrate for anchoring derivatized mesoporous silica particles. The second sample is prepared using 2-bromo-methyl propionic acid as spacer (BMPA). Successively, the carboxylic group of propionic acid is condensed to the aminopropyl derivatization on the external surface of the mesoporous silica particle through covalent bond. In both cases, a continuous deposition (coating thickness is around 10 μm) is obtained, in fact, XPS data do not reveal the metal elements constituting the plate. The nano-engineering of metal surfaces can represent an intriguing opportunity for producing long-term drug release or biomimetic surface.

Immobilization of mesoporous silica particles on stainless steel plates

Energy Technology Data Exchange (ETDEWEB)

Pasqua, Luigi, E-mail: luigi.pasqua@unical.it [University of Calabria, Department of Environmental and Chemical Engineering (Italy); Morra, Marco, E-mail: mmorra@nobilbio.com [Via Valcastellana 26 (Italy)

2017-03-15

A preliminary study aimed to the nano-engineering of stainless steel surface is presented. Aminopropyl-functionalized mesoporous silica is covalently and electrostatically anchored on the surface of stainless steel plates. The anchoring is carried out through the use of a nanometric spacer, and two different spacers are proposed (both below 2 nm in size). The first sample is obtained by anchoring to the stainless steel amino functionalized, a glutaryl dichloride spacer. This specie forms an amide linkage with the amino group while the unreacted acyl groups undergo hydrolysis giving a free carboxylic group. The so-obtained functionalized stainless steel plate is used as substrate for anchoring derivatized mesoporous silica particles. The second sample is prepared using 2-bromo-methyl propionic acid as spacer (BMPA). Successively, the carboxylic group of propionic acid is condensed to the aminopropyl derivatization on the external surface of the mesoporous silica particle through covalent bond. In both cases, a continuous deposition (coating thickness is around 10 μm) is obtained, in fact, XPS data do not reveal the metal elements constituting the plate. The nano-engineering of metal surfaces can represent an intriguing opportunity for producing long-term drug release or biomimetic surface.

Analysis of full and cross-shaped boss membranes with piezoresistors in transversal strain configuration

International Nuclear Information System (INIS)

Tibrewala, A; Phataralaoha, A; Büttgenbach, S

2008-01-01

A 3D force sensor is developed using bulk silicon micromachining for measuring force in the sub-μN range. It is intended for use in high precision coordinate measuring machines. Full and cross-shaped boss membranes are fabricated, where the total chip size is 6.5 × 6.5 mm 2 . The full membrane is 3000 × 3000 µm 2 and the beams of the cross-shaped membrane are 900 × 700 µm 2 with 16 p-diffused piezoresistors in transversal strain configuration. The strains detected by the piezoresistors are measures of the three orthogonal components of the force applied at the tip of the stylus, which is glued on the center of the boss. When a vertical load is applied to the stylus, higher sensitivity is obtained for the cross-shaped membrane than for the full membrane

In vitro biocompatibility of plasma-aided surface-modified 316L stainless steel for intracoronary stents

International Nuclear Information System (INIS)

Bayram, Cem; Denkbas, Emir Baki; Mizrak, Alpay Koray; Aktuerk, Selcuk; Kursaklioglu, Hurkan; Iyisoy, Atila; Ifran, Ahmet

2010-01-01

316L-type stainless steel is a raw material mostly used for manufacturing metallic coronary stents. The purpose of this study was to examine the chemical, wettability, cytotoxic and haemocompatibility properties of 316L stainless steel stents which were modified by plasma polymerization. Six different polymeric compounds, polyethylene glycol, 2-hydroxyethyl methacrylate, ethylenediamine, acrylic acid, hexamethyldisilane and hexamethyldisiloxane, were used in a radio frequency glow discharge plasma polymerization system. As a model antiproliferative drug, mitomycin-C was chosen for covalent coupling onto the stent surface. Modified SS 316L stents were characterized by water contact angle measurements (goniometer) and x-ray photoelectron spectroscopy. C1s binding energies showed a good correlation with the literature. Haemocompatibility tests of coated SS 316L stents showed significant latency (t-test, p < 0.05) with respect to SS 316L and control groups in each test.

Improvement of pitting corrosion resistance of AISI 304L stainless steel by nano-pulsed laser surface melting

International Nuclear Information System (INIS)

Pacquentin, W.; Blanc, C.; Caron, N.; Thro, P.Y.; Cheniere, A.; Tabarant, M.; Moutiers, G.; Miserque, F.; Plouzennec, H.; Oltra, R.

2013-01-01

The stainless steel 304L is widely used, however, in particular conditions, it may be sensitive to pitting corrosion. Nano-pulsed laser surface melting is a surface treatment which allows improving the corrosion resistance of this steel. This treatment consists in focusing a laser beam on the surface of the material, involving its quite immediately melting through a few microns depth, then an ultra-fast solidification occurs with cooling rate about 1011 K/s. The laser parameters control the modifications of the physico-chemical properties. In particular, we studied the influence of the impacts overlap of an ytterbium laser-fiber on the corrosion resistance of a 304L stainless steel in conditions of an aerated and agitated solution of NaCl (concentration of 30 g/L). We obtained an increase of the pitting potential of 220 mV, highlighting an improvement of the corrosion resistance. The study of the chemical and structural modifications is not enough to explain the improvement of the corrosion resistance. Other phenomena must be taken into account, as the quality of the oxide layer, in terms of physico-chemical and mechanical properties. (authors)

CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES

International Nuclear Information System (INIS)

Coupon, Jean; Umetsu, Keiichi; Broadhurst, Tom

2013-01-01

We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M 200 ∼ 1.4-1.8 × 10 14 M ☉ for the optically detected cluster samples, and M 200 ∼ 5.0 × 10 14 M ☉ for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration

Investigation of the physical parameters of duplex stainless steel (DSS surface integrity after turning

Directory of Open Access Journals (Sweden)

G. Krolczyk

2015-01-01

Full Text Available The article presents the influence of machining parameters on the microhardness of surface integrity (SI after turning by means of a coated sintered carbide wedge with a coating with ceramic intermediate layer. The investigation comprised the influence of cutting speed on the SI microhardness in dry machining. The material under investigation was duplex stainless steel with two-phase ferritic-austenitic structure. The results obtained allow for conclusions concerning the exploitation features of processed machine parts.

The role of molybdenum in corrosion resistance of stainless steel

International Nuclear Information System (INIS)

Abdul Razak bin Daud

1989-01-01

The effect of Mo on corrosion properties of stainless steels in 1M MgCl 2 solution was studied using an electrochemical polarization method. Procedure for the preparation of electrochemically polarized samples for surface analysis is described. The samples surface were analyzed using X-ray Photoelectron Spectroscopy (XPS). The stainless steel which has high Mo content has a better resistance to corrosion in Cl containing media. Cr and Mo are enriched in the surface of Mo-bearing stainless steels which have undergone high anodic-metal dissolution. Mo may exist as MoO 2 which is responsible in slowing down the rate of corrosion attack. (author)

SCC of 2304 Duplex Stainless Steel-Microstructure, Residual Stress and Surface Grinding Effects.

Science.gov (United States)

Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

2017-02-23

The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

Directory of Open Access Journals (Sweden)

Nian Zhou

2017-02-01

Full Text Available The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

Science.gov (United States)

Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

2017-01-01

The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental. PMID:28772582

Food-safe modification of stainless steel food processing surfaces to reduce bacterial biofilms.

Science.gov (United States)

Awad, Tarek Samir; Asker, Dalal; Hatton, Benjamin D

2018-06-11

Biofilm formation on stainless steel (SS) surfaces of food processing plants, leading to foodborne illness outbreaks, is enabled by the attachment and confinement within microscale cavities of surface roughness (grooves, scratches). We report Foodsafe Oil-based Slippery Coatings (FOSCs) for food processing surfaces that suppress bacterial adherence and biofilm formation by trapping residual oil lubricant within these surface cavities to block microbial growth. SS surfaces were chemically functionalized with alkylphosphonic acid to preferentially wet a layer of food grade oil. FOSCs reduced the effective surface roughness, the adhesion of organic food residue, and bacteria. FOSCs significantly reduced Pseudomonas aeruginosa biofilm formation on standard roughness SS-316 by 5 log CFU cm-2, and by 3 log CFU cm-2 for mirror-finished SS. FOSCs also enhanced surface cleanability, which we measured by bacterial counts after conventional detergent cleaning. Importantly, both SS grades maintained their anti-biofilm activity after erosion of the oil layer by surface wear with glass beads, which suggests there is a residual volume of oil that remains to block surface cavity defects. These results indicate the potential of such low-cost, scalable approaches to enhance the cleanability of SS food processing surfaces and improve food safety by reducing biofilm growth.

Modeling and Simulated Annealing Optimization of Surface Roughness in CO2 Laser Nitrogen Cutting of Stainless Steel

OpenAIRE

M. Madić; M. Radovanović; B. Nedić

2013-01-01

This paper presents a systematic methodology for empirical modeling and optimization of surface roughness in nitrogen, CO2 laser cutting of stainless steel . The surface roughness prediction model was developed in terms of laser power , cutting speed , assist gas pressure and focus position by using The artificial neural network ( ANN ) . To cover a wider range of laser cutting parameters and obtain an experimental database for the ANN model development, Taguchi 's L27 orthogonal array was im...

Permeability Study of Austenitic Stainless Steel Surfaces Produced by Selective Laser Melting

Directory of Open Access Journals (Sweden)

Emmanuel Segura-Cardenas

2017-11-01

Full Text Available Selective laser melting (SLM is emerging as a versatile process for fabricating different metal components with acceptable mechanical properties and geometrical accuracy. The process has been used in the manufacturing of several parts (e.g., aerospace or biomedical components, and offers the capability to tailor the performance of several surface and mechanical properties. In this work, permeability properties and surface roughness of stainless steel (SS316L surfaces were evaluated through experimentation with three different laser scanning patterns (chessboard, meander, and stripe, and different sloping angles between the fabricated surface and the laser beam incident on the process. Results showed that for each scanning pattern, the roughness decreased as the sloping angle increased consistently in all experimental trials. Furthermore, in the case of the permeability evaluation, the manufactured surfaces showed changes in properties for each series of experiments performed with different scanning patterns. The chessboard pattern showed a change of 67° to 107° in contact angle, while the meander and stripe patterns showed a variation in contact angle in a range of 65° to 85°. The different scanning strategies in the SLM process resulted in an alternative method for surface enhancement with different hydrophobicity properties, valuable for designing the most appropriate permeability characteristics for specific applications.

Special Advanced Studies for Pollution Prevention. Delivery Order 0017: Sol-Gel Surface Preparation for Carbon Steel and Stainless Steel Bonding

National Research Council Canada - National Science Library

Zheng, Haixing

1997-01-01

The objective of this program is to study the feasibility of using sol-gel active alumina coatings for the surface preparation of carbon steel and stainless steel for adhesive bonding, and to optimize...

Failure of Cleaning Verification in Pharmaceutical Industry Due to Uncleanliness of Stainless Steel Surface.

Science.gov (United States)

Haidar Ahmad, Imad A; Blasko, Andrei

2017-08-11

The aim of this work is to identify the parameters that affect the recovery of pharmaceutical residues from the surface of stainless steel coupons. A series of factors were assessed, including drug product spike levels, spiking procedure, drug-excipient ratios, analyst-to-analyst variability, intraday variability, and cleaning procedure of the coupons. The lack of a well-defined procedure that consistently cleaned the coupon surface was identified as the major contributor to low and variable recoveries. Assessment of cleaning the surface of the coupons with clean-in-place solutions (CIP) gave high recovery (>90%) and reproducible results (Srel≤4%) regardless of the conditions that were assessed previously. The approach was successfully applied for cleaning verification of small molecules (MW <1,000 Da) as well as large biomolecules (MW up to 50,000 Da).

Local electrical properties of thermally grown oxide films formed on duplex stainless steel surfaces

Science.gov (United States)

Guo, L. Q.; Yang, B. J.; He, J. Y.; Qiao, L. J.

2018-06-01

The local electrical properties of thermally grown oxide films formed on ferrite and austenite surfaces of duplex stainless steel at different temperatures were investigated by Current sensing atomic force microscopy, X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The current maps and XPS/AES analyses show that the oxide films covering austenite and ferrite surfaces formed at different temperatures exhibit different local electrical characteristics, thickness and composition. The dependence of electrical conductivity of oxide films covering austenite and ferrite surface on the formation temperature is attributed to the film thickness and semiconducting structures, which is intrinsically related to thermodynamics and kinetics process of film grown at different temperature. This is well elucidated by corresponding semiconductor band structures of oxide films formed on austenite and ferrite phases at different temperature.

SURFACE FINISHES ON STAINLESS STEEL REDUCE BACTERIAL ATTACHMENT AND EARLY BIOFILM FORMATION: SCANNING ELECTRON AND ATOMIC FORCE MICROSCOPY STUDY

Science.gov (United States)

Three common finishing treatments of stainless steel that are used for equipment during poultry processing were tested for resistance to bacterial contamination. Methods were developed to measure attached bacteria and to identify factors that make surface finishes susceptible or ...

Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part.

Science.gov (United States)

Ahmed, Yassmin Seid; Fox-Rabinovich, German; Paiva, Jose Mario; Wagg, Terry; Veldhuis, Stephen Clarence

2017-10-25

During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool-chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear.

Intergranular Corrosion of 316L Stainless Steel by Aging and UNSM (Ultrasonic Nano-crystal Surface Modification) treatment

International Nuclear Information System (INIS)

Lee, J. H.; Kim, Y. S.

2015-01-01

Austenitic stainless steels have been widely used in many engineering fields because of their high corrosion resistance and good mechanical properties. However, welding or aging treatment may induce intergranular corrosion, stress corrosion cracking, pitting, etc. Since these types of corrosion are closely related to the formation of chromium carbide in grain boundaries, the alloys are controlled using methods such as lowering the carbon content, solution heat treatment, alloying of stabilization elements, and grain boundary engineering. This work focused on the effects of aging and UNSM (Ultrasonic Nano-crystal Surface Modification) on the intergranular corrosion of commercial 316L stainless steel and the results are discussed on the basis of the sensitization by chromium carbide formation and carbon segregation, residual stress, grain refinement, and grain boundary engineering

Influence of surface treatments on corrosion resistance of stainless steels. Residual stresses in metals

International Nuclear Information System (INIS)

Berge, J. Philippe

1968-05-01

In a first part, this research thesis proposes presentation of the definition of a surface condition: chemical characteristics such as passivity and contamination, physical characteristics (obtained through micrographic methods, X ray diffusion, magnetic methods), and micro-geometrical characteristics. The author notably discusses the measurement of characteristics either by appropriate conventional methods or by an original method in the case of passivity. In a second part, the author reports the study of the influence of surface condition on different types of corrosion of stainless steels in chemical environments (corrosion in sulphuric acid, intergranular corrosion, stress corrosion cracking in magnesium chloride, pitting corrosion) and of high temperature oxidation (corrosion in pressurized water, oxidation in dry vapour or in carbon dioxide)

Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

Science.gov (United States)

Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

2018-03-01

In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

Fitting methods for baryon acoustic oscillations in the Lyman-α forest fluctuations in BOSS data release 9

Energy Technology Data Exchange (ETDEWEB)

Kirkby, David; Margala, Daniel; Blomqvist, Michael [Department of Physics and Astronomy, University of California, Irvine, 92697 (United States); Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton NY 11375 (United States); Bailey, Stephen; Carithers, Bill [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Busca, Nicolás G.; Bautista, Julian E. [APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France); Delubac, Timothée; Rich, James; Palanque-Delabrouille, Nathalie [CEA, Centre de Saclay, IRFU, F-91191 Gif-sur-Yvette (France); Brownstein, Joel R.; Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Croft, Rupert A.C. [Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Miralda-Escudé, Jordi [Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia (Spain); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Pâris, Isabelle; Petitjean, Patrick, E-mail: dkirkby@uci.edu [Université Paris 6 et CNRS, Institut d' Astrophysique de Paris, 98bis blvd. Arago, 75014 Paris (France); and others

2013-03-01

We describe fitting methods developed to analyze fluctuations in the Lyman-α forest and measure the parameters of baryon acoustic oscillations (BAO). We apply our methods to BOSS Data Release 9. Our method is based on models of the three-dimensional correlation function in physical coordinate space, and includes the effects of redshift-space distortions, anisotropic non-linear broadening, and broadband distortions. We allow for independent scale factors along and perpendicular to the line of sight to minimize the dependence on our assumed fiducial cosmology and to obtain separate measurements of the BAO angular and relative velocity scales. Our fitting software and the input files needed to reproduce our main BOSS Data Release 9 results are publicly available.

The effect of machining parameters on surface roughness during turning of stainless steel

International Nuclear Information System (INIS)

El-Belazi, Khalid M.

1991-03-01

Surface roughness is a direct consequence of the cutting tool action, its assessment and control represent an effective way by which the machining process can be studied. The control of surface roughness has become increasingly important during the last thirty years, because the quality of surface is extremely important for machined components that have been designed to stand to static and cyclic loads. This work has two major goals. The first is to develop a new theoretical model based on the assumption that the shape of the cutting tool nose is elliptical to evaluate the surface roughness parameters. The second is to investigate the effect of cutting speed, feed rate, overhang length, tool nose radius (circular sharp), and depth of cut on surface roughness of turned surfaces of austenitic stainless steel grade 12X18H10T. It was found from the theoretical part that the surface roughness values obtained from the elliptical model are much better than those obtained from the other models. It was found from the experimental work that the surface roughness values increase by increasing cutting speed, feed rate, depth of cut, and overhang length, and fluctuates when using cutting tools with various nose radii, during turning of the above mentioned steel by using a brazed carbide cutting tool. (author)

CASE-HARDENING OF STAINLESS STEEL

DEFF Research Database (Denmark)

2004-01-01

The invention relates to case-hardening of a stainless steel article by means of gas including carbon and/or nitrogen, whereby carbon and/or nitrogen atoms diffuse through the surface into the article. The method includes activating the surface of the article, applying a top layer on the activated...

Chemical decontaminating method for stainless steel

International Nuclear Information System (INIS)

Onuma, Tsutomu; Akimoto, Hidetoshi.

1990-01-01

Radioactive metal wastes comprising passivated stainless steels are chemically decontaminated to such a radioactivity level as that of usual wastes. The present invention for chemically decontaminating stainless steels comprises a first step of immersing decontaminates into a sulfuric acid solution and a second step of immersing them into an aqueous solution prepared by adding oxidative metal salts to sulfuric acid, in which a portion of the surface of stainless steels as decontaminates are chemically ground to partially expose substrate materials and then the above-mentioned decontamination steps are applied. More than 90% of radioactive materials are removed in this method by the dissolution of the exposed substrate materials and peeling of cruds secured to the surface of the materials upon dissolution. This method is applicable to decontamination of articles having complicate shapes, can reduce the amount of secondary wastes after decontamination and also remarkably shorten the time required for decontamination. (T.M.)

Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic Stainless Steel by Gaseous Nitriding

DEFF Research Database (Denmark)

Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

2015-01-01

This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of two commercial austenitic stainless steels: AISI 304 and EN 1.4369. The materials were plastically deformed to different equivalent strains by uniaxial...... demonstrate that a case of expanded austenite develops and that, in particular, strain-induced martensite has a large influence on the nitrided zone....

Effect on stress-strain relations brought by surface carburization of 316 stainless steel

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, K [Ishikawajima-Harima Heavy Industries, Tokyo (Japan)

1977-07-01

The effect of sodium. environment on austenitic stainless steels used as structural materials in Liquid Metal Cooled Fast Breeder Reactors (LMFBRs) has long been the subject of extensive studies in many countries. Recent developments tending toward stricter control of the oxygen content permitted to be present in the circulating sodium have come to allay the apprehensions formerly held on the possibility of general corrosion affecting the mechanical properties of structural materials expected to be used In LMFBR plants. Grain boundary corrosion and depletion of elements from the structure surface also have come to be considered to provide little cause of fear in this regard, though some uncertainty is still left concerning the influence that these phenomena might exert toward the end of plant life. What still remains essentially to be clarified relates to carbon mass transfer. Decarburization and/or carburization are phenomena that cannot be disregarded even in the primary heat transfer system of LMFBRs, on account of the temperature dependence of carbon activity in steels, which could cause the carbon to leak out from structural material into the circulating sodium in the higher temperature zones of a circuit, to deposit itself on the channel walls in the lower temperature parts. Recent reports on loop experiments point toward the possibility of carboneous matter leaching into flowing sodium and into the cover gas to produce significant carburization phenomena. Carburization, in particular, can bring about loss of ductility and deterioration of fatigue properties, and hence serious consideration of this aspect is called for in the design of components incorporating thin stainless steel plates. To represent the stress-strain behavior at 550 deg. C of 316 stainless steel affected by surface carburization, an empirical formula was adopted. It was proposed by Voce for relating true stress to true plastic strain: {sigma} = Aexp(C {epsilon}{sub p} ) + B, where {sigma

Tool degradation during sheet metal forming of three stainless steel alloys

DEFF Research Database (Denmark)

Wadman, Boel; Nielsen, Peter Søe; Wiklund, Daniel

2010-01-01

To evaluate if changes in tool design and tool surface preparation are needed when low-Ni stainless steels are used instead of austenitic stainless steels, the effect on tool degradation in the form of galling was investigated with three different types of stainless steel. The resistance to tool ...

Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

Science.gov (United States)

Nassisi, Vincenzo; Delle Side, Domenico; Turco, Vito; Martina, Luigi

2018-01-01

In this work, we study surface modifications of AISI 420 stainless steel specimens in order to improve their surface properties. Oxidation resistance and surface micro-hardness were analyzed. Using an ion beam delivered by a Laser Ion Source (LIS) coupled to an electrostatic accelerator, we performed implantation of low energy yttrium ions on the samples. The ions experienced an acceleration passing through a gap whose ends had a potential difference of 60 kV. The gap was placed immediately before the samples surface. The LIS produced high ions fluxes per laser pulse, up to 3x1011 ions/cm2, resulting in a total implanted flux of 7x1015 ions/cm2. The samples were characterized before and after ion implantation using two analytical techniques. They were also thermally treated to investigate the oxide scale. The crystal phases were identified by an X-ray diffractometer, while the micro-hardness was assayed using the scratch test and a profilometer. The first analysis was applied to blank, implanted and thermally treated sample surface, while the latter was applied only to blank and implanted sample surfaces. We found a slight increase in the hardness values and an increase to oxygen resistance. The implantation technique we used has the advantages, with respect to conventional methods, to modify the samples at low temperature avoiding stray diffusion of ions inside the substrate bulk.

Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

Directory of Open Access Journals (Sweden)

Nassisi Vincenzo

2018-01-01

Full Text Available In this work, we study surface modifications of AISI 420 stainless steel specimens in order to improve their surface properties. Oxidation resistance and surface micro-hardness were analyzed. Using an ion beam delivered by a Laser Ion Source (LIS coupled to an electrostatic accelerator, we performed implantation of low energy yttrium ions on the samples. The ions experienced an acceleration passing through a gap whose ends had a potential difference of 60 kV. The gap was placed immediately before the samples surface. The LIS produced high ions fluxes per laser pulse, up to 3x1011 ions/cm2, resulting in a total implanted flux of 7x1015 ions/cm2. The samples were characterized before and after ion implantation using two analytical techniques. They were also thermally treated to investigate the oxide scale. The crystal phases were identified by an X-ray diffractometer, while the micro-hardness was assayed using the scratch test and a profilometer. The first analysis was applied to blank, implanted and thermally treated sample surface, while the latter was applied only to blank and implanted sample surfaces. We found a slight increase in the hardness values and an increase to oxygen resistance. The implantation technique we used has the advantages, with respect to conventional methods, to modify the samples at low temperature avoiding stray diffusion of ions inside the substrate bulk.

Effect of oil around the pin boss bearing on bearing friction force; Piston pin jikuukebu kinbo no junkatsuyu ga masatsuryoku ni oyobosu eikyo

Energy Technology Data Exchange (ETDEWEB)

Takiguchi, M; Suhara, T; Ato, S; Someya, T [Musashi Institute of Technology, Tokyo (Japan)

1997-10-01

Piston pin bearings are engine parts placed under severe lubricating condition because of the high unit load and temperature and the low sliding speeds. Therefore, they are vulnerable to many lubrication problems such as abnormal wear, scuffs and seizures. In our recent study, the bearing friction were measured using a original measuring device and it was found out that the lubricating conditions of piston pin boss bearings are non-fluid lubrication due to the oil starvation. In this study, we have also measured the lubricating oil behavior around the pin boss bearing using a special cylinder with glass window, and analyzed the relationship between the friction force and the oil behavior at the pin boss bearings in a actual operating gasoline engine. 2 refs., 9 figs., 1 tab.

Angle-dependent lubricated tribological properties of stainless steel by femtosecond laser surface texturing

Science.gov (United States)

Wang, Zhuo; Li, Yang-Bo; Bai, Feng; Wang, Cheng-Wei; Zhao, Quan-Zhong

2016-07-01

Lubricated tribological properties of stainless steel were investigated by femtosecond laser surface texturing. Regular-arranged micro-grooved textures with different spacing and micro-groove inclination angles (between micro-groove path and sliding direction) were produced on AISI 304L steel surfaces by an 800 nm femtosecond laser. The spacing of micro-groove was varied from 25 to 300 μm, and the inclination angles of micro-groove were measured as 90° and 45°. The tribological properties of the smooth and textured surfaces with micro-grooves were investigated by reciprocating ball-on-flat tests against Al2O3 ceramic balls under starved oil lubricated conditions. Results showed that the spacing of micro-grooves significantly affected the tribological property. With the increase of micro-groove spacing, the average friction coefficients and wear rates of textured surfaces initially decreased then increased. The tribological performance also depended on the inclination angles of micro-grooves. Among the investigated patterns, the micro-grooves perpendicular to the sliding direction exhibited the lowest average friction coefficient and wear rate to a certain extent. Femtosecond laser-induced surface texturing may remarkably improve friction and wear properties if the micro-grooves were properly distributed.

Ion-nitriding of austenitic stainless steels

International Nuclear Information System (INIS)

Pacheco, O.; Hertz, D.; Lebrun, J.P.; Michel, H.

1995-01-01

Although ion-nitriding is an extensively industrialized process enabling steel surfaces to be hardened by nitrogen diffusion, with a resulting increase in wear, seizure and fatigue resistance, its direct application to stainless steels, while enhancing their mechanical properties, also causes a marked degradation in their oxidation resistance. However, by adaption of the nitriding process, it is possible to maintain the improved wear resistant properties while retaining the oxidation resistance of the stainless steel. The controlled diffusion permits the growth of a nitrogen supersaturated austenite layer on parts made of stainless steel (AISI 304L and 316L) without chromium nitride precipitation. The diffusion layer remains stable during post heat treatments up to 650 F for 5,000 hrs and maintains a hardness of 900 HV. A very low and stable friction coefficient is achieved which provides good wear resistance against stainless steels under diverse conditions. Electrochemical and chemical tests in various media confirm the preservation of the stainless steel characteristics. An example of the application of this process is the treatment of Reactor Control Rod Cluster Assemblies (RCCAs) for Pressurized Water Nuclear Reactors

Surface integrity and part accuracy in reaming and tapping stainless steel with new vegetable based cutting oils

DEFF Research Database (Denmark)

Belluco, Walter; De Chiffre, Leonardo

2002-01-01

This paper presents an investigation on the effect of new formulations of vegetable oils on surface integrity and part accuracy in reaming and tapping operations with AISI 316L stainless steel. Surface integrity was assessed with measurements of roughness, microhardness, and using metallographic...... as part accuracy. Cutting fluids based on vegetable oils showed comparable or better performance than mineral oils. ÆÉ2002 Published by Elsevier Science Ltd....... techniques, while part accuracy was measured on a coordinate measuring machine. A widely diffused commercial mineral oil was used as reference for all measurements. Cutting fluid was found to have a significant effect on surface integrity and thickness of the strain hardened layer in the sub-surface, as well...

Influence of cutting data on surface quality when machining 17-4 PH stainless steel

Science.gov (United States)

Popovici, T. D.; Dijmărescu, M. R.

2017-08-01

The aim of the research presented in this paper is to analyse the cutting data influence upon surface quality for 17-4 PH stainless steel milling machining. The cutting regime parameters considered for the experiments were established using cutting regimes from experimental researches or from industrial conditions as basis, within the recommended ranges. The experimental program structure was determined by taking into account compatibility and orthogonality conditions, minimal use of material and labour. The machined surface roughness was determined by measuring the Ra roughness parameter, followed by surface profile registration in the form of graphics which were saved on a computer with MarSurf PS1Explorer software. Based on Ra roughness parameter, maximum values were extracted from these graphics and the influence charts of the cutting regime parameters upon surface roughness were traced using Microsoft Excel software. After a thorough analysis of the resulting data, relevant conclusions were drawn, presenting the interdependence between the surface roughness of the machined 17-4 PH samples and the cutting data variation.

Study of wettability and cell viability of H implanted stainless steel

Science.gov (United States)

Shafique, Muhammad Ahsan; Ahmad, Riaz; Rehman, Ihtesham Ur

2018-03-01

In the present work, the effect of hydrogen ion implantation on surface wettability and biocompatibility of stainless steel is investigated. Hydrogen ions are implanted in the near-surface of stainless steel to facilitate hydrogen bonding at different doses with constant energy of 500 KeV, which consequently improve the surface wettability. Treated and untreated sample are characterized for surface wettability, incubation of hydroxyapatite and cell viability. Contact angle (CA) study reveals that surface wettability increases with increasing H-ion dose. Raman spectroscopy shows that precipitation of hydroxyapatite over the surface increase with increasing dose of H-ions. Cell viability study using MTT assay describes improved cell viability in treated samples as compared to the untreated sample. It is found that low dose of H-ions is more effective for cell proliferation and the cell count decreases with increasing ion dose. Our study demonstrates that H ion implantation improves the surface wettability and biocompatibility of stainless steel.

Influence of surface treatment on the crevice corrosion of super duplex stainless steel

International Nuclear Information System (INIS)

Malik, H.

1997-01-01

The aim of this work was to try and discover if changes i surface condition, derived through various methods could influence the resistance to crevice corrosion of super duplex stainless teel (SDS). Such data could then be employed to elucidate the main factors controlling crevice corrosion. Through the manipulation of these parameters it was envisaged that the crevice corrosion temperature of this material may be further advanced and to increase its application within harsher industrial environments. For this reason a series of crevice tests were performed on SDSS heat exchanger tubing both in the as received condition and after various surface treatments. Such modification was carried out by; shot blasting, passivation, pickling and combinations of annealing, shot blasting, pickling and passivation. Results have indicated that the main factor controlling the resistance to crevice corrosion is the level of Cr depletion within a few microns of the steel surface. Although various treatments such as shot blasting and pickling reduce Cr depletion by removal of surface material, the nature of the surface finish itself was not found to affect the corrosion resistance. An increase in Cr content from 20 to 25% within 2 microns of the surface of the tubing was able to increase the crevice corrosion temperature by 20 sub deg. C. (author)

Thermal fatigue of austenitic stainless steel: influence of surface conditions through a multi-scale approach

International Nuclear Information System (INIS)

Le-Pecheur, Anne

2008-01-01

Some cases of cracking of 304L austenitic stainless steel components due to thermal fatigue were encountered in particular on the Residual Heat Removal Circuits (RHR) of the Pressurized Water Reactor (PWR). EDF has initiated a R and D program to understand assess the risks of damage on nuclear plant mixing zones. The INTHERPOL test developed at EDF is designed in order to perform pure thermal fatigue test on tubular specimen under mono-frequency thermal load. These tests are carried out under various loadings, surface finish qualities and welding in order to give an account of these parameters on crack initiation. The main topic of this study is the research of a fatigue criterion using a micro:macro modelling approach. The first part of work deals with material characterization (stainless steel 304L) emphasising the specificities of the surface roughness link with a strong hardening gradient. The first results of the characterization on the surface show a strong work-hardening gradient on a 250 microns layer. This gradient does not evolved after thermal cycling. Micro hardness measurements and TEM observations were intensively used to characterize this gradient. The second part is the macroscopic modelling of INTHERPOL tests in order to determine the components of the stress and strain tensors due to thermal cycling. The third part of work is thus to evaluate the effect of surface roughness and hardening gradient using a calculation on a finer scale. This simulation is based on the variation of dislocation density. A goal for the future is the determination of the fatigue criterion mainly based on polycrystalline modelling. Stocked energy or critical plane being available that allows making a sound choice for the criteria. (author)

The New Age of Bullying and Violence in Health Care: Part 3: Managing the Bullying Boss and Leadership.

Science.gov (United States)

Fink-Samnick, Ellen

PRIMARY PRACTICE SETTING(S):: Applicable to all health care sections where case management is practiced. This article is the third of a 4-part series on the topic of bullying in the health care workplace. Part 3 addresses the dimensions of the bullying boss and leadership, posing major implications for patient safety plus the mental health of staff members. The complex constructs and dynamics broached by the bullying boss and department leadership are explored. These include the underlying forces at play such as power, gender, leadership styles, plus weaves in assessment models. Strategic and proactive management of bullying by leadership is vital to workforce retention and well-being. The increasing incidence and impact of bullying across all sectors have made it a major workforce performance management challenge. Health care settings are especially tense environments, often making it difficult for individuals to distinguish between bullying behavior and high expectations for staff. Bullying impacts both direct targets and bystanders who witness the assaultive behaviors, with ethical implications as well.Case management is poised to promote a safe health care workplace for patients and practitioners alike amid these intricate circumstances. Understanding types of bullying bosses and leadership styles is integral to a case manager's success in the workplace.

Laser cladding of stainless steel with a copper-silver alloy to generate surfaces of high antimicrobial activity

Science.gov (United States)

Hans, Michael; Támara, Juan Carlos; Mathews, Salima; Bax, Benjamin; Hegetschweiler, Andreas; Kautenburger, Ralf; Solioz, Marc; Mücklich, Frank

2014-11-01

Copper and silver are used as antimicrobial agents in the healthcare sector in an effort to curb infections caused by bacteria resistant to multiple antibiotics. While the bactericidal potential of copper and silver alone are well documented, not much is known about the antimicrobial properties of copper-silver alloys. This study focuses on the antibacterial activity and material aspects of a copper-silver model alloy with 10 wt% Ag. The alloy was generated as a coating with controlled intermixing of copper and silver on stainless steel by a laser cladding process. The microstructure of the clad was found to be two-phased and in thermal equilibrium with minor Cu2O inclusions. Ion release and killing of Escherichia coli under wet conditions were assessed with the alloy, pure silver, pure copper and stainless steel. It was found that the copper-silver alloy, compared to the pure elements, exhibited enhanced killing of E. coli, which correlated with an up to 28-fold increased release of copper ions. The results show that laser cladding with copper and silver allows the generation of surfaces with enhanced antimicrobial properties. The process is particularly attractive since it can be applied to existing surfaces.

Influence of plastic deformation on low temperature surface hardening of stainless steel by gaseous nitriding

DEFF Research Database (Denmark)

Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

2015-01-01

This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were...... analysis, reflected light microscopy and microhardness indentation. The results demonstrate that a case of expanded austenite develops and that, in particular, the presence of strain-induced martensite in the initial (deformed) microstructure has a large influence on the nitrided zone....

Electroless Plated Nanodiamond Coating for Stainless Steel Passivation

International Nuclear Information System (INIS)

Li, D.; Korinko, P.; Spencer, W.; Stein, E.

2016-01-01

Tritium gas sample bottles and manifold components require passivation surface treatments to minimize the interaction of the hydrogen isotopes with surface contamination on the stainless steel containment materials. This document summarizes the effort to evaluate electroless plated nanodiamond coatings as a passivation layer for stainless steel. In this work, we developed an electroless nanodiamond (ND)-copper (Cu) coating process to deposit ND on stainless steel parts with the diamond loadings of 0%, 25% and 50% v/v in a Cu matrix. The coated Conflat Flanged Vessel Assemblies (CFVAs) were evaluated on surface morphology, composition, ND distribution, residual hydrogen release, and surface reactivity with deuterium. For as-received Cu and ND-Cu coated CFVAs, hydrogen off-gassing is rapid, and the off-gas rates of H 2 was one to two orders of magnitude higher than that for both untreated and electropolished stainless steel CFVAs, and hydrogen and deuterium reacted to form HD as well. These results indicated that residual H 2 was entrapped in the Cu and ND-Cu coated CFVAs during the coating process, and moisture was adsorbed on the surface, and ND and/or Cu might facilitate catalytic isotope exchange reaction for HD formation. However, hydrocarbons (i.e., CH 3 ) did not form, and did not appear to be an issue for the Cu and ND-Cu coated CFVAs. After vacuum heating, residual H 2 and adsorbed H 2 O in the Cu and ND-Cu coated CFVAs were dramatically reduced. The H 2 off-gassing rate after the vacuum treatment of Cu and 50% ND-Cu coated CFVAs was on the level of 10 -14 l mbar/s cm 2 , while H 2 O off-gas rate was on the level of 10 -15 l mbar/s cm 2 , consistent with the untreated or electropolished stainless steel CFVA, but the HD formation remained. The Restek EP bottle was used as a reference for this work. The Restek Electro-Polished (EP) bottle and their SilTek coated bottles tested under a different research project exhibited very little hydrogen off-gassing and

The Otto Aufranc Award: Enhanced Biocompatibility of Stainless Steel Implants by Titanium Coating and Microarc Oxidation

Science.gov (United States)

Lim, Young Wook; Kwon, Soon Yong; Sun, Doo Hoon

2010-01-01

Background Stainless steel is one of the most widely used biomaterials for internal fixation devices, but is not used in cementless arthroplasty implants because a stable oxide layer essential for biocompatibility cannot be formed on the surface. We applied a Ti electron beam coating, to form oxide layer on the stainless steel surface. To form a thicker oxide layer, we used a microarc oxidation process on the surface of Ti coated stainless steel. Modification of the surface using Ti electron beam coating and microarc oxidation could improve the ability of stainless steel implants to osseointegrate. Questions/purposes The ability of cells to adhere to grit-blasted, titanium-coated, microarc-oxidated stainless steel in vitro was compared with that of two different types of surface modifications, machined and titanium-coated, and microarc-oxidated. Methods We performed energy-dispersive x-ray spectroscopy and scanning electron microscopy investigations to assess the chemical composition and structure of the stainless steel surfaces and cell morphology. The biologic responses of an osteoblastlike cell line (SaOS-2) were examined by measuring proliferation (cell proliferation assay), differentiation (alkaline phosphatase activity), and attraction ability (cell migration assay). Results Cell proliferation, alkaline phosphatase activity, migration, and adhesion were increased in the grit-blasted, titanium-coated, microarc-oxidated group compared to the two other groups. Osteoblastlike cells on the grit-blasted, titanium-coated, microarc-oxidated surface were strongly adhered, and proliferated well compared to those on the other surfaces. Conclusions The surface modifications we used (grit blasting, titanium coating, microarc oxidation) enhanced the biocompatibility (proliferation and migration of osteoblastlike cells) of stainless steel. Clinical Relevance This process is not unique to stainless steel; it can be applied to many metals to improve their biocompatibility

Validation of an HPLC-UV method for the determination of ceftriaxone sodium residues on stainless steel surface of pharmaceutical manufacturing equipments.

Science.gov (United States)

Akl, Magda A; Ahmed, Mona A; Ramadan, Ahmed

2011-05-15

In pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace amounts of drugs have, therefore, to be considered with special attention. An HPLC-UV method for the determination of ceftriaxone sodium residues on stainless steel surface was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with extraction solution (50% water and 50% mobile phase), were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 91.12, 93.8 and 98.7% for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD), were below 1.5%. The method was validated over a concentration range of 1.15-6.92 μg ml(-1). Low quantities of drug residues were determined by HPLC-UV using a Hypersil ODS 5 μm (250×4.6 mm) at 50 °C with an acetonitrile:water:pH 7:pH 5 (39-55-5.5-0.5) mobile phase at flow rate of 1.5 ml min(-1), an injection volume of 20 μl and were detected at 254 nm. A simple, selective and sensitive HPLC-UV assay for the determination of ceftriaxone sodium residues on stainless steel surfaces was developed, validated and applied. Copyright © 2011 Elsevier B.V. All rights reserved.

Application of lap laser welding technology on stainless steel railway vehicles

Science.gov (United States)

Wang, Hongxiao; Wang, Chunsheng; He, Guangzhong; Li, Wei; Liu, Liguo

2016-10-01

Stainless steel railway vehicles with so many advantages, such as lightweight, antirust, low cost of maintenance and simple manufacturing process, so the production of high level stainless steel railway vehicles has become the development strategy of European, American and other developed nations. The current stainless steel railway vehicles body and structure are usually assembled by resistance spot welding process. The weak points of this process are the poor surface quality and bad airtight due to the pressure of electrodes. In this study, the partial penetration lap laser welding process was investigated to resolve the problems, by controlling the laser to stop at the second plate in the appropriate penetration. The lap laser welding joint of stainless steel railway vehicle car body with partial penetration has higher strength and surface quality than those of resistance spot welding joint. The biggest problem of lap laser welding technology is to find the balance of the strength and surface quality with different penetrations. The mechanism of overlap laser welding of stainless steel, mechanical tests, microstructure analysis, the optimization of welding parameters, analysis of fatigue performance, the design of laser welding stainless steel railway vehicles structure and the development of non-destructive testing technology were systematically studied before lap laser welding process to be applied in manufacture of railway vehicles. The results of the experiments and study show that high-quality surface state and higher fatigue strength can be achieved by the partial penetration overlap laser welding of the side panel structure, and the structure strength of the car body can be higher than the requirements of En12663, the standard of structural requirements of railway vehicles bodies. Our company has produced the stainless steel subway and high way railway vehicles by using overlap laser welding technology. The application of lap laser welding will be a big

Surface modification of austenitic stainless steel by titanium ion implantation

International Nuclear Information System (INIS)

Evans, P.J.; Hyvarinen, J.; Samandi, M.

1995-01-01

The wear properties of AISI 316 austenitic stainless steel implanted with Ti were investigated for ion doses in the range (2.3-5.4)x10 16 ionscm -2 and average ion energies of 60 and 90keV. The implanted layer was examined by Rutherford backscattering, from which the retained doses were determined, and glow discharge optical emission spectroscopy. Following implantation, the surface microhardness was observed to increase with the greatest change occurring at higher ion energy. Pin-on-disc wear tests and associated friction measurements were also performed under both dry and lubricated conditions using applied loads of 2N and 10N. In the absence of lubrication, breakthrough of the implanted layer occurred after a short sliding time; only for a dose of 5.1x10 16 ionscm -2 implanted at an average energy of 90keV was the onset of breakthrough appreciably delayed. In contrast, the results of tests with lubrication showed a more gradual variation, with the extent of wear decreasing with implant dose at both 2N and 10N loads. Finally, the influence of Ti implantation on possible wear mechanisms is discussed in the light of information provided by several surface characterization techniques. ((orig.))

Cavitation erosion resistance of diamond-like carbon coating on stainless steel

Energy Technology Data Exchange (ETDEWEB)

Cheng, Feng; Jiang, Shuyun, E-mail: jiangshy@seu.edu.cn

2014-02-15

Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (−200 V/80 A, labeled DLC-1, and −100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

Identification of the mechanism that confers superhydrophobicity on 316L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Escobar, Ana M.; Llorca-Isern, Nuria; Rius-Ayra, Oriol

2016-01-15

This study develops a rapid method to confer superhydrophobicity on 316L stainless steel surfaces with an amphiphilic reagent such as dodecanoic acid. The highest contact angle (approaching 173°) was obtained after forming hierarchical structures with a non-aqueous electrolyte by an electrolytic process. Our goal was to induce superhydrophobicity directly on 316L stainless steel substrates and to establish which molecules cause the effect. The superhydrophobic behaviour is analysed by contact angle measurements, scanning electron microscopy (SEM), IR spectroscopy and atomic force microscopy (AFM). The growth mechanism is analysed using FE-SEM, TOF-SIMS and XPS in order to determine the molecules involved in the reaction and the growth. The TOF-SIMS analysis revealed that the Ni{sup 2+} ions react with lauric acid to create an ester on the stainless steel surface. - Highlights: • This study develops a rapid and facile approach to impart superhydrophobicity properties to 316L stainless steel surfaces with an amphiphilic reagent such as dodecanoic acid. Surface character changes from superhydrophilicity to superhydrophobicity. • This process changes the surface character from superhydrophilicity to superhydrophobicity. • The process based on electrolysis of a nickel salt in lauric acid provides superhydrophobic behaviour in 316L stainless steel. • The growth mechanism is proposed as a mode island (Volmert- Weber mode). • TOF-SIMS and XPS provided the identification of the molecules involved in the surface modification reaction on AISI 316L inducing superhydrophobicity.

NEAR-ULTRAVIOLET SPECTROSCOPY OF STAR-FORMING GALAXIES FROM eBOSS: SIGNATURES OF UBIQUITOUS GALACTIC-SCALE OUTFLOWS

International Nuclear Information System (INIS)

Zhu, Guangtun Ben; Comparat, Johan; Kneib, Jean-Paul; Delubac, Timothée; Raichoor, Anand; Yèche, Christophe; Dawson, Kyle S.; Newman, Jeffrey; Zhou, Xu; Schneider, Donald P.

2015-01-01

We present rest-frame near-ultraviolet (NUV) spectroscopy of star-forming galaxies (SFGs) at 0.6 < z < 1.2 from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) in SDSS-IV. One of the eBOSS programs is to obtain 2″ (about 15 kpc) fiber spectra of about 200,000 emission-line galaxies (ELGs) at redshift z ≳ 0.6. We use the data from the pilot observations of this program, including 8620 spectra of SFGs at 0.6 < z < 1.2. The median composite spectra of these SFGs at 2200 Å < λ < 4000 Å feature asymmetric, preferentially blueshifted non-resonant emission, Fe ii*, and blueshifted resonant absorption, e.g., Fe ii and Mg ii, indicating ubiquitous outflows driven by star formation at these redshifts. For the absorption lines, we find a variety of velocity profiles with different degrees of blueshift. Comparing our new observations with the literature, we do not observe the non-resonant emission in the small-aperture (<40 pc) spectra of local star-forming regions with the Hubble Space Telescope, and find the observed line ratios in the SFG spectra to be different from those in the spectra of local star-forming regions, as well as those of quasar absorption-line systems in the same redshift range. We introduce an outflow model that can simultaneously explain the multiple observed properties and suggest that the variety of absorption velocity profiles and the line ratio differences are caused by scattered fluorescent emission filling in on top of the absorption in the large-aperture eBOSS spectra. We develop an observation-driven, model-independent method to correct the emission infill to reveal the true absorption profiles. Finally, we show that the strengths of both the non-resonant emission and the emission-corrected resonant absorption increase with [O ii] λλ3727, 3730 rest equivalent width and luminosity, with a slightly larger dependence on the former. Our results show that the eBOSS and future dark-energy surveys (e.g., Dark Energy Spectroscopic

Surface effects induced by cathodic hydrogenation in type AISI 304 stainless steel

International Nuclear Information System (INIS)

Silva, T.C.V.

1984-08-01

Cathodic hydrogen charging of type AISI 304 stainless steel modified its austenitic structure, giving rise to the formation of two new martensitic phases and the appearance of cracks, in most cases delayed. As electrolyte a 1 N H 2 S O 4 solution containing As 2 O 3 was employed. The cathodic hydrogenation was carries out at room temperature. The transformed phases were identified with black and white and coloured metallographic techniques, as well as by X-ray diffraction. The effect of cathodic hydrogenation in samples uniaxially tensile tested with constant nominal strain rate was investigated. It was concluded that the number of cracks per unit surface area changes with hydrogenation conditions and that hydrogen should be present for the embrittlement to occur. (author)

Zinc Addition Effects on General Corrosion of Austenitic Stainless Steels in PWR Primary Conditions

International Nuclear Information System (INIS)

Qiao Peipeng; Zhang Lefu; Liu Ruiqin; Jiang Suqing; Zhu Fawen

2010-01-01

Zinc addition effects on general corrosion of austenitic stainless steel 316 and 304 were investigated in simulated PWR primary coolant without zinc or with 50 ppb zinc addition at 315 degree C for 500 h. The results show that with the addition of zinc, the corrosion rate of austenitic stainless steel is effectively reduced, the surface oxide film is thinner, the morphology and chemical composition of surface oxide scales are evidently different from those without zinc. There are needle-like corrosion products on the surface of stainless steel 304. (authors)

Plasma assisted nitriding for micro-texturing onto martensitic stainless steels*

Directory of Open Access Journals (Sweden)

Katoh Takahisa

2015-01-01

Full Text Available Micro-texturing method has grown up to be one of the most promising procedures to form micro-lines, micro-dots and micro-grooves onto the mold-die materials and to duplicate these micro-patterns onto metallic or polymer sheets via stamping or injection molding. This related application requires for large-area, fine micro-texturing onto the martensitic stainless steel mold-die materials. A new method other than laser-machining, micro-milling or micro-EDM is awaited for further advancement of this micro-texturing. In the present paper, a new micro-texturing method is developed on the basis of the plasma assisted nitriding to transform the two-dimensionally designed micro-patterns to the three dimensional micro-textures in the martensitic stainless steels. First, original patterns are printed onto the surface of stainless steel molds by using the dispenser or the ink-jet printer. Then, the masked mold is subjected to high density plasma nitriding; the un-masked surfaces are nitrided to have higher hardness, 1400 Hv than the matrix hardness, 200 Hv of stainless steels. This nitrided mold is further treated by sand-blasting to selectively remove the soft, masked surfaces. Finally, the micro-patterned martensitic stainless steel mold is fabricated as a tool to duplicate these micro-patterns onto the plastic materials by the injection molding.

Molecular carbon nitride ion beams for enhanced corrosion resistance of stainless steel

Science.gov (United States)

Markwitz, A.; Kennedy, J.

2017-10-01

A novel approach is presented for molecular carbon nitride beams to coat stainless surfaces steel using conventional safe feeder gases and electrically conductive sputter targets for surface engineering with ion implantation technology. GNS Science's Penning type ion sources take advantage of the breaking up of ion species in the plasma to assemble novel combinations of ion species. To test this phenomenon for carbon nitride, mixtures of gases and sputter targets were used to probe for CN+ ions for simultaneous implantation into stainless steel. Results from mass analysed ion beams show that CN+ and a variety of other ion species such as CNH+ can be produced successfully. Preliminary measurements show that the corrosion resistance of stainless steel surfaces increased sharply when implanting CN+ at 30 keV compared to reference samples, which is interesting from an application point of view in which improved corrosion resistance, surface engineering and short processing time of stainless steel is required. The results are also interesting for novel research in carbon-based mesoporous materials for energy storage applications and as electrode materials for electrochemical capacitors, because of their high surface area, electrical conductivity, chemical stability and low cost.

Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

Directory of Open Access Journals (Sweden)

Masafumi Matsushita

2011-07-01

Full Text Available Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

Surface Nb-ALLOYING on 0.4C-13Cr Stainless Steel: Microstructure and Tribological Behavior

Science.gov (United States)

Yu, Shengwang; You, Kai; Liu, Xiaozhen; Zhang, Yihui; Wang, Zhenxia; Liu, Xiaoping

2016-02-01

0.4C-13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C-13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3-0.45 and the wear rate after Nb-alloying is only 2-5% of untreated steel.

Electron pulsed beam induced processing of thin film surface by Nb3Ge deposited into a stainless steel tape

International Nuclear Information System (INIS)

Vavra, I.; Korenev, S.A.

1988-01-01

A surface of superconductive thin film of Nb 3 Ge deposited onto a stainless steel tape was processed using the electron beam technique. The electron beam used had the following parameters: beam current density from 400 to 1000 A/cm 2 ; beam energy 100 keV; beam impulse length 300 ns. By theoretical analysis it is shown that the heating of film surface is an adiabatic process. It corresponds to our experimental data and pictures showing a surface remelting due to electron beam influence. After beam processing the superconductive parameters of the film remain unchanged. Roentgenograms have been analysed of Nb 3 Ge film surface recrystallized due to electron beam influence

Electroless Plated Nanodiamond Coating for Stainless Steel Passivation

Energy Technology Data Exchange (ETDEWEB)

Li, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Korinko, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Spencer, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Stein, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-09-15

Tritium gas sample bottles and manifold components require passivation surface treatments to minimize the interaction of the hydrogen isotopes with surface contamination on the stainless steel containment materials. This document summarizes the effort to evaluate electroless plated nanodiamond coatings as a passivation layer for stainless steel. In this work, we developed an electroless nanodiamond (ND)-copper (Cu) coating process to deposit ND on stainless steel parts with the diamond loadings of 0%, 25% and 50% v/v in a Cu matrix. The coated Conflat Flanged Vessel Assemblies (CFVAs) were evaluated on surface morphology, composition, ND distribution, residual hydrogen release, and surface reactivity with deuterium. For as-received Cu and ND-Cu coated CFVAs, hydrogen off-gassing is rapid, and the off-gas rates of H₂ was one to two orders of magnitude higher than that for both untreated and electropolished stainless steel CFVAs, and hydrogen and deuterium reacted to form HD as well. These results indicated that residual H₂ was entrapped in the Cu and ND-Cu coated CFVAs during the coating process, and moisture was adsorbed on the surface, and ND and/or Cu might facilitate catalytic isotope exchange reaction for HD formation. However, hydrocarbons (i.e., CH₃) did not form, and did not appear to be an issue for the Cu and ND-Cu coated CFVAs. After vacuum heating, residual H₂ and adsorbed H₂O in the Cu and ND-Cu coated CFVAs were dramatically reduced. The H₂ off-gassing rate after the vacuum treatment of Cu and 50% ND-Cu coated CFVAs was on the level of 10^-14 l mbar/s cm², while H₂O off-gas rate was on the level of 10^-15 l mbar/s cm², consistent with the untreated or electropolished stainless steel CFVA, but the HD formation remained. The Restek EP bottle was used as a reference for this work. The Restek Electro-Polished (EP) bottle and their Sil

Adsorbed radioactivity and radiographic imaging of surfaces of stainless steel and titanium

Science.gov (United States)

Jung, Haijo

1997-11-01

Type 304 stainless steel used for typical surface materials of spent fuel shipping casks and titanium were exposed in the spent fuel storage pool of a typical PWR power plant. Adsorption characteristics, effectiveness of decontamination by water cleaning and by electrocleaning, and swipe effectiveness on the metal surfaces were studied. A variety of environmental conditions had been manipulated to stimulate the potential 'weeping' phenomenon that often occurs with spent fuel shipping casks during transit. In a previous study, few heterogeneous effects of adsorbed contamination onto metal surfaces were observed. Radiographic images of cask surfaces were made in this study and showed clearly heterogeneous activity distributions. Acquired radiographic images were digitized and further analyzed with an image analysis computer package and compared to calibrated images by using standard sources. The measurements of activity distribution by using the radiographic image method were consistent with that using a HPGe detector. This radiographic image method was used to study the effects of electrocleaning for total and specified areas. The Modulation Transfer Function (MTF) of a film-screen system in contact with a radioactive metal surface was studied with neutron activated gold foils and showed more broad resolution properties than general diagnostic x-ray film-screen systems. Microstructure between normal areas and hot spots showed significant differences, and one hot spot appearing as a dot on the film image consisted of several small hot spots (about 10 μm in diameter). These hot spots were observed as structural defects of the metal surfaces.

Evidence of extensive diversity in bacterial adherence mechanisms that exploit unanticipated stainless steel surface structural complexity for biofilm formation.

Science.gov (United States)

Davis, Elisabeth M; Li, Dongyang; Shahrooei, Mohammad; Yu, Bin; Muruve, Daniel; Irvin, Randall T

2013-04-01

Three protease-resistant bioorganic 304 stainless steel surfaces were created through the reaction of synthetic peptides consisting of the D-enantiomeric isomer (D-K122-4), the retro-inverso D-enantiomeric isomer (RI-K122-4), and a combination of the two peptides (D+RI) of the Pseudomonas aeruginosa PilA receptor binding domain with steel surfaces. The peptides used to produce the new materials differ only in handedness of their three-dimensional structure, but they reacted with the steel to yield materials that differed in their surface electron work function (EWF) while displaying an identical chemical composition and equivalent surface adhesive force properties. These surfaces allowed for an assessment of the relative role of surface EWF in initial biofilm formation. We examined the ability of various bacteria (selected strains of Listeria monocytogenes, L. innocua, Staphylococcus aureus and S. epidermidis) to initiate biofilm formation. The D-K1224 generated surface displayed the lowest EWF (classically associated with greater molecular interactions and more extensive biofilm formation) but was observed to be least effectively colonized by bacteria (>50% decrease in bacterial adherence of all strains). The highest surface EWF with the lowest surface free energy (RI-K122-4 generated) was more extensively colonized by bacteria, with the binding of some strains being equivalent to unmodified steel. The D+RI generated surface was least effective in minimizing biofilm formation, where some strains displayed enhanced bacterial colonization. Fluorescent microscopy revealed that the D and RI peptides displayed similar but clearly different binding patterns, suggesting that the peptides recognized different sites on the steel, and that differential binding of the peptides to the steel surfaces influences the binding of different bacterial strains and species. We have demonstrated that stainless steel surfaces can be easily modified by peptides to generate surfaces with

Babies and bosses: reconciling work and family life : a synthesis of findings for OECD countries

National Research Council Canada - National Science Library

2007-01-01

... of population ageing, and well-designed policies may also help raise fertility rates from the exceptionally low levels that exist in some countries. In recent years, the OECD Babies and Bosses reviews of policies to promote work and family reconciliation covered Australia, Denmark and the Netherlands (OECD, 2002a); Austria, Ireland and ...

Corrosion-resistant powder-metallurgy stainless steel powders and compacts therefrom

International Nuclear Information System (INIS)

Klar, E.; Ro, D.H.; Whitman, C.I.

1980-01-01

Disclosed is a process for improving the corrosion resistance of a stainless steel powder or compact thereof wherein the powder is produced by atomizing a melt of metals in an oxidizing environment whereby the resulting stainless steel powder is surface-enriched in silicon oxides. The process comprises adding an effective proportion of modifier metal to the melt prior to the atomization, the modifier metal selected from the group consisting of tin, aluminum, lead, zinc, magnesium, rare earth metals and like metals capable of enrichment about the surface of the resulting atomized stainless steel powder and effective under reductive sintering conditions in the depletion of the silicon oxides about the surface; and sintering the resulting atomized powder or a compact thereof under reducing conditions, the sintered powder or compact thereof being depleted in the silicon oxides and the corrosion resistance of the powder or compact thereof being improved thereby

Investigating and understanding the effects of multiple femtosecond laser scans on the surface topography of stainless steel 304 and titanium

Energy Technology Data Exchange (ETDEWEB)

Ling, Edwin Jee Yang, E-mail: edwin.ling@mail.mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Saïd, Julien, E-mail: julien.said@ecl2015.ec-lyon.fr [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Brodusch, Nicolas, E-mail: nicolas.brodusch@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Gauvin, Raynald, E-mail: raynald.gauvin@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Servio, Phillip, E-mail: phillip.servio@mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Kietzig, Anne-Marie, E-mail: anne.kietzig@mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada)

2015-10-30

Highlights: • Effect of multiple femtosecond laser scans on stainless steel. • Ellipsoidal cones, columnar and chaotic structures observed on irradiated surface. • Chemical, crystallographic, and topographical analyses of ellipsoidal cones. • Developed mechanism for formation and growth of ellipsoidal cones. - Abstract: The majority of studies performed on the formation of surface features by femtosecond laser radiation focuses on single scan procedures, i.e. manipulating the laser beam once over the target area to fabricate different surface topographies. In this work, the effect of scanning stainless steel 304 multiple times with femtosecond laser pulses is thoroughly investigated over a wide range of fluences. The resultant laser-induced surface topographies can be categorized into two different regimes. In the low fluence regime (F{sub Σline,max} < 130 J/cm{sup 2}), ellipsoidal cones (randomly distributed surface protrusions covered by several layers of nanoparticles) are formed. Based on chemical, crystallographic, and topographical analyses, we conclude that these ellipsoidal cones are composed of unablated steel whose conical geometry offers a significant degree of fluence reduction (35–52%). Therefore, the rest of the irradiated area is preferentially ablated at a higher rate than the ellipsoidal cones. The second, or high fluence regime (F{sub Σline,max} > 130 J/cm{sup 2}) consists of laser-induced surface patterns such as columnar and chaotic structures. Here, the surface topography showed little to no change even when the target was scanned repeatedly. This is in contrast to the ellipsoidal cones, which evolve and grow continuously as more laser passes are applied.

Hydrogel brushes grafted from stainless steel via surface-initiated atom transfer radical polymerization for marine antifouling

Science.gov (United States)

Wang, Jingjing; Wei, Jun

2016-09-01

Crosslinked hydrogel brushes were grafted from stainless steel (SS) surfaces for marine antifouling. The brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-methacryloyloxyethyl phosphorylcholine (MPC) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) respectively with different fractions of crosslinker in the feed. The grafted layers prepared with different thickness were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), ellipsometry and water contact angle measurements. With the increase in the fraction of crosslinker in the feed, the thickness of the grafted layer increased and the surface became smooth. All the brush-coated SS surfaces could effectively reduce the adhesion of bacteria and microalgae and settlement of barnacle cyprids, as compared to the pristine SS surface. The antifouling efficacy of the PEGMA polymer (PPEGMA)-grafted surface was higher than that of the MPC polymer (PMPC)-grafted surfaces. Furthermore, the crosslinked hydrogel brush-grafted surfaces exhibited better fouling resistance than the non-crosslinked polymer brush-grafted surfaces, and the antifouling efficacy increased with the crosslinking density. These hydrogel coatings of low toxicity and excellent anti-adhesive characteristics suggested their useful applications as environmentally friendly antifouling coatings.

Surface Nano crystallization of 3Cr13 Stainless Steel Induced by High-Current Pulsed Electron Beam Irradiation

International Nuclear Information System (INIS)

Han, Z.; Zou, H.; Wang, Z.; Ji, I.; Cai, J.; Guan, Q.

2013-01-01

The nanocrystalline surface was produced on 3Cr13 martensite stainless steel surface using high-current pulsed electron beam (HCPEB) technique. The structures of the nano crystallized surface were characterized by X-ray diffraction and electron microscopy. Two nano structures consisting of fine austenite grains (50-150 nm) and very fine carbides precipitates are formed in melted surface layer after multiple bombardments via dissolution of carbides and crater eruption. It is demonstrated that the dissolution of the carbides and the formation of the supersaturated Fe (C) solid solution play a determining role on the microstructure evolution. Additionally, the formation of fine austenite structure is closely related to the thermal stresses induced by the HCPEB irradiation. The effects of both high carbon content and high value of stresses increase the stability of the austenite, which leads to the complete suppression of martensitic transformation.

Temperature thresholds for surface blistering of platinum and stainless steel exposed to curium-242 alpha radiations

International Nuclear Information System (INIS)

McDonell, W.R.; Dillich, S.

1981-01-01

Implantation of helium in materials exposed to alpha-emitting radionuclides such as 242 Cm causes surface blistering at elevated temperatures. The temperature thresholds for such blistering are of practical importance to the selection of suitable container materials for radionuclides, and are of fundamental interest with regard to the mechanisms of helium blistering of materials in radiation environments. The purpose of this investigation was to establish temperature thresholds for surface blistering of platinum and stainless-steel container materials by post-irradiation heating of specimens exposed at room temperature to alpha particles from an external 242 Cm source. These thresholds were compared with (1) the analogous temperature thresholds for surface blistering of materials exposed to external beams of accelerator helium ions, and (2) thresholds for swelling and grain-boundary cracking of materials in which helium is generated internally by (n,α) reactions during reactor exposures

HIP bonding between niobium/copper/stainless steel materials

International Nuclear Information System (INIS)

Inoue, Hitoshi; Fujino, Takeo; Hitomi, Nobuteru; Saito, Kenji; Yamada, Masahiro; Shibuya, Junichi; Ota, Tomoko

2000-01-01

We have used niobium flanges for the niobium bulk superconducting RF cavities, however, they are expensive. Stainless steel flanges instead of the niobium flanges will be used in the future large scale production of sc cavities like the KEK/JAERI joint project. For a future R and D of the vacuum sealing related to the clean horizontal assembly method or development of cavities welded a helium vessel in the KEK/JAERI joint project, a converter section of niobium material to stainless steel is required. From these requirements we need to develop the converter. We have tried a HIP bonding method between niobium materials and stainless steel or copper material. It was made clear that the technology could offer an enough bonding strength even higher than niobium tensile strength in the joined surface between niobium and stainless steel or copper. (author)

The effect of simulated inflammatory conditions on the surface properties of titanium and stainless steel and their importance as biomaterials

International Nuclear Information System (INIS)

Fonseca-García, Abril; Pérez-Alvarez, J.; Barrera, C.C.; Medina, J.C.; Almaguer-Flores, A.; Sánchez, R. Basurto

2016-01-01

This work compares the surface modifications induced by the immersion in solutions that simulate inflammatory conditions of pure titanium (cpTi) and medical grade stainless steel (SS). The inflammatory conditions were simulated using a mixture of Hartman solution and 50 mM of hydrogen peroxide (H_2O_2) at pH = 5.2. The samples were immersed by 7 days refreshing the solution every day to keep the reactivity of the H_2O_2. The surface characteristics that were investigated were: elemental composition by X-ray photoelectron spectroscopy (XPS); topography by atomic force microscopy (AFM) and profilometry; wettability and surface energy by sessile drop contact angle and point of zero charge by titration. Moreover, the variations in the electrochemical response were evaluated by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) performed before and after the treatment using the Hartman solution as the electrolyte. The XPS results indicated that for both metallic samples, oxidation of the surface was promoted and/or the oxide layer was thicker after the immersion. The roughness and the solid-liquid surface energy were increased; the samples showed a more hydrophilic character after the treatment. However, the surface energy of the solid estimated using the Van Oss–Chaudhury–Good approach showed different trends between the cpTi and the SS surfaces; the polar component decreased for cpTi, while it increased for SS. Finally, the electrochemical results indicated that the corrosion resistance (R_c_o_r) and the pore resistance (R_p_o) significantly decreased for cpTi, while both resistances were not significantly different for the SS. This is indicative of a higher dissolution of the cpTi compared to SS and the lower R_p_o means that the species are easily transported through the surface layer, which can be explained in terms of the formation of a porous TiO_x layer, not observed on the SS. The cpTi surface

The effect of simulated inflammatory conditions on the surface properties of titanium and stainless steel and their importance as biomaterials

Energy Technology Data Exchange (ETDEWEB)

Fonseca-García, Abril [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, Universidad Nacional Autónoma de México, México (Mexico); Pérez-Alvarez, J. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México (Mexico); Barrera, C.C. [Posgrado en Ciencias Médicas, Odontológicas y de la Salud, Universidad Nacional Autónoma de México, México (Mexico); Medina, J.C. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, Universidad Nacional Autónoma de México, México (Mexico); Almaguer-Flores, A. [Facultad de Odontología, Universidad Nacional Autónoma de México, México (Mexico); Sánchez, R. Basurto [Instituto Nacional de Investigaciones Nucleares, México (Mexico); and others

2016-09-01

This work compares the surface modifications induced by the immersion in solutions that simulate inflammatory conditions of pure titanium (cpTi) and medical grade stainless steel (SS). The inflammatory conditions were simulated using a mixture of Hartman solution and 50 mM of hydrogen peroxide (H{sub 2}O{sub 2}) at pH = 5.2. The samples were immersed by 7 days refreshing the solution every day to keep the reactivity of the H{sub 2}O{sub 2}. The surface characteristics that were investigated were: elemental composition by X-ray photoelectron spectroscopy (XPS); topography by atomic force microscopy (AFM) and profilometry; wettability and surface energy by sessile drop contact angle and point of zero charge by titration. Moreover, the variations in the electrochemical response were evaluated by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) performed before and after the treatment using the Hartman solution as the electrolyte. The XPS results indicated that for both metallic samples, oxidation of the surface was promoted and/or the oxide layer was thicker after the immersion. The roughness and the solid-liquid surface energy were increased; the samples showed a more hydrophilic character after the treatment. However, the surface energy of the solid estimated using the Van Oss–Chaudhury–Good approach showed different trends between the cpTi and the SS surfaces; the polar component decreased for cpTi, while it increased for SS. Finally, the electrochemical results indicated that the corrosion resistance (R{sub cor}) and the pore resistance (R{sub po}) significantly decreased for cpTi, while both resistances were not significantly different for the SS. This is indicative of a higher dissolution of the cpTi compared to SS and the lower R{sub po} means that the species are easily transported through the surface layer, which can be explained in terms of the formation of a porous TiO{sub x} layer, not

Field emission study from an array of hierarchical micro protrusions on stainless steel surface generated by femtosecond pulsed laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Singh, A.K., E-mail: anilks@barc.gov.in [Laser & Plasma Technology Division, BARC, Mumbai, 400085 (India); Suryawanshi, Sachin R.; More, M.A. [Department of Physics, Savitribai Phule Pune University, Pune, 411007 (India); Basu, S. [Solid State Physics Division, BARC, Mumbai, 40085 (India); Sinha, Sucharita [Laser & Plasma Technology Division, BARC, Mumbai, 400085 (India)

2017-02-28

Highlights: • Array of self assembled micro-protrusions have been generated on stainless steel surfaces by femtosecond pulsed laser irradiation. • Density of the formed micro-protrusions is ∼5.6 × 105 protrusions/cm{sup 2}. • Laser treated surface is mainly composed of iron oxide and cementite phases. • Micro-structured sample has shown good field emission properties – low turn on field, high field enhancement factor and stable emission current. - Abstract: This paper reports our results on femtosecond (fs) pulsed laser induced surface micro/nano structuring of stainless steel 304 (SS 304) samples and their characterization in terms of surface morphology, formed material phases on laser irradiation and field emission studies. Our investigations reveal that nearly uniform and dense array of hierarchical micro-protrusions (density: ∼5.6 × 10{sup 5} protrusions/cm{sup 2}) is formed upon laser treatment. Typical tip diameters of the generated protrusions are in the range of 2–5 μm and these protrusions are covered with submicron sized features. Grazing incidence X-ray diffraction (GIXRD) analysis of the laser irradiated sample surface has shown formation mainly of iron oxides and cementite (Fe{sub 3}C) phases in the treated region. These laser micro-structured samples have shown good field emission properties such as low turn on field (∼4.1 V/μm), high macroscopic field enhancement factor (1830) and stable field emission current under ultra high vacuum conditions.

Thermal management of metallic surfaces: evaporation of sessile water droplets on polished and patterned stainless steel

Science.gov (United States)

Czerwiec, T.; Tsareva, S.; Andrieux, A.; Bortolini, G. A.; Bolzan, P. H.; Castanet, G.; Gradeck, M.; Marcos, G.

2017-10-01

This communication focus on the evaporation of sessile water droplets on different states of austenitic stainless steel surfaces: mirror polished, mirror polished and aged and patterned by sputtering. The evolution of the contact angle and of the droplet diameter is presented as a function of time at room temperature. For all the surface states, a constant diameter regime (CCR) is observed. An important aging effect on the contact angle is measured on polished surfaces due to atmospheric contamination. The experimental observations are compared to a quasi-static evaporation model assuming spherical caps. The evolution of the droplet volume as a function of time is almost linear with the evaporation time for all the observed surfaces. This is in accordance with the model prediction for the CCR mode for small initial contact angles. In our experiments, the evaporation time is found to be linearly dependent on the initial contact angle. This dependence is not correctly described by the evaporation model

Fouling of roughened stainless steel surfaces during convective heat transfer to aqueous solutions

International Nuclear Information System (INIS)

Herz, A.; Malayeri, M.R.; Mueller-Steinhagen, H.

2008-01-01

The deterioration of heat transfer performance due to fouling is the prime cause for higher energy consumption and inefficiency in many industrial heat exchangers such as those in power plants, refineries, food and dairy industries. Fouling is also a very complex process in which many geometrical, physical and operating parameters are involved with poorly understood interaction. Among them, the surface roughness is an important surface characteristic that would greatly influence crystallisation fouling mechanisms and hence deposition morphology and stickability to the surface. In this work, the effect of the surface roughness of AISI 304 BA stainless steel surfaces on fouling of an aqueous solution with inverse solubility behaviour has been investigated under convective heat transfer. Several experiments have been performed on roughened surfaces ranging from 0.18 to 1.55 μm for different bulk concentrations and heat fluxes. The EDTA titration method was used to measure the concentration of the calcium sulphate salt in order to maintain it at constant value during each fouling run. Experimental results show that the heat transfer coefficient of very rough surfaces (1.55 μm) decreases more rapidly than that of 0.54 μm. Several facts contribute to this behaviour notably (1) increased of primary heterogeneous nucleation rate on the surfaces; (2) reduction of local shear stress in the valleys and (3) reduced removal rate of the crystals from the surfaces where the roughness elements protrude out of the viscous sub-layer. The results also show linear and proportional variation of the fouling rate and heat flux within the range of operating conditions. In addition, the deposition process in terms of fouling rate could only be affected at lower surface contact angles. Such results would particularly be of interest for new surface treatment technologies which aim at altering the surface texture

Prevention of burn-on defect on surface of hydroturbine blade casting of ultra-low-carbon refining stainless steel

Directory of Open Access Journals (Sweden)

Li Ling

2008-08-01

Full Text Available The burn-on sand is common surface defect encountered in CO2-cured silicate-bonded sand casting of hydroturbine blade of ultra-low-carbon martensitic stainless steel, its feature, causes and prevention measures are presented in this paper. Experiments showed that the burn-on defect is caused by oxidization of chromium in the molten steel at high temperature and can be effectively eliminated by using chromium-corundum coating.

Accelerated corrosion of stainless steel in thiocyanate-containing solutions

Energy Technology Data Exchange (ETDEWEB)

Pistorius, P Chris; Li, Wen

2012-09-19

It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk sulfide

The borehole disposal of spent sources (BOSS)

International Nuclear Information System (INIS)

Heard, R.G.

2002-01-01

During the International Atomic Energy Agency (IAEA) Regional Training Course on 'The Management of Low-Level Radioactive Waste from Hospitals and Other Nuclear Applications' hosted by the Atomic Energy Corporation of SA Ltd. (AEC), now NECSA, during July/August 1995, the African delegates reviewed their national radioactive waste programmes. Among the issues raised, which are common to most African countries, were the lack of adequate storage facilities, lack of disposal solutions and a lack of equipment to implement widely used disposal concepts to dispose of their spent sources. As a result of this meeting, a Technical Co-operation (TC) project was launched to look at the technical feasibility and economic viability of such a concept. Phase I and II of the project have been completed and the results can be seen in three reports produced by NECSA. The Safety Assessment methodology used in the evaluation of the concept was that developed during the ISAM programme and detailed in Van Blerk's PhD thesis. This methodology is specifically developed for shallow land repositories, but was used in this case as the borehole need not be more than 100m deep and could fit into the definition of a shallow land disposal system. The studies found that the BOSS concept would be suitable for implementation in African countries as the borehole has a large capacity for sources and it is possible that an entire country's disused sources can be placed in a single borehole. The costs are a lot lower than for a shallow land trench, and the concept was evaluated using radium (226) sources as the most limiting inventory. The conclusion of the initial safety assessment was that the BOSS concept is robust, and provides a viable alternative for the disposal of radium needles. The concept is expected to provide good assurance of safety at real sites. The extension of the safety assessment to other types of spent sources is expected to be relatively straightforward. Disposal of radium needles

Microscopic work function anisotropy and surface chemistry of 316L stainless steel using photoelectron emission microscopy

Energy Technology Data Exchange (ETDEWEB)

Barrett, N., E-mail: nick.barrett@cea.fr [CEA, IRAMIS, SPEC, LENSIS, F-91191 Gif-sur-Yvette (France); Renault, O. [CEA, LETI, Minatec Campus, F-38054 Grenoble Cedex 09 (France); Lemaître, H. [Université de Cergy-Pontoise, Rue d’Eragny, Neuville sur Oise, 95 031 Cergy-Pontoise (France); Surface Dynamics Laboratory, Institut for Fysik og Astronomi Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C (Denmark); Bonnaillie, P. [CEA, DEN, DANS, DMN, SRMP, F-91191 Gif-sur-Yvette (France); Barcelo, F. [CEA, DEN, DANS, DMN, SRMA, LA2M, F-91191 Gif-sur-Yvette (France); Miserque, F. [CEA, DEN, DANS, DPC, SCCME, LECA, F-91191 Gif-sur-Yvette (France); Wang, M.; Corbel, C. [Laboratoire des Solides Irradis, Ecole Polytechnique, route de Saclay, F-91128 Palaiseau (France)

2014-08-15

Highlights: • PEEM and EBSD study of spatial variations in local work function of 316L steel. • Correlation between work function and crystal grain orientation at the surface of 316L steel. • Spatially resolved chemistry of residual oxide layer. - Abstract: We have studied the variation in the work function of the surface of sputtered cleaned 316L stainless steel with only a very thin residual oxide surface layer as a function of grain orientation using X-ray photoelectron emission microscopy (XPEEM) and Electron Backscattering Diffraction. The grains are mainly oriented [1 1 1] and [1 0 1]. Four distinct work function values spanning a 150 meV energy window are measured. Grains oriented [1 1 1] have a higher work function than those oriented [1 0 1]. From core level XPEEM we deduce that all grain surfaces are Cr enriched and Ni depleted whereas the Cr/Fe ratio is similar for all grains. The [1 1 1] oriented grains show evidence for a Cr{sub 2}O{sub 3} surface oxide and a higher concentration of defective oxygen sites.

Influence of Plastic Deformation on Low-Temperature Surface Hardening of Austenitic Stainless Steel by Gaseous Nitriding

DEFF Research Database (Denmark)

Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

2015-01-01

This article addresses an investigation of the influence of plastic deformation on low-temperature surface hardening by gaseous nitriding of two commercial stainless steels: EN 1.4369 and AISI 304. The materials were plastically deformed to several levels of equivalent strain by conventional......, reflected-light microscopy, and microhardness testing. The results demonstrate that a case of expanded austenite develops and that the presence of plastic deformation has a significant influence on the morphology of the nitrided case. The presence of strain-induced martensite favors the formation of Cr...

Investigation of the antibiofilm capacity of peptide-modified stainless steel.

Science.gov (United States)

Cao, Pan; Li, Wen-Wu; Morris, Andrew R; Horrocks, Paul D; Yuan, Cheng-Qing; Yang, Ying

2018-03-01

Biofilm formation on surfaces is an important research topic in ship tribology and medical implants. In this study, dopamine and two types of synthetic peptides were designed and attached to 304 stainless steel surfaces, aiming to inhibit the formation of biofilms. A combinatory surface modification procedure was applied in which dopamine was used as a coupling agent, allowing a strong binding ability with the two peptides. X-ray photoelectron spectroscopy (XPS), elemental analysis, contact angle measurement and surface roughness test were used to evaluate the efficiency of the peptide modification. An antibiofilm assay against Staphylococcus aureus was conducted to validate the antibiofilm capacity of the peptide-modified stainless steel samples. XPS analysis confirmed that the optimal dopamine concentration was 40 µg ml -1 in the coupling reaction. Element analysis showed that dopamine and the peptides had bound to the steel surfaces. The robustness assay of the modified surface demonstrated that most peptide molecules had bound on the surface of the stainless steel firmly. The contact angle of the modified surfaces was significantly changed. Modified steel samples exhibited improved antibiofilm properties in comparison to untreated and dopamine-only counterpart, with the peptide 1 modification displaying the best antibiofilm effect. The modified surfaces showed antibacterial capacity. The antibiofilm capacity of the modified surfaces was also surface topography sensitive. The steel sample surfaces polished with 600# sandpaper exhibited stronger antibiofilm capacity than those polished with other types of sandpapers after peptide modification. These findings present valuable information for future antifouling material research.

Surface-induced dissociation and chemical reactions of C2D4(+) on stainless steel, carbon (HOPG), and two different diamond surfaces.

Science.gov (United States)

Feketeová, Linda; Zabka, Jan; Zappa, Fabio; Grill, Verena; Scheier, Paul; Märk, Tilmann D; Herman, Zdenek

2009-06-01

Surface-induced interactions of the projectile ion C(2)D(4)(+) with room-temperature (hydrocarbon covered) stainless steel, carbon highly oriented pyrolytic graphite (HOPG), and two different types of diamond surfaces (O-terminated and H-terminated) were investigated over the range of incident energies from a few eV up to 50 eV. The relative abundance of the product ions in dependence on the incident energy of the projectile ion [collision-energy resolved mass spectra, (CERMS) curves] was determined. The product ion mass spectra contained ions resulting from direct dissociation of the projectile ions, from chemical reactions with the hydrocarbons on the surface, and (to a small extent) from sputtering of the surface material. Sputtering of the surface layer by low-energy Ar(+) ions (5-400 eV) indicated the presence of hydrocarbons on all studied surfaces. The CERMS curves of the product ions were analyzed to obtain both CERMS curves for the products of direct surface-induced dissociation of the projectile ion and CERMS curves of products of surface reactions. From the former, the fraction of energy converted in the surface collision into the internal excitation of the projectile ion was estimated as 10% of the incident energy. The internal energy of the surface-excited projectile ions was very similar for all studied surfaces. The H-terminated room-temperature diamond surface differed from the other surfaces only in the fraction of product ions formed in H-atom transfer surface reactions (45% of all product ions formed versus 70% on the other surfaces).

Nitrogen plasma immersion ion implantation for surface treatment and wear protection of austenitic stainless steel X6CrNiTi1810

International Nuclear Information System (INIS)

Blawert, C.; Mordike, B.L.

1999-01-01

Plasma immersion ion implantation is an effective surface treatment for stainless steels. The influence of treatment parameters (temperature, plasma density and pressure) on the sliding wear resistance are studied here. At moderate temperatures, nitrogen remains in solid solution without forming nitrides. This increases the surface hardness and the wear resistance without affecting the passivation of the steel. This may allow the use of such steels in applications where their poor wear resistance would normally prohibit their use. (orig.)

Surface study of stainless steel electrode deposition from soil electrokinetic (EK) treatment using X-ray photoelectron spectroscopy (XPS)

Energy Technology Data Exchange (ETDEWEB)

Embong, Zaidi, E-mail: zaidi@uthm.edu.my [Faculty of Science, Technology and Human Development, Universiti Tun Hussien Onn Malaysia (UTHM) 86400, Parit Raja, Batu, Johor (Malaysia); Research Centre for Soft Soils (RECESS), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia); Johar, Saffuwan [Faculty of Science, Technology and Human Development, Universiti Tun Hussien Onn Malaysia (UTHM) 86400, Parit Raja, Batu, Johor (Malaysia); Tajudin, Saiful Azhar Ahmad [Research Centre for Soft Soils (RECESS), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia); Sahdan, Mohd Zainizan [Microelectronics and Nanotechnology Centre (MiNT-SRC), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia)

2015-04-29

Electrokinetic (EK) remediation relies upon application of a low-intensity direct current through the soil between stainless steel electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions and positively charged organic compounds move toward the cathode. Anions such as chloride, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Here, this remediation techniques lead to a formation of a deposition at the both cathode and anode surface that mainly contributed byanion and cation from the remediated soil. In this research, Renggam-Jerangau soil species (HaplicAcrisol + RhodicFerralsol) with a surveymeter reading of 38.0 ± 3.9 μR/hr has been investigation in order to study the mobility of the anion and cation under the influence electric field. Prior to the EK treatment, the elemental composition of the soil and the stainless steel electrode are measured using XRF analyses. Next, the soil sample is remediated at a constant electric potential of 30 V within an hour of treatment period. A surface study for the deposition layer of the cathode and anode using X-ray Photoelectron spectroscopy (XPS) revealed that a narrow photoelectron signal from oxygen O 1s, carbon, C 1s silica, Si 2p, aluminium, Al 2p and chromium, Cr 2p exhibited on the electrode surface and indicate that a different in photoelectron intensity for each element on both electrode surface. In this paper, the mechanism of Si{sup 2+} and Al{sup 2+} cation mobility under the influence of voltage potential between the cathode and anode will be discussed in detail.

Surface study of stainless steel electrode deposition from soil electrokinetic (EK) treatment using X-ray photoelectron spectroscopy (XPS)

International Nuclear Information System (INIS)

Embong, Zaidi; Johar, Saffuwan; Tajudin, Saiful Azhar Ahmad; Sahdan, Mohd Zainizan

2015-01-01

Electrokinetic (EK) remediation relies upon application of a low-intensity direct current through the soil between stainless steel electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions and positively charged organic compounds move toward the cathode. Anions such as chloride, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Here, this remediation techniques lead to a formation of a deposition at the both cathode and anode surface that mainly contributed byanion and cation from the remediated soil. In this research, Renggam-Jerangau soil species (HaplicAcrisol + RhodicFerralsol) with a surveymeter reading of 38.0 ± 3.9 μR/hr has been investigation in order to study the mobility of the anion and cation under the influence electric field. Prior to the EK treatment, the elemental composition of the soil and the stainless steel electrode are measured using XRF analyses. Next, the soil sample is remediated at a constant electric potential of 30 V within an hour of treatment period. A surface study for the deposition layer of the cathode and anode using X-ray Photoelectron spectroscopy (XPS) revealed that a narrow photoelectron signal from oxygen O 1s, carbon, C 1s silica, Si 2p, aluminium, Al 2p and chromium, Cr 2p exhibited on the electrode surface and indicate that a different in photoelectron intensity for each element on both electrode surface. In this paper, the mechanism of Si 2+ and Al 2+ cation mobility under the influence of voltage potential between the cathode and anode will be discussed in detail

Modification and characterization of the AISI 410 martensitic stainless steels surface; Modificacao e caracterizacao da superficie do aco inoxidavel martensitico AISI 410

Energy Technology Data Exchange (ETDEWEB)

Bincoleto, A.V.L. [Universidade Federal de Sao Carlos (PPG-CEM/UFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Nascente, P.A.P. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

2010-07-01

Steam turbines are used in the generation of more than half the electric energy produced in the world nowadays. It is important the study which aims to improve the efficiency by means of the optimization of leaks and of the aerodynamic profiles, as well as to maintain the integrity of the components. The martensitic stainless steels are widely employed due to the combination of their good mechanical properties with higher corrosion resistance. However, their lower wear resistance and their poor tribological behavior limit their use, since they decrease the component life time. In order to evaluate the improvement in the performance of the AISI 410 stainless steel, several process of surface modification were employed. Five samples were produced: the first one was not treated, the second one received liquid nitriding, the third, gas nitriding, the forth, thermal aspersion of tungsten carbide, and the fifth, boronizing. The samples were characterized by optical microscopy, surface microhardness, and X-ray diffractometry. (author)

Surface integrity and fatigue behaviour of electric discharged machined and milled austenitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Lundberg, Mattias, E-mail: mattias.lundberg@liu.se; Saarimäki, Jonas; Moverare, Johan J.; Calmunger, Mattias

2017-02-15

Machining of austenitic stainless steels can result in different surface integrities and different machining process parameters will have a great impact on the component fatigue life. Understanding how machining processes affect the cyclic behaviour and microstructure are of outmost importance in order to improve existing and new life estimation models. Milling and electrical discharge machining (EDM) have been used to manufacture rectangular four-point bend fatigue test samples; subjected to high cycle fatigue. Before fatigue testing, surface integrity characterisation of the two surface conditions was conducted using scanning electron microscopy, surface roughness, residual stress profiles, and hardness profiles. Differences in cyclic behaviour were observed between the two surface conditions by the fatigue testing. The milled samples exhibited a fatigue limit. EDM samples did not show the same behaviour due to ratcheting. Recrystallized nano sized grains were identified at the severely plastically deformed surface of the milled samples. Large amounts of bent mechanical twins were observed ~ 5 μm below the surface. Grain shearing and subsequent grain rotation from milling bent the mechanical twins. EDM samples showed much less plastic deformation at the surface. Surface tensile residual stresses of ~ 500 MPa and ~ 200 MPa for the milled and EDM samples respectively were measured. - Highlights: •Milled samples exhibit fatigue behaviour, but not EDM samples. •Four-point bending is not suitable for materials exhibiting pronounced ratcheting. •LAGB density can be used to quantitatively measure plastic deformation. •Grain shearing and rotation result in bent mechanical twins. •Nano sized grains evolve due to the heat of the operation.

Activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces

Directory of Open Access Journals (Sweden)

Tatiane Karen Cabeça

2012-09-01

Full Text Available The purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. Numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effective. Scanning electron microscopy observations revealed that cells adhered on stainless steel surface after treatment with the disinfectants. No viable planktonic cells were observed after treatment with the same disinfectants. Based on our findings, we concluded that biofilm cells might be more resistant to disinfectants than plancktonic cells.

BigBOSS: The Ground-Based Stage IV BAO Experiment

Energy Technology Data Exchange (ETDEWEB)

Schlegel, David; Bebek, Chris; Heetderks, Henry; Ho, Shirley; Lampton, Michael; Levi, Michael; Mostek, Nick; Padmanabhan, Nikhil; Perlmutter, Saul; Roe, Natalie; Sholl, Michael; Smoot, George; White, Martin; Dey, Arjun; Abraham, Tony; Jannuzi, Buell; Joyce, Dick; Liang, Ming; Merrill, Mike; Olsen, Knut; Salim, Samir

2009-04-01

The BigBOSS experiment is a proposed DOE-NSF Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with an all-sky galaxy redshift survey. The project is designed to unlock the mystery of dark energy using existing ground-based facilities operated by NOAO. A new 4000-fiber R=5000 spectrograph covering a 3-degree diameter field will measure BAO and redshift space distortions in the distribution of galaxies and hydrogen gas spanning redshifts from 0.2< z< 3.5. The Dark Energy Task Force figure of merit (DETF FoM) for this experiment is expected to be equal to that of a JDEM mission for BAO with the lower risk and cost typical of a ground-based experiment.

Clustering of quasars in SDSS-IV eBOSS: study of potential systematics and bias determination

Energy Technology Data Exchange (ETDEWEB)

Laurent, Pierre; Goff, Jean-Marc Le; Burtin, Etienne; Bourboux, Hélion du Mas des; Palanque-Delabrouille, Nathalie [IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); Eftekharzadeh, Sarah; Myers, Adam [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); White, Martin [Lawrence Berkeley National Lab, 1 Cyclotron Rd, Berkeley CA 94720 (United States); Ross, Ashley J. [Center for Cosmology and AstroParticle Physics, The Ohio State University, Columbus, OH 43210 (United States); Tinker, Jeremy [Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, 10003 (United States); Tojeiro, Rita [School of Physics and Astronomy, North Haugh, St. Andrews KY16 9SS (United Kingdom); Bautista, Julian; Dawson, Kyle [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Brinkmann, Jonathan [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Comparat, Johan [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, 85748 Garching (Germany); Kneib, Jean-Paul [Laboratoire d' Astrophysique, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); McGreer, Ian D. [Steward Observatory, University of Arizona, Tucson, AZ 85721–0065 (United States); Percival, Will J. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama building, PO1 3FX, Portsmouth (United Kingdom); Prada, Francisco, E-mail: jmlegoff@cea.fr [Instituto de Fìsica Teórica (IFT) UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); and others

2017-07-01

We study the first year of the eBOSS quasar sample in the redshift range 0.9< z <2.2 which includes 68,772 homogeneously selected quasars. We show that the main source of systematics in the evaluation of the correlation function arises from inhomogeneities in the quasar target selection, particularly related to the extinction and depth of the imaging data used for targeting. We propose a weighting scheme that mitigates these systematics. We measure the quasar correlation function and provide the most accurate measurement to date of the quasar bias in this redshift range, b {sub Q} = 2.45 ± 0.05 at z-bar =1.55, together with its evolution with redshift. We use this information to determine the minimum mass of the halo hosting the quasars and the characteristic halo mass, which we find to be both independent of redshift within statistical error. Using a recently-measured quasar-luminosity-function we also determine the quasar duty cycle. The size of this first year sample is insufficient to detect any luminosity dependence to quasar clustering and this issue should be further studied with the final ∼500,000 eBOSS quasar sample.

Spectroellipsometric, AFM and XPS probing of stainless steel surfaces subjected to biological influences

Science.gov (United States)

Vinnichenko, M.; Chevolleau, Th; Pham, M. T.; Poperenko, L.; Maitz, M. F.

2002-11-01

Surface modification of austenitic stainless steel (SS) 316L after incubation in growing cell cultures and cell-free media as control has been studied. The following treatments were applied: mouse fibrosarcoma cells L929 for 3 and 7 days, polymorphonuclear neutrophils for 3 and 7 days and human osteosarcoma cells SAOS-2 for 7 and 14 days. Cells were enzymatically removed in all cases. The modified surfaces were probed in comparison with untreated ones by means of spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). XPS shows the appearance of the peak of bonded nitrogen at 400.5 eV characteristic for adsorbed proteins on the surface for each type of cells and for the cell-free medium. Migration of Ni in the adsorbed layer is observed in all cases for samples after the cell cultures. The protein layer thickness is ellipsometrically determined to be within 2.5-6.0 nm for all treated samples with parameterization of its optical constants in Cauchy approach. The study showed that for such biological treatments of the SS the protein layer adsorption is the dominating process in the first 2 weeks, which could play a role in the process of corrosion by complex forming properties with metal ions.

Spectroellipsometric, AFM and XPS probing of stainless steel surfaces subjected to biological influences

International Nuclear Information System (INIS)

Vinnichenko, M.; Chevolleau, Th.; Pham, M.T.; Poperenko, L.; Maitz, M.F.

2002-01-01

Surface modification of austenitic stainless steel (SS) 316L after incubation in growing cell cultures and cell-free media as control has been studied. The following treatments were applied: mouse fibrosarcoma cells L929 for 3 and 7 days, polymorphonuclear neutrophils for 3 and 7 days and human osteosarcoma cells SAOS-2 for 7 and 14 days. Cells were enzymatically removed in all cases. The modified surfaces were probed in comparison with untreated ones by means of spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). XPS shows the appearance of the peak of bonded nitrogen at 400.5 eV characteristic for adsorbed proteins on the surface for each type of cells and for the cell-free medium. Migration of Ni in the adsorbed layer is observed in all cases for samples after the cell cultures. The protein layer thickness is ellipsometrically determined to be within 2.5-6.0 nm for all treated samples with parameterization of its optical constants in Cauchy approach. The study showed that for such biological treatments of the SS the protein layer adsorption is the dominating process in the first 2 weeks, which could play a role in the process of corrosion by complex forming properties with metal ions

Stainless steel recycle FY94 progress report

International Nuclear Information System (INIS)

Imrich, K.J.

1994-01-01

The Materials Technology Section (MTS) of the Savannah River Technology Center (SRTC) was asked to demonstrate the practicality of recycling previously contaminated stainless steel components such as reactor heat exchanger heads, process water piping and slug buckets into 208 liters (55 gallon) drums and 2.8 cubic meter (100 ft 3 ) storage boxes. Radioactively contaminated stainless steel scrap will be sent to several industrial partners where it will be melted, decontaminated/cast into ingots, and rolled into plate and sheet and fabricated into the drums and boxes. As part of this recycle initiative, MTS was requested to demonstrate that radioactively contaminated Type 304L stainless steel could be remelted and cast to meet the applicable ASTM specification for fabrication of drums and boxes. In addition, MTS was requested to develop the technical basis of melt decontamination and establish practicality of using this approach for value added products. The findings presented in this investigation lead to the following conclusions: recycle of 18 wt% Cr-8 wt% Ni alloy can be achieved by melting Type 304 stainless steel in a air vacuum induction furnace; limited melt decontamination of the contaminated stainless steel was achieved, surface contamination was removed by standard decontamination techniques; carbon uptake in the as-cast ingots resulted from the graphite susceptor used in this experiment and is unavoidable with this furnace configuration. A new furnace optimized for melting stainless steel has been installed and is currently being tested for use in this program

Paraequilibrium Carburization of Duplex and Ferritic Stainless Steels

Science.gov (United States)

Michal, G. M.; Gu, X.; Jennings, W. D.; Kahn, H.; Ernst, F.; Heuer, A. H.

2009-08-01

AISI 301 and E-BRITE stainless steels were subjected to low-temperature (743 K) carburization experiments using a commercial technology developed for carburization of 316 austenitic stainless steels. The AISI 301 steel contained ~40 vol pct ferrite before carburization but had a fully austenitic hardened case, ~20- μm thick, and a surface carbon concentration of ~8 at. pct after treatment; this “colossal” paraequilibrium carbon supersaturation caused an increase in lattice parameter of ~3 pct. The E-BRITE also developed a hardened case, 12- to 18- μm thick, but underwent a more modest (~0.3 pct) increase in lattice parameter; the surface carbon concentration was ~10 at. pct. While the hardened case on the AISI 301 stainless steel appeared to be single-phase austenite, evidence for carbide formation was apparent in X-ray diffractometer (XRD) scans of the E-BRITE. Paraequilibrium phase diagrams were calculated for both AISI 301 and E-BRITE stainless steels using a CALPHAD compound energy-based interstitial solid solution model. In the low-temperature regime of interest, and based upon measured paraequilibrium carbon solubilities, more negative Cr-carbon interaction parameters for austenite than those in the current CALPHAD data base may be appropriate. A sensitivity analysis involving Cr-carbon interaction parameters for ferrite found a strong dependence of carbon solubility on relatively small changes in the magnitude of these parameters.

Hydrogel brushes grafted from stainless steel via surface-initiated atom transfer radical polymerization for marine antifouling

Energy Technology Data Exchange (ETDEWEB)

Wang, Jingjing, E-mail: jjwang1@hotmail.com; Wei, Jun

2016-09-30

Highlights: • Crosslinked hydrogel brushes were grafted from SS surfaces for marine antifouling. • All brush-coated SS surfaces could effectively reduce the adhesion of biofouling. • The antifouling efficacy increased with the crosslinking density of hydrogels. - Abstract: Crosslinked hydrogel brushes were grafted from stainless steel (SS) surfaces for marine antifouling. The brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-methacryloyloxyethyl phosphorylcholine (MPC) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) respectively with different fractions of crosslinker in the feed. The grafted layers prepared with different thickness were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), ellipsometry and water contact angle measurements. With the increase in the fraction of crosslinker in the feed, the thickness of the grafted layer increased and the surface became smooth. All the brush-coated SS surfaces could effectively reduce the adhesion of bacteria and microalgae and settlement of barnacle cyprids, as compared to the pristine SS surface. The antifouling efficacy of the PEGMA polymer (PPEGMA)-grafted surface was higher than that of the MPC polymer (PMPC)-grafted surfaces. Furthermore, the crosslinked hydrogel brush-grafted surfaces exhibited better fouling resistance than the non-crosslinked polymer brush-grafted surfaces, and the antifouling efficacy increased with the crosslinking density. These hydrogel coatings of low toxicity and excellent anti-adhesive characteristics suggested their useful applications as environmentally friendly antifouling coatings.

Hydrogel brushes grafted from stainless steel via surface-initiated atom transfer radical polymerization for marine antifouling

International Nuclear Information System (INIS)

Wang, Jingjing; Wei, Jun

2016-01-01

Highlights: • Crosslinked hydrogel brushes were grafted from SS surfaces for marine antifouling. • All brush-coated SS surfaces could effectively reduce the adhesion of biofouling. • The antifouling efficacy increased with the crosslinking density of hydrogels. - Abstract: Crosslinked hydrogel brushes were grafted from stainless steel (SS) surfaces for marine antifouling. The brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-methacryloyloxyethyl phosphorylcholine (MPC) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) respectively with different fractions of crosslinker in the feed. The grafted layers prepared with different thickness were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), ellipsometry and water contact angle measurements. With the increase in the fraction of crosslinker in the feed, the thickness of the grafted layer increased and the surface became smooth. All the brush-coated SS surfaces could effectively reduce the adhesion of bacteria and microalgae and settlement of barnacle cyprids, as compared to the pristine SS surface. The antifouling efficacy of the PEGMA polymer (PPEGMA)-grafted surface was higher than that of the MPC polymer (PMPC)-grafted surfaces. Furthermore, the crosslinked hydrogel brush-grafted surfaces exhibited better fouling resistance than the non-crosslinked polymer brush-grafted surfaces, and the antifouling efficacy increased with the crosslinking density. These hydrogel coatings of low toxicity and excellent anti-adhesive characteristics suggested their useful applications as environmentally friendly antifouling coatings.

Impact of roughness, wettability and hydrodynamic conditions on the incrustation on stainless steel surfaces

International Nuclear Information System (INIS)

Bogacz, Wojciech; Lemanowicz, Marcin; Al-Rashed, Mohsen H.; Nakonieczny, Damian; Piotrowski, Tomasz; Wójcik, Janusz

2017-01-01

Highlights: • Steel plates (X5CrNi18-10) with different roughness and wettability were prepared. • Incrustation of MgSO 4 ·7H 2 O under laminar flow (Re = 59–178) was investigated. • Influence of surface properties and fluid velocity on incrustation was found. • Wettability and surface roughness cannot be considered separately. • Analysis of heat transfer and incrustation time-lapse videos are presented. - Abstract: The goal of this work was to investigate the influence of the stainless steel surface roughness and wettability on incrustation of MgSO 4 ·7H 2 O from aqueous solutions and resulting heat transfer resistance. The experiments were done for laminar flow (Re = 59–178) which is characteristic for regions of apparatus where fouling usually begin. A series of steel plates (X5CrNi18-10) were prepared and used as a heat transfer surfaces. Their properties, i.e. roughness, wettability and elementary composition of surfaces were determined. The experiments were done using specially designed flow cell equipped with Peltier element. Each incrustation measurement lasted for two hours, during which heat transfer resistance was measured as a function of time. After the experiments the mass of crystalline deposit was weighted. It was proved that wettability as well as surface roughness cannot be considered separately in the case of incrustation phenomenon. The knowledge of surface roughness is insufficient due to the fact, that it is possible to obtain surfaces with similar roughness but substantially different wettability for the same material.

Cutting characteristics and deformed layer of type 316LN stainless steel

International Nuclear Information System (INIS)

Oh, Sun Sae; Yi, Won

2004-01-01

The cutting characteristics and the deformed layer of Nitrogen(N)-added type 316LN stainless steel were comparatively investigated to type 316L stainless steel. The cutting force, the surface roughness(Ra) and the tool wear in face milling works were measured with cutting conditions, and the deformed layers were obtained from micro-hardness testing method. The cutting resistance of type 316LN was similar to type 316L in spite of its high strength. The surface roughness of type 316LN was superior to type 316L for all the cutting conditions. In particular, in the high cutting speed above 345m/min, the surface roughness of the two stainless steels was closely same. The deformed layer thickness of the two stainless steels was generated in the 150μm-300μm ranges, and its value of type 316LN was lower than that of type 316L. This is due to the high strength properties by nitrogen effect. It was found that type 316LN was higher in the tool wear than that type 316L, and flank wear was dominant to crater wear. In face milling works of type 316LN steel, tool wear is regarded as a important problem

Advances in stainless steels

International Nuclear Information System (INIS)

Baldev Raj; Jayakumar, T.; Saibaba, Saroja; Sivaprasad, P.V.; Shankar, P.

2010-01-01

This book covers a broad spectrum of topics spanning the entire life cycle of stainless steel-from alloy design and characterization to engineering design, fabrication, mechanical properties, corrosion, quality assurance of components, in-service performance assessment, life prediction and finally failure analysis of materials and components. The contents provide useful feedback for further developments aimed at effective utilization of this class of materials. The book comprises articles that bring out contemporary developments in stainless steels and is thematically classified into the following sections. 1. Component design, modelling and structural integrity, 2. Manufacturing technology, 3. Property evaluation, 4. Alloy development and applications, 5. NDE methods, 6. Corrosion and surface modification. The book commences with articles on component design and structural integrity, thus opening up the areas of challenge for researchers and academia. The articles in the book relevant to INIS are indexed separately

In vitro assessment of photocatalytic titanium oxide surface modified stainless steel orthodontic brackets for antiadherent and antibacterial properties against Lactobacillus acidophilus.

Science.gov (United States)

Shah, Alok Girish; Shetty, Pradeep Chandra; Ramachandra, C S; Bhat, N Sham; Laxmikanth, S M

2011-11-01

To assess the antiadherent and antibacterial properties of surface modified stainless steel orthodontic brackets with photocatalytic titanium oxide (TiO(2)) against Lactobacillus acidophilus. This study was done on 120 specimens of stainless steel preadjusted edgewise appliance (PEA) orthodontic brackets. The specimens were divided into four test groups. Each group consisted of 30 specimens. Groups containing uncoated brackets acted as a control group for their respective experimental group containing coated brackets. Surface modification of brackets was carried out by the radiofrequency (RF) magnetron sputtering method with photocatalytic TiO(2). Brackets then were subjected to microbiological tests for assessment of the antiadherent and antibacterial properties of photocatalytic TiO(2) coating against L acidophilus. Orthodontic brackets coated with photocatalytic TiO(2) showed an antiadherent effect against L acidophilus compared with uncoated brackets. The bacterial mass that was bound to the TiO(2)-coated brackets was less when compared with the uncoated brackets. Furthermore, TiO(2)-coated brackets had a bactericidal effect on L acidophilus, which causes dental caries. Surface modification of orthodontic brackets with photocatalytic TiO(2) can be used to prevent the accumulation of dental plaque and the development of dental caries during orthodontic treatment.

In vitro bioactivity of micro metal injection moulded stainless steel with defined surface features

Directory of Open Access Journals (Sweden)

C Brose

2012-05-01

Full Text Available Micrometre- and nanometre-scale surface structuring with ordered topography features may dramatically enhance orthopaedic implant integration. In this study we utilised a previously optimised micron metal injection moulding (µ-MIM process to produce medical grade stainless steel surfaces bearing micrometre scale, protruding, hemispheres of controlled dimensions and spatial distribution. Additionally, the structured surfaces were characterised by the presence of submicrometre surface roughness resulting from metal grain boundary formation. Following cytocompatibility (cytotoxicity evaluation using 3T3 mouse fibroblast cell line, the effect on primary human cell functionality was assessed focusing on cell attachment, shape and cytoskeleton conformation. In this respect, and by day 7 in culture, significant increase in focal adhesion size was associated with the microstructured surfaces compared to the planar control. The morphological conformation of the seeded cells, as revealed by fluorescence cytoskeleton labelling, also appeared to be guided in the vertical dimension between the hemisphere bodies. Quantitative evaluation of this guidance took place using live cytoplasm fluorescence labelling and image morphometry analysis utilising both, compactness and elongation shape descriptors. Significant increase in cell compactness was associated with the hemisphere arrays indicating collective increase in focused cell attachment to the hemisphere bodies across the entire cell population. Micrometre-scale hemisphere array patterns have therefore influenced cell attachment and conformation. Such influence may potentially aid in enhancing key cellular events such as, for example, neo-osteogenesis on implanted orthopaedic surfaces.

Mechanical Characteristic of Remanufacturing of FV520B Precipitation Hardening Stainless Steel Using MAG Surfacing Deposition

Directory of Open Access Journals (Sweden)

LIU Jian

2017-10-01

Full Text Available Surfacing deposition forming method was adopted to carry out remanufacturing experiment of FV520B precipitation hardening stainless steel. Then the mechanical property characteristic of the remanufacturing layer was tested and studied, contrasted with the corresponding property of substrate. The results show that the remanufacturing layer, formed with MAG surfacing of FV520B precipitation hardening stainless steel has mechanical characteristic with high strength and hardness, the tensile strength reaches 1195MPa, exceeds 1092MPa of substrate, yield strength is 776MPa and average hardness is 336HV, is close to the corresponding property of substrate which is 859MPa and 353HV respectively; however, the elongation and impact toughness of the remanufacturing layer is merely 8.92% and 61J/cm2 respectively, it has a large gap with the corresponding property 19.72% and 144J/cm2 respectively of substrate. Fracture and microstructure analysis on specimens shows that the microstructure of remanufacturing layer is fast cooling non-equilibrium crystallized lath martensite, and carbide precipitated strengthening phase such as NbC, MoC, M23C6,etc, which is the reason that remanufacturing layer has high strength and high hardness. But as lack of aging treatment and Cu strengthening phase, and the weak interface between contaminating brittle phase or large size spherical particles and substrate will deteriorate the deformability and induce stress concentration and cracking when the material is load-carrying, and is the main reason of the remanufacturing layer having lower static tensile elongation and impact toughness.

Microstructure of rapidly solidified Al2O3-dispersion-strengthened Type 316 stainless steel

International Nuclear Information System (INIS)

Megusar, J.; Arnberg, L.; Vander Sande, J.B.; Grant, N.J.

1981-01-01

An aluminum oxide dispersion strengthened 316 stainless steel was developed by surface oxidation. Surface oxidation was chosen as a preferred method in order to minimize formation of less stable chromium oxides. Ultra low C+N 316 stainless steel was alloyed with 1 wt % Al, rapidly solidified to produce fine powders and attrited to approximately 0.5 μm thick flakes to provide for surface oxidation. Oxide particles in the extruded material were identified mostly as Al oxides. In the preirradiated condition, oxide dispersion retarded crystallization and grain growth and had an effect on room temperature tensile properties. These structural modifications are expected to have an effect on the swelling resistance, structure stability and high temperature strength of austenitic stainless steels

Sandblasting induced stress release and enhanced adhesion strength of diamond films deposited on austenite stainless steel

Science.gov (United States)

Li, Xiao; Ye, Jiansong; Zhang, Hangcheng; Feng, Tao; Chen, Jianqing; Hu, Xiaojun

2017-08-01

We firstly used sandblasting to treat austenite stainless steel and then deposited a Cr/CrN interlayer by close field unbalanced magnetron sputtering on it. After that, diamond films were prepared on the interlayer. It is found that the sandblasting process induces phase transition from austenite to martensite in the surface region of the stainless steel, which decreases thermal stress in diamond films due to lower thermal expansion coefficient of martensite phase compared with that of austenite phase. The sandblasting also makes stainless steel's surface rough and the Cr/CrN interlayer film inherits the rough surface. This decreases the carburization extent of the interlayer, increases nucleation density and modifies the stress distribution. Due to lower residual stress and small extent of the interlayer's carburization, the diamond film on sandblast treated austenite stainless steel shows enhanced adhesion strength.

Effect of Cavitation on Surface Damage of 16.7Cr-10Ni-2Mo Stainless Steel in Marine Environment

Energy Technology Data Exchange (ETDEWEB)

Chong, Sang-Ok; Han, Min-Su; Kim, Seong-Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

2015-10-15

Stainless steel is generally known to have characteristics of excellent corrosion resistance and durability, but in a marine environment it can suffer from localized corrosion due to the breakdown of passivity film due to chloride ion in seawater. Furthermore, the damage behaviors are sped up under a cavitation environment because of complex damage from electrochemical corrosion and cavitation-erosion. In this study the characteristics of electrochemical corrosion and cavitation erosion behavior were evaluated on 16.7Cr-10Ni-2Mo stainless steel under a cavitation environment in natural seawater. The electrochemical experiments have been conducted at both static conditions and dynamic conditions inducing cavitation with different current density parameters. The surface morphology and damage behaviors were compared after the experiment. After the cavitation test with time variables morphological examinations on damaged specimens were analyzed by using a scanning electron microscope and a 3D microscope. the galvanostatic experiment gave a cleaner surface morphology presented with less damage depth at high current density regions. It is due to the effect of water cavitation peening under the cavitation condition. In the cavitation experiment, with amplitude of 30 μm and seawater temperature of 25 ℃, weight loss and cavitation-erosion damage depth were dramatically increased after 5 hours inducing cavitation.

Modeling and Simulated Annealing Optimization of Surface Roughness in CO2 Laser Nitrogen Cutting of Stainless Steel

Directory of Open Access Journals (Sweden)

M. Madić

2013-09-01

Full Text Available This paper presents a systematic methodology for empirical modeling and optimization of surface roughness in nitrogen, CO2 laser cutting of stainless steel . The surface roughness prediction model was developed in terms of laser power , cutting speed , assist gas pressure and focus position by using The artificial neural network ( ANN . To cover a wider range of laser cutting parameters and obtain an experimental database for the ANN model development, Taguchi 's L27 orthogonal array was implemented in the experimental plan. The developed ANN model was expressed as an explicit nonlinear function , while the influence of laser cutting parameters and their interactions on surface roughness were analyzed by generating 2D and 3D plots . The final goal of the experimental study Focuses on the determinationof the optimum laser cutting parameters for the minimization of surface roughness . Since the solution space of the developed ANN model is complex, and the possibility of many local solutions is great, simulated annealing (SA was selected as a method for the optimization of surface roughness.

Stainless steel in contact with food and bevarage

Directory of Open Access Journals (Sweden)

Sveto Cvetkovski

2012-12-01

Full Text Available Stainless steels are probably the most important materials in the food and beverage industries. The main reason for such broad implementation of stainless steel in contact with food are excellent properties which they possess such as corrosion resistance, resistance to high and low temperatures, very good mechanical and physical properties, aesthetic appeal, inertness of surface, durability, easy cleaning and recycling. Low thermal conductivity of these steels produces steeper temperature coefficient provoking an increased distortion, shrinkage and stresses compared with carbon steel.

The residual stress distribution in welded pipe inner surface of stainless steel from the nuclear power plant in Ringhals

International Nuclear Information System (INIS)

Larsson, L.E.

1984-06-01

The axial residual stress distribution on the inner surface of welded pipes of stainless steel SS 2333 (AISI 304) have been measured using the X-ray diffraction technique. Four halves of two pipes with the outer diameter of 114 mm and wall thickness of 10 mm were investigated. The result on the pipe inner surface shows compressive stresses in the weld metal and tensile stresses within a region between 8-23 mm with a maximum of 180MPa at a distance of 17 mm from the weld centerline. The maximum axial and circumferential residual stresses on the pipe outer surface are of the magnitude of 100 MPa. By cutting the pipes into two halves these stresses are relaxed by about 35 MPa. (author)

Surface decontamination of Type 304L stainless steel with electrolytically generated hydrogen: Design and operation of the electrolyzer

International Nuclear Information System (INIS)

Bellanger, G.

1993-01-01

The surface of tritiated Type 304L stainless steel is decontaminated by isotopic exchange with the hydrogen generated in an electrolyzer. This steel had previously been exposed to tritium in a tritium gas facility for several years. The electrolyzer for the decontamination uses a conducting solid polymer electrolyte made of a Nafion membrane. The cathode where the hydrogen is formed is nickel deposited on one of the polymer surfaces. This cathode is placed next to the region of the steel to be decontaminated. The decontamination involves, essentially, the tritiated oxide layers of which the initial radioactivity is ∼ 5 kBq/cm 2 . After treatment for 1 h, the decontamination factor is 8. 9 refs., 16 figs., 2 tabs

Effects of nitrogen on corrosion of stainless steels in a liquid sodium environment

International Nuclear Information System (INIS)

Suzuki, Tadashi; Mutoh, Isao

1990-01-01

The corrosion of ferritic stainless steels using sodium at 650degC in a maximum isothermal region contained in a non-isothermal sodium loop constructed of a Type 316 stainless steel has been examined. Also, previous results on corrosion of austenitic stainless steels in sodium at 700degC in the same loop have been reproduced. The selective dissolution and absorption of nickel, the selective dissolution of chromium, and the resultant increase in iron in the surface of stainless steels in the loop mainly determine the corrosion loss of the stainless steel specimens. The austenitic steels hardly decarburize, but denitride. The ferritic steels decarburize and denitride and the denitriding is more remarkable than the decarburizing. The vanadium and niobium, carbide and nitride formers, in the ferritic steels inhibit the decarburizing to some extent, but barely inhibit the denitriding. The nitrogen in the steels rapidly diffuses to the grain boundaries, and rapidly dissolves into sodium, which will lower surface energy of the steels to enhance the dissolution of other elements. The dissolved N in sodium would then be transported to the free surface of the sodium adjacent to the argon cover gas of sodium and easily be released into the cover gas. This mechanism would cause the rapid dissolution of nitrogen into sodium and the enhancement of the corrosion rate of the steels containing nitrogen. (orig.)

The effect of internal hydrogen on surface slip localisation on polycrystalline AISI 316L stainless steel

International Nuclear Information System (INIS)

Aubert, Isabelle; Olive, Jean-Marc; Saintier, Nicolas

2010-01-01

A statistical analysis of the effect of internal hydrogen on the surface slip morphology of relatively high nickel content AISI 316L type austenitic stainless steel was carried out on high resolution data obtained by atomic force microscopy. Surface plastic strain localisation was studied for different hydrogen contents, two grain sizes, and two plastic strain levels. The height and spacing of approximately 8000 slip bands, observed on 12 specimens, are shown to follow log-normal distributions. Hydrogen increased the mean slip-band height and the mean slip-band spacing for the two macroscopic plastic strain levels considered, and for the two hydrogen concentrations in coarse-grained specimens. The hydrogen effect was also observed for fine-grained specimens, but only for the highest hydrogen concentration. In addition, the emerging dislocation velocity increased by a factor 3 for high hydrogen content.

Method of chemical decontamination of stainless steel

International Nuclear Information System (INIS)

Onuma, Tsutomu; Akimoto, Hidetoshi.

1989-01-01

The present invention concerns a decontamination method of chemically decontaminating radioactive metal wastes of passivated stainless steels to a radioactivity level identical with usual wastes, in which the amount of oxidizable metal salts used is decreased. Metal wastes of stainless steels contaminated at their surface with radioactive materials are immersed in a sulfuric acid solution. In this case, a voltage is applied for a certain period of time so that the potential of the stainless steels comes to an active region. Then, oxidizable metal salt (tetravalent cerium) is added into the sulfuric acid solution. According to this method, since most of radioactive materials are removed in the immersing step to the sulfuric acid solution, the amount of the tetravalent cerium used is as less as 1/700 and the decontamination time is as short as 1/4 as compared with those in the conventional method. (K.M.)

Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces.

Science.gov (United States)

Secker, T J; Pinchin, H E; Hervé, R C; Keevil, C W

2015-01-01

Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.

Biocompatibility of 17-4 PH stainless steel foam for implant applications.

Science.gov (United States)

Mutlu, Ilven; Oktay, Enver

2011-01-01

In this study, biocompatibility of 17-4 PH stainless steel foam for biomedical implant applications was investigated. 17-4 PH stainless steel foams having porosities in the range of 40-82% with an average pore size of around 600 μm were produced by space holder-sintering technique. Sintered foams were precipitation hardened for times of 1-6 h at temperatures between 450-570 °C. Compressive yield strength and Young's modulus of aged stainless steel foams were observed to vary between 80-130 MPa and 0.73-1.54 GPa, respectively. Pore morphology, pore size and the mechanical properties of the 17-4 PH stainless steel foams were close to cancellous bone. In vitro evaluations of cytotoxicity of the foams were investigated by XTT and MTT assays and showed sufficient biocompatibility. Surface roughness parameters of the stainless steel foams were also determined to characterize the foams.

Localized corrosion of high alloyed austenitic stainless steels

International Nuclear Information System (INIS)

Morach, R.; Schmuki, P.; Boehni, H.

1992-01-01

The susceptibility of several high alloyed stainless steels against localized corrosion was investigated by traditional potentiostatic and -kinetic methods and the current transient technique. Different test cells, proposed in literature, were evaluated for use in testing of plate materials. The AVESTA-cell showed to be not useful for potentiokinetic current density potential curves, but useable for pitting experiments. After pickling and prepassivation epoxy embedded materials proved to be resistant to crevice corrosion at the metal-resin interface. The electrode in form of a wire was the most reliable crevice free cell design. The grinding of the samples in the pretreatment procedure was found to have a large effect on the pitting corrosion behaviour. Using different paper types with varying grit, a drop in pitting potential for rougher surfaces and an increase in metastable pitting activity was found. Increasing surface roughness led also to changes in the electronic structure of the passive film reflected by a lower bandgap energy. High alloyed stainless steels showed no breakdown potential within the examined potential range. Compared to 18/8 type stainless steels significantly less transients were found. The number of transients decreases with increasing molybdenum and chromium content

Influence of Heat Treatment on Mercury Cavitation Resistance of Surface Hardened 316LN Stainless Steel

Energy Technology Data Exchange (ETDEWEB)

Pawel, Steven J [ORNL; Hsu, Julia [Massachusetts Institute of Technology (MIT)

2010-11-01

The cavitation-erosion resistance of carburized 316LN stainless steel was significantly degraded but not destroyed by heat treatment in the temperature range 500-800 C. The heat treatments caused rejection of some carbon from the carburized layer into an amorphous film that formed on each specimen surface. Further, the heat treatments encouraged carbide precipitation and reduced hardness within the carburized layer, but the overall change did not reduce surface hardness fully to the level of untreated material. Heat treatments as short as 10 min at 650 C substantially reduced cavitation-erosion resistance in mercury, while heat treatments at 500 and 800 C were found to be somewhat less detrimental. Overall, the results suggest that modest thermal excursions perhaps the result of a weld made at some distance to the carburized material or a brief stress relief treatment will not render the hardened layer completely ineffective but should be avoided to the greatest extent possible.

Microstructural-Scale Model for Surfaces Spreading of Intergranular Corrosion in Sensitized Stainless Steels and Aluminum-Magnesium (AA5XXX) Alloys

Science.gov (United States)

Jain, Swati

Components from AA5XXX (Al-Mg alloys with more than 3 wt% Mg) alloys are X attractive due to availability of low cost, high strength to weight ratio and good weldability. Therefore, these alloys have potential applications in Naval ships. However, these alloys become susceptible to IGC (intergranular corrosion) due to beta-phase precipitation due to improper heat treatment or inadvertent thermal exposure. Stainless steels may also become susceptible due to carbide precipitation and chromium depletion on grain boundaries. IGC susceptibility depends on the interplay between the metallurgical conditions, electrochemical conditions, and chemical conditions. Specific combinations cause IGC while others do not. The objective of this study is to investigate the conditions which bring about surface spreading of IGC in these alloy classes. To accomplish this goal, a microstructure scale model was developed with experimental inputs to understand the 2-D IGC spreading in stainless steels and AA5XXX alloys. The conditions strongly affecting IGC spreading were elucidated. Upon natural and artificial aging, the stainless steels become susceptible to intergranular corrosion because of chromium depletion in the grain boundaries. After aging Al-Mg (AA5XXX) alloys show susceptibility due to the precipitation of the beta-phase (Al3Mg7) in the grain boundaries. Chromium depleted grain boundaries in stainless steels are anodically more active as compared to the interior of the grains. (3-phase rich grain boundaries have lower OCP (open circuit potential) and pitting potentials as compared to the Al-Mg solid solutions. A new approach to modeling the IGC surface spreading in polycrystalline materials that is presented. This model is the first to couple several factors into one granular scale model that illustrates the way in which they interact and IGC occurs. It sheds new information on conditions which cause IGC spreading in two alloy classes and describes a new theory for the critical

Chromium depletion from stainless steels during vacuum annealing

International Nuclear Information System (INIS)

Smith, A.F.; Hales, R.

1977-01-01

During selective chromium oxidation of stainless steels the changes in chromium concentration at the metal surface and in the metal have an important bearing on the overall oxidation performance. It has been proposed that an analogue of chromium behaviour during selective oxidation is obtained from volatilisation of chromium during high temperature vacuum annealing. In the present report the evaporation of chromium from 316 type of steel, vacuum annealed at 1,000 0 C, has been investigated by means of energy dispersive X-ray analysis and by neutron activation analysis. It was established that chromium loss from austenitic stainless steels is rate controlled by interdiffusion in the alloy. As predicted the chromium concentration at the metal surface decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in good agreement with the previously derived model apart from an anomalous region near the surface. Here the higher resolution of the neutron activation technique indicated a zone within approximately 2μm of the surface where the chromium concentration decreased more steeply than expected. (orig.) [de

Prevention of weld-decay in austenitic stainless steel by using surface mechanical attrition treatment

Science.gov (United States)

Laleh, Majid; Kargar, Farzad; Rouhaghdam, Alireza Sabour

2012-11-01

Surface mechanical attrition treatment (SMAT) was applied to the samples of a type AISI 304 stainless steel in order to induce grain refinement as well as formation of twins. Transmission electron microscopy and X-ray diffraction analysis results showed that the average grain size at the surface of the SMATed sample was about 10 nm. The untreated and SMATed samples were then welded using a one-pass gas tungsten arc procedure. The heat-affected zone (HAZ) of the samples was examined by optical microscopy and corrosion tests. Results of the double loop electrochemical potentiokinetic reactivation tests showed that the degree of sensitization in the HAZ for the SMATed sample was very low as compared to that of the untreated one. The pre-SMATed sample was resistant to intergranular corrosion. This is mainly due to the formation of high density of twins which are not prone to carbide precipitation because of their regular and coherent atomic structure and extreme low grain boundary energy as compared with those of other grain boundaries.

Minister Mr. P.P. van Bosse en de fiscale wetgeving rond het midden van de 19e eeuw

NARCIS (Netherlands)

Viersen, Jacob

1997-01-01

This dissertation focuses on the following two topics: 1. Van Bosse, both as an individual and as a member of Dutch cabinets; with an assessment of his ministerships (Chapter I), and 2. the changes which took place in fiscal legislation in the period from 1848 to 1853. This dissertation also

Au-coated ZnO nanorods on stainless steel fiber for self-cleaning solid phase microextraction-surface enhanced Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Li, Bo; Shi, Yu-e; Cui, Jingcheng; Liu, Zhen; Zhang, Xiaoli; Zhan, Jinhua, E-mail: jhzhan@sdu.edu.cn

2016-06-07

Solid phase microextraction-surface enhanced Raman spectroscopy (SPME–SERS), combining the pretreatment and determination functions, has been successfully used in environmental analysis. In this work, Au-coated ZnO nanorods were fabricated on stainless steel fiber as a self-cleaning SERS-active SPME fiber. The ZnO nanorods grown on stainless steel fiber were prepared via a simple hydrothermal approach. Then the obtained nanostructures were decorated with Au nanoparticles through ion-sputtering at room temperature. The obtained SERS-active SPME fiber is a reproducible sensitivity sensor. Taking p-aminothiophenol as the probe molecule, the RSD value of the SERS-active SPME fiber was 8.9%, indicating the fiber owned good uniformity. The qualitative and quantitative detection of crystal violet and malachite green was also achieved. The log–log plot of SERS intensity to crystal violet and malachite green concentration showed a good linear relationship. Meanwhile, this SERS-active SPME fiber can achieve self-cleaning owning to the excellent photocatalytic performance of ZnO nanorods. Crystal violet was still successfully detected even after five cycles, which indicated the high reproducibility of this SERS-active SPME fiber. - Graphical abstract: Au-coated ZnO NRs on stainless steel fiber were used as SERS-active SPME fiber with good extraction effect, high SERS sensitivity. Self-cleaning function of the fiber was achieved based on the photocatalytic degradation property of ZnO nanorods by UV irradiation. - Highlights: • Au-coated ZnO nanorods on stainless steel fiber as a SERS-active SPME fiber was fabricated. • The SERS-active SPME fiber can directly extract and detect the crystal violet and malachite green. • The SERS-active SPME fiber owns good extraction effect, and high SERS sensitivity. • Self-cleaning property of the fiber were achieved based on the photocatalytic degradation property of ZnO.

Au-coated ZnO nanorods on stainless steel fiber for self-cleaning solid phase microextraction-surface enhanced Raman spectroscopy

International Nuclear Information System (INIS)

Li, Bo; Shi, Yu-e; Cui, Jingcheng; Liu, Zhen; Zhang, Xiaoli; Zhan, Jinhua

2016-01-01

Solid phase microextraction-surface enhanced Raman spectroscopy (SPME–SERS), combining the pretreatment and determination functions, has been successfully used in environmental analysis. In this work, Au-coated ZnO nanorods were fabricated on stainless steel fiber as a self-cleaning SERS-active SPME fiber. The ZnO nanorods grown on stainless steel fiber were prepared via a simple hydrothermal approach. Then the obtained nanostructures were decorated with Au nanoparticles through ion-sputtering at room temperature. The obtained SERS-active SPME fiber is a reproducible sensitivity sensor. Taking p-aminothiophenol as the probe molecule, the RSD value of the SERS-active SPME fiber was 8.9%, indicating the fiber owned good uniformity. The qualitative and quantitative detection of crystal violet and malachite green was also achieved. The log–log plot of SERS intensity to crystal violet and malachite green concentration showed a good linear relationship. Meanwhile, this SERS-active SPME fiber can achieve self-cleaning owning to the excellent photocatalytic performance of ZnO nanorods. Crystal violet was still successfully detected even after five cycles, which indicated the high reproducibility of this SERS-active SPME fiber. - Graphical abstract: Au-coated ZnO NRs on stainless steel fiber were used as SERS-active SPME fiber with good extraction effect, high SERS sensitivity. Self-cleaning function of the fiber was achieved based on the photocatalytic degradation property of ZnO nanorods by UV irradiation. - Highlights: • Au-coated ZnO nanorods on stainless steel fiber as a SERS-active SPME fiber was fabricated. • The SERS-active SPME fiber can directly extract and detect the crystal violet and malachite green. • The SERS-active SPME fiber owns good extraction effect, and high SERS sensitivity. • Self-cleaning property of the fiber were achieved based on the photocatalytic degradation property of ZnO.

Weldability of Stainless Steels

International Nuclear Information System (INIS)

Saida, Kazuyoshi

2010-01-01

It gives an outline of metallographic properties of welding zone of stainless steels, generation and mechanisms of welding crack and decreasing of corrosion resistance of welding zone. It consists of seven chapters such as introduction, some kinds of stainless steels and properties, metallographic properties of welding zone, weld crack, toughness of welding zone, corrosion resistance and summary. The solidification modes of stainless steels, each solidification mode on the cross section of Fe-Cr-Ni alloy phase diagram, each solidification mode of weld stainless steels metal by electron beam welding, segregation state of alloy elements at each solidification mode, Schaeffler diagram, Delong diagram, effects of (P + S) mass content in % and Cr/Ni equivalent on solidification cracking of weld stainless steels metal, solidification crack susceptibility of weld high purity stainless steels metal, effects of trace impurity elements on solidification crack susceptibility of weld high purity stainless steels metal, ductile fracture susceptibility of weld austenitic stainless steels metal, effects of H2 and ferrite content on generation of crack of weld 25Cr-5N duplex stainless steels, effects of O and N content on toughness of weld SUS 447J1 metals, effect of ferrite content on aging toughness of weld austenitic stainless steel metal, corrosion morphology of welding zone of stainless steels, generation mechanism of knife line attack phenomenon, and corrosion potential of some kinds of metals in seawater at room temperature are illustrated. (S.Y.)

Development of liner cutting method for stainless steel liner

International Nuclear Information System (INIS)

Takahata, Masato; Wignarajah, Sivakmaran; Kamata, Hirofumi

2005-01-01

The present work is an attempt to develop a laser cutting method for cutting and removing stainless steel liners from concrete walls and floors in cells and fuel storage pools of nuclear facilities. The effects of basic laser cutting parameters such as cutting speed, assist gas flow etc. were first studied applying a 1 kW Nd:YAG laser to mock up concrete specimens lined with 3 mm thick stainless steel sheets. These initial studies were followed by studies on the effect of unevenness of the liner surface and on methods of confining contamination during the cutting process. The results showed that laser cutting is superior to other conventional cutting methods from the point of view of safety from radioactivity and work efficiency when cutting contaminated stainless steel liners. In addition to the above results, this paper describes the design outline of a laser cutting system for cutting stainless liners at site and evaluates its merit and cost performance. (author)

Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic and Precipitation Hardening Stainless Steels by Gaseous Nitriding

DEFF Research Database (Denmark)

Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

2015-01-01

This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were...... case included X-ray diffraction analysis, reflected light microscopy and microhardness. The results demonstrate that a case of expanded austenite develops and that, in particular, strain-induced martensite has a large influence on the nitrided zone....

High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

International Nuclear Information System (INIS)

Prajitno, Djoko Hadi; Syarif, Dani Gustaman

2014-01-01

The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO 2 . The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe 2 O 3 . Minor element such as Cr 2 O 3 is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO 2 appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate

Depth distribution of martensite in xenon implanted stainless steels

International Nuclear Information System (INIS)

Johansen, A.; Johnson, E.; Sarholt-Kristensen, L.; Steenstrup, S.; Hayashi, N.; Sakamoto, I.

1989-01-01

The amount of stress-induced martensite and its distribution in depth in xenon implanted austenitic stainless steel poly- and single crystals have been measured by Rutherford backscattering and channeling analysis, depth selective conversion electron Moessbauer spectroscopy, cross-sectional transmission electron microscopy and x-ray diffraction analysis. In low nickel 17/7, 304 and 316 commercial stainless steels and in 17:13 single crystals the martensitic transformation starts at the surface and develops towards greater depth with increasing xenon fluence. The implanted layer is nearly completely transformed, and the interface between martensite and austenite is rather sharp and well defined. In high nickel 310 commercial stainless steel and 15:19 and 20:19 single crystals, on the other hand, only insignificant amounts of martensite are observed. (orig.)

SCC susceptibility of cold-worked stainless steel with minor element additions

International Nuclear Information System (INIS)

Nakano, Junichi; Nemoto, Yoshiyuki; Tsukada, Takashi; Uchimoto, Tetsuya

2011-01-01

To examine the effects of minor elements on stress corrosion cracking (SCC) susceptibility of low carbon stainless steels with a work hardened layer, a high purity type 304 stainless steel was fabricated and minor elements, Si, S, P, C or Ti, were added. A work hardened layer was introduced by shaving on the surface of stainless steels. The specimens were exposed to a boiling 42% MgCl 2 solution for 20 h and the number and the length of initiated cracks were examined. SCC susceptibility of the specimen with P was the highest and that of the specimen with C was the lowest in all specimens. By magnetic force microscope examination, a magnetic phase expected to be a martensitic phase was detected near the surface. Since corrosion resistance of martensite is lower than that of austenite, the minor elements additions would affect SCC susceptibility through the amount of the transformed martensite.

Surface characterisation and electrochemical behaviour of porous titanium dioxide coated 316L stainless steel for orthopaedic applications

International Nuclear Information System (INIS)

Nagarajan, S.; Rajendran, N.

2009-01-01

Porous titanium dioxide was coated on surgical grade 316L stainless steel (SS) and its role on the corrosion protection and enhanced biocompatibility of the materials was studied. X-ray diffraction analysis (XRD), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were carried out to characterise the surface morphology and also to understand the structure of the as synthesised coating on the substrates. The corrosion behaviour of titanium dioxide coated samples in simulated body fluid was evaluated using polarisation and impedance spectroscopy studies. The results reveal that the titanium dioxide coated 316L SS exhibit a higher corrosion resistance than the uncoated 316L SS. The titanium dioxide coated surface is porous, uniform and also it acts as a barrier layer to metallic substrate and the porous titanium dioxide coating induces the formation of hydroxyapatite layer on the metal surface.

Weldability, machinability and surfacing of commercial duplex stainless steel AISI2205 for marine applications - A recent review.

Science.gov (United States)

Vinoth Jebaraj, A; Ajaykumar, L; Deepak, C R; Aditya, K V V

2017-05-01

In the present review, attempts have been made to analyze the metallurgical, mechanical, and corrosion properties of commercial marine alloy duplex stainless steel AISI 2205 with special reference to its weldability, machinability, and surfacing. In the first part, effects of various fusion and solid-state welding processes on joining DSS 2205 with similar and dissimilar metals are addressed. Microstructural changes during the weld cooling cycle such as austenite reformation, partitioning of alloying elements, HAZ transformations, and the intermetallic precipitations are analyzed and compared with the different welding techniques. In the second part, machinability of DSS 2205 is compared with the commercial ASS grades in order to justify the quality of machining. In the third part, the importance of surface quality in a marine exposure is emphasized and the enhancement of surface properties through peening techniques is highlighted. The research gaps and inferences highlighted in this review will be more useful for the fabrications involved in the marine applications.

Metallurgical study of low-temperature plasma carbon diffusion treatments for stainless steels

International Nuclear Information System (INIS)

Lewis, D.B.; Leyland, A.; Stevenson, P.R.; Cawley, J.; Matthews, A.

1993-01-01

We recently reported a novel low-temperature carbon diffusion technique for surface hardening of stainless steels. The treatment was shown to provide benefits in terms of abrasive wear resistance. There is also evidence to suggest that by performing diffusion treatments at low temperatures (i.e. below 400 C), these benefits can be achieved without compromising corrosion resistance. Here a variety of surface analysis and depth profiling techniques have been used to determine the physical and mechanical properties of carbon-rich layers produced on a range of stainless steel substrate materials. X-ray diffraction (XRD) was employed to determine the crystallographic structure, whilst wavelength dispersive X-ray analysis (WDX) and glow discharge optical spectroscopy (GDOS) gave information on the concentration and distribution of the diffused species within the treated layers. A variety of carbide-based structures was detected, including the expected M 23 C 6 and, more surprisingly, M 3 C. Optical and electron microscopy techniques were used to provide information on layer morphology. The surfaces produced by the low-temperature carbon-diffusion process generally exhibit a distinct diffusion layer of between 1 and 20 μm, depending on the material and the treatment conditions. Austenitic stainless steels appear to give the best response to treatment, however other types of stainless steel can be treated, particularly if the microstructure contains above 5% retained austenite. Here we discuss the changes in mechanical and metallurgical properties provided by this technique and its potential value for treatment of both austenitic and other stainless steel substrate materials. (orig.)

Infrared electro-thermal NDE of stainless steel

International Nuclear Information System (INIS)

Green, D.R.; Hassberger, J.A.

1975-01-01

Electro-thermal examination, a branch of thermal testing, is a promising method being developed for nondestructive examination of stainless steel welds. This paper describes the first phase of development; i.e., preliminary demonstration and laboratory evaluation of the method's sensitivity to notches in Type 304 stainless steel plate specimens. It also includes a description of the basic principles, together with a description of the hardware and experimental results showing that electrical discharge machined notches down to 0.16 cm long x 0.08 cm deep were detected. A qualitative technique for interpreting the test results to determine whether defects are at the surface or deeper within the material is demonstrated

Ultraviolet-C efficacy against a norovirus surrogate and hepatitis A virus on a stainless steel surface.

Science.gov (United States)

Park, Shin Young; Kim, An-Na; Lee, Ki-Hoon; Ha, Sang-Do

2015-10-15

In this study, the effects of 10-300 mWs/cm(2) of ultraviolet radiation (UV-C) at 260 nm were investigated for the inactivation of two foodborne viruses: murine norovirus-1 (MNV-1; a human norovirus [NoV] surrogate) and hepatitis A virus (HAV). We used an experimentally contaminated stainless steel surface, a common food-contact surface, to examine the effects of low doses of UV-C radiation on MNV-1 and HAV titers. The modified Gompertz equation was used to generate non-linear survival curves and calculate dR-values as the UV-C dose of 90% reduction for MNV-1 (R(2)=0.95, RMSE=0.038) and HAV (R(2)=0.97, RMSE=0.016). Total MNV-1 and HAV titers significantly decreased (pradiation than MNV-1. These data suggest that low doses of UV-C light on food contact surfaces could be effective to inactivate human NoV and HAV in restaurant, institutional, and industrial kitchens and facilities. Copyright © 2015 Elsevier B.V. All rights reserved.

Fatigue and creep-fatigue in sodium of 316 1 stainless steel

International Nuclear Information System (INIS)

Ardellier, A.

1982-01-01

Equipment and results obtained on type 316 L stainless stee1 at 450 0 C and 600 0 C with low-cycle fatique and creep fatigue tests are described. Comparison with runs in air on type 316 L stainless steel shows a better low-cycle fatigue behavior in a sodium environment. This beneficial effect can be attributed to the low oxygen content which limits the surface oxidazation

High temperature oxidation behavior of AISI 304L stainless steel—Effect of surface working operations

International Nuclear Information System (INIS)

Ghosh, Swati; Kumar, M. Kiran; Kain, Vivekanand

2013-01-01

Highlights: ► Surface working resulted in thinner oxide on the surface. ► Oxides on machined/ground surfaces richer in Cr, higher in specific resistivity. ► Additional ionic transport process at the metal-oxide for ground sample established. ► Presence of fragmented grains and martensite influenced oxide nature/morphology. - Abstract: The oxidation behavior of grade 304L stainless steel (SS) subjected to different surface finishing (machining and grinding) operations was followed in situ by contact electric resistance (CER) and electrochemical impedance spectroscopy (EIS) measurements using controlled distance electrochemistry (CDE) technique in high purity water (conductivity −1 ) at 300 °C and 10 MPa in an autoclave connected to a recirculation loop system. The results highlight the distinct differences in the oxidation behavior of surface worked material as compared to solution annealed material in terms of specific resistivity and low frequency Warburg impedance. The resultant oxide layer was characterized for (a) elemental analyses by glow discharge optical emission spectroscopy (GDOES) and (b) morphology by scanning electron microscopy (SEM). Oxide layers with higher specific resistivity and chromium content were formed in case of machined and ground conditions. Presence of an additional ionic transport process has also been identified for the ground condition at the metal/oxide interface. These differences in electrochemical properties and distinct morphological features of the oxide layer as a result of surface working were attributed to the prevalence of heavily fragmented grain structure and presence of martensite.

RESEARCH OF THE ENTRANCE ANGLE EFFECT ON THE REFLECTANCE SPECTRA OF THE STAINLESS STEEL SURFACE OXIDIZED BY PULSED LASER RADIATION

Directory of Open Access Journals (Sweden)

V. P. Veiko

2016-05-01

Full Text Available Subject of Research.Oxide films on the metal surfaces can be obtained both by surface-uniform infrared heating and local laser treatment e.g. by sequence of nanosecond laser pulses. Due to interference in created films the coloration of treated area is observed. The present work shows the results of spectrophotometric measurements for various light entrance angles in the range of 10-60°. Method. AISI 304 stainless steel plates were oxidized by two methods: in muffle furnace FM - 10 (Т= 500-600° С, t = 5-7 min. and at line-by-line scanning by sequence of nanosecond laser pulses (λ = 1.06 μm, τ =100 ns, r = 25 μm,q=2.91∙107 W/cm2, Nx = 30, Ny = 1. Surface research in optical resolution was realized by Carl Zeiss Axio Imager A1M. Reflectance spectra were obtained with spectrophotometer Lambda Perkin 1050 with integrating sphere at different fixed light incidence angles. Topographic features were detected by scanning probe microscopy investigation with NanoEducator equipment. Main Results. The quantitative surface geometry characteristics of AISI 304 stainless steel patterns treated by different methods are obtained. It was found that the increase of light entrance angle has no influence on the form of reflection coefficient dependence from a wavelength, but a blue-shift occurs especially for the case of laser treatment. This difference can be caused by surface topology formed by laser heating and variety of oxide film thickness. This effect results in more significant change in observed sample color for laser treatment then for infrared heating. Practical Relevance. The results obtained in the present work can be used to implement a new element of product protection against forgery with the product marking.

The effects of various surface treatments on the shear bond strengths of stainless steel brackets to artificially-aged composite restorations.

Science.gov (United States)

Eslamian, Ladan; Borzabadi-Farahani, Ali; Mousavi, Nasim; Ghasemi, Amir

2011-05-01

To compare the shear bond strengths (SBS) of stainless steel brackets bonded to artificially-aged composite restorations after different surface treatments. Forty-five premolar teeth were restored with a nano-hybrid composite (Tetric EvoCeram), stored in deionised water for one week and randomly divided into three equal groups: Group I, he restorations were exposed to 5 per cent hydrofluoric acid for 60 seconds; Group II, the restorations were abraded with a micro-etcher (50 Iim alumina particles); Group III, the restorations were roughened with a coarse diamond bur. Similar premolar brackets were bonded to each restoration using the same resin adhesive and the specimens were then cycled in deionised water between 5 degrees C and 55 degrees C (500 cycles). The shear bond strengths were determined with a universal testing machine at a crosshead speed of 1 mm/min. The teeth and brackets were examined under a stereomicroscope and the adhesive remnants on the teeth scored with the adhesive remnant index (ARI). Specimens treated with the diamond bur had a significantly higher SBS (Mean: 18.45 +/- 3.82 MPa) than the group treated with hydrofluoric acid (Mean: 12.85 +/- 5.20 MPa). The mean SBS difference between the air-abrasion (Mean: 15.36 +/- 4.92 MPa) and hydrofluoric acid groups was not significant. High ARI scores occurred following abrasion with a diamond bur (100 per cent) and micro-etcher (80 per cent). In approximately two thirds of the teeth no adhesive was left on the restoration after surface treatment with hydofluoric acid. Surface treatment with a diamond bur resulted in a high bond strength between stainless steel brackets and artificially-aged composite restorations and was considered to be a safe and effective method of surface treatment. Most of the adhesive remained on the tooth following surface treatment with either the micro-etcher or the diamond bur.

Laser-treated stainless steel mini-screw implants: 3D surface roughness, bone-implant contact, and fracture resistance analysis.

Science.gov (United States)

Kang, He-Kyong; Chu, Tien-Min; Dechow, Paul; Stewart, Kelton; Kyung, Hee-Moon; Liu, Sean Shih-Yao

2016-04-01

This study investigated the biomechanical properties and bone-implant intersurface response of machined and laser surface-treated stainless steel (SS) mini-screw implants (MSIs). Forty-eight 1.3mm in diameter and 6mm long SS MSIs were divided into two groups. The control (machined surface) group received no surface treatment; the laser-treated group received Nd-YAG laser surface treatment. Half in each group was used for examining surface roughness (Sa and Sq), surface texture, and facture resistance. The remaining MSIs were placed in the maxilla of six skeletally mature male beagle dogs in a randomized split-mouth design. A pair with the same surface treatment was placed on the same side and immediately loaded with 200 g nickel-titanium coil springs for 8 weeks. After killing, the bone-implant contact (BIC) for each MSI was calculated using micro computed tomography. Analysis of variance model and two-sample t test were used for statistical analysis with a significance level of P titanium alloy MSIs. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Effects of laser shock processing on mechanical properties and micro-structure of ANSI 304 austenitic stainless steel

International Nuclear Information System (INIS)

Luo, K.Y.; Lu, J.Z.; Zhang, Y.K.; Zhou, J.Z.; Zhang, L.F.; Dai, F.Z.; Zhang, L.; Zhong, J.W.; Cui, C.Y.

2011-01-01

Highlights: → Effects of LSP on mechanical properties of stainless steel ANSI 304 are evaluated. → LSP can clearly enhance the values of mechanical properties in the shocked region. → Martensite transformation does not take place in the surface layer subjected to LSP. → Enhancement mechanisms of LSP on mechanical property of stainless steel are revealed. → The results can provide some insights on the surface modification of stainless steel. - Abstract: The aim of this article is to address the effects of a single laser shock processing (LSP) impact on the nano-hardness, elastic modulus, residual stress and phase transformation of ANSI 304 austenitic stainless steel. Residual stress distribution of the LSP-shocked region is determined by X-ray diffraction (XRD) with sin 2 ψ method, and the micro-structural features in the near-surface layer are characterized by using cross-sectional optical microscopy (OM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). By comparing with the untreated samples, LSP can clearly improve nano-hardness, elastic modulus, and residual stress in the LSP-shocked region. The underlying enhancement mechanisms of LSP on nano-hardness, elastic modulus and residual stress of stainless steel ANSI 304 are also revealed. These studies may provide some important insights into surface modification for metal materials.

Decontamination of stainless steel using cerium(IV): Material recycle and reuse

International Nuclear Information System (INIS)

Kurath, D.E.; Bray, L.A.; Jarrett, J.H.

1997-01-01

It has been demonstrated that the Cerium(IV) process can effectively remove radioactive contamination from stainless steel. Ce(IV) is a powerful oxidizing agent that is applied in an inorganic acid solution or as an atomized spray by injection into steam directed at the contaminated surface. Ce(IV) attacks the oxide layer and underlying metal surface to remove a 0.5-μm to 3-μm layer. This process has been implemented in a number of actual operations. In one application, a Ce(IV) steam decontamination process was instrumental in renovating hot cells at the High-Level Radiochemistry Facility (325-A building) at the Hanford site. The initial dose rate of approximately 100,000 mR/h was reduced to <50 mR/h and allowed manned entry during hot cell renovation activities. These valuable facilities have been returned to full operation. In an application at the West Valley Nuclear Services Co., Inc., the surfaces of stainless steel canisters that had been filled with vitrified high-level waste have been decontaminated. In some cases the free release levels for surface contamination have been achieved. In another application, five plutonium contaminated stainless steel vessels were decontaminated during decommissioning of the Critical Mass Facility at Hanford

Mitigation of inside surface residual stress of type 304 stainless steel pipe welds by inside water cooling method

International Nuclear Information System (INIS)

Sasaki, R.

1980-01-01

The weld residual stress distributions, macro- and microstructures of heat affected zone and IGSCC susceptibility of Type 304 stainless steel pipe welds by natural and inside water cooling methods have been investigated. The residual stresses of pipe welds by the natural cooling method are high tensile on both the inside and the outside surface. While the residual stresses on the inside surface of pipe welds by the inside water cooling method are compressive in both axial and circumferential directions for each pipe size from 2 to 24 inch diameter. The sensitized zones of welds by the inside water cooling method are closer to the fusion line, much narrower and milder than those by the natural cooling method. According to the constant extension rate test results for specimens taken from the inside surface of pipe welds, the inside water cooled welds are more resistant to IGSCC than naturally cooled ones

Atmospheric-pressure-plasma-enhanced fabrication of nonfouling nanocoatings for 316 stainless steel biomaterial interfaces

Science.gov (United States)

Huang, Chun; Lin, Jin-He; Li, Chi-Heng; Yu, I.-Chun; Chen, Ting-Lun

2018-03-01

Atmospheric-pressure plasma, which was generated with electrical RF power, was fed to a tetramethyldisiloxane/argon gas mixture to prepare bioinert organosilicon coatings for 316 stainless steel. The surface characteristics of atmospheric-pressure-plasma-deposited nanocoatings were evaluated as a function of RF plasma power, precursor gas flow, and plasma working distance. After surface deposition, the chemical features, elemental compositions, and surface morphologies of the organosilicon nanocoatings were examined. It was found that RF plasma power and plasma working distance are the essential factors that affect the formation of plasma-deposited nanocoatings. Fourier transform infrared spectroscopy spectra indicate that the atmospheric-pressure-plasma-deposited nanocoatings formed showed inorganic features. Atomic force microscopy analysis showed the surface roughness variation of the plasma-deposited nanocoating at different RF plasma powers and plasma working distances during surface treatment. From these surface analyses, it was found that the plasma-deposited organosilicon nanocoatings under specific operational conditions have relatively hydrophobic and inorganic characteristics, which are essential for producing an anti-biofouling interface on 316 stainless steel. The experimental results also show that atmospheric-pressure-plasma-deposited nanocoatings have potential use as a cell-resistant layer on 316 stainless steel.

Plasma-nitriding assisted micro-texturing into stainless steel molds

Directory of Open Access Journals (Sweden)

Aizawa Tatsuhiko

2015-01-01

Full Text Available Micro-texturing has grown up to be one of the most promising procedures. This related application required for large-area, fine micro-texturing onto the stainless steel mold materials. A new method other than laser-machining, micro-milling or micro-EDM was awaited for further advancement of this micro-texturing. In the present paper, a plasma nitriding assisted micro-texturing was developed to make various kinds of micro-patterns onto the martensitic stainless steels. First, original patterns were printed onto the surface of substrate by using the ink-jet printer. Then, the masked substrate was subjected to high density plasma nitriding; the un-masked surfaces were nitrided to have higher hardness. This nitrided substrate was further treated by sand-blasting to selectively dig the soft, masked surfaces. Finally, the micro-patterned martensitic stainless steel substrate was fabricated as a mold to duplicate these micro-patterns onto the work materials. The spatial resolution and depth profile controllability of this plasma nitriding assisted micro-texturing was investigated for variety of initial micro-patterns. The original size and dimension of initial micro-patterns were precisely compared with the three dimensional geometry of micro-textures after blasting treatment. The plastic cover case for smart cellular phones was employed to demonstrate how useful this processing is in practice.

SCC susceptibility of cold-worked stainless steel with minor element additions

Energy Technology Data Exchange (ETDEWEB)

Nakano, Junichi, E-mail: nakano.junnichi@jaea.go.jp [Japan Atomic Energy Agency, Shirakatashirane 2-4, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Nemoto, Yoshiyuki, E-mail: yoshiyuki.nemoto@oecd.org [OECD Nuclear Energy Agency, Le Seine St-Germain, 12, boulevard des Iles, F-92130 Issy-les-Moulineaux (France); Tsukada, Takashi, E-mail: tsukada.takashi@jaea.go.jp [Japan Atomic Energy Agency, Shirakatashirane 2-4, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Uchimoto, Tetsuya, E-mail: uchimoto@ifs.tohoku.ac.jp [Tohoku University, Aoba-ku, Sendai-shi, Miyagi-ken 980-8577 (Japan)

2011-10-01

To examine the effects of minor elements on stress corrosion cracking (SCC) susceptibility of low carbon stainless steels with a work hardened layer, a high purity type 304 stainless steel was fabricated and minor elements, Si, S, P, C or Ti, were added. A work hardened layer was introduced by shaving on the surface of stainless steels. The specimens were exposed to a boiling 42% MgCl{sub 2} solution for 20 h and the number and the length of initiated cracks were examined. SCC susceptibility of the specimen with P was the highest and that of the specimen with C was the lowest in all specimens. By magnetic force microscope examination, a magnetic phase expected to be a martensitic phase was detected near the surface. Since corrosion resistance of martensite is lower than that of austenite, the minor elements additions would affect SCC susceptibility through the amount of the transformed martensite.

Effect of copper, tin, phosphorous and arsenic on the surface cracking of a 18-8 stainless steel during hot compression tests

International Nuclear Information System (INIS)

Botella, J.; Fernandez, M.T.; Fernandez de Castillo, I.

1998-01-01

The effect of certain different concentrations of Cu, Sn, P and As on the surface cracking of 18-8 austenitic stainless steel hot compressed specimens has been studied, at 1,123 and 1,273 K, in an oxidizing atmosphere (air). A procedure for determining surface cracking has been established, and the cracking factor obtained in this ways is correlated with the chemical composition of the materials at both temperatures. The cracking factors obtained at 1,273 K have been compared with the reduction of area drops obtained by hot tension tests at the same temperature. (Author) 5 refs

Ion nitriding in 316=L stainless steel

International Nuclear Information System (INIS)

Rojas-Calderon, E.L.

1989-01-01

Ion nitriding is a glow discharge process that is used to induce surface modification in metals. It has been applied to 316-L austenitic stainless steel looking for similar benefits already obtained in other steels. An austenitic stainless steel was selected because is not hardenable by heat treatment and is not easy to nitride by gas nitriding. The samples were plastically deformed to 10, 20, 40, 50 AND 70% of their original thickness in order to obtain bulk hardening and to observe nitrogen penetration dependence on it. The results were: an increase of one to two rockwell hardness number (except in 70% deformed sample because of its thickness); an increase of even several hundreds per cent in microhardness knoop number in nitrided surface. The later surely modifies waste resistance which would be worth to quantify in further studies. Microhardness measured in an internal transversal face to nitrided surface had a gradual diminish in its value with depth. Auger microanalysis showed a higher relative concentration rate C N /C F e near the surface giving evidence of nitrogen presence till 250 microns deep. The color metallography etchant used, produced faster corrosion in nitrited regions. Therefore, corrosion studies have to be done before using ion nitrited 316-L under these chemicals. (Author)

THE COMPOSITE SPECTRUM OF BOSS QUASARS SELECTED FOR STUDIES OF THE Ly α FOREST

Energy Technology Data Exchange (ETDEWEB)

Harris, David W.; Jensen, Trey W.; Bautista, Julian E.; Dawson, Kyle S.; Vivek, M.; Brownstein, Joel R.; Olmstead, Matthew D. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Suzuki, Nao [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, 277-8583 (Japan); Ge, Jian; Hamann, Fred; Herbst, H. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Jiang, Linhua [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Moran, Sarah E. [Barnard College, 3009 Broadway, New York, NY 10027 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Schneider, Donald P., E-mail: davidharris314@gmail.com [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

2016-06-01

The Baryon Oscillation Spectroscopic Survey (BOSS) has collected more than 150,000 2.1 ≤  z  ≤ 3.5 quasar spectra since 2009. Using this unprecedented sample, we create a composite spectrum in the rest-frame of 102,150 quasar spectra from 800–3300 Å at a signal-to-noise ratio close to 1000 per pixel (Δ v of 69 km s{sup −1}). Included in this analysis is a correction to account for flux calibration residuals in the BOSS spectrophotometry. We determine the spectral index as a function of redshift of the full sample, warp the composite spectrum to match the median spectral index, and compare the resulting spectrum to Sloan Digital Sky Survey (SDSS) photometry used in target selection. The quasar composite matches the color of the quasar population to 0.02 mag in g  −  r , 0.03 mag in r  −  i , and 0.01 mag in i  −  z over the redshift range 2.2 <  z  < 2.6. The composite spectrum deviates from the imaging photometry by 0.05 mag around z = 2.7, likely due to differences in target selection as the quasar colors become similar to the stellar locus at this redshift. Finally, we characterize the line features in the high signal-to-noise composite and identify nine faint lines not found in the previous composite spectrum from SDSS.

IMPURITY SEGREGATION OF STAINLESS STEEL STUDIED BY ATOM-PROBE AND AUGER ELECTRON SPECTROSCOPY

OpenAIRE

Koguchi , Y.; Takahashi , K.; Ishikawa , Y.

1987-01-01

The surface compositions of type 304 stainless steel heated in vacuum at 600-900°C were determined by an atom-probe and Auger electron spectroscopic analysis. In addition to enrichment and depletion of alloying elements in the surface of the stainless steel, segregation of impurity elements such as carbon, nitrogen, phosphorus and sulfur is known to occur. In this paper the atom-probe was used to measure the impurity segregation in the grains as well as in the grain boundary while the AES was...

High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

Energy Technology Data Exchange (ETDEWEB)

Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id; Syarif, Dani Gustaman, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia)

2014-03-24

The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

NH3/O2 mixed gas plasmas alter the interaction of blood components with stainless steel.

Science.gov (United States)

Chen, Meng; Zamora, Paul O; Peña, Louis; Som, Prantika; Osaki, Shigemasa

2003-12-01

Stainless steel treated with a mixed gas plasma of NH(3) plus O(2) had chemical and biologic characteristics distinct from untreated stainless steel or stainless steel treated with NH(3) or O(2) plasmas used separately. NH(3)/O(2) plasmas deposited nitrogen as both -CN (organic) and -NO (nitrate, nitrite)--materials not found on untreated stainless steel--and the contact angle changed from 44 degrees to 23 degrees. Treatment of stainless steel (and titanium) resulted in surfaces with enhanced resistance to platelet and leukocyte attachment. A gas plasma of N(2)O/O(2) also was found to reduce platelet and leukocyte attachment, suggesting that these properties may be common to surfaces coated with oxynitrites (nitrides). Upon subcutaneous implantation, no inflammation, hemolysis, or untoward thrombosis was noted in the tissue surrounding the wafers treated with the NH(3)/O(2) plasmas, although the cellular density was considerably reduced by 2 weeks after implant. Collectively, the results suggest that NH(3)/O(2) plasmas impart a unique character to stainless steel that may be useful in the construction of medical devices. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 994-1000, 2003

Evaluation of modified stainless steel surfaces targeted to reduce biofilm formation by common milk sporeformers.

Science.gov (United States)

Jindal, Shivali; Anand, Sanjeev; Huang, Kang; Goddard, Julie; Metzger, Lloyd; Amamcharla, Jayendra

2016-12-01

The development of bacterial biofilms on stainless steel (SS) surfaces poses a great threat to the quality of milk and other dairy products as the biofilm-embedded bacteria can survive thermal processing. Established biofilms offer cleaning challenges because they are resistant to most of the regular cleaning protocols. Sporeforming thermoduric organisms entrapped within biofilm matrix can also form heat-resistant spores, and may result in a long-term persistent contamination. The main objective of this study was to evaluate the efficacy of different nonfouling coatings [AMC 18 (Advanced Materials Components Express, Lemont, PA), Dursan (SilcoTek Corporation, Bellefonte, PA), Ni-P-polytetrafluoroethylene (PTFE, Avtec Finishing Systems, New Hope, MN), and Lectrofluor 641 (General Magnaplate Corporation, Linden, NJ)] on SS plate heat exchanger surfaces, to resist the formation of bacterial biofilms. It was hypothesized that modified SS surfaces would promote a lesser amount of deposit buildup and bacterial adhesion as compared with the native SS surface. Vegetative cells of aerobic sporeformers, Geobacillus stearothermophilus (ATCC 15952), Bacillus licheniformis (ATCC 6634), and Bacillus sporothermodurans (DSM 10599), were used to study biofilm development on the modified and native SS surfaces. The adherence of these organisms, though influenced by surface energy and hydrophobicity, exhibited no apparent relation with surface roughness. The Ni-P-PTFE coating exhibited the least bacterial attachment and milk solid deposition, and hence, was the most resistant to biofilm formation. Scanning electron microscopy, which was used to visualize the extent of biofilm formation on modified and native SS surfaces, also revealed lower bacterial attachment on the Ni-P-PTFE as compared with the native SS surface. This study thus provides evidence of reduced biofilm formation on the modified SS surfaces. Copyright © 2016 American Dairy Science Association. Published by Elsevier

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

Science.gov (United States)

Finn, Sarah; Händler, Kristian; Condell, Orla; Colgan, Aoife; Cooney, Shane; McClure, Peter; Amézquita, Aléjandro; Hinton, Jay C. D.

2013-01-01

Consumers trust commercial food production to be safe, and it is important to strive to improve food safety at every level. Several outbreaks of food-borne disease have been caused by Salmonella strains associated with dried food. Currently we do not know the mechanisms used by Salmonella enterica serovar Typhimurium to survive in desiccated environments. The aim of this study was to discover the responses of S. Typhimurium ST4/74 at the transcriptional level to desiccation on a stainless steel surface and to subsequent rehydration. Bacterial cells were dried onto the same steel surfaces used during the production of dry foods, and RNA was recovered for transcriptomic analysis. Subsequently, dried cells were rehydrated and were again used for transcriptomic analysis. A total of 266 genes were differentially expressed under desiccation stress compared with a static broth culture. The osmoprotectant transporters proP, proU, and osmU (STM1491 to STM1494) were highly upregulated by drying. Deletion of any one of these transport systems resulted in a reduction in the long-term viability of S. Typhimurium on a stainless steel food contact surface. The proP gene was critical for survival; proP deletion mutants could not survive desiccation for long periods and were undetectable after 4 weeks. Following rehydration, 138 genes were differentially expressed, with upregulation observed for genes such as proP, proU, and the phosphate transport genes (pstACS). In time, this knowledge should prove valuable for understanding the underlying mechanisms involved in pathogen survival and should lead to improved methods for control to ensure the safety of intermediate- and low-moisture foods. PMID:23666329

Effectiveness of Disinfectants in Killing Enterobacter sakazakii in Suspension, Dried on the Surface of Stainless Steel, and in a Biofilm▿

OpenAIRE

Kim, Hoikyung; Ryu, Jee-Hoon; Beuchat, Larry R.

2006-01-01

The effectiveness of 13 disinfectants used in hospitals, day-care centers, and food service kitchens in killing Enterobacter sakazakii in suspension, dried on the surface of stainless steel, and in biofilm was determined. E. sakazakii exhibited various levels of resistance to the disinfectants, depending on the composition of the disinfectants, amount and type of organic matrix surrounding cells, and exposure time. Populations of planktonic cells suspended in water (7.22 to 7.40 log CFU/ml) d...

Surface Modification of AISI 440B Stainless Steel and its Influence on Surgical Drill Bits Performance

Directory of Open Access Journals (Sweden)

Łępicka M.

2016-09-01

Full Text Available The development of modern invasive surgery is highly dependent on the performance of surgical instruments, understood as long-term efficiency arising from high resistance to wear and corrosion. In order to maintain sufficient reliability, surgical cutting instruments are often made of martensitic stainless steels. Nevertheless, the use of ferrous alloys in medical applications is still a concern due to their questionable corrosion and wear resistance. To extend their biocompatibility, improve stability in variable environmental conditions, improve ease of handling, and maximize their performance, diffusion layers and coatings are applied to the surface. The aim of this work was to evaluate the effect of TiN and diamond-like carbon (DLC surface modification on the performance of surgical drill bits, that is, wear and corrosion resistance, measured in model and field tests. Based on the findings presented, DLC layers can be recommended as anti-wear and anti-corrosion coatings for surgical drill bits.

Surface layer investigation of duplex stainless steel S32205 after stress peening utilizing X-ray diffraction

International Nuclear Information System (INIS)

Feng, Qiang; Jiang, Chuanhai; Xu, Zhou

2013-01-01

Highlights: ► The stress shot peening is superior to the conventional shot peening. ► Residual stresses along the loaded direction are bigger than transverse direction. ► Higher prestress leads to smaller domain size, high density of dislocation. ► Compared to ferrite, austenite has much higher hardness and work hardening. ► Ferrite has higher recover of elastic deformation than austenite after unloading. - Abstract: Residual stresses and micro-hardness of duplex stainless steel S32205 after stress peening are measured and domain sizes and microstrain are calculated. The results show that stress peening can significantly improve the compressive residual stresses and micro-hardness in both austenite and ferrite, and the former is affected by both the prestress and the measurement directions. Microstructure investigation reveals that material deformation is enhanced after stress peening, and smaller domain sizes and higher microstrain are introduced. The compressive residual stress enhancement by stress peening in ferrite is more than that in austenite under the same stress peening, which is due to the more elastic deformation recover in ferrite. Therefore, the difference of residual stresses between ferrite and austenite can be narrowed down by conducting appropriate stress peening. Based on these investigations, it is concluded that stress peening is superior to conventional shot peening treatment to improve the surface properties of duplex stainless steel

Environmental scanning electron microscopy analysis of Proteus mirabilis biofilms grown on chitin and stainless steel.

Science.gov (United States)

Fernández-Delgado, Milagro; Duque, Zoilabet; Rojas, Héctor; Suárez, Paula; Contreras, Monica; García-Amado, María A; Alciaturi, Carlos

Proteus mirabilis is a human pathogen able to form biofilms on the surface of urinary catheters. Little is known about P. mirabilis biofilms on natural or industrial surfaces and the potential consequences for these settings. The main aim of this work was to assess and compare the adhesion and biofilm formation of P. mirabilis strains from different origins on chitin and stainless steel surfaces within 4 to 96 h. Using environmental scanning electron microscopy, the biofilms of a clinical strain grown on chitin at 4 h showed greater adhesion, aggregation, thickness, and extracellular matrix production than those grown on stainless steel, whereas biofilms of an environmental strain had less aggregation on both surfaces. Biofilms of both P. mirabilis strains developed different structures on chitin, such as pillars, mushrooms, channels, and crystalline-like precipitates between 24 and 96 h, in contrast with flat-layer biofilms produced on stainless steel. Significant differences ( p  biofilm formation. This represents the first study of P. mirabilis showing adhesion, biofilm formation, and development of different structures on surfaces found outside the human host.

Electroless nickel plating on stainless steels and aluminum

Science.gov (United States)

1966-01-01

Procedures for applying an adherent electroless nickel plating on 303 SE, 304, and 17-7 PH stainless steels, and 7075 aluminum alloy was developed. When heat treated, the electroless nickel plating provides a hard surface coating on a high strength, corrosion resistant substrate.

Weldability, machinability and surfacing of commercial duplex stainless steel AISI2205 for marine applications – A recent review

Directory of Open Access Journals (Sweden)

A. Vinoth Jebaraj

2017-05-01

Full Text Available In the present review, attempts have been made to analyze the metallurgical, mechanical, and corrosion properties of commercial marine alloy duplex stainless steel AISI 2205 with special reference to its weldability, machinability, and surfacing. In the first part, effects of various fusion and solid-state welding processes on joining DSS 2205 with similar and dissimilar metals are addressed. Microstructural changes during the weld cooling cycle such as austenite reformation, partitioning of alloying elements, HAZ transformations, and the intermetallic precipitations are analyzed and compared with the different welding techniques. In the second part, machinability of DSS 2205 is compared with the commercial ASS grades in order to justify the quality of machining. In the third part, the importance of surface quality in a marine exposure is emphasized and the enhancement of surface properties through peening techniques is highlighted. The research gaps and inferences highlighted in this review will be more useful for the fabrications involved in the marine applications.

Use of a stainless steel washer platform to study Acinetobacter baumannii adhesion and biofilm formation on abiotic surfaces.

Science.gov (United States)

Orsinger-Jacobsen, Samantha J; Patel, Shenan S; Vellozzi, Ernestine M; Gialanella, Phillip; Nimrichter, Leonardo; Miranda, Kildare; Martinez, Luis R

2013-12-01

Acinetobacter baumannii is a frequent cause of hospital-acquired pneumonia, and has recently increased in incidence as the causative agent of severe disease in troops wounded in Afghanistan and Iraq. Clinical approaches are limited since A. baumannii strains isolated from patients are extremely resistant to current antimicrobials. A. baumannii can survive desiccation and during outbreaks has been recovered from various sites in the patients' environment. To better understand its prevalence in hospital settings, we used a stainless steel washer (SSW) platform to investigate A. baumannii biofilm formation on abiotic surfaces. Scanning electron microscopy demonstrated that A. baumannii forms strong biofilms on stainless steel surfaces. This platform was combined with a colorimetric 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay to observe the metabolic activity of bacterial cells, and to facilitate the manipulation and comparison of multiple A. baumannii clinical strains. A strong correlation between XTT and c.f.u. assays was demonstrated. To complement the cell viability assays, A. baumannii biofilm mass was measured by crystal violet staining. Furthermore, the effect of commonly used disinfectants and environmental stressors on A. baumannii biofilms and planktonic cells was compared and characterized. Biofilms on SSWs were significantly more resistant than their planktonic counterparts, providing additional evidence that may allow us to understand the high prevalence of this microbe in hospital settings. Our results validate that SSWs are a simple, versatile and innovative method to study A. baumannii biofilms in vitro.

X-ray impact induced desorption of gases from surfaces

International Nuclear Information System (INIS)

Brumbach, S.; Kaminsky, M.

1976-02-01

Measurements of gases released from 302 stainless steel and gold surfaces before and after discharge cleaning were made in ultrahigh vacuum using x-rays with an energy distribution typical of a tungsten bremsstrahlung spectrum. Similar measurements were also made for Al 2 O 3 surfaces which had not been discharge cleaned. For the non-discharge-cleaned surfaces of stainless steel, Al 2 O 3 , and gold the predominant gas species observed mass spectrometrically was CO 2 . For some stainless steel and Al 2 O 3 surfaces CO and O 2 were also readily observed. Mean quantum yields for CO, O 2 and CO 2 release from such stainless steel surfaces, for example, ranged from less than 6 x 10 -5 to 9 x 10 -4 molecules per photons in the bremsstrahlung spectrum characteristic for 50 keV electron energy. After discharge cleaning a decrease in the mean quantum yields was observed for the stainless steel and gold surfaces

Grain size measurements by ultrasonic Rayleigh surface waves

International Nuclear Information System (INIS)

Palanichamy, P.; Jayakumar, T.

1996-01-01

The use of Rayleigh surface waves to determine average grain size nondestructively in an austenitic stainless steel AISI type 316 stainless is discussed. Two commercial type 4MHz frequency surface wave transducers, one as transmitter and the other as receiver were employed for the measurement of surface wave amplitudes. Relative amplitudes of the Rayleigh surface waves were correlated with the metallographically obtained grain sizes. Results indicate that surface/sub-surface average grain sizes of AISI type 316 austenitic stainless steel can be estimated with a confidence level of more than 80% in the grain size range 30-170 μm. (author)

Study of the Mechanical Properties of a Nanostructured Surface Layer on 316L Stainless Steel

Directory of Open Access Journals (Sweden)

F. C. Lang

2016-01-01

Full Text Available A nanostructured surface layer (NSSL was generated on a 316L stainless steel plate through surface nanocrystallization (SNC. The grains of the surface layer were refined to nanoscale after SNC treatment. Moreover, the microstructure and mechanical properties of NSSL were analyzed with a transmission electron microscope (TEM and scanning electron microscope (SEM, through nanoindentation, and through reverse analysis of finite element method (FEM. TEM results showed that the grains in the NSSL measured 8 nm. In addition, these nanocrystalline grains took the form of random crystallographic orientation and were roughly equiaxed in shape. In situ SEM observations of the tensile process confirmed that the motions of the dislocations were determined from within the material and that the motions were blocked by the NSSL, thus improving overall yielding stress. Meanwhile, the nanohardness and the elastic modulus of the NSSL, as well as those of the matrix, were obtained with nanoindentation technology. The reverse analysis of FEM was conducted with MARC software, and the process of nanoindentation on the NSSL and the matrix was simulated. The plastic mechanical properties of NSSL can be derived from the simulation by comparing the results of the simulation and of actual nanoindentation.

Polarization and fluence effects in femtosecond laser induced micro/nano structures on stainless steel with antireflection property

Science.gov (United States)

Yao, Caizhen; Ye, Yayun; Jia, Baoshen; Li, Yuan; Ding, Renjie; Jiang, Yong; Wang, Yuxin; Yuan, Xiaodong

2017-12-01

In this paper, micro/nano structures on stainless steel were prepared in single spot irradiation mode and scan mode by using femtosecond laser technique. The influence of polarization and fluence on the formation of micro/nano structures were explored. Surface morphology, microstructure, roughness and composition of prepared samples were characterized. The antireflection property and wettability of laser treated samples were also tested and compared with that of original stainless steel.Results showed that the laser-induced spot consists of two distinct regions due to the Gaussian beam profile: a core region of moth-eye-like structure and a peripheral region of nanoparticles-covered laser-induced periodic surface structure (NC-LIPSS). The proportion of the core region and dimension of micro/nano structure increase with increasing laser fluence. Polarization can be used to tune the direction of NC-LIPSS. Atomic ratios of Cr and Mn increase and atomic ratio of Ni decreases after laser irradiation. Oxygen is not detected on laser irradiated samples, indicating that oxidation reactions are not significant during the interaction process between femtosecond laser and 304 stainless steel. These are good for the application of stainless steel as its physical properties would not change or even enhanced. The overlaps between two laser scan lines significantly influence the surface roughness and should be controlled carefully during the preparation process. The laser irradiated surface has a better antireflection property in comparison with that of original stainless steel, which may due to the scattering and absorption of micro/nano structures. Contact angle of micro/nano structured stainless steel decreases with the increase of laser fluence. The hydrophilic property can be explained by Wenzel's model. The interference between the surface plasmon wave and the incident light wave leads to the formation of NC-LIPSS.

Development of laser cutting method for stainless steel liner

International Nuclear Information System (INIS)

Ishihara, Satoshi; Takahata, Masato; Wignarajah, Sivakumaran; Kamata, Hirofumi

2007-01-01

The present work is an attempt to develop a laser cutting method for cutting and removing stainless steel liners from concrete walls and floors in nuclear facilities. The effect of basic laser cutting parameters such as energy, cutting speed, assist gas flow etc. were first studied through cutting experiments on mock-up concrete specimens lined with 3mm thick stainless steel sheets using a 1kW Nd:YAG laser. These initial studies were followed by further studies on the effect of unevenness of the liner surface and on a new method of confining contamination during the cutting process using a sliding evacuation hood attached to the laser cutting head. The results showed that laser cutting is superior to other conventional cutting methods from the point of view of safety from radioactivity and work efficiency when cutting contaminated stainless steel liners. (author)

Effect of temperature, pH, and water activity on biofilm formation by Salmonella enterica enteritidis PT4 on stainless steel surfaces as indicated by the bead vortexing method and conductance measurements.

Science.gov (United States)

Giaouris, E; Chorianopoulos, N; Nychas, G J E

2005-10-01

An assay was developed in an effort to elucidate the effect of important environmental parameters (temperature, pH, and water activity [aw]) on Salmonella Enteritidis biofilm formation on stainless steel surfaces. To achieve this, a modified microbiological technique used for biofilm studying (the bead vortexing method) and a rapid method based on conductivity measurements were used. The ability of the microorganism to generate biofilm on the stainless surfaces was studied at three temperatures (5, 20, and 37 degrees C), four pH values (4.5, 5.5, 6.5, and 7.4), and four aw values (0.5, 1.5, 5.5, and 10.5% NaCl). Results obtained by the bead vortexing method show that maximum numbers of adherent bacteria per square centimeter (106 CFU/cm2) were attained in 6 days at 20 degrees C. Biofilm formation after 7 days of incubation at 20 degrees C was found to be independent of the pH value. In addition, the high concentration of sodium chloride (10.5% NaCl, aw = 0.94) clearly inhibited the adherence of cells to the coupons. Conductance measurements were used as a supplementary tool to measure indirectly the attachment and biofilm formation of bacterial cells on stainless steel surfaces via their metabolic activity (i.e., changes in the conductance of the growth medium due to microbial growth or metabolism). Results obtained by conductance measurements corresponded well to those of the bead vortexing method. Furthermore, we were able to detect cells that remained attached on the metal surfaces even after vortexing via their metabolic activity. The results, except for demonstrating environmental-dependent Salmonella Enteritidis biofilm formation, indicated that traditional vortexing with beads did not remove completely biofilm cells from stainless steel; hence, conductance measurements seem to provide a more sensitive test capable to detect down to one single viable organism.

Coating stainless steel plates with Ag/TiO2 for chlorpyrifos decontamination

Science.gov (United States)

Abdel Fattah, Wafa I.; Gobara, Mohammed M.; El-Hotaby, Walid; Mostafa, Sherif F. M.; Ali, Ghareib W.

2016-05-01

Spray coatings of either nanosilver (Ag), titanium (TiO2) or nanosilver titanium (Ag/TiO2) on stainless steel substrates prepared by sol-gel process were successfully achieved. The efficiency of the Ag/TiO2 coat onto 316 stainless steel surface towards cloropyrifos degradation as a chemical warfare agent (CWA) was proved. The crystalline structure and morphological characterization, as well as surface roughness measurements, were assessed. X-ray diffraction results proved the crystalline TiO2 anatase phase. The uniform distribution of Ag along with TiO2 nanoparticles was evidenced through transmission electron microscopy and scanning electron microscopy mapping. The hydrophilic nature of individual Ag, TiO2 and Ag/TiO2 coats was proved by contact angle measurements. The loading of Ag nanoparticles influenced positively the Ag/TiO2 coats surface roughness. The photocatalytic cloropyrifos degradation achieved about 50% within one-hour post UV treatment proving, therefore, the promising Ag/TiO2 continued decontamination efficiency. In conclusion, tuning the physical and morphological properties of TiO2 coated on stainless steel surface could be significantly enhanced by Ag nanoparticles incorporation. The developed Ag/TiO2 coat could be conveniently applied as CWA decontaminant.

Effect of Carvacrol on Salmonella Saintpaul Biofilms on Stainless ...

African Journals Online (AJOL)

2025 ... carvacrol on S. saintpaul biofilms on stainless steel surface was evaluated on ... cultures S. saintpaul at 35 ºC were diluted 1:100 .... characteristics of biofilm formation that occur in .... aureus and Salmonella enterica serovar Typhmurium.

Deposition of DLC Film on Stainless Steel Substrates Coated by Nickel Using PECVD Method.

Science.gov (United States)

Khalaj, Zahra; Ghoranneviss, Mahmood; Vaghri, Elnaz; Saghaleini, Amir; Diudea, Mircea V

2012-06-01

Research on diamond-like carbon (DLC) films has been devoted to find both optimized conditions and characteristics of the deposited films on various substrates. In the present work, we investigate the quality of the DLC films grown on stainless steel substrates using different thickness of the nickel nanoparticle layers on the surface. Nickel nanoparticles were sputtered on the stainless steel substrates at 200 °C by a DC-sputtering system to make a good adherence between DLC coating and steel substrates. Atomic Force Microscopy was used to characterize the surface roughness and distribution function of the nickel nanoparticles on the substrate surface. Diamond like carbon films were deposited on stainless steel substrates coated by nickel using pure acetylene and C2H2/H2 with 15% flow ratio by DC-Plasma Enhanced Chemical Vapor Deposition (PECVD) systems. Microstructural analysis by Raman spectroscopy showed a low intensity ratio ID/IG for DLC films by increasing the Ni layer thickness on the stainless steel substrates. Fourier Transforms Infrared spectroscopy (FTIR) evidenced the peaks attributed to C-H bending and stretching vibration modes in the range of 1300-1700 cm-1 and 2700-3100 cm-1, respectively, in good agreement with the Raman spectroscopy and confirmed the DLC growth in all samples.

Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

International Nuclear Information System (INIS)

Okano, Shigetaka; Ihara, Ryohei; Kanamaru, Daisuke; Mochizuki, Masahito

2015-01-01

In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

Inactivation of Vegetative Cells, but Not Spores, of Bacillus anthracis, B. cereus, and B. subtilis on Stainless Steel Surfaces Coated with an Antimicrobial Silver- and Zinc-Containing Zeolite Formulation

Science.gov (United States)

Galeano, Belinda; Korff, Emily; Nicholson, Wayne L.

2003-01-01

Stainless steel surfaces coated with paints containing a silver- and zinc-containing zeolite (AgION antimicrobial) were assayed in comparison to uncoated stainless steel for antimicrobial activity against vegetative cells and spores of three Bacillus species, namely, B. anthracis Sterne, B. cereus T, and B. subtilis 168. Under the test conditions (25°C and 80% relative humidity), the zeolite coating produced approximately 3 log10 inactivation of vegetative cells within a 5- to 24-h period, but viability of spores of the three species was not significantly affected. PMID:12839825

Electrochemical characterisation of a martensitic stainless steel in a neutral chloride solution

International Nuclear Information System (INIS)

Marcelin, Sabrina; Pébère, Nadine; Régnier, Sophie

2013-01-01

Highlights: ► A better knowledge of the electrochemical behaviour of a martensitic stainless steel in bulk electrolyte was obtained. ► Quantitative parameters were obtained from impedance measurements. ► The study will be used as reference to investigate crevice corrosion using a thin layer cell. - Abstract: This paper focuses on the characterisation of the electrochemical behaviour of a martensitic stainless steel in 0.1 M NaCl + 0.04 M Na 2 SO 4 solution and is a part of a study devoted to crevice corrosion resistance of stainless steels. Polarisation curves and electrochemical impedance measurements were obtained for different experimental conditions in bulk electrolyte. X-ray photoelectron spectroscopy (XPS) was used to analyse the passive films. At the corrosion potential, the stainless steel was in the passive state and the corrosion process was controlled by the properties of the passive film formed during air exposure. During immersion in the deaerated solution, the passive film was only slightly modified, whereas it was altered both in composition and thickness during immersion in the aerated solution. After cathodic polarisation of the stainless steel electrode surface, the oxide film was almost totally removed and the surface appeared to be uniformly active for oxygen reduction. The new passive film, formed at the corrosion potential, was enriched with iron species and less protective. Impedance diagrams allowed the characterisation of both the oxide film (high-frequency range) and the charge transfer process (low-frequency range).

Surface Texturing-Plasma Nitriding Duplex Treatment for Improving Tribological Performance of AISI 316 Stainless Steel

Directory of Open Access Journals (Sweden)

Naiming Lin

2016-10-01

Full Text Available Surface texturing-plasma nitriding duplex treatment was conducted on AISI 316 stainless steel to improve its tribological performance. Tribological behaviors of ground 316 substrates, plasma-nitrided 316 (PN-316, surface-textured 316 (ST-316, and duplex-treated 316 (DT-316 in air and under grease lubrication were investigated using a pin-on-disc rotary tribometer against counterparts of high carbon chromium bearing steel GCr15 and silicon nitride Si3N4 balls. The variations in friction coefficient, mass loss, and worn trace morphology of the tested samples were systemically investigated and analyzed. The results showed that a textured surface was formed on 316 after electrochemical processing in a 15 wt % NaCl solution. Grooves and dimples were found on the textured surface. As plasma nitriding was conducted on a 316 substrate and ST-316, continuous and uniform nitriding layers were successfully fabricated on the surfaces of the 316 substrate and ST-316. Both of the obtained nitriding layers presented thickness values of more than 30 μm. The nitriding layers were composed of iron nitrides and chromium nitride. The 316 substrate and ST-316 received improved surface hardness after plasma nitriding. When the tribological tests were carried out under dry sliding and grease lubrication conditions, the tested samples showed different tribological behaviors. As expected, the DT-316 samples revealed the most promising tribological properties, reflected by the lowest mass loss and worn morphologies. The DT-316 received the slightest damage, and its excellent tribological performance was attributed to the following aspects: firstly, the nitriding layer had high surface hardness; secondly, the surface texture was able to capture wear debris, store up grease, and then provide continuous lubrication.

Low Temperature Surface Carburization of Stainless Steels

Energy Technology Data Exchange (ETDEWEB)

Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

2007-12-07

Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys �

Carbohydrate sources of microfouling material developed on aluminium and stainless steel panels

Digital Repository Service at National Institute of Oceanography (India)

Bhosle, N.B.; Sankaran, P.D.; Wagh, A.B.

. pp. 151 -164 Reprints available directly from the pUblishcr Photocopying permitted by license only © 1990 Harwood Academic Publishers GmbH Printed in Great Britain CARBOHYDRATE SOURCES OF MICROFOULING MATERIAL DEVELOPED ON ALUMINIUM AND STAINLESS... plant material and grasses appear to be the major sources contributing to the carbohydrates ofthe microfouling material. KEY WORDS: Carbohydratc. microfouling. sources, aluminium, stainless steel, Arabian Sea, Bay of Hengal. INTRODUCTION Solid surfaces...

The influence of cold work on the oxidation behaviour of stainless steel

International Nuclear Information System (INIS)

Langevoort, J.C.

1985-01-01

In this thesis the study of the interaction of oxygen gas with stainless steel surfaces is described. Thermogravimetry, microscopy and ellipsometry have been used to follow the oxidation in situ, while EDX, AES and XPS have been used to determine the oxide compositions. The aim of this thesis is to reveal the influence on the oxidation behaviour of stainless steel of i) cold work (rolling, drawing, milling, polishing and Ar ion bombardment) ii) the initially formed oxide and iii) the experimental conditions. Two types of stainless steels have been used (AISI 304 (a 18/8 Cr/Ni steel) and Incoloy 800 H (a 20/30 Cr/Ni steel)). (Auth.)

Aging of cast duplex stainless steels in LWR systems

International Nuclear Information System (INIS)

Chopra, O.K.; Chung, H.M.

1984-10-01

A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are evaluated to determine the expected embrittlement of cast components during the operating lifetime of reactors and to define the objectives and scope of the investigation. This presentation describes the status of the program. Data for the metallurgical characterization of the various cast stainless steels used in the investigation are presented. Charpy impact tests on short-term aged material indicate that CF-3 stainless steels are less susceptible to embrittlement than CF-8 or CF-8M stainless steels. Microstructural characterization of cast stainless steels that were obtained from Georg Fischer Co. and aged for up to 70,000 h at 300, 350, and 400 0 C reveals the formation of four different types of precipitates that are not α'. Embrittlement of the ferrite phase is primarily due to pinning of the dislocations by two of these precipitates, designated as Type M and Type X. The ferrite phase is embrittled after approx. 8 y at 300 0 C and shows cleavage fracture. Examination of the fracture surfaces of the impact-test specimens indicates that the toughness of the long-term aged material is determined by the austenite phase. 8 figures, 3 tables

Effects of microstructure on ultrasonic examination of stainless steel

International Nuclear Information System (INIS)

Kupperman, D.S.; Reimann, K.J.

1976-01-01

Ultrasonic inspection of cast stainless steel components or stainless steel welds is difficult, and the results obtained are hard to interpret. The present study describes the effects of stainless steel microstructure on ultrasonic test results. Welded coupons, 2.5 and 5.0 cm thick, were fabricated from Type 304 stainless steel, with Type 308 stainless steel as the weld material. Metallography of the base material shows grain sizes of 15 and 80 μm, and dendrites aligned from the top to the bottom surface in cast material. X-ray diffraction and ultrasonic velocity measurements indicate a random crystal orientation in the base material, but the cast sample had aligned dendrites. The weld material exhibits a dendritic structure with a preferred (100) direction perpendicular to the weld pass. Spectral analysis of ultrasonic broad-band signals through the base materials shows drastic attenuation of higher frequencies with increasing grain size (Rayleigh scattering). Annealing and recrystallization increases the ultrasonic attenuation and produces carbide precipitation at grain boundaries. The microstructural differences of the base metal, heat-affected zone, and weld metal affect the amplitude of ultrasonic reflections from artificial flaws in these zones. Data obtained from two samples of different grain sizes indicate that grain size has little effect when a 1-MHz transducer is used. When going from a 15 to an 80-μm crystalline structure, a 5-MHz unit suffers a 30-dB attenuation in the detection of a 1.2 mm deep notch. The anisotropy of the dendritic structure in stainless steel renewed the interest in the effect of shear-wave polarization. In the (110) crystallographic orientation of stainless steel, two modes of shear waves can be generated, which have velocities differing by a factor of two. This effect may be helpful in ''tuning'' of shear waves by polarization to obtain better penetration in large grain materials such as welds

Microstructure and antibacterial properties of microwave plasma nitrided layers on biomedical stainless steels

International Nuclear Information System (INIS)

Lin, Li-Hsiang; Chen, Shih-Chung; Wu, Ching-Zong; Hung, Jing-Ming; Ou, Keng-Liang

2011-01-01

Nitriding of AISI 303 austenitic stainless steel using microwave plasma system at various temperatures was conducted in the present study. The nitrided layers were characterized via scanning electron microscopy, glancing angle X-ray diffraction, transmission electron microscopy and Vickers microhardness tester. The antibacterial properties of this nitrided layer were evaluated. During nitriding treatment between 350 deg. C and 550 deg. C, the phase transformation sequence on the nitrided layers of the alloys was found to be γ → (γ + γ N ) → (γ + α + CrN). The analytical results revealed that the surface hardness of AISI 303 stainless steel could be enhanced with the formation of γ N phase in nitriding process. Antibacterial test also demonstrated the nitrided layer processed the excellent antibacterial properties. The enhanced surface hardness and antibacterial properties make the nitrided AISI 303 austenitic stainless steel to be one of the essential materials in the biomedical applications.

STUDIES ON WETTABILITY OF STAINLESS STEEL 316L POWDER IN LASER MELTING PROCESS

Directory of Open Access Journals (Sweden)

KURIAN ANTONY

2014-10-01

Full Text Available Laser sintering is one of the techniques used in additive manufacturing processes. The main objective of the work is to study the effects of process parameters on wetting phenomenon and interfacial energy during laser melting of stainless steel powder. This paper reports wetting of laser melted powder particles and its use for the determination of surface energy of stainless steel powder under laser beam exposure. Process parameters such as laser power, scan speed and beam diameter are considered for study. This study also identifies the process parameters for better wettability which produces smooth surfaces.

Electron Microscopy Study of Stainless Steel Radiation Damage Due to Long-Term Irradation by Alpha Particles Emitted From Plutonium

Energy Technology Data Exchange (ETDEWEB)

Unlu, Kenan [Univ. of Texas, Austin, TX (United States); Rios-Martinez, Carlos [Univ. of Texas, Austin, TX (United States); Saglam, Mehmet [Univ. of Texas, Austin, TX (United States); Hart, Ron R. [Texas A & M Univ., College Station, TX (United States); Shipp, John D. [Texas A & M Univ., College Station, TX (United States); Rennie, John [Texas A & M Univ., College Station, TX (United States)

1998-04-16

Radiation damage and associated surface and microstructural changes produced in stainless steel encapsulation by high-fluence alpha particle irradiations from weapons-grade plutonium of 316-stainless steel are being investigated.

Impact of the surface roughness of AISI 316L stainless steel on biofilm adhesion in a seawater-cooled tubular heat exchanger-condenser.

Science.gov (United States)

García, Sergio; Trueba, Alfredo; Vega, Luis M; Madariaga, Ernesto

2016-11-01

The present study evaluated biofilm growth in AISI 316L stainless steel tubes for seawater-cooled exchanger-condensers that had four different arithmetic mean surface roughness values ranging from 0.14 μm to 1.2 μm. The results of fluid frictional resistance and heat transfer resistance regarding biofilm formation in the roughest surface showed increases of 28.2% and 19.1% respectively, compared with the smoothest surface. The biofilm thickness taken at the end of the experiment showed variations of up to 74% between the smoothest and roughest surfaces. The thermal efficiency of the heat transfer process in the tube with the roughest surface was 17.4% greater than that in the tube with the smoothest surface. The results suggest that the finish of the inner surfaces of the tubes in heat exchanger-condensers is critical for improving energy efficiency and avoiding biofilm adhesion. This may be utilised to reduce biofilm adhesion and growth in the design of heat exchanger-condensers.

Copper contamination in thin stainless steel sheet

International Nuclear Information System (INIS)

Holbert, R.K. Jr.; Dobbins, A.G.; Bennett, R.K. Jr.

1986-01-01

The standard welding technique used at Oak Ridge Y-12 Plant for joining thin stainless sheet is the gas tungsten arc (GTA) welding process. One of the reoccurring problems with the sheet welds is surface cracking in the heat-affected zone (HAZ). Metallography shows that the cracks are only about 0.05 mm (0.002 in.) deep which is significant in a 0.25 mm (0.01 in.) thick sheet. Thus, welding requirements do not permit any surfacing cracking as detected by a fluorescent dye penetrant test conducted on every part after welding. Surface cracks have been found in both of the two most common weld designs in the thin sheet fabricated at the Oak Ridge Y-12 Plant. These butt joints are welded between two 0.25 mm thick stainless steel sheets and a tube with eyelet welded to a 25 mm (0.98 in.) thick sheet. The weld between the two sheets is made on a semiautomatic seam welding unit, whereas the tube-to-eyelet-to-sheet welds are done manually. The quality of both welds is very dependent on the welding procedure and the way the parts are placed in the weld fixturing. Metallographic examination has indicated that some welded parts with surface cracking in the weld region had copper particles on the surface, and the question of copper contamination has been raised. With the aid of a scanning electron microscope and an electron microprobe, the existence of copper in an around the surface cracks has been verified. The copper is on the surface of the parts prior to welding in the form of small dust particles

Analysis of surface integrity in machining of AISI 304 stainless steel under various cooling and cutting conditions

Science.gov (United States)

Klocke, F.; Döbbeler, B.; Lung, S.; Seelbach, T.; Jawahir, I. S.

2018-05-01

Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers from low yield strength that limits its technological applications. In this paper, liquid nitrogen (LN2) as cryogenic coolant, as well as minimum quantity lubrication (MQL), was applied and investigated. As a reference, conventional flood cooling was examined. Besides the cooling conditions, the feed rate was varied in four steps. A large rounded cutting edge radius and finishing cutting parameters were chosen to increase the mechanical load on the machined surface. The surface integrity was evaluated at both, the microstructural and the topographical levels. After turning experiments, a detailed analysis of the microstructure was carried out including the imaging of the surface layer and hardness measurements at varying depths within the machined layer. Along with microstructural investigations, different topological aspects, e.g., the surface roughness, were analyzed. It was shown that the resulting microstructure strongly depends on the cooling condition. This study also shows that it was possible to increase the micro hardness in the top surface layer significantly.

Radiation influence on heterogenous processes in stainless steel contact with sea-water

International Nuclear Information System (INIS)

Agayev, T.N.; Garibov, A.A.; Velibekova, G.Z.; Aliyev, A.Q.; Aliyev, S.M.

2005-01-01

Full text: Austenitic stainless steel (s.s.) with Cr content 16 %, Ni - 15 % is widely used in nuclear reactors as construction material, for fuel cladding production and also is used in oil and gas production and transportation. They possess comparatively large section of slow neutron capture and as a result high corrosion resistance. In real exploitation condition of nuclear reactors s.s. are exposed to ionizing radiation influence in contact of different media. That's why during their corrosion and destruction processes the surface defect formation processes and further heterogenous processes with their participation are of great importance. The research results of mechanism during radiation-heterogenous processes in nuclear reactor stainless steel contact with sea-water under the influence of γ-radiation in temperature interval 300-1074 K are represented in the given work. Radiolytic processes in water are comprehensively studied and therefore it was taken as model system for dating the surface defects and secondary electrons emitted from metal. The same model system was applied also in sea-water radiolysis processes. It's been established that radiation processes in s.s. lead to molecular hydrogen yield increase and at T=300 K up to 6.5 molec./100 eV. With the temperature increase molecular hydrogen yield increase up to 25.3 molec./100 eV at T≤773 K. During the further temperature increase up to 1073 K radiation constituent of radiation-thermal process in comparison with thermal becomes unnoticeable and W T (H 2 )≅W p (H 2 ). The kinetics of oxide phase formation of investigated sample surface in the result of thermal and radiation-thermal processes in their contact with sea-water has been studied. At that it's been shown that radiation leads to protective oxidation process rate increase and promotes the beginning of stainless steel destruction oxidation in contact with sea-water. At T≥573 K insoluble oxide phase is formed on metal surface that promotes

Electrochemical behaviour of iron and AISI 304 stainless steel in simulated acid rain solution

Energy Technology Data Exchange (ETDEWEB)

Pilic, Zora; Martinovic, Ivana [Mostar Univ. (Bosnia and Herzegovina). Dept. of Chemistry

2016-10-15

The growth mechanism and properties of the oxide films on iron and AISI 304 stainless steel were studied in simulated acid rain (pH 4.5) by means of electrochemical techniques and atomic absorption spectrometry. The layer-pore resistance model was applied to explain a potentiodynamic formation of surface oxides. It was found that the growth of the oxide film on iron takes place by the low-field migration mechanism, while that on the stainless steel takes place by the high-field mechanism. Kinetic parameters were determined. Impedance measurements revealed that Fe surface film has no protective properties at the open circuit potential, while the resistance of stainless steel oxide film is very high. The concentration of the metallic ions released into solution and measured by atomic absorption spectroscopy was in accordance with the results obtained from the electrochemical techniques.

Influence of the chemical composition, heat and surface treatment in the biofouling of austenitic stainless steels; Influencia de la composicion quimica, del tratamiento termico y del acabado supreficial en el bioensuciamiento de aceros inoxidables austeniticos

Energy Technology Data Exchange (ETDEWEB)

Sarro, M. I.; Aleman, O.; Moreno, D. A.; Roso, M.; Ranninger, C.

2004-07-01

The main objective of this study was to analyse the biofouling processes in the kinds of stainless steels used normally in industry (UNS S30400, UNS S30403 and UNS S31600), with different surface treatments after grinding and polishing. The study was developed using two microscopy techniques. Scanning Electron Microscopy (SEM) was used to evaluate the microorganisms distribution in the materials, and Epi fluorescence Microscopy was used to evaluate the viability of cells in the biofilm. The results revealed the influence of the material, heat treatment, surface treatment and roughness in the biofouling processes in the stainless steel assays. (Author) 33 refs.

Case histories of microbiologically influenced corrosion of austenitic stainless steel weldments

International Nuclear Information System (INIS)

Borenstein, S.W.; Buchanan, R.A.; Dowling, N.J.E.

1990-01-01

Microbiologically influenced corrosion (MIC) is initiated or accelerated by microorganisms and is currently recognized as a serious problem affecting the construction and operation of many industrial facilities, including nuclear power plants. The purpose of this paper is to review how biofouling and MIC can occur and discuss current mechanistic theories. A case history of MIC attack in power plants is examined with emphasis on the role of welding and heat treatment variables using laboratory electrochemical analyses. Although MIC can occur on a variety of alloys, pitting corrosion failures of austenitic stainless steels are often associated with weldments. MIC occurs as the result of a consortium of microorganisms colonizing on the metal surface and their variety (fungi, bacteria, algae, mold, and slimes) enables them to form support systems for cross feeding to enhance survival. The metabolic processes influence corrosion behaviour of materials by destroying protective coatings, producing a localized acid environment, creating corrosive deposits, or altering anodic and cathodic reactions. On stainless steels, biofilms destroy the passive oxide film on the surface of the steels and subject them to localized forms of corrosion. Many of the MIC failures in industry result in pitting to austenitic stainless steel weldments. Pitting primarily occurs in the weld metal, heat affected zones, and adjacent to the weld in the base metal. Depending on the conditions of the concentration cell created by the biofilm, either phase of the two-phase duplex stainless steel, austenite or delta ferrite, may be selectively attacked. Theories have been proposed about the mechanism of MIC on austenitic stainless steel and and a general understanding is that some function associated with the biofilm formation directly affects the electrochemical process

One-dimensional power spectrum and neutrino mass in the spectra of BOSS

International Nuclear Information System (INIS)

Borde, Arnaud

2014-01-01

The framework of the studies presented in this thesis is the one-dimensional power spectrum of the transmitted flux in the Lyman-alpha forests. The Lyman-alpha forest is an absorption pattern seen in the spectra of high redshift quasars corresponding to the absorption of the quasar light by the hydrogen clouds along the line of sight. It is a powerful cosmological tool as it probes relatively small scales, of the order of a few Mpc. It is also sensible to small non-linear effects such as the one induced by massive neutrinos. First, we have developed two independent methods to measure the one-dimensional power spectrum of the transmitted flux in the Lyman-alpha forest. The first method is based on a Fourier transform, and the second on a maximum likelihood estimator. The two methods are independent and have different systematic uncertainties. The determination of the noise level in the data spectra was subject to a novel treatment, because of its significant impact on the derived power spectrum. We applied the two methods to 13,821 quasar spectra from SDSS-III/BOSS DR9 selected from a larger sample of over 60,000 spectra on the basis of their high quality, large signal-to-noise ratio, and good spectral resolution. The power spectra measured using either approach are in good agreement over all twelve redshift bins from =2.2 to =4.4, and scales from 0.001 (km/s)"-"1 to 0.02 (km/s)"-"1. We carefully determined the methodological and instrumental systematic uncertainties of our measurements. Then, we present a suite of cosmological N-body simulations with cold dark matter, baryons and neutrinos aiming at modeling the low-density regions of the IGM as probed by the Lyman-alpha forests at high redshift. The simulations are designed to match the requirements imposed by the quality of BOSS and eBOSS data. They are made using either 768"3 or 192"3 particles of each type, spanning volumes ranging from (25 Mpc/h)"3 for high-resolution simulations to (100 Mpc/h)"3 for large

Evaluation on machined surface of hardened stainless steel generated by hard turning using coated carbide tools with wiper geometry

International Nuclear Information System (INIS)

Noordin, M.Y.; Kurniawan, D.; Sharif, S.

2007-01-01

Hard turning has been explored to be the finish machining operation for parts made of hardened steel. Its feasibility is determined partially by the quality of the resulting machined surface. This study evaluates the surface integrity of martensitic stainless steel (48 HRC) resulting from hard turning using coated carbide tool with wiper geometry at various cutting speed and feed and compares to that obtained using coated carbide tool with conventional geometry. The wiper coated carbide tool is able to produce machined surface which is of finer finish (Ra is finer than 0.4 μm at most cutting parameters) and yet is similarly inducing only minor microstructural alteration compared to its conventional counterpart. From the view of the chip morphology where continuous type of chip is desired rather than sawtooth chip type, the wiper tool generates continuous chip at almost similar range of cutting parameters compared to the case when using conventional tool. Additionally, the use of wiper tool also induces the preferred compressive residual stress at the machined surface. (author)

Effect of Carvacrol on Salmonella Saintpaul Biofilms on Stainless ...

African Journals Online (AJOL)

Purpose: To evaluate the effect of carvacrol against Salmonella Saintpaul biofilms on stainless steel surface. Methods: The effects of carvacrol on planktonic cells were evaluated by determining the minimum inhibitory concentration and minimal bactericidal concentration. The action of carvacrol on Salmonella Saintpaul ...

Laser heat treatment of welds for various stainless steels

Science.gov (United States)

Dontu, O.; Ganatsios, S.; Alexandrescu, N.; Predescu, C.

2008-03-01

The paper presents a study concerning the post - weld heat treatment of a duplex stainless steel. Welded joint samples were surface - treated using the same laser source adopted during welding in order to counterbalance the excess of ferrite formed in the welding process.

Redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS

International Nuclear Information System (INIS)

Beifiori, Alessandra; Saglia, Roberto P.; Bender, Ralf; Senger, Robert; Thomas, Daniel; Maraston, Claudia; Steele, Oliver; Masters, Karen L.; Pforr, Janine; Tojeiro, Rita; Johansson, Jonas; Nichol, Robert C.; Chen, Yan-Mei; Wake, David; Bolton, Adam; Brownstein, Joel R.; Leauthaud, Alexie; Schneider, Donald P.; Skibba, Ramin; Pan, Kaike

2014-01-01

We study the redshift evolution of the dynamical properties of ∼180, 000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1 ≤ z ≤ 0.6. The typical stellar mass of this sample is M * ∼2 × 10 11 M ☉ . We analyze the evolution of the galaxy parameters effective radius, stellar velocity dispersion, and the dynamical to stellar mass ratio with redshift. As the effective radii of BOSS galaxies at these redshifts are not well resolved in the Sloan Digital Sky Survey (SDSS) imaging we calibrate the SDSS size measurements with Hubble Space Telescope/COSMOS photometry for a sub-sample of galaxies. We further apply a correction for progenitor bias to build a sample which consists of a coeval, passively evolving population. Systematic errors due to size correction and the calculation of dynamical mass are assessed through Monte Carlo simulations. At fixed stellar or dynamical mass, we find moderate evolution in galaxy size and stellar velocity dispersion, in agreement with previous studies. We show that this results in a decrease of the dynamical to stellar mass ratio with redshift at >2σ significance. By combining our sample with high-redshift literature data, we find that this evolution of the dynamical to stellar mass ratio continues beyond z ∼ 0.7 up to z > 2 as M dyn /M * ∼(1 + z) –0.30±0.12 , further strengthening the evidence for an increase of M dyn /M * with cosmic time. This result is in line with recent predictions from galaxy formation simulations based on minor merger driven mass growth, in which the dark matter fraction within the half-light radius increases with cosmic time.

Redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS

Energy Technology Data Exchange (ETDEWEB)

Beifiori, Alessandra; Saglia, Roberto P.; Bender, Ralf; Senger, Robert [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Thomas, Daniel; Maraston, Claudia; Steele, Oliver; Masters, Karen L.; Pforr, Janine; Tojeiro, Rita; Johansson, Jonas; Nichol, Robert C. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Chen, Yan-Mei; Wake, David [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States); Bolton, Adam; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Leauthaud, Alexie [Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Chiba 277-8582 (Japan); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Skibba, Ramin [Department of Physics, Center for Astrophysics and Space Sciences, University of California, 9500 Gilman Drive, San Diego, CA 92093 (United States); Pan, Kaike, E-mail: beifiori@mpe.mpg.de [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); and others

2014-07-10

We study the redshift evolution of the dynamical properties of ∼180, 000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1 ≤ z ≤ 0.6. The typical stellar mass of this sample is M{sub *} ∼2 × 10{sup 11} M{sub ☉}. We analyze the evolution of the galaxy parameters effective radius, stellar velocity dispersion, and the dynamical to stellar mass ratio with redshift. As the effective radii of BOSS galaxies at these redshifts are not well resolved in the Sloan Digital Sky Survey (SDSS) imaging we calibrate the SDSS size measurements with Hubble Space Telescope/COSMOS photometry for a sub-sample of galaxies. We further apply a correction for progenitor bias to build a sample which consists of a coeval, passively evolving population. Systematic errors due to size correction and the calculation of dynamical mass are assessed through Monte Carlo simulations. At fixed stellar or dynamical mass, we find moderate evolution in galaxy size and stellar velocity dispersion, in agreement with previous studies. We show that this results in a decrease of the dynamical to stellar mass ratio with redshift at >2σ significance. By combining our sample with high-redshift literature data, we find that this evolution of the dynamical to stellar mass ratio continues beyond z ∼ 0.7 up to z > 2 as M{sub dyn}/M{sub *} ∼(1 + z){sup –0.30±0.12}, further strengthening the evidence for an increase of M{sub dyn}/M{sub *} with cosmic time. This result is in line with recent predictions from galaxy formation simulations based on minor merger driven mass growth, in which the dark matter fraction within the half-light radius increases with cosmic time.

Cathodic properties of different stainless steels in natural seawater

International Nuclear Information System (INIS)

Johnsen, R.; Bardal, E.

1985-01-01

The cathodic properties of a number of stainless steels, which were exposed to natural seawater flowing at 0 to 2.5 m/s and polarized to potentials from -300 to -950 mV SCE, have been studied. The current density development at constant potential and the free corrosion potential during the exposure time were recorded continuously. At the end of the exposure period, after approximately 28 to 36 days of exposure, polarization curves were determined. After one to three weeks of exposure, depending on the water velocity, microbiological activity on the surface caused an increase in the current density requirement of the specimen. An explanation for the mechanism behind the current density increase caused by slime production from marine bacteria may be increased exchange current density, i 0 . There was no measurable calcareous deposit on the stainless steel surfaces at the end of the exposure periods

Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

Science.gov (United States)

Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

2016-05-01

Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

Use of stainless stell for cost competitive bipolar plates in the SPFC

Energy Technology Data Exchange (ETDEWEB)

Makkus, R.C.; Janssen, A.H.H.; Bruijn, F.A. de; Mallant, R.K.A.M. [Netherlands Energy Research Foundation, Department of Fuels, Conversion and Environment, Petten (Netherlands)

2000-03-01

Bipolar plate materials for the Solid Polymer Fuel Cell (SPFC), alternative to the presently used graphite, should fulfil the following requirements in order to be applicable: low-cost, easy to machine or to shape, lightweight and low volume, mechanically and sufficiently chemically stable, and having a low contact resistance. Stainless steel is a low-cost material that is easy to shape, and thin sheets can be used to yield low volume and weight. Several stainless steels have been tested for their applicability (1.4439, 1.4404, 1.4541, 1.4529, 1.3974). The compaction pressure is of large influence on the contact resistance. Also, the pre-treatment of the surface is of influence; this is a permanent effect. Stainless steel constituents slowly dissolve into the Membrane Electrode Assembly (MEA). It has been found that the anode side stainless steel flow plate is the main source of contamination. Direct contact between the stainless steel and the membrane greatly enhances the contaminant level. Using an appropriate pre-treatment and a coating or gasket preventing direct contact between stainless steel and the membrane, one alloy was found to satisfy the requirements for use as a low cost material for the flow plate of an SPFC. (orig.)

76 FR 87 - Grant of Authority for Subzone Status; ThyssenKrupp Steel and Stainless USA, LLC; (Stainless and...

Science.gov (United States)

2011-01-03

... at the stainless and carbon steel products manufacturing facility of ThyssenKrupp Steel and Stainless... to the manufacturing of stainless and carbon steel products at the facility of ThyssenKrupp Steel and... Status; ThyssenKrupp Steel and Stainless USA, LLC; (Stainless and Carbon Steel Products) Calvert, AL...

Flat friction tests applied to austenic stainless steels with several surface finish. Analysis of adhesion conditions in friction

International Nuclear Information System (INIS)

Coello, J.; Miguel, V.; Ferrer, C.; Calatatyd, A.; Martinez, A.

2008-01-01

The main purpose of this work is to evaluate the tribological behaviour of austenic stainless steels AISI 304 with bright surface finishing (B). The assays have been carried out in flat faced dies system with mineral oil of 200 cts viscosity, S 2 Mo grease and in dry conditions. The relationship between friction coefficient and pressure and velocity has been established for the mineral oil as lubricant. In these conditions, a strong adhesive tendency has been found in boundary lubrication regime. The results obtained here, show us that S 2 Mo grease leads to lowest values for the friction coefficient. A minor adhesive behaviour tendency for AISI 316 steel, harder than 304 grades, has been found. A relevant plowing phenomena has been observed for the more critical friction conditions tried out. A surface hardener is produced as a consequence of that. (Author) 19 refs

Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

DEFF Research Database (Denmark)

Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per

2010-01-01

Bacterial contamination is a major concern in many areas. In this study, silver was added to type 316 stainless steels in order to obtain an expected bacteria inhibiting property to reduce the occurrence of bacterial contamination. Silver-bearing 316 stainless steels were prepared by vacuum melting...... in areas where hygiene is a major requirement. The possible mechanisms of silver dissolution from the surfaces of silver-bearing 316 stainless steels were also discussed in this report....

Methane formation in tritium gas exposed to stainless steel

International Nuclear Information System (INIS)

Morris, G.A.

1977-01-01

Tests were performed to determine the effect cleanliness of a surface exposed to tritium gas had on methane formation. These tests performed on 304 stainless steel vessels, cleaned in various ways, showed that the methane formation was reduced by the use of various cleaning procedures

Preparation of diamond like carbon thin film on stainless steel and ...

Indian Academy of Sciences (India)

Diamond-like carbon; buffer layer; plasma CVD; surface characterization; biomedical applications. Abstract. We report the formation of a very smooth, continuous and homogeneous diamond-like carbon DLC thin coating over a bare stainless steel surface without the need for a thin Si/Cr/Ni/Mo/W/TiN/TiC interfacial layer.

Nanosized TiN-SBR hybrid coating of stainless steel as bipolar plates for polymer electrolyte membrane fuel cells

International Nuclear Information System (INIS)

Kumagai, Masanobu; Myung, Seung-Taek; Asaishi, Ryo; Sun, Yang-Kook; Yashiro, Hitoshi

2008-01-01

In attempt to improve interfacial electrical conductivity of stainless steel for bipolar plates of polymer electrolyte membrane fuel cells, TiN nanoparticles were electrophoretically deposited on the surface of stainless steel with elastic styrene butadiene rubber (SBR) particles. From transmission electron microscopic observation, it was found that the TiN nanoparticles (ca. 50 nm) surrounded the spherical SBR particles (ca. 300-600 nm), forming agglomerates. They were well adhered on the surface of the type 310S stainless steel. With help of elasticity of SBR, the agglomerates were well fitted into the interfacial gap between gas diffusion layer (GDL) and stainless steel bipolar plate, and the interfacial contact resistance (ICR), simultaneously, was successfully reduced. A single cell using the TiN nanoparticles-coated bipolar plates, consequently, showed comparable cell performance with the graphite employing cell at a current density of 0.5 A cm -2 (12.5 A). Inexpensive TiN nanoparticle-coated type 310S stainless steel bipolar plates would become a possible alternate for the expensive graphite bipolar plates as use in fuel cell applications

Study of Stainless Steel Resistance in Conditions of Tribocorrosion Wear

Directory of Open Access Journals (Sweden)

Goran Rozing

2015-07-01

Full Text Available Analyzed was the influence of tribocorrosion wear due to effects of fatty acids present in the processed medium. The analysis was conducted on samples made of two austenitic and two martensitic stainless steels. Austenitic steels were tested in their nitrided state and martensitic in their induction hardened state. Conducted were laboratory tests of corrosion resistance of samples, analysis of the microstructure and hardness. To see how the applied processes for modifying the surface of stainless steels behave in realistic conditions, it was conducted the examination of samples/parts of a sunflower cake chain conveyer. Based on the comparison of results obtained in the laboratory and in real conditions, it was estimated that steels AISI 420 and AISI 431 with induction hardened surfaces have a satisfactory resistance to abrasive-adhesive wear in the presence of fatty acids.

Corrosion behavior of stainless steel and zirconium in nitric acid containing highly oxidizing species

International Nuclear Information System (INIS)

Mayuzumi, Masami; Fujita, Tomonari

1994-01-01

Corrosion behavior of 304ELC, 310Nb stainless steels and Zirconium was investigated in the simulated dissolver solution of a reprocessing plant to obtain fundamental data for life prediction. Corrosion of heat transfer surface was also investigated in nitric acid solutions containing Ce ion. The results obtained are as follows: (1) Stainless steels showed intergranular corrosion in the simulated dissolver solution. The corrosion rate increased with time and reached to a constant value after several hundred hours of immersing time. The constant corrosion rate changed depending on potential suggesting that corrosion potential dominates the corrosion process. 310Nb showed superior corrosion resistance to 304ELC. (2) Corrosion rate of stainless steels increased in the heat transfer condition. The causes of corrosion enhancement are estimated to be higher corrosion potential and higher temperature of heat transfer surface. (3) Zirconium showed perfect passivity in all the test conditions employed. (author)

Behaviour of steels in natural environments: focus on stainless steels in natural sea water

International Nuclear Information System (INIS)

Feron, D.

2005-01-01

Corrosion behaviour of steels and alloys in natural environments is not only dependent to material parameters and environmental chemistry, but also to micro-organisms which may be there. The global approach used to investigate the behaviour of alloys in natural environments is illustrated by the work done on stainless steels in seawater. In aerated seawater, studies led to the proposal of an 'enzymatic model' based on the enzymatic catalyze of the cathodic reaction and which allows reproducing the electrochemical behaviour of stainless steels in natural seawater and the crevice corrosion phenomena observed in natural sea waters. Coupling areas under aerobic and anaerobic conditions leads to the worst situation for stainless steel behaviour: the catalysis of the cathodic reaction on aerobic exposed surfaces and the decrease of the corrosion resistance of anaerobic surfaces due to sulphides. These results lead to the concept of electro-active bio-films. (author)

Martensitic transformation of type 304 stainless steel by high-energy ion implantation

International Nuclear Information System (INIS)

Chayahara, A.; Satou, M.; Nakashima, S.; Hashimoto, M.; Sasaki, T.; Kurokawa, M.; Kiyama, S.

1991-01-01

The effect of high-energy ion implantation on the structural changes of type 304 stainless steel were investigated. Gold, copper and silicon ions with an energy of 1.5 MeV was implanted into stainless steel. The fluences were in the range from 5x10 15 to 10 17 ions/cm 2 . It was found that the structure of stainless steel was transformed form the austenitic to the martensitic structure by these ion implantations. This structural change was investigated by means of X-ray diffraction and transmission electron microscopy (TEM). The depth profile of the irradiated ions was also analyzed by secondary ion mass spectroscopy (SIMS) and glow discharge spectroscopy (GDS). The degree of martensitic transformation was found to be strongly dependent on the surface pretreatment, either mechanical or electrolytic polishing. When the surface damages or strains by mechanical polishing were present, the martensitic transformation was greatly accelerated presumably due to the combined action of ion irradiation and strain-enhanced transformation. Heavier ions exhibit a high efficiency for the transformation. (orig.)

Experimental electro-thermal method for nondestructively testing welds in stainless steel pipes

International Nuclear Information System (INIS)

Green, D.R.

1979-01-01

Welds in austenitic stainless steel pipes are notoriously difficult to nondestructively examine using conventional ultrasonic and eddy current methods. Survace irregularities and microscopic variations in magnetic permeability cause false eddy current signal variations. Ultrasonic methods have been developed which use computer processing of the data to overcome some of the problems. Electro-thermal nondestructive testing shows promise for detecting flaws that are difficult to detect using other NDT methods. Results of a project completed to develop and demonstrate the potential of an electro-thermal method for nondestructively testing stainless steel pipe welds are presented. Electro-thermal NDT uses a brief pulse of electrical current injected into the pipe. Defects at any depth within the weld cause small differences in surface electrical current distribution. These cause short-lived transient temperature differences on the pipe's surface that are mapped using an infrared scanning camera. Localized microstructural differences and normal surface roughness in the welds have little effect on the surface temperatures

Integrated Computational Modelling of Thermochemical Surface Engineering of Stainless Steel

DEFF Research Database (Denmark)

Kücükyildiz, Ömer Can; Sonne, Mads Rostgaard; Thorborg, Jesper

2017-01-01

An implicit finite difference method (FDM) based numerical model for the prediction of composition- and stress-depth profiles developing during low temperature gas nitriding (LTGN) of 316 stainless steel is presented. The essential effects governing the kinetics of composition and coupled stress...... a plane-stress mechanical state. Huge compressive stress levels and steep stress gradients have previously been suggested to have an influence on the concentration profile. The corresponding large plastic deformation that occurs in the developing case is addressed in the model by isotropic plasticity...

Microbial electrocatalysis with Geobacter sulfurreducens biofilm on stainless steel cathodes

International Nuclear Information System (INIS)

Dumas, Claire; Basseguy, Regine; Bergel, Alain

2008-01-01

Stainless steel and graphite electrodes were individually addressed and polarized at -0.60 V vs. Ag/AgCl in reactors filled with a growth medium that contained 25 mM fumarate as the electron acceptor and no electron donor, in order to force the microbial cells to use the electrode as electron source. When the reactor was inoculated with Geobacter sulfurreducens, the current increased and stabilized at average values around 0.75 A m -2 for graphite and 20.5 A m -2 for stainless steel. Cyclic voltammetry performed at the end of the experiment indicated that the reduction started at around -0.30 V vs. Ag/AgCl on stainless steel. Removing the biofilm formed on the electrode surface made the current totally disappear, confirming that the G.sulfurreducens biofilm was fully responsible for the electrocatalysis of fumarate reduction. Similar current densities were recorded when the electrodes were polarized after being kept in open circuit for several days. The reasons for the bacteria presence and survival on non-connected stainless steel coupons were discussed. Chronoamperometry experiments performed at different potential values suggested that the biofilm-driven catalysis was controlled by electrochemical kinetics. The high current density obtained, quite close to the redox potential of the fumarate/succinate couple, presents stainless steel as a remarkable material to support biocathodes

The effect of different surface treatments of stainless steel crown and different bonding agents on shear bond strength of direct composite resin veneer

Directory of Open Access Journals (Sweden)

Ajami B

2007-01-01

Full Text Available Background and Aim: Stainless steel crown (SSC is the most durable and reliable restoration for primary teeth with extensive caries but its metalic appearance has always been a matter of concern. With advances in restorative materials and metal bonding processes, composite veneer has enhanced esthetics of these crowns in clinic. The aim of this study was to evaluate the shear bond strength of SSC to composite resin using different surface treatments and adhesives. Materials and Methods: In this experimental study, 90 stainless steel crowns were selected. They were mounted in molds and divided into 3 groups of 30 each (S, E and F. In group S (sandblast, buccal surfaces were sandblasted for 5 seconds. In group E (etch acidic gel was applied for 5 minutes and in group F (fissure bur surface roughness was created by fissure diamond bur. Each group was divided into 3 subgroups (SB, AB, P based on different adhesives: Single Bond, All Bond2 and Panavia F. Composite was then bonded to specimens. Cases were incubated in 100% humidity at 37°C for 24 hours. Shear bond strength was measured by Zwick machine with crosshead speed of 0.5 mm/min. Data were analyzed by ANOVA test with p0.05 so the two variables were studied separately. No significant difference was observed in mean shear bond strength of composite among the three kinds of adhesives (P>0.05. Similar results were obtained regarding surface treatments (P>0.05. Conclusion: Based on the results of this study, treating the SSC surface with bur and using single bond adhesive and composite can be used successfully to obtain esthetic results in pediatric restorative treatments.

Adsorption study of CO and H2O on carbon materials, Ni and stainless steel

International Nuclear Information System (INIS)

Kato, S.

1991-01-01

Adsorption of CO and water vapor on single crystalline graphite, diamond and an amorphous carbon film at room temperature was investigated by low energy ion scattering (ISS) and compared with stainless steel and nickel surfaces. Even for a CO exposure up to 10 4 L, the C intensity stayed constant and no O peak appeared in the ISS spectra from graphite while Ni and O intensities from Ni surface changed strikingly. Intensities of FE and O signals from stainless steel seriously decrease and increase with increasing exposure of H 2 O, respectively, but did not reach saturation even at an exposure of 10 3 L. On the other hand, C and O intensities from carbon surfaces changed moderately to reach saturation at an exposure of some 100 L. These results indicate that CO and H 2 O do not adsorb significantly on carbon surfaces in contrast to nickel and stainless steel surfaces. As a by-product survival probabilities of scattered He + ions from graphite for the primary energy of 0.6-2 keV were measured to be in a range of 10 -4 to 10 -2 and the survival parameter was deduced to be 5.0 x 10 7 cm s -1 . (author)

The role of cold work and applied stress on surface oxidation of 304 stainless steel

Energy Technology Data Exchange (ETDEWEB)

Lozano-Perez, Sergio, E-mail: sergio.lozano-perez@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Rd., Oxford OX1 3PH (United Kingdom); Kruska, Karen [Department of Materials, University of Oxford, Parks Rd., Oxford OX1 3PH (United Kingdom); Iyengar, Ilya [Winchester College, College Street, Winchester SO23 9LX (United Kingdom); Terachi, Takumi; Yamada, Takuyo [Institute of Nuclear Safety System (INSS), 64 Sata, Mihama-cho, Mikata-gun, Fukui 919-1205 (Japan)

2012-03-15

Highlights: Black-Right-Pointing-Pointer FIB 3D sequential sectioning is an ideal technique to characterize surface oxidation. Black-Right-Pointing-Pointer 3D models of the oxide can be produced with nanometre resolution. Black-Right-Pointing-Pointer The effects of stress and cold work in grain boundary oxidation have been analysed. Black-Right-Pointing-Pointer At least three different oxidation modes are observed when stress is applied. - Abstract: FIB 3-dimensional (3D) sequential sectioning has been used to characterize environmental degradation of 304 stainless steels in pressurized water reactor (PWR) simulated primary water. In particular, the effects of cold work and applied stress on oxidation have been studied in detail. It was found that a description of the oxidation behaviour of this alloy is only complete if it is treated statistically, since it can suffer from high variability depending on the feature described.

Increased recombination of CH3 radicals on stainless steel

International Nuclear Information System (INIS)

Gorodetsky, A.E.; Zalavutdinov, R.Kh.; Zakharov, A.P.; Vnukov, S.P.; Varshavskaya, I.G.; Makhankov, A.N.; Mazul, I.V.; Federici, G.

2005-01-01

By using a so-called 'stream technique', which consists of flowing gas in laminar regime along a quartz tube, we determine that CH 3 radicals are completely removed from the pumped mixture (CH 4 /C X H Y /H 2 /H/CH 3 ) after several hundred collisions with the inner surface of a stainless steel insert (T = 380-470 K). The methyl sticking coefficient decreased to ∼10 -6 and the recombination coefficient increased up to ∼0.01 at impingement with the metal surface. After passing through the heated zone no hydrocarbon deposition occurred at 300 K. However, unsaturated hydrocarbons, which formed in discharge zone and appeared as a result of interaction of radicals with stainless steel, condensed in a liquid phase at a temperature of ∼130 K and partial pressure of 0.01-0.1 Pa. Liquid films underwent partial polymerization and formed island deposits, which were stable at 300 K

Investigation of Microstructure and Corrosion Propagation Behaviour of Nitrided Martensitic Stainless Steel Plates

OpenAIRE

Abidin Kamal Ariff Zainal; Ismail Elya Atikah; Zainuddin Azman; Hussain Patthi

2014-01-01

Martensitic stainless steels are commonly used for fabricating components. For many applications, an increase in surface hardness and wear resistance can be beneficial to improve performance and extend service life. However, the improvement in hardness of martensitic steels is usually accompanied by a reduction in corrosion strength. The objective of this study is to investigate the effects of nitriding on AISI 420 martensitic stainless steel, in terms of microstructure and corrosion propagat...

Electrochemical Corrosion of Stainless Steel in Thiosulfate Solutions Relevant to Gold Leaching

Science.gov (United States)

Choudhary, Lokesh; Wang, Wei; Alfantazi, Akram

2016-01-01

This study aims to characterize the electrochemical corrosion behavior of stainless steel in the ammoniacal thiosulfate gold leaching solutions. Electrochemical corrosion response was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy, while the semi-conductive properties and the chemical composition of the surface film were characterized using Mott-Schottky analysis and X-ray photoelectron spectroscopy, respectively. The morphology of the corroded specimens was analyzed using scanning electron microscopy. The stainless steel 316L showed no signs of pitting in the ammoniacal thiosulfate solutions.

Chemical and physical changes at sodium-stainless steel interfaces in fast reactors

Energy Technology Data Exchange (ETDEWEB)

Mathews, C K [Bhabha Atomic Research Centre, Bombay (India). Radiochemistry Div.

1977-01-01

In the sodium loops of a fast reactor, mass transfer occurs due to the interaction of flowing sodium on stainless steel surfaces. Under the non-isothermal conditions prevailing in the loop some elements are preferentially leached from the surface layers of the hot zone and transported by sodium to the cooled zone where deposition may take place. The available information on the mass transport in non-isothermal sodium loops has been summarised, and an attempt has been made to understand the mechanisms involved, of which the chemical reactions at the sodium-stainless steel interface are especially important. The rate of diffusion towards the solid/liquid interface may be the rate-determining step in some of these reactions. When a ferritic surface layer is formed by the selective removal of austenitic stabilizing elements, diffusion of alloying constituents through the ferritic layer limits the growth of this layer. Only when the surface film is adherent, the diffusion across this layer becomes important. NaCrO/sub 2/, for instance, has poor adherence, and a surface film of this compound may not inhibit further corrosion.

Failure of Stainless Steel Welds Due to Microstructural Damage Prevented by In Situ Metallography

Directory of Open Access Journals (Sweden)

Juan Manuel Salgado Lopez

Full Text Available Abstract In stainless steels, microstructural damage is caused by precipitation of chromium carbides or sigma phase. These microconstituents are detrimental in stainless steel welds because they lead to weld decay. Nevertheless, they are prone to appear in the heat affected zone (HAZ microstructure of stainless steel welds. This is particularly important for repairs of industrial components made of austenitic stainless steel. Non-destructive metallography can be applied in welding repairs of AISI 304 stainless steel components where it is difficult to ensure that no detrimental phase is present in the HAZ microstructure. The need of microstructural inspection in repairs of AISI 304 is caused because it is not possible to manufacture coupons for destructive metallography, with which the microstructure can be analyzed. In this work, it is proposed to apply in situ metallography as non-destructive testing in order to identify microstructural damage in the microstructure of AISI 304 stainless steel welds. The results of this study showed that the external surface micrographs of the weldment are representative of HAZ microstructure of the stainless steel component; because they show the presence of precipitated metallic carbides in the grain boundaries or sigma phase in the microstructure of the HAZ.

Contribution to the study of physico-chemical properties of surfaces modified by laser treatment. Application to the enhancement of localized corrosion resistance of stainless steels

International Nuclear Information System (INIS)

Pacquentin, W.

2011-01-01

Metallic materials are more and more used in severe conditions with particularly strong request for improving their behavior in aggressive environment and especially over long periods. The objective of this PhD work is to estimate the potentiality of a laser surface melting treatment on the improvement of the stainless steel 304L corrosion resistance, surface treatments by laser can be revisited on the basis of a recent change in the laser technology. In the frame of this work, a nano-pulsed laser fiber was chosen: it allows the treated surface to be melted for few microns in depth, followed by an ultra-fast solidification occurring with cooling rates up to 1011 K/s. The combination of these processes leads to the elimination of the surface defects, the formation (trapping) of metastable phases, the segregation of chemical elements and the growth of a new oxide layer which properties are governed by the laser parameters. To correlate these latter to the electrochemical reactivity of the surface, the influence of two laser parameters on the physico-chemical properties of the surface was studied: the laser power and the overlap of the laser impacts. To support this approach, the pitting corrosion resistance of the samples was determined by standard electrochemical tests. For specific laser parameters, the pitting potential of a 304L stainless steel was increased by more than 500 mV corresponding to an important enhancement in localized corrosion resistance in chloride environment. The interdependence of the different phenomena resulting from the laser treatment lead to a quite complex prioritization of their role on the sensibility of the 304L. However, it was demonstrated that the nature of the thermal oxide formed during the laser surface melting and the induced defects are first-order parameters for the initiation of pits. (author) [fr

Characterization of interference thin films grown on stainless steel surface by alternate pulse current in a sulphochromic solution

Directory of Open Access Journals (Sweden)

Rosa Maria Rabelo Junqueira

2008-12-01

Full Text Available The aim of this work was to characterize thin interference films grown on the surface of AISI 304 stainless steel for decorative purposes. Films were grown in a sulphochromic solution at room temperature by an alternating pulse current method. The morphology and chemical state of the elements in the films were investigated by field emission scanning electron microscopy (FESEM, atomic force microscopy (AFM, glow discharge optical emission spectrometry (GDOES, and infrared Fourier transform spectroscopy (FTIR. Depth-sensing indentation (DSI experiments and wear abrasion tests were employed to assess the mechanical resistance of the films. The coloration process resulted in porous thin films which increased the surface roughness of the substrate. The interference films mainly consisted of hydrated chromium oxide containing iron. Increasing film thickness produced different colors and affected the mechanical properties of the coating-substrate system. Thicker films, such as those producing gold and green colors, were softer but more abrasion resistant.

On the processing, microstructure, mechanical and wear properties of cermet/stainless steel layer composites

International Nuclear Information System (INIS)

Farid, Akhtar; Guo Shiju

2007-01-01

This study deals with layer composites of carbide reinforcements and stainless steel prepared successfully by powder technology. The layer material consisted of two layers. The top layer consisted of reinforcements (TiC and NbC) and 465 stainless steel as the binder material for the carbides. The bottom layer was entirely of binder material (465 stainless steel). The microstructure of the composite was characterized by scanning electron microscopy. The microstructural study revealed that the top layer (TiC-NbC/465 stainless steel) showed the typical core-rim microstructure of conventional steel bonded cermets and the bottom layer showed the structure of sintered steel. An intermediate layer was found with a gradient microstructure, having a higher carbide content towards the cermet layer and lower carbide content towards the stainless steel layer. The bending strength of the layered material measured in the direction perpendicular to the layer alignment was remarkably high. The variation of strength as a function of the thickness of the bottom layer revealed that the character of the material changed from the cermet, to a layer composite and then towards metallic materials. The wear resistance of the top layer was studied against high speed steel. The wear mechanisms were discussed by means of microscopical observations on the worn surfaces. The wear was severe at higher wear loads and lower TiC content. Microploughing of the stainless steel matrix was found to be the dominant wear mechanism. Heavy microploughing and rapid removal of material from the wear surface was observed at high wear load. The fracture morphologies of the top, bottom and intermediate layers are reported

Atom probe, AFM and STM study on vacuum fired stainless steel

International Nuclear Information System (INIS)

Stupnik, A.; Frank, P.; Leisch, M.

2008-01-01

Full text: Stainless steel is one of the most commonly used structural materials for vacuum equipment. An efficient method to reduce the outgassing rate from stainless steel is a high temperature bakeout in vacuum (vacuum firing). This procedure reduces significantly the amount of dissolved hydrogen in the bulk. For the outgassing process the recombination rate of hydrogen atoms to the molecules plays the determining role and recombination is strongly related to the surface structure and composition. To get more detailed information about the surface morphology and composition AFM, STM and atom probe studies were carried out. Experiments on AISI 304L stainless steel samples show that the surface reconstructs completely during vacuum firing and large atomically flat terraces bounded by bunched steps and facets are formed. The large flat terraces can be assigned to (111) planes. The bunched steps and facets are corresponding in orientation almost to (110) planes and (100) planes. Surface inspection after vacuum firing by Auger electron spectroscopy (AES) gives reason for a composition change indicated by a reduction of the chromium signal in relation to the iron and nickel signal. Since the information depth of AES covers several atomic layers not only the top atomic layer of the sample surface is probed. For this reason 3D atom probe was used as well suited tool to investigate the segregation behavior of this alloy with the goal to examine the change in local chemical composition due to the high temperature treatment. As a result of vacuum firing the atom probe experiments show a significant enrichment of nickel at the top surface layer. In the second atomic layer chromium enrichment is detected. After vacuum firing the average composition below the second atomic layer shows certain chromium depletion up to 2 nm in depth. The observed changes in surface chemistry influence recombination and desorption probability from the surface and may contribute to the present

Corrosion resistance of the welded AISI 316L after various surface treatments

Directory of Open Access Journals (Sweden)

Tatiana Liptáková

2014-01-01

Full Text Available The main aim of this work is to monitor the surface treatment impact on the corrosion resistance of the welded stainless steel AISI 316L to local corrosion forms. The excellent corrosion resistance of austenitic stainless steel is caused by the existence of stable, thin and well adhering passive layer which quality is strongly influenced by welding. Therefore surface treatment of stainless steel is very important with regard to its local corrosion susceptibility Surfaces of welded stainless steel were treated by various mechanical methods (grinding, garnet blasting. Surface properties were studied by SEM, corrosion resistance was evaluated after exposition tests in chlorides environment using weight and metalographic analysis. The experimental outcomes confirmed that the mechanical finishing has a significant effect on the corrosion behavior of welded stainless steel AISI 316L.

Using an equation based on flow stress to estimate structural integrity of annealed Type 304 stainless steel plate and pipes containing surface defects

International Nuclear Information System (INIS)

Reuter, W.G.; Place, T.A.

1981-01-01

An accurate assessment of the influence of defects on structural component integrity is needed. Generally accepted analytical techniques are not available for the very ductile materials used in many nuclear reactor components. Some results are presented from a test programme to obtain data by which to evaluate proposed models. Plate and pipe specimens containing surface flaws were fabricated from annealed Type 304 stainless steel and tested at room temperature. An evaluation of an empirical equation based on flow stress is presented. In essentially all instances the flow stress is not a constant but varies as a function of the size of the surface flaw. (author)

Diamond deposition on siliconized stainless steel

International Nuclear Information System (INIS)

Alvarez, F.; Reinoso, M.; Huck, H.; Rosenbusch, M.

2010-01-01

Silicon diffusion layers in AISI 304 and AISI 316 type stainless steels were investigated as an alternative to surface barrier coatings for diamond film growth. Uniform 2 μm thick silicon rich interlayers were obtained by coating the surface of the steels with silicon and performing diffusion treatments at 800 deg. C. Adherent diamond films with low sp 2 carbon content were deposited on the diffused silicon layers by a modified hot filament assisted chemical vapor deposition (HFCVD) method. Characterization of as-siliconized layers and diamond coatings was performed by energy dispersive X-ray analysis, scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

Effects of chitosan inhibitor on the electrochemical corrosion behavior of 2205 duplex stainless steel

Science.gov (United States)

Yang, Se-fei; Wen, Ying; Yi, Pan; Xiao, Kui; Dong, Chao-fang

2017-11-01

The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency (IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl3 solution.

An experimental study of crevice corrosion behaviour of 316L stainless steel in artificial seawater

Energy Technology Data Exchange (ETDEWEB)

Cai Baoping [School of Electromechanical Engineering, China University of Petroleum, Dongying, Shandong 257061 (China); Liu Yonghong, E-mail: liuyhupc@126.co [School of Electromechanical Engineering, China University of Petroleum, Dongying, Shandong 257061 (China); Tian Xiaojie; Wang Fei; Li Hang; Ji Renjie [School of Electromechanical Engineering, China University of Petroleum, Dongying, Shandong 257061 (China)

2010-10-15

The effects of applied torque on corrosion behaviour of 316L stainless steel with crevices were investigated using the cyclic potentiodynamic polarization method. Three kinds of crevices (316L-to-polytetrafluoroethylene, 316L-to-fluoroelastomeric and 316L-to-316L) were tested in artificial seawater at 50 {sup o}C. Corroded surface morphology was also investigated using scanning electron microscopy. Results indicate similar trends in crevice corrosion susceptibility with increasing applied torque. Among the three crevices, the 316L stainless steel specimen, coupled to the 316L stainless steel crevice former, is the most susceptible to crevice corrosion.

An experimental study of crevice corrosion behaviour of 316L stainless steel in artificial seawater

International Nuclear Information System (INIS)

Cai Baoping; Liu Yonghong; Tian Xiaojie; Wang Fei; Li Hang; Ji Renjie

2010-01-01

The effects of applied torque on corrosion behaviour of 316L stainless steel with crevices were investigated using the cyclic potentiodynamic polarization method. Three kinds of crevices (316L-to-polytetrafluoroethylene, 316L-to-fluoroelastomeric and 316L-to-316L) were tested in artificial seawater at 50 o C. Corroded surface morphology was also investigated using scanning electron microscopy. Results indicate similar trends in crevice corrosion susceptibility with increasing applied torque. Among the three crevices, the 316L stainless steel specimen, coupled to the 316L stainless steel crevice former, is the most susceptible to crevice corrosion.

Surface deformation effects on stainless steel, Ni, Cu and Mo produced by medium energy He ions irradiation

International Nuclear Information System (INIS)

Constantinescu, B.; Florescu, V.; Sarbu, C.

1993-01-01

To investigate dose and energy dependence of surface deformation effects (blistering and flaking), different kinds of candidate CTR first wall materials as 12KH18N10T, W-4541, W-4016 and SS-304 stainless steels, Ni, Cu, Mo were irradiated at room temperature with 3.0, 4.7 and 6.8 MeV He + ions at IAP Cyclotron. The effects were investigated by means of a TEMSCAN 200 CX electron microscope and two metallographic Orthoplan Pol Leitz and Olympus microscopes. We observed two dose dependent main phenomena: blistering and flaking (craters). So, blisters occurrence on the irradiated surface is almost instantaneous when a critical dose (number of He ions accumulated in the region at the end of alpha particles range) is reached. Increasing irradiation dose, we reached flaking stage. So, isolated submicronic fissures along grain boundaries were observed on the blister skin, chronologically followed by large (5-20 μm) deep cracks of hundreds of microns in length, blisters opening and, finally, flaking appearance. (author) 8 figs., 1 tab

Structure and properties of the Stainless steel AISI 316 nitrided with microwave plasma

International Nuclear Information System (INIS)

Becerril R, F.

1999-01-01

In this work were presented the results obtained by nitridation on stainless steel AISI 316 using a plasma generated through a microwave discharge with an external magnetic field using several moistures hydrogen / nitrogen to form a plasma. The purpose of nitridation was to increase the surface hardness of stainless steel through a phase formation knew as γN which has been reported that produces such effect without affect the corrosion resistance proper of this material. (Author)

Development and Application of High-Cr Ferritic Stainless Steels as Building Exterior Materials

International Nuclear Information System (INIS)

Kim, Yeong H.; Lee, Yong H.; Lee, Yong D.

2008-01-01

Stainless Steels have been widely used as a building exterior materials in Asian countries for the last decade. It is required for the materials in this field to have an aesthetic appearance,a relatively high strength, and an excellent corrosion resistance. Other metallic materials such as copper, aluminum, and carbon steels have been also used as the exterior materials. Considering the cost of maintenance, stainless steel, having the outstanding corrosion resistance, is replacing other materials in the several parts in the building exteriors. Ferritic stainless steel has been applied as the roofing materials because its thermal expansion is much smaller than that of austenitic stainless steel. Therefore, it is suitable for the large-scale construction such as airport terminal, convention center, and football stadium. To improve the corrosion resistance of the ferritic stainless steels, the modification of alloy composition has been studied to develop new grade materials and the progress in the surface technology has been introduced. Corrosion properties, of these materials were evaluated in the laboratory and in the field for longer than two years. High-Cr ferritic stainless steel showed excellent corrosion resistance to the atmospheric environments. In the region close to the sea, the corrosion resistance of high-Cr ferritic stainless steel was much superior to that of other materials, which may prove this steel to be the appropriate materials for the construction around seashore. In some of the large constructions around seashore in South Korea, high-Cr ferritic stainless steels have been used as the building exterior materials for six years

Development and Application of High-Cr Ferritic Stainless Steels as Building Exterior Materials

Energy Technology Data Exchange (ETDEWEB)

Kim, Yeong H.; Lee, Yong H.; Lee, Yong D. [POSCO Technical Reseaarch Lab., Pohang (Korea, Republic of)

2008-12-15

Stainless Steels have been widely used as a building exterior materials in Asian countries for the last decade. It is required for the materials in this field to have an aesthetic appearance,a relatively high strength, and an excellent corrosion resistance. Other metallic materials such as copper, aluminum, and carbon steels have been also used as the exterior materials. Considering the cost of maintenance, stainless steel, having the outstanding corrosion resistance, is replacing other materials in the several parts in the building exteriors. Ferritic stainless steel has been applied as the roofing materials because its thermal expansion is much smaller than that of austenitic stainless steel. Therefore, it is suitable for the large-scale construction such as airport terminal, convention center, and football stadium. To improve the corrosion resistance of the ferritic stainless steels, the modification of alloy composition has been studied to develop new grade materials and the progress in the surface technology has been introduced. Corrosion properties, of these materials were evaluated in the laboratory and in the field for longer than two years. High-Cr ferritic stainless steel showed excellent corrosion resistance to the atmospheric environments. In the region close to the sea, the corrosion resistance of high-Cr ferritic stainless steel was much superior to that of other materials, which may prove this steel to be the appropriate materials for the construction around seashore. In some of the large constructions around seashore in South Korea, high-Cr ferritic stainless steels have been used as the building exterior materials for six years.

Grafting of antibacterial polymers on stainless steel via surface-initiated atom transfer radical polymerization for inhibiting biocorrosion by Desulfovibrio desulfuricans.

Science.gov (United States)

Yuan, S J; Xu, F J; Pehkonen, S O; Ting, Y P; Neoh, K G; Kang, E T

2009-06-01

To enhance the biocorrosion resistance of stainless steel (SS) and to impart its surface with bactericidal function for inhibiting bacterial adhesion and biofilm formation, well-defined functional polymer brushes were grafted via surface-initiated atom transfer radical polymerization (ATRP) from SS substrates. The trichlorosilane coupling agent, containing the alkyl halide ATRP initiator, was first immobilized on the hydroxylated SS (SS-OH) substrates for surface-initiated ATRP of (2-dimethylamino)ethyl methacrylate (DMAEMA). The tertiary amino groups of covalently immobilized DMAEMA polymer or P(DMAEMA), brushes on the SS substrates were quaternized with benzyl halide to produce the biocidal functionality. Alternatively, covalent coupling of viologen moieties to the tertiary amino groups of P(DMAEMA) brushes on the SS surface resulted in an increase in surface concentration of quaternary ammonium groups, accompanied by substantially enhanced antibacterial and anticorrosion capabilities against Desulfovibrio desulfuricans in anaerobic seawater, as revealed by antibacterial assay and electrochemical studies. With the inherent advantages of high corrosion resistance of SS, and the good antibacterial and anticorrosion capabilities of the viologen-quaternized P(DMAEMA) brushes, the functionalized SS is potentially useful in harsh seawater environments and for desalination plants. Copyright 2009 Wiley Periodicals, Inc.

Chemical coloring on stainless steel by ultrasonic irradiation.

Science.gov (United States)

Cheng, Zuohui; Xue, Yongqiang; Ju, Hongbin

2018-01-01

To solve the problems of high temperature and non-uniformity of coloring on stainless steel, a new chemical coloring process, applying ultrasonic irradiation to the traditional chemical coloring process, was developed in this paper. The effects of ultrasonic frequency and power density (sound intensity) on chemical coloring on stainless steel were studied. The uniformity of morphology and colors was observed with the help of polarizing microscope and scanning electron microscopy (SEM), and the surface compositions were characterized by X-ray photoelectric spectroscopy (XPS), meanwhile, the wear resistance and the corrosion resistance were investigated, and the effect mechanism of ultrasonic irradiation on chemical coloring was discussed. These results show that in the process of chemical coloring on stainless steel by ultrasonic irradiation, the film composition is the same as the traditional chemical coloring, and this method can significantly enhance the uniformity, the wear and corrosion resistances of the color film and accelerate the coloring rate which makes the coloring temperature reduced to 40°C. The effects of ultrasonic irradiation on the chemical coloring can be attributed to the coloring rate accelerated and the coloring temperature reduced by thermal-effect, the uniformity of coloring film improved by dispersion-effect, and the wear and corrosion resistances of coloring film enhanced by cavitation-effect. Ultrasonic irradiation not only has an extensive application prospect for chemical coloring on stainless steel but also provides an valuable reference for other chemical coloring. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of oxides of stainless steel UNS S30400 formed in offshore environment

Energy Technology Data Exchange (ETDEWEB)

Cindra Fonseca, M. [Universidade Federal Fluminense, PGMEC - Programa de Pos-Graduacao em Engenharia Mecanica, Rua Passo da Patria, 156, Bl. D, Sala 302, 24210-240 Niteroi-RJ (Brazil); Bastos, I.N. [Instituto Politecnico/UERJ, Rua Alberto Rangel s/n, 28630-050 Nova Friburgo-RJ (Brazil); Baggio-Saitovitch, E., E-mail: esaitovitch@yahoo.com.br [Centro Brasileiro de Pesquisas Fisicas, Rua Xavier Sigaud, 150, 22290-180 Rio de Janeiro-RJ (Brazil); Sanchez, D.R. [Instituto de Fisica, Universidade Federal Fluminense, Campus da Praia Vermelha, 24210-346 Niteroi-RJ (Brazil)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Thick corrosion products of stainless steel were characterized by Moessbauer spectroscopy. Black-Right-Pointing-Pointer High content of akaganeite on the surface exposed to marine environment. Black-Right-Pointing-Pointer Nanoparticles of akaganeite were always observed. - Abstract: Thick corrosion products of austenitic stainless steel obtained from a steam turbine structure exposed in offshore environment were studied by optical stereomicroscopy, X-ray diffraction, Moessbauer and energy-dispersive X-ray spectroscopy. The external surface of mechanical structure was exposed to a marine atmosphere and the internal one to a combustion gas for two decades. Characterization of corrosion products showed high content of akaganeite in the outer region and a mixture of akaganeite and hematite in the inner surface. Besides these characteristics, a distribution of nanosized superparamagnetic particles of akaganeite was found in the rusts.

Effects of Hydrogen Ion Implantation on TiC-C Coating of Stainless Steel

Institute of Scientific and Technical Information of China (English)

ZHANG Rui-qian; LIU Yao-guang; HUANG Ning-kang

2008-01-01

Titanium carbide coatings are widely used as various wear-resistant material.The hydrogen erosion resistance of TiC-C films and the effect of hydrogen participation on TiC-C films were studied.Seventy-five percent TiC-C films are prepared on stainless steel surface by using ion mixing,where TiC-C films are deposited by rf magnetron sputtering followed by argon ion bombardment.The samples are then submitted to hydrogen ion implantation at 1.2×10-3 Pa.Characterization for the 75% TiC-C films was done with SIMS,XRD,AES,and XPS.Secondary ion mass spectroscopy (SIMS) was used to analyze hydrogen concentration variation with depth,X-Ray diffraction (XRD) was used to identify the phases,and Auger electron spectra (AES) as well as X-ray photoelectron spectra (XPS) were used to check the effects of hydrogen on shifts of chemical bonding states of C and Ti in the TiC-C films.It is found that TiC-C films on stainless steel surface can prevent hydrogen from entering stainless steel.

Surface quality and microstructure of low-vacuum sintered orthodontic bracket 17-4 PH stainless steel fabricated by MIM process

Science.gov (United States)

Suharno, Bambang; Suharno, Lingga Pradinda; Saputro, Hantoro Restucondro; Irawan, Bambang; Prasetyadi, Tjokro; Ferdian, Deni; Supriyadi, Sugeng

2018-02-01

Surface roughness and microstructure play important role on orthodontic bracket quality. Therefore, orthodontic brackets need to have smooth surface roughness to reduce the friction and bacterial adhesion. Microstructure of orthodontic brackets also determine the mechanical properties and corrosion resistance. There are two methods to produce orthodontic bracket, investment casting and metal injection molding. The purpose of this study is to observe the surface roughness and microstructure of orthodontic bracket which were made from two different fabrication methods. To produce orthodontic bracket with metal injection molding method, 17-4 PH stainless steel feedstock was injected to the orthodontic bracket mold using injection molding machine. After injection, the binder was eliminated with solvent and thermal debinding. Solvent debinding process was conducted with hexane at 50 °C on magnetic stirrer for 1.5 hours. Thermal debinding process was conducted at 510 °C with 0.5 °C/min heat rate and 120 min holding time. Hereafter, sintering process were performed with vacuum tube furnace at 1360 °C with heat rate 5 °C/min and 90 min holding time in low vacuum atmosphere. To produce orthodontic bracket with investment casting method, the wax was injected into the mold then the wax pattern was arranged into the tree form. The tree form was then dipped into ceramic slurry and allowed to harden, the ceramic slurry has a thickness in the region of 10 mm. The ceramic mold was then heated at a temperature of over than 1100°C to strengthen the ceramic mold and to remove the remaining wax. After that, the molten 17-4 PH stainless steel was poured into the ceramic mold at a temperature of over 1600°C. The natural cooling process was carried out at temperature of 25°C, after which the ceramic mold was broken away. Then, the orthodontic bracket was cut from the tree form. The results show that the orthodontic bracket which were made with investment casting fabrication

Hot Corrosion Behavior of Stainless Steel with Al-Si/Al-Si-Cr Coating

Science.gov (United States)

Fu, Guangyan; Wu, Yongzhao; Liu, Qun; Li, Rongguang; Su, Yong

2017-03-01

The 1Cr18Ni9Ti stainless steel with Al-Si/Al-Si-Cr coatings is prepared by slurry process and vacuum diffusion, and the hot corrosion behavior of the stainless steel with/without the coatings is studied under the condition of Na2SO4 film at 950 °C in air. Results show that the corrosion kinetics of stainless steel, the stainless steel with Al-Si coating and the stainless steel with Al-Si-Cr coating follow parabolic laws in several segments. After 24 h corrosion, the sequence of the mass gain for the three alloys is the stainless steel with Al-Si-Cr coating coating coating. The corrosion products of the three alloys are layered. Thereinto, the corrosion products of stainless steel without coating are divided into two layers, where the outside layer contains a composite of Fe2O3 and FeO, and the inner layer is Cr2O3. The corrosion products of the stainless steel with Al-Si coating are also divided into two layers, of which the outside layer mainly consists of Cr2O3, and the inner layer is mainly SiO2. The corrosion film of the stainless steel with Al-Si-Cr coating is thin and dense, which combines well with substrate. Thereinto, the outside layer is mainly Cr2O3, and the inside layer is Al2O3. In the matrix of all of the three alloys, there exist small amount of sulfides. Continuous and protective films of Cr2O3, SiO2 and Al2O3 form on the surface of the stainless steel with Al-Si and Al-Si-Cr coatings, which prevent further oxidation or sulfide corrosion of matrix metals, and this is the main reason for the much smaller mass gain of the two alloys than that of the stainless steel without any coatings in the 24 h hot corrosion process.

Influence of Citric Acid on the Metal Release of Stainless Steels

Energy Technology Data Exchange (ETDEWEB)

Mazinanian, N.; Wallinder, I. Odnevall; Hedberg, Y. S. [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Stockholm (Sweden)

2015-08-15

Knowledge of how metal releases from the stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessment. A new European standard test protocol for testing metal release in food contact materials made from metals and alloys has recently been published by the Council of Europe. The major difference from earlier test protocols is the use of citric acid as the worst-case food simulant. The objectives of this study were to assess the effect of citric acid at acidic, neutral, and alkaline solution pH on the extent of metal release for stainless steel grades AISI 304 and 316, commonly used as food contact materials. Both grades released lower amounts of metals than the specific release limits when they were tested according to test guidelines. The released amounts of metals were assessed by means of graphite furnace atomic absorption spectroscopy, and changes in the outermost surface composition were determined using X-ray photoelectron spectroscopy. The results demonstrate that both the pH and the complexation capacity of the solutions affected the extent of metal release from stainless steel and are discussed from a mechanistic perspective. The outermost surface oxide was significantly enriched in chromium upon exposure to citric acid, indicating rapid passivation by the acid. This study elucidates the effect of several possible mechanisms, including complex ion- and ligand-induced metal release, that govern the process of metal release from stainless steel under passive conditions in solutions that contain citric acid.

Electrochemical study of corrosion inhibition of stainless steel in phosphoric medium

Energy Technology Data Exchange (ETDEWEB)

Hnini, K.; Chtaini, A. [Laboratoire d' Electrochimie et de Bio Corrosion, Faculte des Sciences et Techniques, Beni-Mellal (Morocco); Khouili, M.; Elbouadili, A. [Laboratoire de Chimie Organique et Analytique, Faculte des Sciences et Techniques, Beni-Mellal (Morocco)

2004-07-01

The corrosion of metals represents a terrible waste of both natural resources and money, the failure of some stainless steel resulting from pitting corrosion is some times considered a technological problem, consequently, much effort has been expended in attempting to understand and overcome the corrosion therefore, many stainless steel/ environment combinations have been studied. The use of heterocyclic compounds as inhibitors is one of the most practical methods for protection against corrosion in acidic media. In continuation of our work on development of macrocyclic compounds as corrosion inhibitors we report in our study the corrosion inhibiting behaviour of organic compound Methoxy-2-Allyl-4 Phenol (MAP) containing coordinating and conjugation groups, at three forms (natural, polymerized and chemically treated) on the corrosion of stainless steel in phosphoric acid. This study focused on the comparison for corrosion inhibition proprieties of these different applications using potentiodynamic polarization, electrochemical impedance spectroscopy and SEM. The specimen was evaluated to determine change in his corrosion potential and resistance polarization; These MAP products have exhibited corrosion inhibition by maintaining a high resistance polarization (low corrosion rate) in each application. These results reveal that this compound is efficient inhibitor in all forms; the most inhibition efficiency is obtained with polymerized form. To further evaluate the test data, the steel surfaces were analyzed using scanning electron microscopy, SEM observations of surface treated concrete confirmed presence of inhibitor on the steel surfaces. (authors)

Nitride alloy layer formation of duplex stainless steel using nitriding process

Science.gov (United States)

Maleque, M. A.; Lailatul, P. H.; Fathaen, A. A.; Norinsan, K.; Haider, J.

2018-01-01

Duplex stainless steel (DSS) shows a good corrosion resistance as well as the mechanical properties. However, DSS performance decrease as it works under aggressive environment and at high temperature. At the mentioned environment, the DSS become susceptible to wear failure. Surface modification is the favourable technique to widen the application of duplex stainless steel and improve the wear resistance and its hardness properties. Therefore, the main aim of this work is to nitride alloy layer on the surface of duplex stainless steel by the nitriding process temperature of 400°C and 450°C at different time and ammonia composition using a horizontal tube furnace. The scanning electron microscopy and x-ray diffraction analyzer are used to analyse the morphology, composition and the nitrided alloy layer for treated DSS. The micro hardnesss Vickers tester was used to measure hardness on cross-sectional area of nitrided DSS. After nitriding, it was observed that the hardness performance increased until 1100 Hv0.5kgf compared to substrate material of 250 Hv0.5kgf. The thickness layer of nitride alloy also increased from 5μm until 100μm due to diffusion of nitrogen on the surface of DSS. The x-ray diffraction results showed that the nitride layer consists of iron nitride, expanded austenite and chromium nitride. It can be concluded that nitride alloy layer can be produced via nitriding process using tube furnace with significant improvement of microstructural and hardness properties.

Detection of the pairwise kinematic Sunyaev-Zel'dovich effect with BOSS DR11 and the Atacama Cosmology Telescope

Energy Technology Data Exchange (ETDEWEB)

Bernardis, F. De; Vavagiakis, E.M.; Niemack, M.D.; Gallardo, P.A. [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Aiola, S. [Department of Physics and Astronomy, University of Pittsburgh, and Pittsburgh Particle Physics, Astrophysics, and Cosmology Center, 3941 O' Hara Street, Pittsburgh, PA 15260 (United States); Battaglia, N. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Beall, J.; Becker, D.T.; Cho, H.; Fox, A. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Bond, J.R. [CITA, University of Toronto, 60 St. George St., Toronto, ON M5S 3H8 (Canada); Calabrese, E.; Dunkley, J. [Sub-Department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Coughlin, K.; Datta, R. [Department of Physics, University of Michigan Ann Arbor, MI 48109 (United States); Devlin, M. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Dunner, R. [Instituto de Astrofísica and Centro de Astro-Ingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile); Ferraro, S. [Miller Institute for Basic Research in Science, University of California, Berkeley, CA 94720 (United States); Halpern, M. [University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver BC V6T 1Z1 (Canada); Hand, N., E-mail: fdeberna@gmail.com [Astronomy Department, University of California, Berkeley, CA 94720 (United States); and others

2017-03-01

We present a new measurement of the kinematic Sunyaev-Zel'dovich effect using data from the Atacama Cosmology Telescope (ACT) and the Baryon Oscillation Spectroscopic Survey (BOSS). Using 600 square degrees of overlapping sky area, we evaluate the mean pairwise baryon momentum associated with the positions of 50,000 bright galaxies in the BOSS DR11 Large Scale Structure catalog. A non-zero signal arises from the large-scale motions of halos containing the sample galaxies. The data fits an analytical signal model well, with the optical depth to microwave photon scattering as a free parameter determining the overall signal amplitude. We estimate the covariance matrix of the mean pairwise momentum as a function of galaxy separation, using microwave sky simulations, jackknife evaluation, and bootstrap estimates. The most conservative simulation-based errors give signal-to-noise estimates between 3.6 and 4.1 for varying galaxy luminosity cuts. We discuss how the other error determinations can lead to higher signal-to-noise values, and consider the impact of several possible systematic errors. Estimates of the optical depth from the average thermal Sunyaev-Zel'dovich signal at the sample galaxy positions are broadly consistent with those obtained from the mean pairwise momentum signal.

Electron beam cladding of titanium on stainless steel plate

International Nuclear Information System (INIS)

Tomie, Michio; Abe, Nobuyuki; Yamada, Masanori; Noguchi, Shuichi.

1990-01-01

Fundamental characteristics of electron beam cladding was investigated. Titanium foil of 0.2mm thickness was cladded on stainless steel plate of 3mm thickness by scanning electron beam. Surface roughness and cladded layer were analyzed by surface roughness tester, microscope, scanning electron microscope and electron probe micro analyzer. Electron beam conditions were discussed for these fundamental characteristics. It is found that the energy density of the electron beam is one of the most important factor for cladding. (author)

Structural materialization of stainless steel molds and dies by the low temperature high density plasma nitriding

Directory of Open Access Journals (Sweden)

Aizawa Tatsuhiko

2015-01-01

Full Text Available Various kinds of stainless steels have been widely utilized as a mold substrate material for injection molding and as a die for mold-stamping and direct stamping processes. Since they suffered from high temperature transients and thermal cycles in practice, they must be surface-treated by dry and wet coatings, or, by plasma nitriding. Martensitic stainless steel mold was first wet plated by the nickel phosphate (NiP, which was unstable at the high temperature stamping condition; and, was easy to crystalize or to fracture by itself. This issue of nuisance significantly lowered the productivity in fabrication of optical elements at present. In the present paper, the stainless steel mold was surface-treated by the low-temperature plasma nitriding. The nitrided layer by this surface modification had higher nitrogen solute content than 4 mass%; the maximum solid-solubility of nitrogen is usually 0.1 mass% in the equilibrium phase diagram. Owing to this solid-solution with high nitrogen concentration, the nitrided layer had high hardness of 1400 Hv within its thickness of 40 μm without any formation of nitrides after 14.4 ks plasma nitriding at 693 K. This nitrogen solid-solution treated stainless steel had thermal resistivity even at the mold-stamping conditions up to 900 K.

Strain-induced phase transformation at the surface of an AISI-304 stainless steel irradiated to 4.4 dpa and deformed to 0.8% strain

Energy Technology Data Exchange (ETDEWEB)

Gussev, M.N., E-mail: gussevmn@ornl.gov; Field, K.G.; Busby, J.T.

2014-03-15

Surface relief due to localized deformation in a 4.4-dpa neutron-irradiated AISI 304 stainless steel was investigated using scanning electron microscopy coupled with electron backscattering diffraction and scanning transmission electron microscopy. It was found a body-centered-cubic (BCC) phase (deformation-induced martensite) had formed at the surface of the deformed specimen along the steps generated from dislocation channels. Martensitic hill-like formations with widths of ∼1 μm and depths of several microns were observed at channels with heights greater than ∼150 nm above the original surface. Martensite at dislocation channels was observed in grains along the [0 0 1]–[1 1 1] orientation but not in those along the [1 0 1] orientation.

Strain-induced phase transformation at the surface of an AISI-304 stainless steel irradiated to 4.4 dpa and deformed to 0.8% strain

International Nuclear Information System (INIS)

Gussev, M.N.; Field, K.G.; Busby, J.T.

2014-01-01

Surface relief due to localized deformation in a 4.4-dpa neutron-irradiated AISI 304 stainless steel was investigated using scanning electron microscopy coupled with electron backscattering diffraction and scanning transmission electron microscopy. It was found a body-centered-cubic (BCC) phase (deformation-induced martensite) had formed at the surface of the deformed specimen along the steps generated from dislocation channels. Martensitic hill-like formations with widths of ∼1 μm and depths of several microns were observed at channels with heights greater than ∼150 nm above the original surface. Martensite at dislocation channels was observed in grains along the [0 0 1]–[1 1 1] orientation but not in those along the [1 0 1] orientation

Development of new high-performance stainless steels

International Nuclear Information System (INIS)

Park, Yong Soo

2002-01-01

This paper focused on high-performance stainless steels and their development status. Effect of nitrogen addition on super-stainless steel was discussed. Research activities at Yonsei University, on austenitic and martensitic high-performance stainless, steels, and the next-generation duplex stainless steels were introduced

Sunlight-enhanced calcareous deposition on cathodic stainless steel in natural seawater

Digital Repository Service at National Institute of Oceanography (India)

Eashwar, M.; SathishKumar, P.; Ravishankar, R.; Subramanian, G.

In replicate series of experiments in natural seawater, one in full darkness and the other in a 1:1 diurnal cycle with as little as 5 percent of natural solar illumination, sunlight promoted calcareous deposition on cathodic stainless steel surfaces...

Experimental Investigation of Surface Color Changes in Vacuum Evaporation Process for Gold-like Stainless Steel

Directory of Open Access Journals (Sweden)

Yang Baojian

2016-01-01

Full Text Available In order to reduce the environmental pollution caused by the three wastes during the process of electroplating of gold-like film on stainless steel, in this paper, the "vacuum evaporation and annealing" composite technologies were adopted to evaporate gold-like film in 16 stainless steel 304 substrates, and electronic color cards and color software were also used for analyzing the color and luster of the gold-like film. Experiments shows that the negative pressure, annealing temperature and mass fraction of the double copper alloys have influence on preparation of imitation in assaying the fineness of gold film, the annealing temperature has significant effects on imitation in assaying the fineness of gold film.

Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

Energy Technology Data Exchange (ETDEWEB)

Zaleski, Tania M. [San Jose State Univ., CA (United States)

2008-10-30

Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

Inactivation of Clostridium perfringens spores adhered onto stainless steel surface by agents used in a clean-in-place procedure.

Science.gov (United States)

Alzubeidi, Yasmeen S; Udompijitkul, Pathima; Talukdar, Prabhat K; Sarker, Mahfuzur R

2018-07-20

Enterotoxigenic Clostridium perfringens, a leading foodborne pathogen can be cross-contaminated from food processing stainless steel (SS) surfaces to the finished food products. This is mostly due to the high resistance of C. perfringens spores adhered onto SS surfaces to various disinfectants commonly used in food industries. In this study, we aimed to investigate the survivability and adherence of C. perfringens spores onto SS surfaces and then validate the effectiveness of a simulated Clean-in-Place (CIP) regime on inactivation of spores adhered onto SS surfaces. Our results demonstrated that, 1) C. perfringens spores adhered firmly onto SS surfaces and survived for at-least 48 h, unlike their vegetative cells who died within 30 min, after aerobic incubation at refrigerated and ambient temperatures; 2) Spores exhibited higher levels of hydrophobicity than vegetative cells, suggesting a correlation between cell surface hydrophobicity and adhesion to solid surfaces; 3) Intact spores were more hydrophobic than the decoated spores, suggesting a positive role of spore coat components on spores' hydrophobicity and thus adhesion onto SS surfaces; and finally 4) The CIP regime (NaOH + HNO 3 ) successfully inactivated C. perfringens spores adhered onto SS surfaces, and most of the effect of CIP regime appeared to be due to the NaOH. Collectively, our current findings may well contribute towards developing a strategy to control cross-contamination of C. perfringens spores into food products, which should help reducing the risk of C. perfringens-associated food poisoning outbreaks. Copyright © 2018 Elsevier B.V. All rights reserved.

Antibacterial inorganic-organic hybrid coatings on stainless steel via consecutive surface-initiated atom transfer radical polymerization for biocorrosion prevention.

Science.gov (United States)

Yuan, S J; Pehkonen, S O; Ting, Y P; Neoh, K G; Kang, E T

2010-05-04

To enhance the corrosion resistance of stainless steel (SS) and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, well-defined inorganic-organic hybrid coatings, consisting of a polysilsesquioxane inner layer and quaternized poly(2-(dimethyamino)ethyl methacrylate) (P(DMAEMA)) outer blocks, were prepared via successive surface-initiated atom transfer radical polymerization (ATRP) of 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). The cross-linked P(TMASPMA), or polysilsesquioxane, inner layer provided a durable and resistant coating to electrolytes. The pendant tertiary amino groups of the P(DMAEMA) outer block were quaternized with alkyl halide to produce a high concentration of quaternary ammonium groups with biocidal functionality. The so-synthesized inorganic-organic hybrid coatings on the SS substrates exhibited good anticorrosion and antibacterial effects and inhibited biocorrosion induced by sulfate-reducing bacteria (SRB) in seawater media, as revealed by antibacterial assay and electrochemical analyses, and they are potentially useful to steel-based equipment under harsh industrial and marine environments.

Characterizing Sky Spectra Using SDSS BOSS Data

Science.gov (United States)

Florez, Lina Maria; Strauss, Michael A.

2018-01-01

In the optical/near-infrared spectra gathered by a ground-based telescope observing very faint sources, the strengths of the emission lines due to the Earth’s atmosphere can be many times larger than the fluxes of the sources we are interested in. Thus the limiting factor in faint-object spectroscopy is the degree to which systematics in the sky subtraction can be minimized. Longwards of 6000 Angstroms, the night-sky spectrum is dominated by multiple vibrational/rotational transitions of the OH radical from our upper atmosphere. While the wavelengths of these lines are the same in each sky spectrum, their relative strengths vary considerably as a function of time and position on the sky. The better we can model their strengths, the better we can hope to subtract them off. We expect that the strength of lines from common upper energy levels will be correlated with one another. We used flux-calibrated sky spectra from the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (SDSS BOSS) to explore these correlations. Our aim is to use these correlations for creating improved sky subtraction algorithms for the Prime Focus Spectrograph (PFS) on the 8.2-meter Subaru Telescope. When PFS starts gathering data in 2019, it will be the most powerful multi-object spectrograph in the world. Since PFS will be gathering data on sources as faint as 24th magnitude and fainter, it's of upmost importance to be able to accurately measure and subtract sky spectra from the data that we receive.

The wettability modification of bio-grade stainless steel in contact with simulated physiological liquids by the means of laser irradiation

International Nuclear Information System (INIS)

Hao, L.; Lawrence, J.; Li, L.

2005-01-01

Early surface events that occur rapidly upon implantation of a biomaterial into biological fluids determine the subsequent response. These involve wetting by physiological liquids followed by adsorption of proteins and cells to the biomaterials surface. A CO 2 laser and high power diode laser (HPDL) were used to modify the surface properties of the material and thus manipulate the wettability of the material and its interaction with physiological liquids. The contact angles, θ, of selected test liquids including simulated physiological liquids shows that the wettability of the stainless steel improved after CO 2 and HPDL treatment. The determined adhesion work of stainless steel towards stimulated physiological fluid enhanced after laser treatment, implying better interaction with the biological liquids. It is demonstrated that the laser could be a novel and controllable technique for enhancing the biocompatibility of bio-grade stainless steel

Influence of laser shock peening on irradiation defects in austenitic stainless steels

Science.gov (United States)

Lu, Qiaofeng; Su, Qing; Wang, Fei; Zhang, Chenfei; Lu, Yongfeng; Nastasi, Michael; Cui, Bai

2017-06-01

The laser shock peening process can generate a dislocation network, stacking faults, and deformation twins in the near surface of austenitic stainless steels by the interaction of laser-driven shock waves with metals. In-situ transmission electron microscopy (TEM) irradiation studies suggest that these dislocations and incoherent twin boundaries can serve as effective sinks for the annihilation of irradiation defects. As a result, the irradiation resistance is improved as the density of irradiation defects in laser-peened stainless steels is much lower than that in untreated steels. After heating to 300 °C, a portion of the dislocations and stacking faults are annealed out while the deformation twins remain stable, which still provides improved irradiation resistance. These findings have important implications on the role of laser shock peening on the lifetime extension of austenitic stainless steel components in nuclear reactor environments.

Hydrogen effects in stainless steel

International Nuclear Information System (INIS)

Caskey, G.R. Jr.

1983-01-01

The effects of hydrogen on stainless steels have been reviewed and are summarized in this paper. Discussion covers hydrogen solution and transport in stainless steels as well as the effects of hydrogen on deformation and fracture under various loading conditions. Damage is caused also by helium that arises from decay of the hydrogen isotope tritium. Austenitic, ferritic, martensite, and precipitation-hardenable stainless steels are included in the discussion. 200 references

Feasibility study on infrared electro-thermal NDE of stainless steel

International Nuclear Information System (INIS)

Green, D.R.; Hassberger, J.A.

1975-11-01

Electro-thermal examination, a branch of thermal testing (TT), is a promising method being developed for NDE of stainless steel welds. This report describes the first phase of development; i.e., preliminary demonstration and laboratory evaluation of the method's sensitivity to notches in Type 304 stainless steel plate specimens. It also includes a description of the basic principles, together with a description of the hardware and experimental results showing that electrical discharge machined notches down to 0.16 cm (0.06 in.) long x 0.08 cm (0.03 in.) deep were detected. A qualitative technique for interpreting the test results to determine whether defects are at the surface or deeper within the material is demonstrated

Hydroxyapatite coating on stainless steel by biomimetic method

International Nuclear Information System (INIS)

Dias, V.M.; Maia Filho, A.L.M.; Silva, G.; Sousa, E. de; Cardoso, K.R.

2010-01-01

Austenitic stainless steels are widely used in implants due to their high mechanical strength and corrosion, however, are not able to connect to bone tissue and were classified as bioinert. The calcium phosphate ceramics such as hydroxyapatite (HA) are bioactive materials and create strong chemical bonds with bone tissue, but its brittleness and low fracture toughness render its use in conditions of high mechanical stress. The coating of steel with the bioactive ceramics such as HA, combines the properties of interest of both materials, accelerating bone formation around the implant. In this study, austenitic stainless steel samples were coated with apatite using the biomimetic method. The effect of three different surface conditions of steel and the immersion time in the SBF solution on the coating was evaluated. The samples were characterized by SEM, EDS and X-ray diffraction. (author)