Tribological properties of multifunctional coatings with Shape Memory Effect in abrasive wear

Science.gov (United States)

Blednova, Zh. M.; Dmitrenko, D. V.; Balaev, E. U. O.

2018-01-01

The article gives research results of the abrasive wear process on samples made of Steel 1045, U10 and with applied composite surface layer "Nickel-Multicomponent material with Shape Memory Effect (SME) based on TiNi". For the tests we have chosen TiNiZr, which is in the martensite state and TiNiHfCu, which is in the austenitic state at the test temperature. The formation of the surface layer was carried out by high-speed oxygen-fuel deposition in a protective atmosphere of argon. In the wear test, Al2O3 corundum powder was used as an abrasive. It is shown that the wear rate of samples with a composite surface layer of multicomponent materials with SME is significantly reduced in comparison with the base, which is explained by reversible phase transformations of the surface layer with SME. After carrying out the additional surface plastic deformation (SPD), the resistance of the laminated composition to abrasion wear has greatly enhanced, due to the reinforcing effect of the SPD. It is recommended for products working in conditions of abrasive wear and high temperatures to use the complex formation technology of the surface composition "steel-nickel-material with high-temperature SME", including preparation of the substrate surface and the deposited material, high-speed spraying in the protective atmosphere of argon, followed by SPD.

Two-body, dry abrasive wear of Fe/Cr/C experimental alloys - relationship between microstructure and mechanical properties

International Nuclear Information System (INIS)

Kwok, C.K.S.

1982-01-01

A systematic study of abrasive wear resistance of Fe/Cr/Mn based alloys has been carried out using a two body pin-on-disc wear machine. Abrasives used were silicon carbide, alumina and quartz. The objective of this study was to evaluate the abrasive wear resistance and to investigate the relationships between microstructure, mechanical properties, and abrasive wear resistance for these experimental alloys. Several commercial alloys were also tested to provide a basis for comparison. The goal of this study was to develop information so as to improve wear resistance of these experimental alloys by means of thermal treatments. Grain-refinement by double heat treatment was carried out in this research

Abrasive Wear of Alloyed Cast Steels Applied for Heavy Machinery

Directory of Open Access Journals (Sweden)

Studnicki A.

2015-03-01

Full Text Available In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were performed using the modified in Department of Foundry pin-on-disc method.

Abrasion Wear Resistance, Hardness and Microstructure of Hard Linings Deposited by Means of a Submerged Arc. Dureza, microestructura y resistencia al desgaste por abrasion de recargues duros depositados con arco sumergido

Energy Technology Data Exchange (ETDEWEB)

Paranhos, R; Alcoforado, J M; Castillo, J A; Sauer, A

1989-01-01

Consumable materials for submerged arc welding of the types alloyed flux-neutral electrode and neutral flux-alloyed electrode were used to form, through multipass welding, a light alloy hard lining of the C-Mn type on ASTM A36 Type structural steel. Emphasis was put on microstructural characterization of the linings surveyed under electron scanning microscopy, and tests were performed to study their hardness and abrasion wear resistance at low pressures. As a result of these tests, a great influence of welding parameters on hardness and abrasion resistance properties of the combination active flux-neutral electrode was noticed. As the results showed no relationship between the hardness and the abrasion wear resistance of the linings surveyed, an attempt was made to relate the resulting microstructure with their abrasion wear resistance. (Author)

Wear of dentine in vitro by toothpaste abrasives and detergents alone and combined.

Science.gov (United States)

Moore, C; Addy, M

2005-12-01

To measure in vitro the abrasion of dentine by toothpaste detergents and abrasives alone and combined. Detergents used were tego betain, sodium lauryl sulphate (SLS), adinol and pluronic diluted to 1% w/v. Abrasives were three artificial silicas, tixosil 73 and 123 and Zeodent 113, and calcium carbonate used at 2.5% w/v. Flat human dentine specimens were brushed with aqueous detergent solutions or abrasive slurries, detergent abrasive slurries and water for 20,000 brush strokes. Dentine loss was measured by non-contacting profilometry at 10,000 and 20,000 strokes. Silica particle size distribution was measured by laser deflection. Loss of dentine occurred with all detergents, abrasives and detergent abrasion combinations, but was not linear with number of brush strokes. Water appeared to remove the smear layer only, but all detergents exceeded the predicted smear layer thickness. The silica abrasives differed in abrasion properties despite similar particle size distribution. Different detergents modulated the abrasives actions in mainly positive or mainly negative directions. Detergents appear able to attack the dentine surface to produce wear. Abrasives vary considerably in wear produced under similar conditions. Detergents modulate the effect of abrasives in a way that may reflect the rheological properties of the mixture.

Assessment of thermal spray coatings for wear and abrasion resistance applications

Science.gov (United States)

Karode, Ishaan Nitin

Thermal spray cermet and metallic coatings are extensively used for wear, abrasion and corrosion control in a variety of industries. The first part of the thesis focuses mainly on testing of sand erosion resistance of thermal spray coatings on carbon composites used in the manufacture of helicopter rotor blades. The test set-up employed is a sand blasting machine and is an effort to duplicate the in-flight conditions especially those encountered in hot arid conditions. The technique adopted follows the Department of Defence test method standard. Carbon Composites have excellent stiffness, strength and low weight/density. The strength to weight ratio is high. Hence, these are used in aerospace applications to a large extent. However, the biggest problem encountered with carbon composites is its low abrasion resistance as its surface is very weak. Hence, thermal spray coatings are used to improve the surface properties of CFRP. Zinc bond coats and WC-Co coatings were tested. However, high amount of thermal stresses were developed between the substrate and the coating due to large differences in the CTE's of the both, leading to high mass losses within two minutes and just 130 grams of sand sprayed on to the coatings with the sand blasting machine built; and hence the coatings with CC as a substrate could not qualify for the application. The second part of the thesis focuses on the assessment of different thermal spray coatings used for manufacture of mechanical seals in pumps and analyze the best coating material for the wear resistance application through detail quantification of material loss by block-on-ring test set-up. A machine based on Block-on-ring test set-up following ASTM G77 (Measurement of Adhesive wear resistance of thermal spray coatings) standards was built to duplicate the pump conditions. Thermally sprayed coated materials were tested in different conditions (Load, time, abrasive). WC-Co had the highest wear resistance (lower volume losses) and

Abrasive wear of enamel by bioactive glass-based toothpastes.

Science.gov (United States)

Mahmood, Asad; Mneimne, Mohammed; Zou, Li Fong; Hill, Robert G; Gillam, David G

2014-10-01

To determine the abrasivity of a 45S5 bioactive glass based toothpaste on enamel as a function of the particle size and shape of the glass. 45S5 glass was synthesized ground and sieved to give various particle sized fractions toothpastes and their tooth brush abrasivity measured according to BS EN ISO11609 methodology. Enamel loss increased with increasing particle size. The percussion milled powder exhibited particles that had sharp edges and the pastes were significantly more abrasive than the pastes made with round ball milled powders. One interesting observation made during the present study was that there was preferential wear of the enamel at the dentin-enamel junction (DEJ), particularly with the coarse particle sized pastes.

Three-body abrasive wear behaviour of metastable spheroidal carbide cast irons with different chromium contents

Energy Technology Data Exchange (ETDEWEB)

Efremenko, Vasily; Pastukhova, Tatiana; Chabak, Yuliia; Efremenko, Alexey [Pryazovskyi State Technical Univ., Mariupol (Ukraine); Shimizu, Kazumichi; Kusumoto, Kenta [Muroran Institute of Technology, Hokkaido (Japan); Brykov, Michail [Zaporozhye National Technical Univ., Zaporozhye (Ukraine)

2018-02-15

The effect of heat treatment and chromium contents (up to 9.1 wt.%) on the wear resistance of spheroidal carbide cast iron (9.5 wt.% V) was studied using optical and scanning electron microscopy, X-ray diffractometry, dilatometry and three-body abrasive testing. It was found that quenching from 760 C and 920 C improved the alloys' wear resistance compared to the as-cast state due to the formation of metastable austenite transforming into martensite under abrasion. The wear characteristics of alloys studied are 1.6 - 2.3 times higher than that of reference cast iron (12 wt.% V) having stable austenitic matrix. Chromium addition decreases surface damage due to the formation of M{sub 7}C{sub 3} carbides, while it reduces wear resistance owing to austenite stabilization to abrasion-induced martensite transformation. The superposition of these factors results in decreasing the alloys' wear behaviour with chromium content increase.

Abrasive wear mechanisms and surface layer structure of refractory materials after mechanical working

International Nuclear Information System (INIS)

Milman, Y.V.; Lotsko, D.V.

1989-01-01

The mechanisms of abrasive wear and surface layer structure formation after different kinds of mechanical working are considered in terms of fracture and plastic deformation mechanisms for various refractory materials. The principles for classification of abrasive wear mechanisms are proposed, the four types of wear mechanisms are distinguished for various combinations of fractures and plastic deformation types. The concept of characteristic deformation temperature t * (knee temperature) is used. Detailed examples are given of investigating the surface layer structures in grinded crystals of sapphire and molybdenum. The amorphisation tendency of the thinnest surface layer while mechanical polishing is discussed separately. 19 refs., 11 figs., 2 tabs. (Author)

Solutionizing temperature and abrasive wear behaviour of cast Al-Si-Mg alloys

International Nuclear Information System (INIS)

Sharma, Rajesh; Anesh; Dwivedi, D.K.

2007-01-01

In the present paper, the influence of solutionizing temperature during artificial age hardening treatment (T 6 ) of cast Al-(8, 12, 16%)Si-0.3%Mg on abrasive wear behaviour has been reported. Alloys were prepared by controlled melting and casting. Cast alloys were given artificial age hardening treatment having a sequence of solutionizing, quenching and artificial aging. All the alloys were solutionized at 450 deg. C, 480 deg. C, 510 deg. C, and 550 deg. C for 8 h followed by water quenching (30 deg. C) and aging hardening at 170 deg. C for 12 h. Abrasive wear tests were conducted against 320 grade SiC polishing papers at 5 N and 10 N normal loads. It was observed that the silicon content and solution temperature affected the wear resistance significantly. Increase in solution temperature improved the wear resistance. Hypereutectic alloy showed better wear resistance than the eutectic and hypoeutectic alloys under identical conditions. Optical microstructure study of alloys revealed that the increase in solutionizing temperature improved distribution of silicon grains. Scanning electron microscopy (SEM) of wear surface was carried out to analyze the wear mechanism

Controlled wear of vitrified abrasive materials for precision grinding ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

2Machining Research Group, Department of Engineering, University of ... ods are applied to analyse the cutting mechanism in grinding. .... (d) Chemical reaction between abrasive and workpiece material at elevated temperatures ... most common method used for measuring wear flat area employs an optical, or an electron.

The effect of daily fluoride mouth rinsing on enamel erosive/abrasive wear in situ.

Science.gov (United States)

Stenhagen, K R; Hove, L H; Holme, B; Tveit, A B

2013-01-01

It is not known whether application of fluoride agents on enamel results in lasting resistance to erosive/abrasive wear. We investigated if one daily mouth rinse with sodium fluoride (NaF), stannous fluoride (SnF(2)) or titanium tetrafluoride (TiF(4)) solutions protected enamel against erosive/abrasive wear in situ (a paired, randomised and blind study). Sixteen molars were cut into 4 specimens, each with one amalgam filling (measurement reference surface). Two teeth (2 × 4 specimens) were mounted bilaterally (buccal aspects) on acrylic mandibular appliances and worn for 9 days by 8 volunteers. Every morning, the specimens were brushed manually with water (30 s) extra-orally. Then fluoride solutions (0.4% SnF(2) pH 2.5; 0.15% TiF(4) pH 2.1; 0.2% NaF pH 6.5, all 0.05 M F) were applied (2 min). Three of the specimens from each tooth got different treatment, and the fourth served as control. At midday, the specimens were etched for 2 min in 300 ml fresh 0.01 M hydrochloric acid and rinsed in tap water. This etch procedure was repeated in the afternoon. Topographic measurements were performed by a white-light interferometer. Mean surface loss (±SD) for 16 teeth after 9 days was: SnF(2) 1.8 ± 1.9 µm, TiF(4) 3.1 ± 4.8 µm, NaF 26.3 ± 4.7 µm, control 32.3 ± 4.4 µm. Daily rinse with SnF(2), TiF(4) and NaF resulted in 94, 90 and 18% reduction in enamel erosive/abrasive wear, respectively, compared with control (p < 0.05). The superior protective effect of daily rinse with either stannous or titanium tetrafluoride solutions on erosive/abrasive enamel wear is promising. Copyright © 2012 S. Karger AG, Basel.

Development of the white cast iron with niobium alloy, heat treating, to wear of the abrasive resistance

International Nuclear Information System (INIS)

Farah, Alessandro Fraga

1997-01-01

This work presents the heat treatment and abrasion tests results of a white cast iron with niobium alloy. The hardening heat treatment were made 950, 1000, 1050 e 110 deg C temperatures cooled by forced air. The tempering treatment were made at 450, 500 e 550 deg C temperatures. The heat treating alloy were compared, in the abrasive tests, with commercial alloys used as hardfacing by welding process in wear pieces. The abrasion tests was realized in pin on disk test. Additional tests were carried out for microstructural characterization to identify the different phases presents in the alloys. In a general way, the alloy studies showed the best wear rate for the heat treatments that results in higher hardness. It performance was superior than that of the commercial alloys. (author)

Abrasive wear behaviour of bio-active glass ceramics containing ...

Indian Academy of Sciences (India)

In this study, abrasive wear behaviour of bio-active glass ceramic materials produced with two different processes is studied. Hot pressing process and conventional casting and controlled crystallization process were used to produce bio-active ceramics. Fracture toughness of studied material was calculated by fracture ...

Wear resistance and structural changes in nitrogen-containing high-chromium martensitic steels under conditions of abrasive wear and sliding friction

International Nuclear Information System (INIS)

Makarov, A.V.; Korshunov, L.G.; Schastlivtsev, V.M.; Chernenko, N.L.

1998-01-01

Martensitic nitrogen-containing steels Kh17N2A0.14, Kh13A0.14, Kh14G4A0.22 as well as steel 20Kh13 were studied for their wear resistance under conditions of friction and abrasion. Metallography, X ray diffraction analysis and electron microscopy were used to investigate the structural changes taking place in a thin surface layer on wearing. It is shown that an increase of nitrogen content of 0.14 to 0.22% promotes an enhancement of steel resistance to abrasive and adhesive wear, especially after tempering in the range of 500-550 deg C. Typically, the nitrogen-containing steels exhibit lower resistance to various types of wear in comparison with the steels with high-carbon martensite due to their lower deformability under conditions of friction loading

Abrasive wear resistance and microstructure of Ni-Cr-B-Si hardfacing alloys with additions of Al, Nb, Mo, Fe, Mn and C

International Nuclear Information System (INIS)

Berns, H.; Fischer, A.; Theisen, W.

1987-01-01

The development of new Ni-base hardfacing alloys for filler wire welding or metal spraying should result in materials with a good resistance against high temperature corrosion and abrasive wear. The first step is to design microstructures, which obtain a satisfactory abrasive wear behaviour at room temperature. Thus, different alloys are melted and scrutinized as to their microstructure and their abrasive wear resistance in laboratory. Compared to commercial Ni-base hardfacing alloys they show a higher volume fraction of coarse hard phases due to the additional, initial solidification of Nb-carbides and Cr-, and Mo-borides. Thus, the abrasive wear resistance is improved. For hard abrasive particles, such as corundum, the Ni-base alloys are more wear resistant than harder Fe-base alloys investigate earlier. This is due to the tougher Ni metal matrix that results in microcracking not to be the most significantly acting wear mechanism

Strength and gas-abrasive wear-resistance of zirconium carbide based cerments

International Nuclear Information System (INIS)

Samsonov, G.V.; Dan'kin, A.A.; Markov, A.A.; Bogomol, I.V.

1976-01-01

Results relating to a study of cermet strength and wear resistance by means of a gas-abrasive flow are presented. It has been found that with a higher amount of the metallic binder (over 25 at.%) in zirconium carbide-based cermets the bending and compression strength and also hardness and wear resistance within the systems ZrC-Nb, ZrC-Mo, ZrC-W become lower. The interrelation of the cermet wear resistance of the various systems and their bending and compression strengths, which, in turn, depend on the electronic structure is shown

Investigations on mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites

International Nuclear Information System (INIS)

Suresha, B.; Kumar, Kunigal N. Shiva

2009-01-01

The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites. The measured wear volume loss increases with increase in abrading distance/abrasive particle size. However, the specific wear rate decreases with increase in abrading distance and decrease in abrasive particle size. The results showed that the highest specific wear rate is for glass fabric reinforced vinyl ester composite with a value of 10.89 x 10 -11 m 3 /Nm and the lowest wear rate is for carbon fabric reinforced vinyl ester composite with a value of 4.02 x 10 -11 m 3 /Nm. Mechanical properties were evaluated and obtained values are compared with the wear behaviour. The worn surface features have been examined using scanning electron microscope (SEM). Photomicrographs of the worn surfaces revealed higher percentage of broken glass fiber as compared to carbon fiber. Also better interfacial adhesion between carbon and vinyl ester in carbon reinforced vinyl ester composite was observed.

Aging temperature and abrasive wear behaviour of cast Al-(4%, 12%, 20%)Si-0.3% Mg alloys

International Nuclear Information System (INIS)

Shah, K.B.; Kumar, Sandeep; Dwivedi, D.K.

2007-01-01

In the present paper, influence of aging temperature during artificial age hardening treatment (T 6 ) of cast Al-(4, 12, 20%)Si-0.3% Mg on abrasive wear behaviour has been reported. Alloys were prepared by controlled melting and casting. Cast alloys were given age hardening treatment having sequence of solutionizing, quenching and artificial aging. All the alloys were solutionized at 510 deg. C for 8 h followed by water quenching (30 deg. C) and aging hardening at 150, 170, 190, 210 and 230 deg. C for 12 h. Abrasive wear tests were conducted against of 320 grade SiC abrasive medium at 5 and 10 N normal loads. It was observed that the silicon content and aging temperature significantly affect the wear resistance. Increase in aging temperature improves the wear resistance. Hypereutectic alloy showed better wear resistance than the eutectic alloy under identical conditions. Optical microstructure study of alloys under investigation has shown that cast dendritic structure is destroyed besides the spheroidization of eutectic silicon crystals after the heat treatment. The extent of change in structure depends on aging temperature. Scanning electron microscopy (SEM) of wear surface was carried to analyze the wear mechanism

An experimental modeling and acoustic emission monitoring of abrasive wear in a steel/diabase pair

Science.gov (United States)

Korchuganov, M. A.; Filippov, A. V.; Tarasov, S. Yu.; Podgornyh, O. A.; Shamarin, N. N.; Filippova, E. O.

2016-11-01

The earthmoving of permafrost soil is a critical task for excavation of minerals and construction on new territories. Failure by abrasive wear is the main reason for excavation parts of earthmoving and soil cutting machines. Therefore investigation of this type of wear is a challenge for developing efficient and wear resistant working parts. This paper is focused on conducting tribological experiments with sliding the steel samples over the surface of diabase stone sample where abrasive wear conditions of soil cutting are modeled experimentally. The worn surfaces of all samples have been examined and transfer of metal and stone particles revealed. The acoustic emission (AE) signals have been recorded and related to the results of worn surface analysis. he acoustic emission (AE) signals have been recorded and related to the results of worn surface analysis. As shown the wear intensity correlates to that of acoustic emission. Both acoustic emission signal median frequency and energy are found to be sensitive to the wear mode.

Study on Abrasive Wear of Brake Pad in the Large-megawatt Wind Turbine Brake Based on Deform Software

Science.gov (United States)

Zhang, Shengfang; Hao, Qiang; Sha, Zhihua; Yin, Jian; Ma, Fujian; Liu, Yu

2017-12-01

For the friction and wear issues of brake pads in the large-megawatt wind turbine brake during braking, this paper established the micro finite element model of abrasive wear by using Deform-2D software. Based on abrasive wear theory and considered the variation of the velocity and load in the micro friction and wear process, the Archard wear calculation model is developed. The influence rules of relative sliding velocity and friction coefficient in the brake pad and disc is analysed. The simulation results showed that as the relative sliding velocity increases, the wear will be more serious, while the larger friction coefficient lowered the contact pressure which released the wear of the brake pad.

Micro-scale abrasive wear behavior of medical implant material Ti-25Nb-3Mo-3Zr-2Sn alloy on various friction pairs.

Science.gov (United States)

Wang, Zhenguo; Huang, Weijiu; Ma, Yanlong

2014-09-01

The micro-scale abrasion behaviors of surgical implant materials have often been reported in the literature. However, little work has been reported on the micro-scale abrasive wear behavior of Ti-25Nb-3Mo-3Zr-2Sn (TLM) titanium alloy in simulated body fluids, especially with respect to friction pairs. Therefore, a TE66 Micro-Scale Abrasion Tester was used to study the micro-scale abrasive wear behavior of the TLM alloy. This study covers the friction coefficient and wear loss of the TLM alloy induced by various friction pairs. Different friction pairs comprised of ZrO2, Si3N4 and Al2O3 ceramic balls with 25.4mm diameters were employed. The micro-scale abrasive wear mechanisms and synergistic effect between corrosion and micro-abrasion of the TLM alloy were investigated under various wear-corrosion conditions employing an abrasive, comprised of SiC (3.5 ± 0.5 μm), in two test solutions, Hanks' solution and distilled water. Before the test, the specimens were heat treated at 760°C/1.0/AC+550°C/6.0/AC. It was discovered that the friction coefficient values of the TLM alloy are larger than those in distilled water regardless of friction pairs used, because of the corrosive Hanks' solution. It was also found that the value of the friction coefficient was volatile at the beginning of wear testing, and it became more stable with further experiments. Because the ceramic balls have different properties, especially with respect to the Vickers hardness (Hv), the wear loss of the TLM alloy increased as the ball hardness increased. In addition, the wear loss of the TLM alloy in Hanks' solution was greater than that in distilled water, and this was due to the synergistic effect of micro-abrasion and corrosion, and this micro-abrasion played a leading role in the wear process. The micro-scale abrasive wear mechanism of the TLM alloy gradually changed from two-body to mixed abrasion and then to three-body abrasion as the Vickers hardness of the balls increased. Copyright �

Abrasive wear of WC-NiMoCrFeCo thermally sprayed coatings in dependence on different types of abrasive sands

Czech Academy of Sciences Publication Activity Database

Kašparová, M.; Zahálka, F.; Houdková, Š.; Ctibor, Pavel

2010-01-01

Roč. 48, č. 1 (2010), s. 75-85 ISSN 0023-432X R&D Projects: GA AV ČR 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : WC-Hastelloy * abrasive wear * Al2O3 sand * SiO2 sand * braun size * abrasive efficiency Subject RIV: JG - Metallurgy Impact factor: 0.471, year: 2010 http://kovmat.sav.sk/abstract.php?rr=48&cc=1&ss=73

Influence of the microstructure of WC-Co cemented carbides on the fracture toughness and abrasive wear

International Nuclear Information System (INIS)

Zum Gahr, K.H.; Fischer, A.

1981-01-01

Fracture toughness and abrasive wear resistance of WC-Co cemented carbides were investigated by using the indentation cracking test (Palmqvist test) and the pin-on-disk method respectively. Size distribution of tungsten carbides and means free path between them were found to be important microstructural parameters related to the mechanical behavior. Results showed that selection of cemented carbides for heavy wear loading is complicated by contradictory influence of microstructural parameters on fracture toughness and abrasion resistance. Knowledge of the relation between microstructure and resistance to fracture or wear is necessary for optimum use of cemented carbides. (orig.) [de

Wear behavior of carbon fiber/aluminium-composites during abrasive loading; Verschleissverhalten von Kohlenstoffaser/Aluminium-Verbunden unter abrasiver Beanspruchung

Energy Technology Data Exchange (ETDEWEB)

Wielage, B.; Dorner, A. [Technische Univ. Chemnitz (Germany). Lehrstuhl fuer Verbundwerkstoffe

1998-07-01

Abrasive wear resistance of aluminium is significantly improved by the reinforcement with a high volume percentage of carbon fibres. The wear of unreinforced aluminium after scratching by a diamond indenter can be described as pure microgrooving without any micro-chipping. After integration of 70 vol.-% carbon fibers the damage mechanism is considerably altered and a great amount of micro-chipping occurs. The abrasive wear is strongly influenced by the fiber orientation. The best wear resistance is observed when the fibers are orientated perpendicular to the wear surface. (orig.) [Deutsch] Die Verstaerkung von Aluminium mit einem hohen Volumengehalt endloser Kohlenstoffasern verbessert erkennbar dessen Resistenz gegenueber Abrasionsverschleiss. Der Verschleiss von unverstaerktem Aluminium infolge des Ritzens mit einem Diamantindenter erfolgt in Form von reinem Mikrofurchen ohne Spanbildung. Aufgrund der Integration von 70 Vol.-% Kohlenstoffasern wird eine erhebliche Zunahme des Schaedigungsmechanismus Mikrospanen festgestellt. Die Faserorientierung hat merklichen Einfluss auf die Sensibilitaet gegenueber Abrasion. Orientierung der anisotropen Kohlenstoffasern senkrecht zur Verschleissoberflaeche bedingt den geringsten Abrasionsverschleiss. (orig.)

A Study on Abrasive Wear Behavior of Spacer Grid Materials for Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Park, J. M.; Kim, J. H. [Chungnam National University, Daejeon (Korea, Republic of); Park, J. K.; Jeon, K. L. [Korea Nuclear Fuel, Daejeon (Korea, Republic of)

2010-10-15

Spacer grid is one of the key components of a light water reactor (LWR) fuel assembly. The most important function of it is to hold the fuel rods to maintain the distance between the fuel rods inside a fuel assembly. At the reactor core in operating power plants, a fretting damage has been frequently reported between a nuclear fuel rod and its supporting spring/dimple of the fuel assemblies. This is due to a flow induced vibration (FIV), Which results from the primary coolant that rapidly passes around the fuel rod to remove the excess heat generated by the nuclear reaction. Fretting damage is generally caused by fretting wear, which includes various wear mechanisms such as an oxidative, adhesive, abrasive wear, etc., or fretting fatigue, which includes a surface or bulk fatigue. The purpose of the present work are to investigate the variation of the materials with increasing number of cycles and sliding velocity under abrasive wear test and to examine the wear mechanism at each test condition

Effect of heat treatment on strength and abrasive wear behaviour of ...

Indian Academy of Sciences (India)

Administrator

Aluminum 6061 has been used as matrix material owing to its ... Mechanical properties such as microhardness, tensile strength, and abrasive wear tests have been ... heat treatment conditions, adopted Al6061–SiCp composites exhibited better microhardness and tensile ... corrosion resistance (Ramesh et al 2005).

Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments

Directory of Open Access Journals (Sweden)

Marcela Charantola Rodrigues

2013-04-01

Full Text Available Objective: To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products. Material and Methods: Fifty (50 fragments of bovine enamel (15 mm × 5 mm were randomly assigned to five groups (n=10 according to the product utilized: G1 (control= silicone polisher (TDV, G2= 37% phosphoric acid (3M/ESPE + pumice stone (SS White, G3= Micropol (DMC Equipment, G4= Opalustre (Ultradent and G5= Whiteness RM (FGM Dental Products. Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p≤0.05 which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p≤0.05. Results: Means and standard deviations of roughness and wear (µm after all the promoted stages were: G1=7.26(1.81/13.16(2.67, G2=2.02(0.62/37.44(3.33, G3=1.81(0.91/34.93(6.92, G4=1.92(0.29/38.42(0.65 and G5=1.98(0.53/33.45(2.66. At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion. Conclusions: In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear.

An investigation of two-body abrasive wear of laser processed surfaces

International Nuclear Information System (INIS)

Abass, G.

1995-01-01

This paper reports two body abrasive wear studies of alloy and composite deposits produced with a 2 kW continuous wave CO/sub 2/ laser. Stellite alloy 6, Alloy 4815, Stainless steel and SiC powders were used to produce alloy and composite deposits on an En 3b mild steel substrate. The cladding material was injected into the laser produced melt pool by means of a pneumatic powder delivery system. In the present studies instead of using the conventional pin-on-disc method of wear measurement, a more realistic and practical wear testing procedure was adopted. The wear testing machine used was capable of measuring wear of three comparatively larger (30 x 30 x 10 mm) clad samples by abrading simultaneously against a revolving alumina disc. A comparative study of microstructure, hardness and wear of alloy and composite clads was made. The clad deposits were found sound and continuous. The hardness and wear resistance of the composites were markedly higher than that of the alloy clads. (author) 9 figs

The effect of fiber treatment on abrasive wear properties of palm fiber reinforced epoxy composite

Science.gov (United States)

Razak, Muhammad Firdaus Abdul; Bakar, Mimi Azlina Abu; Kasolang, Salmiah; Ahmad, Mohamad Ali

2017-12-01

Oil palm industries generate at least 30 million tons of lignocellulosic biomass annually in the form of oil palm trunks (OPT), empty fruit bunches (EFB), oil palm fronds (OPF) and palm pressed fibres (PPF). The palm fiber is one of the natural fibers used as reinforcement in composite materials in order to decrease environmental issues and promotes utilization of renewable resources. This paper presents a study on the effect of alkaline treatment on wear properties of palm fiber reinforced epoxy resin composite. Abrasive wear testing was deployed to investigate the wear profile of the composite surfaces. Testing was carried out which focused on the effect of alkaline treatment to the palm fiber under different amounts of fiber loading i.e. 1 wt%, 3 wt%, 5 wt% and 7 wt%. The palm fibers were soaked into 6 % of alkaline solution or natrium hydroxide (NaOH) for 12 hours. The fiber was treated in order to remove amorphous materials such as hemicelluloses, lignins and pectins of the fiber. The wear test samples were fabricated using hand lay-up technique and cured at room temperature for 24 hours. Surface roughness of the composite material was also measured using the surface measuring instrument. Dry sliding wear test was performed at room temperature at a constant velocity of 1.4 m/s with a constant load of 10 N by using the Abrasion Test Machine. Result shows that 5 wt% and 7 wt% treated palm fiber loadings have better specific wear rate compared to lower fiber loadings. The finding of this study contributes towards material development and utilization in promoting `waste into wealth' which is in line with national aspiration.

Abrasive wear resistance optimization of three different carbide coatings by the Taguchi method

Energy Technology Data Exchange (ETDEWEB)

Guer, Ali Kaya [Firat Univ., Elazig (Turkey). Dept. of Metallurgy and Materials; Kaya, Sinan [Firat Univ., Elazig (Turkey). Faculty of Technology

2017-06-01

In this study, FeCrC, SiC and B{sub 4}C powders were alloyed on the surface of AISI 430 ferritic stainless steel by plasma arc welding. The mass losses of the abrasive wear of the AISI 430 substrate were examined under the loads of 6, 10 and 16 N and in the distances of 10, 20 and 30 m by using Taguchi design method. The results of abrasive wear test were optimized by the minimum optimal control characteristics of the Taguchi procedure and the results were analyzed by using graphical methods. The Taguchi procedure is an important approach to achieve high quality without increasing the cost during the optimization of process parameters. The orthogonal planes of maximum effects of the controllable process parameters and minimum effects of uncontrollable process parameters were employed in the Taguchi method.

Abrasive wear response of TIG-melted TiC composite coating: Taguchi approach

Science.gov (United States)

Maleque, M. A.; Bello, K. A.; Adebisi, A. A.; Dube, A.

2017-03-01

In this study, Taguchi design of experiment approach has been applied to assess wear behaviour of TiC composite coatings deposited on AISI 4340 steel substrates by novel powder preplacement and TIG torch melting processes. To study the abrasive wear behaviour of these coatings against alumina ball at 600° C, a Taguchi’s orthogonal array is used to acquire the wear test data for determining optimal parameters that lead to the minimization of wear rate. Composite coatings are developed based on Taguchi’s L-16 orthogonal array experiment with three process parameters (welding current, welding speed, welding voltage and shielding gas flow rate) at four levels. In this technique, mean response and signal-to-noise ratio are used to evaluate the influence of the TIG process parameters on the wear rate performance of the composite coated surfaces. The results reveal that welding voltage is the most significant control parameter for minimizing wear rate while the current presents the least contribution to the wear rate reduction. The study also shows the best optimal condition has been arrived at A3 (90 A), B4 (2.5 mm/s), C3 (30 V) and D3 (20 L/min), which gives minimum wear rate in TiC embedded coatings. Finally, a confirmatory experiment has been conducted to verify the optimized result and shows that the error between the predicted values and the experimental observation at the optimal condition lies within the limit of 4.7 %. Thus, the validity of the optimum condition for the coatings is established.

Analysis of abrasive wear behavior of PTFE composite using Taguchi’s technique

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Yusuf Şahin

2015-12-01

Full Text Available Polymeric composites are widely used for structural, aerospace, and automobile sectors due to their good combination of high specific strength and specific modulus. These two main characteristics make these materials attractive, compared to conventional materials like metal or alloy ones. Some of their typical benefits include easy processing, corrosion resistance, low friction, and damping of noise and vibrations. Wear behavior of Polytetrafluoroethylenes (PTFE and its composites including glass-filled composites and carbon-filled composites are investigated using a pin-on-disc configuration. A plan of experiments in terms of Taguchi technique is carried out to acquire data in controlled way. An orthogonal array (L9 and the analysis of variance are employed to investigate the influence of process parameters on the wear of these composites. Volume loss increased with abrasive size, load, and distance. Furthermore, specific wear rate decreased with increasing grit size, load, sliding distance, whereas, slightly with compressive strength. Optimal process parameters, which minimize the volume loss, were the factor combinations of L1, G3, D1, and C3. Confirmation experiments were conducted to verify the optimal testing parameters. It was found that in terms of volume loss, there was a good agreement between the estimated and the experimental value of S/N ratio with an error of 1.604%. Moreover, abrasive size, load, and sliding distance exerted a great effect on the specific wear rate, at 51.14, 27.77, and 14.70%, respectively.

The Abrasive Wear Resistance of the Segmented Linear Polyurethane Elastomers Based on a Variety of Polyols as Soft Segments

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Konrad Kwiatkowski

2017-12-01

Full Text Available The presented results make an original contribution to the development of knowledge on the prediction and/or modeling of the abrasive wear properties of polyurethanes. A series of segmented linear polyurethane elastomers (PUR—In which the hard segments consist of 4,4′-methylene bis(phenylisocyanate and 1,4-butanodiol, whilst polyether, polycarbonate, or polyester polyols constitute the soft segments—Were synthesized and characterized. The hardness and wear performance as functions of the variable chemical composition of polyurethane elastomers were evaluated in order to define the relationship between studied factors. The microstructure was characterized in detail, including analysis of the hydrogen bonding by Fourier transformed infrared (FT-IR spectroscopy and the phase structure by X-ray scattering (WAXS and differential scanning calorimetry (DSC methods. The presented studies provide the key features of the polymer composition affecting the abrasive resistance as well as attempts to explain the origin of the differences in the polyurethane elastomers’ performance.

Influence of Heat Treatment on Abrasive Wear Resistance of Silumin Matrix Composite Castings

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Gawdzińska K.

2016-03-01

Full Text Available The authors attempted at examining the effect of heat treatment on abrasive wear resistance of metal composite castings. Metal matrix composites were made by infiltrating preforms created from unordered short fibers (graphite or silumin with liquid aluminium alloy AlSi12(b. Thus prepared composites were subject to solution heat treatment at a temperature of 520°C for four hours, then aging at a temperature of 220°C for four hours. Abrasion resistance of the material was tested before and after thermal treatment.

Effect of nitrogen alloying on the microstructure and abrasive wear of stainless steels

International Nuclear Information System (INIS)

Hawk, J.A.; Simmons, J.W.; Rawers, J.C.

1994-01-01

Alloying stainless steels with nitrogen has distinct advantages. Nitrogen is a strong austenite stabilizer and a potent solid-solution strengthener, and nitrogen has greater solubility than carbon iron. This study investigates the relationship among nitrogen concentration, precipitate microstructure, and abrasive wear using two high-nitrogen stainless steel alloys: Fe-19Cr-5Mn-5Ni-3Mo (SS1) and Fe-16Cr-7Mn-5Ni(SS2). Alloy SS1 contained 0.7 wt% N and was solution annealed at 1,150 C, thereby dissolving the nitrogen interstitially in the austenite. Subsequent aging, or cold work and aging, at 900 C led to the grain-boundary, cellular, and transgranular precipitation of Cr 2 N. Alloy SS2 was remelted in a high-pressure (200 MPa) N 2 atmosphere, leading to a spatial gradient of nitrogen in the alloy in the form of interstitial nitrogen and Cr 2 N and CrN precipitates. Nitrogen contents varied from a low of approximately 0.7 wt% at the bottom of the billet to a high of 3.6 wt% at the top. Nitrogen in excess of approximately 0.7 wt% formed increasingly coarser and more numerous Cr 2 N and CrN precipitates. The precipitate morphology created in alloy SS1 due to aging, or cold work and aging, had little effect on the abrasive wear of the alloy. However, a decrease in the abrasive wear rate in alloy SS2 was observed to correspond to the increase in number and size of the Cr 2 N and CrN precipitates

Fissure sealants: in vitro evaluation of abrasion wear and superficial roughness

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Vanessa Pardi

2008-06-01

Full Text Available The aim of this study was to compare the in vitro wear and superficial roughness of four materials (Delton Dyract Flow, Dentsply; Filtek Flow, Vitremer, 3M ESPE used as fissure sealant in 32 extracted human molars divided in four groups (n = 8 after abrasion with toothbrush/dentifrice. Impressions of each occlusal surface were made to analyze wear and circular specimens were prepared to analyze the roughness. Teeth and specimens were mounted in a toothbrushing machine. The replicas were observed using a SEM to determine the superficial wear. Wear: there were no statistically significant differences either between Delton and Filtek Flow or between Dyract Flow and Vitremer. Roughness: there were no statistical differences between Filtek Flow and Dyract Flow, Dyract Flow and Vitremer, Vitremer and Delton., Considering the clinical practice, if caries activity is present the use of Vitremer is suggested not only for its well known fluoride release, but it presented good roughness results.

Standard Test Method for Abrasive Wear Resistance of Cemented

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

1.1 This test method covers the determination of abrasive wear resistance of cemented carbides. 1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units are in parentheses and may be approximate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Study of abrasive wear process of lining of grinding chamber of vortex-acoustic disperser

Science.gov (United States)

Perelygin, D. N.

2018-03-01

The theoretical and experimental studies of the process of gas-abrasive wear of the lining of a vortex-acoustic disperser made it possible to establish the conditions and patterns of their occurrence and also to develop proposals for its reduction.

Nitriding the influence of plasma in resistance to wear micro abrasive tool steel AISI D2

International Nuclear Information System (INIS)

Gobbi, Vagner Joao; Gobb, Silvio Jose; Silva, Cosme Roberto Moreira da

2010-01-01

This work studies the influence of time of treatment in the formation of nitride layer of AISI D2 tool steel and the resistance to micro-abrasive wear from the technique of nitriding in plasma. The samples were nitrides at 400 ° C with a pressure of 4.5 mbar (450 Pa) and using a gas mixture of 80% vol.H2 and 20% vol.N2. The times of treatment were: 30, 60, 120, 180 and 360 minutes. The properties of the layers in the samples obtained nitrides were assessed by surface microhardness, profiles of microhardness, metallography analysis, X-ray diffraction and test for resistance to micro-abrasive wear. The best results for nitriding to 400 deg C, was obtained with the time of treatment of 360 minutes. In this case the increase in surface hardness was 94.6% and resistance to micro-abrasive wear of 15%. This increase in hardness may be associated with high concentration of nitrogen in the crystalline network of iron-α and additional training of nitrides. Low temperature of nitriding reduces between grain fragility to reduce the likelihood of precipitation of nitrides in a continuous manner in the austenite grain boundaries and the absence of previous ε'+ γ phases. (author)

New Rock Abrasivity Test Method for Tool Life Assessments on Hard Rock Tunnel Boring: The Rolling Indentation Abrasion Test (RIAT)

Science.gov (United States)

Macias, F. J.; Dahl, F.; Bruland, A.

2016-05-01

The tunnel boring machine (TBM) method has become widely used and is currently an important presence within the tunnelling industry. Large investments and high geological risk are involved using TBMs, and disc cutter consumption has a great influence on performance and cost, especially in hard rock conditions. Furthermore, reliable cutter life assessments facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory tests for rock abrasivity assessments are needed. A new abrasivity test method by rolling disc named Rolling Indentation Abrasion Test (RIAT) has been developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than the traditionally used methods. Wear by rolling contact on intact rock samples is introduced and several rock types, covering a wide rock abrasiveness range, have been tested by RIAT. The RIAT procedure indicates a great ability of the testing method to assess abrasive wear on rolling discs. In addition and to evaluate the newly developed RIAT test method, a comprehensive laboratory testing programme including the most commonly used abrasivity test methods and the mineral composition were carried out. Relationships between the achieved results from conventional testing and RIAT results have been analysed.

development and performance evaluation of an abrasive wear

African Journals Online (AJOL)

User

advanced countries are not available in Ghana. This makes ... experiment was arranged in a completely randomized design with the soils from the five sites as ... Design of the wear equipment ..... tion of Wear Characteristics of Drill Cultures.

Solidification structure and abrasion resistance of high chromium white irons

Science.gov (United States)

Doğan, Ö. N.; Hawk, J. A.; Laird, G.

1997-06-01

Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic, eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect to the macrostructural transitions of the castings, solidification paths, and resulting microstructures when poured with varying superheats. Completely equiaxed macrostructures were produced in thick section castings with slightly hypereutectic compositions. High-stress abrasive wear tests were then performed on the various alloys to examine the influence of both macrostructure and microstructure on wear resistance. Results indicated that the alloys with a primarily austenitic matrix had a higher abrasion resistance than similar alloys with a pearlitic/bainitic matrix. Improvement in abrasion resistance was partially attributed to the ability of the austenite to transform to martensite at the wear surface during the abrasion process.

The use of ion implantation for the improvement of abrasive wear resistance

International Nuclear Information System (INIS)

Delves, B.G.; Dearnaley, G.

1979-01-01

At the conclusion of the 1977 IPAT conference a practical problem was described which called for an economically feasible method of improving the resistance of tool steel, chromium and other alloys to abrasive wear sustained during the injection moulding of phenolic resin. This paper will describe subsequent work to investigate ion implantation as a possible means of treating steel taps, injection nozzles, feed wear pads, cavity moulds etc. Various problems were encountered and it will be described how most of these have now been overcome. Under favourable conditions factors of 4, and sometimes up to 10 times the normal life can be achieved. An attempt will be made to estimate some of the economic benefits of the process. (author)

A method for increase abrasive wear resistance parts by obtaining on methods casting on gasifying models

Science.gov (United States)

Sedukhin, V. V.; Anikeev, A. N.; Chumanov, I. V.

2017-11-01

Method optimizes hardening working layer parts’, working in high-abrasive conditions looks in this work: bland refractory particles WC and TiC in respect of 70/30 wt. % prepared by beforehand is applied on polystyrene model in casting’ mould. After metal poured in mould, withstand for crystallization, and then a study is carried out. Study macro- and microstructure received samples allows to say that thickness and structure received hardened layer depends on duration interactions blend harder carbides and liquid metal. Different character interactions various dispersed particles and matrix metal observed under the same conditions. Tests abrasive wear resistance received materials of method calculating residual masses was conducted in laboratory’ conditions. Results research wear resistance showed about that method obtaining harder coating of blend carbide tungsten and carbide titanium by means of drawing on surface foam polystyrene model before moulding, allows receive details with surface has wear resistance in 2.5 times higher, than details of analogy steel uncoated. Wherein energy costs necessary for transformation units mass’ substances in powder at obtained harder layer in 2.06 times higher, than materials uncoated.

Usage of abrasion-resistant materials in agriculture

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J Votava

2014-06-01

Full Text Available Agricultural soil-processing machines are subject to an extensive abrasive wear. This paper analyses technical materials and their fitness to exchangeable parts of plough bottoms, such as edge-tools and whole plough cutting edges. There were tested abrasion-resistant steels with different microstructures: austenite, martensite-bainite, and carbide. Steel with the pearlite-ferrite structure was used as an etalon. Abrasion resistance tests were processed in compliance with the norm CSN 01 5084, which is a test of abrasion wear on abrasive cloth.

Modelling and analysis of abrasive wear performance of composites ...

African Journals Online (AJOL)

It has been observed that fibre length plays a major role in wear phenomenon. The length of the fibre has been optimized using a popular evolutionary technique known as particle swarm optimization (PSO) and neural network. The study recommends that fibre length should be 7-8 mm for minimum wear of the composites.

Comparison of performance coatings thermally sprayed subject to testing adhesive wear

International Nuclear Information System (INIS)

Marangoni, G.F.; Arnt, A.B.C.; Rocha, M.R. da

2014-01-01

In this work, the microstructural changes and wear resistance adhesive coatings obtained from powders thermally sprayed by high velocity oxy-fuel (HVOF) were evaluated. Based coatings chrome-nickel and tungsten-cobalt are applied in conditions subject to intense wear especially abrasive. With the aim of evaluate the performance of these coatings under conditions of adhesive wear, these coatings samples were tested by the standard ASTM G99. As test parameters were used: Tungsten carbide pin (SAE 52100) with 6 mm diameter, normal load of 50N and a tangential velocity of 0.5 m / s. The worn surfaces of the coatings were characterized by optical and scanning electron microscopy and X-ray diffraction. Results indicate that the performance front wear is related to the conditions of adhesion and uniformity of the coating applied. (author)

Adhesive Wear Performance of CFRP Multilayered Polyester Composites Under Dry/wet Contact Conditions

Science.gov (United States)

Danaelan, D.; Yousif, B. F.

The tribo-performance of a new engineering composite material based on coconut fibers was investigated. In this work, coconut fibers reinforced polyester (CFRP) composites were developed. The tribo-experiments were conducted by using pin-on-disc machine under dry and wet sliding contact condition against smooth stainless steel counterface. Worn surfaces were observed using optical microscope. Friction coefficient and specific wear rate were presented as a function of sliding distance (0-0.6 km) at different sliding velocities (0.1-0.28 m/s). The effect of applied load and sliding velocity was evaluated. The results showed that all test parameters have significant influence on friction and wear characteristics of the composites. Moreover, friction coefficient increased as the normal load and speed increased, the values were about 0.7-0.9 under dry contact condition. Meanwhile, under wet contact condition, there was a great reduction in the friction coefficient, i.e. the values were about 0.1-0.2. Furthermore, the specific wear rates were found to be around 2-4 (10-3) mm3/Nm under dry contact condition and highly reduced under wet condition. In other words, the presence of water as cleaner and polisher assisted to enhance the adhesive wear performance of CFRP by about 10%. The images from optical microscope showed evidence of adhesive wear mode with transition to abrasive wear mode at higher sliding velocities due to third body abrasion. On the other hand, optical images for wet condition showed less adhesive wear and smooth surfaces.

Abrasive wear of BA1055 bronze with additives of Si, Cr, Mo and/or W

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B. P. Pisarek

2008-10-01

Full Text Available Aluminium bronzes belong to the high-grade constructional materials applied on the put under strongly load pieces of machines, aboutgood sliding, resistant properties on corrosion both in the cast state how and after the thermal processing. It moves to them Cr and Si in the aim of the improvement of their usable proprieties. The additions Mo and/or W were not applied so far. It was worked out therefore the new kind of bronzes casting including these elements. Make additions to the Cu-Al-Fe-Ni bronze of Si, Cr, Mo and/or W in the rise of these properties makes possible. The investigations of the surface distribution of the concentration of elements in the microstructure of the studied bronze on X-ray microanalyzer were conducted. It results from conducted investigations, that in the aluminium bronze BA1055 after makes additions Si, Cr, Mo and/or W the phases of the type κFe, κNi crystallize, probably as complex silicides. Elements such as: Fe and Si dissolve first of all in phases κ, in smaller stage in the matrix of the bronze; Mn, Ni and W they dissolve in matrix and phases κ. It dissolves Cr and Mo in the larger stage in phases κ than in the matrix. The sizes of the abrasive wear were compared in the state cast multicomponentnew casting Cu-Al-Fe-Ni bronzes with the additives Cr, Mo or W with the wear of the bronze CuAl10Fe5Ni5Si. The investigations of thewear were conducted on the standard device. It results from conducted investigations, that make additions to bronze BA1055 of the additives of Si, Cr, Mo, and/or W it influences the rise of the hardness (HB of the bronze in the cast state, in the result of the enlarged quantity separates of hard phases κ, and in the consequence the decrease of the abrasive wear. The addition of molybdenum made possible obtainment of the microhardness of the phase α and γ 2 on the comparable level. From the microstructure of the bronze CuAl10Fe5Ni5MoSi is characterizes the smallest abrasive wear among

High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

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YANG Jiao-xi

2016-06-01

Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

Performance Degradation Analysis of Aviation Hydraulic Piston Pump Based on Mixed Wear Theory

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C. Zhang

2017-06-01

Full Text Available This paper focuses on the mathematical modeling of axial piston pump through dividing the failure development of friction pair into lubrication, mixed lubrication and abrasion. Directing to the wedge-shaped oil film between cylinder block and valve plate, the support force distribution under the temperature variance was obtained. Considering the rough peak of valve plate, the contact load model is built under plastic deformation and elastic deformation and the corresponding wear volume is calculated. Computing the wear and tear along the counter-clockwise, the total amount of friction and wear can be calculated. Simulation and preliminary wear particle monitoring test indicates that proposed modeling and analysis can effectively reflect the real abrasion process of hydraulic piston pump.

Wear behavior of pressable lithium disilicate glass ceramic.

Science.gov (United States)

Peng, Zhongxiao; Izzat Abdul Rahman, Muhammad; Zhang, Yu; Yin, Ling

2016-07-01

This article reports effects of surface preparation and contact loads on abrasive wear properties of highly aesthetic and high-strength pressable lithium disilicate glass-ceramics (LDGC). Abrasive wear testing was performed using a pin-on-disk device in which LDGC disks prepared with different surface finishes were against alumina pins at different contact loads. Coefficients of friction and wear volumes were measured as functions of initial surface finishes and contact loads. Wear-induced surface morphology changes in both LDGC disks and alumina pins were characterized using three-dimensional laser scanning microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results show that initial surface finishes of LDGC specimens and contact loads significantly affected the friction coefficients, wear volumes and wear-induced surface roughness changes of the material. Both wear volumes and friction coefficients of LDGC increased as the load increased while surface roughness effects were complicated. For rough LDGC surfaces, three-body wear was dominant while for fine LDGC surfaces, two-body abrasive wear played a key role. Delamination, plastic deformation, and brittle fracture were observed on worn LDGC surfaces. The adhesion of LDGC matrix materials to alumina pins was also discovered. This research has advanced our understanding of the abrasive wear behavior of LDGC and will provide guidelines for better utilization and preparation of the material for long-term success in dental restorations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 968-978, 2016. © 2015 Wiley Periodicals, Inc.

Tribological performance evaluation of coated steels with TiNbCN subjected to tribo-chemical wear in Ringers solution

International Nuclear Information System (INIS)

Caballero G, J.; Aperador, W.; Caicedo, J. C.

2016-01-01

With the aim of generating solutions against the deterioration of the joint prostheses, it was studied the tribo-corrosive behavior of titanium niobium carbonitride (TiNbCN) deposited on stainless steel AISI 316 LVM using the technique of magnetron sputtering physical vapor deposition. The tests were performed in a balanced saline solution (Ringers solution) which represents the characteristics of the body fluids, using an equipment where the micro-abrasive wear is generated by the contact of micro particles in the system; the micro-abrasion-corrosion mechanism is described by means of the incorporation of an electrochemical cell consisting of three electrodes. Both the substrate and the coating, were subjected to micro-abrasive wear simultaneously with the electrochemical tests of Tafel polarization curves and electrochemical impedance spectroscopy (EIS); subsequently of the tests, the specimens were analyzed by optical microscopy and scanning electron microscopy characterizing the surface morphology. It was observed that the coating presents an increase in its corrosion and wear resistance with the presence of a simulated biological fluid. The samples were characterized via X-ray diffraction. (Author)

Tribological performance evaluation of coated steels with TiNbCN subjected to tribo-chemical wear in Ringers solution

Energy Technology Data Exchange (ETDEWEB)

Caballero G, J.; Aperador, W. [Universidad Militar Nueva Granada, Volta Research Group, 101-80 Bogota (Colombia); Caicedo, J. C., E-mail: g.ing.materiales@gmail.com [Universidad del Valle, Tribology Polymers, Powder Metallurgy and Processing of Solid Recycled Research Group, Cali (Colombia)

2016-11-01

With the aim of generating solutions against the deterioration of the joint prostheses, it was studied the tribo-corrosive behavior of titanium niobium carbonitride (TiNbCN) deposited on stainless steel AISI 316 LVM using the technique of magnetron sputtering physical vapor deposition. The tests were performed in a balanced saline solution (Ringers solution) which represents the characteristics of the body fluids, using an equipment where the micro-abrasive wear is generated by the contact of micro particles in the system; the micro-abrasion-corrosion mechanism is described by means of the incorporation of an electrochemical cell consisting of three electrodes. Both the substrate and the coating, were subjected to micro-abrasive wear simultaneously with the electrochemical tests of Tafel polarization curves and electrochemical impedance spectroscopy (EIS); subsequently of the tests, the specimens were analyzed by optical microscopy and scanning electron microscopy characterizing the surface morphology. It was observed that the coating presents an increase in its corrosion and wear resistance with the presence of a simulated biological fluid. The samples were characterized via X-ray diffraction. (Author)

Protective Effect of Adhesive Systems associated with Neodymium-doped Yttrium Aluminum Garnet Laser on Enamel Erosive/Abrasive Wear.

Science.gov (United States)

Crastechini, Erica; Borges, Alessandra B; Becker, Klaus; Attin, Thomas; Torres, Carlos Rg

2017-10-01

This study evaluated the efficacy of self-etching adhesive systems associated or not associated with the neodymium-doped yttrium aluminum garnet (Nd:YAG) laser on the protection against enamel erosive/abrasive wear. Bovine enamel specimens were demineralized with 0.3% citric acid (5 minutes). The samples were randomly assigned to eight groups (n = 20): SB - Single Bond Universal (3M/ESPE); SB+L - Single Bond Universal + laser (80 mJ/10 Hz); FB - Futurabond U (Voco); FB+L -Futurabond U + laser; GEN - G-aenial bond (GC); GEN+L -G-aenial bond + laser; L - laser irradiation; and C - no treatment. The laser was applied before light curing. The samples were subjected to erosive/abrasive challenges (0.3% citric acid - 2 minutes and tooth brushing four times daily for 5 days). Enamel surface loss was recovered profilometrically by comparison of baseline and final profiles. The adhesive layer thickness, retention percentage of the protective layer, and microhardness of cured adhesive were measured. Data were analyzed using one-way analysis of variance and Tukey's test (5%). There were significant differences for all parameters (p = 0.0001). Mean values ± SD and results of the Tukey's test were: Surface wear: GEN - 4.88 (±1.09)a, L - 5.04 ± 0.99)a, FB - 5.32 (±0.93)ab, GEN + L - 5.46 (±1.27)abc, SB + L - 5.78 (±1.12)abc, FB + L - 6.23 (±1.25)bc, SB - 6.35 (±1.11)c, and C - 6.46 (±0.61)c; layer thickness: GEN - 15.2 (±8.63)c, FB - 5.06 (±1.96)a, GEN + L - 13.96 (±7.07)bc, SB + L - 4.24 (±2.68)a, FB + L - 9.03 (±13.02)abc, and SB - 7.49 (±2.80)ab; retention: GEN - 68.89 (±20.62)c, FB - 54.53 (±24.80)abc, GEN + L - 59.90 (±19.79)abc, SB + L - 63.37 (±19.30)bc, FB + L - 42.23 (±17.68) a, and SB - 47.78 (±18.29)ab; microhardness: GEN - 9.27 (±1.75)c; FB - 6.99 (±0.89)b; GEN + L - 6.22 (±0.87)ab; SB + L - 15.48 (±2.51)d; FB + L - 10.67 (±1.58)c; SB - 5.00 (±1.60)a. The application of Futurabond U and G-aenial bond on enamel surface, as well as the Nd

Influence of Corrosion on the Abrasion of Cutter Steels Used in TBM Tunnelling

Science.gov (United States)

Espallargas, N.; Jakobsen, P. D.; Langmaack, L.; Macias, F. J.

2015-01-01

Abrasion on tunnel boring machine (TBM) cutters may be critical in terms of project duration and costs. Several researchers are currently studying the degradation of TBM cutter tools used for excavating hard rock, soft ground and loose soil. So far, the primary focus of this research has been directed towards abrasive wear. Abrasive wear is a very common process in TBM excavation, but with a view to the environment in which the tools are working, corrosion may also exert an influence. This paper presents a selection of techniques that can be used to evaluate the influence of corrosion on abrasion on TBM excavation tools. It also presents the influence of corrosion on abrasive wear for some initial tests, with constant steel and geomaterial and varying properties of the excavation fluids (soil conditioners, anti-abrasion additives and water). The results indicate that the chloride content in the water media greatly influences the amount of wear, providing evidence of the influence of corrosion on the abrasion of the cutting tools. The presence of conditioning additives tailored to specific rock or soil conditions reduces wear. However, when chloride is present in the water, the additives minimise wear rates but fail to suppress corrosion of the cutting tools.

Development of the white cast iron with niobium alloy, heat treating, to wear of the abrasive resistance; Desenvolvimento de uma liga de ferro fundido branco alto cromo com niobio, tratada termicamente, para resistencia ao desgaste abrasivo

Energy Technology Data Exchange (ETDEWEB)

Farah, Alessandro Fraga

1997-07-01

This work presents the heat treatment and abrasion tests results of a white cast iron with niobium alloy. The hardening heat treatment were made 950, 1000, 1050 e 110 deg C temperatures cooled by forced air. The tempering treatment were made at 450, 500 e 550 deg C temperatures. The heat treating alloy were compared, in the abrasive tests, with commercial alloys used as hardfacing by welding process in wear pieces. The abrasion tests was realized in pin on disk test. Additional tests were carried out for microstructural characterization to identify the different phases presents in the alloys. In a general way, the alloy studies showed the best wear rate for the heat treatments that results in higher hardness. It performance was superior than that of the commercial alloys. (author)

Researches concerning the ultasonic energy influence on the resistence to the abrasive wear of loaded welded parts

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Gh. Amza

2013-01-01

Full Text Available The researches presented in the paper refer to the effect of ultrasounds propagation in the liquid metal bath on the process of transferring the additive material through the electric arch and on the crystallization process, and all these effects are analyzed for loaded welded parts solicited at the abrasive wear. All these influences are conferred to these two basic phenomena due to the ultrasounds propagation in liquid environments, namely, ultra-acoustic cavitation and acceleration of the diffusion process. The results concerns the resistance to the wear obtained for the loaded parts through manual welding with electric arch and classically covered electrode and ultrasonically activated.

A level set methodology for predicting the effect of mask wear on surface evolution of features in abrasive jet micro-machining

International Nuclear Information System (INIS)

Burzynski, T; Papini, M

2012-01-01

A previous implementation of narrow-band level set methodology developed by the authors was extended to allow for the modelling of mask erosive wear in abrasive jet micro-machining (AJM). The model permits the prediction of the surface evolution of both the mask and the target simultaneously, by representing them as a hybrid and continuous mask–target surface. The model also accounts for the change in abrasive mass flux incident to both the target surface and, for the first time, the eroding mask edge, that is brought about by the presence of the mask edge itself. The predictions of the channel surface and eroded mask profiles were compared with measurements on channels machined in both glass and poly-methyl-methacrylate (PMMA) targets at both normal and oblique incidence, using tempered steel and elastomeric masks. A much better agreement between the predicted and measured profiles was found when mask wear was taken into account. Mask wear generally resulted in wider and deeper glass target profiles and wider PMMA target profiles, respectively, when compared to cases where no mask wear was present. This work has important implications for the AJM of complex MEMS and microfluidic devices that require longer machining times. (paper)

Microstructure and abrasive wear properties of M(Cr,Fe7C3 carbides reinforced high-chromium carbon coating produced by gas tungsten arc welding (GTAW process

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Soner BUYTOZ

2010-01-01

Full Text Available In the present study, high-chromium ferrochromium carbon hypereutectic alloy powder was coated on AISI 4340 steel by the gas tungsten arc welding (GTAW process. The coating layers were analyzed by optical microscopy, X-ray diffraction (XRD, field-emission scanning electron microscopy (FE-SEM, X-ray energy-dispersive spectroscopy (EDS. Depending on the gas tungsten arc welding pa-rameters, either hypoeutectic or hypereutectic microstructures were produced. Wear tests of the coatings were carried out on a pin-on-disc apparatus as function of contact load. Wear rates of the all coating layers were decreased as a function of the loading. The improvement of abrasive wear resistance of the coating layer could be attributed to the high hardness of the hypereutectic M7C3 carbides in the microstruc-ture. As a result, the microstructure of surface layers, hardness and abrasive wear behaviours showed different characteristics due to the gas tungsten arc welding parameters.

The abrasive effect of commercial whitening toothpastes on eroded enamel.

Science.gov (United States)

Mosquim, Victor; Martines Souza, Beatriz; Foratori Junior, Gerson Aparecido; Wang, Linda; Magalhães, Ana Carolina

2017-06-01

To evaluate the in vitro abrasive effect of commercial whitening toothpastes on eroded bovine enamel samples in respect to erosive tooth wear. 72 bovine crowns were embedded, polished and subjected to the baseline profile analysis. The samples were then protected in 2/3 of the enamel surface and were randomly assigned to six groups (n= 12/group): G1: Oral-B 3D White, G2: Close-up Diamond Attraction Power White, G3: Sorriso Xtreme White 4D, G4: Colgate Luminous White, G5: Crest (conventional toothpaste), G6:erosion only (control). All samples were submitted to an erosive pH cycling (4 x 90 seconds in 0.1% citric acid, pH 2.5, per day) and abrasive challenges (2 x 15 seconds, per day) for 7 days. After the first and the last daily cycles, the samples were subjected to abrasive challenges, using a toothbrushing machine, soft toothbrushes and slurry of the tested toothpastes (1.5 N). Between the challenges, the samples were immersed in artificial saliva. The final profile was obtained and overlaid to the baseline profile for the calculation of the erosive tooth wear (μm). The data were subjected to Kruskal-Wallis/Dunn tests (Penamel wear (3.68±1.06 μm), similarly to G3 (3.17± 0.80 μm) and G4 (3.44± 1.29 μm). G3 and G4 performed similarly between them and compared with G5 (2.35± 1.44 μm). G2 (1.51± 0.95 μm) and G6 (0.85± 0.36 μm) showed the lowest enamel wear, which did not differ between them and from G5. Oral-B 3D White showed the highest abrasive potential while Close-up Diamond Attraction Power White showed the lowest abrasive potential on eroded enamel in vitro. This study showed that some commercial whitening toothpastes, especially those containing pyrophosphate associated with hydrated silica, enhanced enamel erosive wear.

Abrasion-resistant concrete mix designs for precast bridge deck panels.

Science.gov (United States)

2010-08-01

The report documents laboratory investigations undertaken to develop high performance concrete (HPC) for precast and pre-stressed bridge deck components that would reduce the life-cycle cost of bridges by improving the studded tire wear (abrasion) re...

A comparison of the tribological behaviour of Y-TZP in tea and coffee under micro-abrasion conditions

International Nuclear Information System (INIS)

Sharifi, S; Stack, M M

2013-01-01

The micro-abrasion of Y-TZP, a candidate dental restorative material, was investigated in a range of caffeine-containing solutions which included tea and coffee. Additions of sugar and milk were used to test the effects of viscosity and pH on the wear rate. The results indicated a significant increase in wear rate in the various solutions, with some correlation between wear rate and increases in viscosity and this was linked to enhance particle entrainment in the more viscous solutions. The generally lower wear rate in tea compared to coffee was associated with a longer ageing period in this solution before uniform wear was observed. Micro-abrasion maps were used to characterize the differences in performance for the material in the environments studied. (paper)

A comparison of the tribological behaviour of Y-TZP in tea and coffee under micro-abrasion conditions

Science.gov (United States)

Sharifi, S.; Stack, M. M.

2013-10-01

The micro-abrasion of Y-TZP, a candidate dental restorative material, was investigated in a range of caffeine-containing solutions which included tea and coffee. Additions of sugar and milk were used to test the effects of viscosity and pH on the wear rate. The results indicated a significant increase in wear rate in the various solutions, with some correlation between wear rate and increases in viscosity and this was linked to enhance particle entrainment in the more viscous solutions. The generally lower wear rate in tea compared to coffee was associated with a longer ageing period in this solution before uniform wear was observed. Micro-abrasion maps were used to characterize the differences in performance for the material in the environments studied.

Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition

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Myszka D.

2015-04-01

Full Text Available The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were performed on two groups of austempered ductile iron - one of which contained 1.5% Ni and 0.5% Mo, while the other contained 1.9% Ni and 0.9% Cu. Each group has been heat treated according to the three different heat treatment variants and then the material was subjected to detailed testing of mechanical properties and abrasion wear resistance, measuring also hardness and magnetic properties, and conducting microstructural examinations. The results indicated that each of the tested materials was senstive to the surface hardening effect, which resulted in high wear resistance. It has been found that high temperature of austempering, i.e. 370°C, favours high wear resistance of ductile iron containing nickel and molybdenum. Low temperature of austempering, i.e. 270°C, develops high wear resistance in ductile iron containing nickel and copper. Both these materials offer completely different mechanical properties and as such can be used for different and specific applications.

Three body abrasion of laser surface alloyed aluminium AA1200

CSIR Research Space (South Africa)

Mabhali, Luyolo AB

2012-06-01

Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4 kW Nd:YAG laser to improve the abrasion wear resistance. Aluminium surfaces reinforced with metal matrix composites and intermetallic phases were achieved. The phases present depended...

Use of dentifrices to prevent erosive tooth wear: harmful or helpful?

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Ana Carolina Magalhães

2014-01-01

Full Text Available Dental erosion is the loss of dental hard tissues caused by non-bacterial acids. Due to acid contact, the tooth surface becomes softened and more prone to abrasion from toothbrushing. Dentifrices containing different active agents may be helpful in allowing rehardening or in increasing surface resistance to further acidic or mechanical impacts. However, dentifrices are applied together with brushing and, depending on how and when toothbrushing is performed, as well as the type of dentifrice and toothbrush used, may increase wear. This review focuses on the potential harmful and helpful effects associated with the use of dentifrices with regard to erosive wear. While active ingredients like fluorides or agents with special anti-erosive properties were shown to offer some degree of protection against erosion and combined erosion/abrasion, the abrasive effects of dentifrices may increase the surface loss of eroded teeth. However, most evidence to date comes from in vitro and in situ studies, so clinical trials are necessary for a better understanding of the complex interaction of active ingredients and abrasives and their effects on erosive tooth wear.

Characterization and wear performance of boride phases over tool steel substrates

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Edgar E Vera Cárdenas

2016-02-01

Full Text Available This research work was conducted to characterize boride phases, obtained from the powder-pack process, on AISI H13 and D2 steel substrates, and investigate their tribological behavior. The boriding was developed at a temperature of 1273 K with an exposure time of 8 h. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were conducted on the borided material to characterize the presence of the FeB, Fe2B, and CrB phases and the distribution of heavy elements on the surface of the substrates. The adherence of the boride layers was evaluated, in a qualitative form, through the Daimler-Benz Rockwell-C indentation technique. Sliding wear tests were then performed using a reciprocating wear test machine. All tests were conducted in dry conditions at room temperature. A frequency of 10 Hz and 15-mm sliding distance were used. The applied Hertzian pressure was 2.01 GPa. Scanning electron microscopy was used to observe and analyze the wear mechanisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. Experimental results showed that the characteristic wear mechanism for the borided surface was plastic deformation and mild abrasive wear; for unborided substrates, cracking and spalling were observed.

A new methodology for predictive tool wear

Science.gov (United States)

Kim, Won-Sik

An empirical approach to tool wear, which requires a series of machining tests for each combination of insert and work material, has been a standard practice for industries since early part of the twentieth century. With many varieties of inserts and work materials available for machining, the empirical approach is too experiment-intensive that the demand for the development of a model-based approach is increasing. With a model-based approach, the developed wear equation can be extended without additional machining experiments. The main idea is that the temperatures on the primary wear areas are increasing such that the physical properties of the tool material degrade substantially and consequently tool wear increases. Dissolution and abrasion are identified to be the main mechanisms for tool wear. Flank wear is predominantly a phenomenon of abrasion as evident by the presence of a scoring mark on the flank surface. Based on this statement, it is reasonable to expect that the flank-wear rate would increase with the content of hard inclusions. However, experimental flank wear results did not necessary correspond to the content of cementite phase present in the steels. Hence, other phenomena are believed to significantly affect wear behavior under certain conditions. When the cutting temperature in the flank interface is subjected to high enough temperatures, pearlitic structure austenizes. During the formation of a new austenitic phase, the existing carbon is dissolved into the ferrite matrix, which will reduce the abrasive action. To verify the austenitic transformation, turning tests were conducted with plain carbon steels. The machined surface areas are imaged using X-ray diffraction the Scanning Electron Microscope (SEM) and the Transmission Electron Microscope (TEM). On the other hand, crater wear occurs as a result of dissolution wear and abrasive wear. To verify the wear mechanisms of crater wear, various coating inserts as well as uncoated inserts were

Influence of the metallic matrix ratio on the wear resistance (dry and slurry abrasion) of plasma sprayed cermet (chromia / stainless steel) coatings

Czech Academy of Sciences Publication Activity Database

Ageorges, H.; Ctibor, Pavel; Medarhri, Z.; Touimi, S.; Fauchais, P.

2006-01-01

Roč. 201, č. 5 (2006), s. 2006-2011 ISSN 0257-8972 R&D Projects: GA AV ČR(CZ) 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * composite coating * tribology * hardness * wear * abrasion * chromia/stainless steel Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.559, year: 2006

Investigation of Wear Behavior of Aluminum Matrix Composite Reinforced by Al2O3 and Produced by Hot Pressing Process

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Halil ARIK

2017-12-01

Full Text Available In this study, Al powder produced by gas atomization technique has 72.06 µm average particle size and 99 % purity was mixed with as a reinforcement Al2O3 has 99.52% purity and 45 submicron particle size in a high energy ball mill for two hours. In order to obtain disk samples with 30 mm diameter and 6 mm thick mixed powders, after the characterization of particle size and morphology, were compacted in a single action press. Compaction process were carried out from mixed powders by hot pressing at 200 MPa pressure and 550 °C temperature for two hours. Then microstructural analysis, hardness and density measurements of powder metal composite parts were performed. After, the characterization of samples abrasion wear tests were performed according to ASTM-G99-05 by using TRIBOMETER T10/20 ball-on-disk abrasive wearing device. After the abrasive wear test of aluminum and composite powder metal parts produced under the identical test parameters, test results were compared and effect of Al2O3 on the wear properties of composite materials was exhibited. The test results showed that the composite parts have 62 % extra harness and better abrasion wear performance according to aluminum powder metal parts produced and tested under the identical conditions

Neural network approximation of tip-abrasion effects in AFM imaging

International Nuclear Information System (INIS)

Bakucz, Peter; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf; Yacoot, Andrew

2008-01-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods

Neural network approximation of tip-abrasion effects in AFM imaging

Science.gov (United States)

Bakucz, Peter; Yacoot, Andrew; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf

2008-06-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods.

Tooth wear

Directory of Open Access Journals (Sweden)

Tušek Ivan

2014-01-01

Full Text Available Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction, which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to tooth abfraction and microfracture. Wear of tooth surfaces due to the presence of microscopic imperfections of tooth surfaces is clinically manifested as sanding veneers. Tribology, as an interdisciplinary study of the mechanisms of friction, wear and lubrication at the ultrastructural level, has defined a universal model according to which the etiopathogenesis of tooth wear is caused by the following factors: health and diseases of the digestive tract, oral hygiene, eating habits, poor oral habits, bruxism, temporomandibular disorders and iatrogenic factors. Attrition and dental erosion are much more common in children with special needs (Down syndrome. Erosion of teeth usually results from diseases of the digestive tract that lead to gastroesophageal reflux (GER of gastric juice (HCl. There are two basic approaches to the assessment of the degree of wear and dental erosion. Depending on the type of wear (erosion, attrition, abfraction, the amount of calcium that was realised during the erosive attack could be determined qualitatively and quantitatively, or changes in optical properties and hardness of enamel could be recorded, too. Abrasion of teeth (abrasio dentium is the loss of dental hard tissue caused by friction between the teeth and exogenous foreign substance. It is most commonly provoked by prosthetic dentures and bad habits, while its effect depends on the size of abrasive particles and their amount, abrasive particle hardness and hardness of tooth

Resistance to abrasion of extrinsic porcelain esthetic characterization techniques.

Science.gov (United States)

Chi, Woo J; Browning, William; Looney, Stephen; Mackert, J Rodway; Windhorn, Richard J; Rueggeberg, Frederick

2017-01-01

A novel esthetic porcelain characterization technique involves mixing an appropriate amount of ceramic colorants with clear, low-fusing porcelain (LFP), applying the mixture on the external surfaces, and firing the combined components onto the surface of restorations in a porcelain oven. This method may provide better esthetic qualities and toothbrush abrasion resistance compared to the conventional techniques of applying color-corrective porcelain colorants alone, or applying a clear glaze layer over the colorants. However, there is no scientific literature to support this claim. This research evaluated toothbrush abrasion resistance of a novel porcelain esthetic characterization technique by subjecting specimens to various durations of simulated toothbrush abrasion. The results were compared to those obtained using the conventional characterization techniques of colorant application only or colorant followed by placement of a clear over-glaze. Four experimental groups, all of which were a leucite reinforced ceramic of E TC1 (Vita A1) shade, were prepared and fired in a porcelain oven according to the manufacturer's instructions. Group S (stain only) was characterized by application of surface colorants to provide a definitive shade of Vita A3.5. Group GS (glaze over stain) was characterized by application of a layer of glaze over the existing colorant layer as used for Group S. Group SL (stain+LFP) was characterized by application of a mixture of colorants and clear low-fusing add-on porcelain to provide a definitive shade of Vita A3.5. Group C (Control) was used as a control without any surface characterization. The 4 groups were subjected to mechanical toothbrushing using a 1:1 water-to-toothpaste solution for a simulated duration of 32 years of clinical use. The amount of wear was measured at time intervals simulating every 4 years of toothbrushing. These parameters were evaluated longitudinally for all groups as well as compared at similar time points among

Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

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Francisco Silva

2017-02-01

Full Text Available It is well known that injection of glass fibre–reinforced plastics (GFRP causes abrasive wear in moulds’ cavities and runners. Physical vapour deposition (PVD coatings are intensively used to improve the wear resistance of different tools, also being one of the most promising ways to increase the moulds’ lifespan, mainly when used with plastics strongly reinforced with glass fibres. This work compares four different thin, hard coatings obtained using the PVD magnetron sputtering process: TiAlN, TiAlSiN, CrN/TiAlCrSiN and CrN/CrCN/DLC. The first two are monolayer coatings while the last ones are nanostructured and consist of multilayer systems. In order to carry out the corresponding tribological characterization, two different approaches were selected: A laboratorial method, using micro-abrasion wear tests based on a ball-cratering configuration, and an industrial mode, analysing the wear resistance of the coated samples when inserted in a plastic injection mould. As expected, the wear phenomena are not equivalent and the results between micro-abrasion and industrial tests are not similar due to the different means used to promote the abrasion. The best wear resistance performance in the laboratorial wear tests was attained by the TiAlN monolayer coating while the best performance in the industrial wear tests was obtained by the CrN/TiAlCrSiN nanostructured multilayer coating.

Effect of filler type on 3-body abrasion of dental composite

Directory of Open Access Journals (Sweden)

Yasini E.

2005-06-01

Full Text Available Statement of Problem: The relatively poor wear resistance of dental composite in stress bearing posterior situations has restricted wider clinical application of this restorative material. Purpose: The aim of this study was to evaluate the three body abrasive wear of a dental composite based on a new filler (leucite: KAl Si2O6 and to compare it with the wear resistance of a composite based on commonly used Aluminium – Barium Silicate filler. Materials and Methods: This research was an interventional study done in Iran polymer institute. Five specimens were considered in each group. All ceramic IPS Empress® (Ivoclar- Vivadent ingots based on leucite crystals were ball milled, passed through an 800 sieve and used as filler. Experimental composites were prepared by mixing the silane- treated fillers with monomers (BisGMA and TEGDMA. Camphorquinone and amine were used as photoinitiator system. Degree of conversion of the light-cured and post-cured composites was measured using FTIR spectroscopy. The prepared pastes were inserted into plexy-glass mold and light cured (700 mw/cm2, 40 s. Then for maximum degree of conversion specimens were post- cured (120ºC, 5 hours. Three body abrasion wear testing was performed using a wear machine with 50 rpm rotational movement. In this machine, pumice (150 meshes was used as the third body. Weight loss of specimens in each group was measured by balance after each 50 hours. After wear testing SEM examination was made specimens in each group. The data were analyzed and compared using ANOVA and Tukey HSD tests (P<0.05. Tetric Ceram was tested as commercial composite. Results: There were significantly differences between three body abrasive wear of composites. The ranking from lowest to highest was as follows: leucite composite (19% < Tetric Ceram (22% < glass composite (28%. leucite composite showed the highest wear resistance value, propably due to the crystalliniy and hardness of filler. Conclusion

Wear of PEEK-OPTIMA® and PEEK-OPTIMA®-Wear Performance articulating against highly cross-linked polyethylene.

Science.gov (United States)

East, Rebecca H; Briscoe, Adam; Unsworth, Anthony

2015-03-01

The idea of all polymer artificial joints, particularly for the knee and finger, has been raised several times in the past 20 years. This is partly because of weight but also to reduce stress shielding in the bone when stiffer materials such as metals or ceramics are used. With this in mind, pin-on-plate studies of various polyetheretherketone preparations against highly cross-linked polyethylene were conducted to investigate the possibility of using such a combination in the design of a new generation of artificial joints. PEEK-OPTIMA(®) (no fibre) against highly cross-linked polyethylene gave very low wear factors of 0.0384 × 10(-6) mm(3)/N m for the polyetheretherketone pins and -0.025 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates. The carbon-fibre-reinforced polyetheretherketone (PEEK-OPTIMA(®)-Wear Performance) also produced very low wear rates in the polyetheretherketone pins but produced very high wear in the highly cross-linked polyethylene, as might have been predicted since the carbon fibres are quite abrasive. When the fibres were predominantly tangential to the sliding plane, the mean wear factor was 0.052 × 10(-6) mm(3)/N m for the pins and 49.3 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates; a half of that when the fibres ran axially in the pins (0.138 × 10(-6) mm(3)/N m for the pins and 97.5 × 10(-6) mm/ N m for the cross-linked polyethylene plates). PEEK-OPTIMA(®) against highly cross-linked polyethylene merits further investigation. © IMechE 2015.

Comprehensive study of the abrasive wear and slurry erosion behavior of an expanded system of high chromium cast iron and microstructural modification for enhanced wear resistance

Science.gov (United States)

Chung, Reinaldo Javier

High chromium cast irons (HCCIs) have been demonstrated to be an effective material for a wide range of applications in aggressive environments, where resistances to abrasion, erosion and erosion-corrosion are required. For instance, machinery and facilities used in mining and extraction in Alberta's oil sands suffer from erosion and erosion-corrosion caused by silica-containing slurries, which create challenges for the reliability and maintenance of slurry pumping systems as well as other processing and handling equipment. Considerable efforts have been made to determine and understand the relationship between microstructural features of the HCCIs and their wear performance, in order to guide the material selection and development for specific service conditions with optimal performance. The focus was previously put on a narrow group of compositions dictated by ASTM A532. However, with recent advances in casting technology, the HCCI compositional range can be significantly expanded, which potentially brings new alloys that can be superior to those which are currently employed. This work consists of three main aspects of study. The first one is the investigation of an expanded system of white irons with their composition ranging from 1 to 6 wt.% C and 5 to 45 wt.% Cr, covering 53 alloys. This work has generated wear and corrosion maps and established correlation between the performance and microstructural features for the alloys. The work was conducted in collaboration with the Materials Development Center of Weir Minerals in Australia, and the results have been collected in a database that is used by the company to guide materials selection for slurry pump components in Alberta oil sands and in other mining operations throughout the world. The second part consists of three case studies on effects of high chromium and high carbon, respectively, on the performance of the HCCIs. The third aspect is the development of an approach to enhance the wear resistance of

Wear properties of metal ion implanted 4140 steel

International Nuclear Information System (INIS)

Evans, P.J.; Paoloni, F.J.

1994-01-01

AISI type 4140 (high tensile) steel has been implanted with tungsten and titanium using a metal vapour vacuum arc ion source. Doses in the range (1-5)x10 16 ionscm -2 were implanted to a depth of approximately 30nm. The relative wear resistance between non-implanted and implanted specimens has been estimated using pin-on-disc and abrasive wear tests. Implantation of titanium decreased the area of wear tracks by a factor of 5 over unimplanted steel. In some cases the steel was also hardened by a liquid carburization treatment before implantation. Abrasion tests revealed a further improvement in wear resistance on this material following ion irradiation. ((orig.))

Cleaning, abrasion, and polishing effect of novel perlite toothpaste abrasive.

Science.gov (United States)

Wang, Bo

2013-01-01

This study was intended to optimize perlite particle size and morphology for better tooth cleaning and lower tooth abrasion, and to evaluate the performance of a whitening toothpaste containing the optimized perlite abrasive for tooth cleaning, abrasion, and polishing. Perlite toothpaste abrasive samples were prepared by air classifying a commercial expanded perlite product. The tooth cleaning and abrasion properties for these classified perlite samples were reported via the pellicle cleaning ratio (PCR) and relative dentin abrasion (RDA). Performance of the whitening toothpaste containing the optimized perlite abrasive in tooth cleaning, polishing, and abrasion was evaluated against a widely used synthetic high-cleaning silica. Air classification removes large perlite particles and also physically changes perlite particle morphology from mostly three dimensional and angular particles to mainly two dimensional and platy particles. All the classified samples show good tooth cleaning effect, but tooth abrasion decreases significantly with decreasing particle size. Compared to high-cleaning silica whitening toothpaste, the whitening toothpaste containing the optimized perlite abrasive (PerlClean) is slightly better at tooth cleaning, lower in tooth abrasion, and significantly better at tooth polishing. Fine platy perlite particles are effective in tooth cleaning with low tooth abrasion. The enhanced performance of optimized perlite toothpaste abrasive compared to high-cleaning silica in a whitening toothpaste is attributed to the optimized particle size distribution and the unique platy particle geometry.

Selected Properties And Tribological Wear Alloys Co-Cr-Mo And Co-Cr-Mo-W Used In Dental Prosthetics

Directory of Open Access Journals (Sweden)

Augustyn-Pieniążek J.

2015-09-01

Full Text Available The presented work provides the results of the abrasive wear resistance tests performed on Co-Cr-Mo and Co-Cr-Mo-W alloys with the use of the Miller’s apparatus. The analyzed alloys underwent microstructure observations as well as hardness measurements, and the abraded surfaces of the examined materials were observed by means of electron scanning microscopy. The performed examinations made it possible to state that the Co-Cr alloys characterized in a high hardness, whereas the changes in the mass decrement were minimal, which proved a high abrasive wear resistance.

Anti-abrasive nanocoatings current and future applications

CERN Document Server

2015-01-01

This book provides an overview of the fabrication methods for anti-abrasive nanocoatings. The connections among fabrication parameters, the characteristics of nanocoatings and the resulting properties (i.e. nanohardness, toughness, wear rate, load-bearing ability, friction coefficient, and scratch resistance) are discussed. Size-affected mechanical properties of nanocoatings are examined, including their uses. Anti-abrasive nanocoatings, including metallic-, ceramic-, and polymeric-based layers, as well as different kinds of nanostructures, such as multi-layered nanocomposites and thin films, are reviewed. * Provides a comprehensive overview of the fabrication methods for anti-abrasive nanocoatings* Discusses the connections among fabrication parameters, the characteristics of nanocoatings and the resulting properties* Reviews advantages and drawbacks of fabrication methods for anti-abrasive nanocoatings and clarifies the place of these nanocoatings in the world of nanotechnology

Wear properties of metal ion implanted 4140 steel

Energy Technology Data Exchange (ETDEWEB)

Evans, P.J. (Applications of Nuclear Physics, Ansto, Private Mail Bag 1, Menai, NSW 2234 (Australia)); Paoloni, F.J. (Department of Electrical and Computer Engineering, University of Wollongong, GPO Box 1144, Wollongong, NSW 2500 (Australia))

1994-07-01

AISI type 4140 (high tensile) steel has been implanted with tungsten and titanium using a metal vapour vacuum arc ion source. Doses in the range (1-5)x10[sup 16]ionscm[sup -2] were implanted to a depth of approximately 30nm. The relative wear resistance between non-implanted and implanted specimens has been estimated using pin-on-disc and abrasive wear tests. Implantation of titanium decreased the area of wear tracks by a factor of 5 over unimplanted steel. In some cases the steel was also hardened by a liquid carburization treatment before implantation. Abrasion tests revealed a further improvement in wear resistance on this material following ion irradiation. ((orig.))

Investigation of wear land and rate of locally made HSS cutting tool

Science.gov (United States)

Afolalu, S. A.; Abioye, A. A.; Dirisu, J. O.; Okokpujie, I. P.; Ajayi, O. O.; Adetunji, O. R.

2018-04-01

Production technology and machining are inseparable with cutting operation playing important roles. Investigation of wear land and rate of cutting tool developed locally (C=0.56%) with an HSS cutting tool (C=0.65%) as a control was carried out. Wear rate test was carried out using Rotopol -V and Impact tester. The samples (12) of locally made cutting tools and one (1) sample of a control HSS cutting tool were weighed to get the initial weight and grit was fixed at a point for the sample to revolve at a specific time of 10 mins interval. Approach of macro transfer particles that involved mechanism of abrasion and adhesion which was termed as mechanical wear to handle abrasion adhesion processes was used in developing equation for growth wear at flank. It was observed from the wear test that best minimum wear rate of 1.09 × 10-8 and 2.053 × 10-8 for the tools developed and control were measured. MATLAB was used to simulate the wear land and rate under different conditions. Validated results of both the experimental and modeling showed that cutting speed has effect on wear rate while cutting time has predicted measure on wear land. Both experimental and modeling result showed best performances of tools developed over the control.

Wear-resistance of Aluminum Matrix Microcomposite Materials

Directory of Open Access Journals (Sweden)

M. Kandeva

2011-03-01

Full Text Available A procedure is developed for the study of wear of aluminum alloys AlSi7 obtained by casting, reinforced by TiC microparticles, before and after heat treatment. Tribological study is realized under conditions of friction on counterbody with fixed abrasive. Experimental results were obtained for mass wear, wear rate, wear intensity and wear-resistance of the alloys with different wt% of microparticles.

Single-asperity contributions to multi-asperity wear simulated with molecular dynamics

International Nuclear Information System (INIS)

Eder, S J; Cihak-Bayr, U; Bianchi, D

2016-01-01

We use a molecular dynamics approach to simulate the wear of a rough ferrite surface due to multiple hard, abrasive particles under variation of normal pressure, grinding direction, and particle geometry. By employing a clustering algorithm that incorporates some knowledge about the grinding process such as the main grinding direction, we can break down the total wear volume into contributions from the individual abrasive particles in a time-resolved fashion. The resulting analysis of the simulated grinding process allows statements on wear particle generation, distribution, and stability depending on the initial topography, the grinding angle, the normal pressure, as well as the abrasive shape and orientation with respect to the surface. (paper)

CFD Based Erosion Modelling of Abrasive Waterjet Nozzle using Discrete Phase Method

International Nuclear Information System (INIS)

Kamarudin, Naqib Hakim; Prasada Rao, A K; Azhari, Azmir

2016-01-01

In Abrasive Waterjet (AWJ) machining, the nozzle is the most critical component that influences the performance, precision and economy. Exposure to a high speed jet and abrasives makes it susceptible to wear erosion which requires for frequent replacement. The present works attempts to simulate the erosion of the nozzle wall using computational fluid dynamics. The erosion rate of the nozzle was simulated under different operating conditions. The simulation was carried out in several steps which is flow modelling, particle tracking and erosion rate calculation. Discrete Phase Method (DPM) and K-ε turbulence model was used for the simulation. Result shows that different operating conditions affect the erosion rate as well as the flow interaction of water, air and abrasives. The simulation results correlates well with past work. (paper)

Wear mechanisms of dental composite restorative materials by two different in-vitro methods

Directory of Open Access Journals (Sweden)

Juliana Antonino de Souza

2013-04-01

Full Text Available In this work two very simple apparatuses, namely the ball crater (or ball-on-plate and the linear reciprocating (or pin-on-plate tests, were used in order to investigate the wear mechanisms of TPH Spectrum® and Resilab Master® dental composite resins. Loads in the range of 100 g to 1 kg and a total number of up to 24000 cycles were employed. During some of these tests, aqueous aluminum oxide suspensions were used as abrasive agent either diluted or not in distilled water. In case of the ball-on-plate test wear is dominated by abrasive and/or adhesive mechanisms, and is characterized by scratches which are composed of wear defects comprising particle detachment, wear of the polymer matrix and ceramic particle abrasion. However, the relative contributions of the two wear mechanisms could not be determined separately. In case of the pin-on-plate test wear is governed by the fatigue mechanism, although abrasive and adhesive wear mechanism are also present. After a certain number of cycles fatigue wear dominates the wear behavior and results in severe material loss. This mechanism seems to be more important in case of more brittle materials and when higher loads are employed. Qualitative analysis of the results suggests that the combination of these two very simple methods under appropriate conditions can yield sound results which may be representative of a number of clinical situations.

Wear mechanisms of dental composite restorative materials by two different in-vitro methods

Directory of Open Access Journals (Sweden)

Juliana Antonino de Souza

2012-01-01

Full Text Available In this work two very simple apparatuses, namely the ball crater (or ball-on-plate and the linear reciprocating (or pin-on-plate tests, were used in order to investigate the wear mechanisms of TPH Spectrum® and Resilab Master® dental composite resins. Loads in the range of 100 g to 1 kg and a total number of up to 24000 cycles were employed. During some of these tests, aqueous aluminum oxide suspensions were used as abrasive agent either diluted or not in distilled water. In case of the ball-on-plate test wear is dominated by abrasive and/or adhesive mechanisms, and is characterized by scratches which are composed of wear defects comprising particle detachment, wear of the polymer matrix and ceramic particle abrasion. However, the relative contributions of the two wear mechanisms could not be determined separately. In case of the pin-on-plate test wear is governed by the fatigue mechanism, although abrasive and adhesive wear mechanism are also present. After a certain number of cycles fatigue wear dominates the wear behavior and results in severe material loss. This mechanism seems to be more important in case of more brittle materials and when higher loads are employed. Qualitative analysis of the results suggests that the combination of these two very simple methods under appropriate conditions can yield sound results which may be representative of a number of clinical situations.

A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

International Nuclear Information System (INIS)

Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok

2012-01-01

Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

Abrasion Properties of Steel Fiber Reinforced Silica Fume Concrete According to Los Angeles and Water Abrasion Tests

Directory of Open Access Journals (Sweden)

Tsan-Ching CHENG

2014-12-01

Full Text Available The current study mainly investigated the influence of different tests on the abrasion resistance of concrete mixed with steel fibers and silica fume. The abrasion resistance was assessed at 28, 56 and 91 days on concretes with water-binder ratios of 0.35 and 0.55 where in some mixes silica fume was substituted by 5 % of cement by weight. Steel fibers of 0.5 % and 1.0 % of concrete volume were also added into the test concrete by replacement of coarse and fine aggregates. The results showed that concrete with higher compressive strength in Los Angeles abrasion tests also had better abrasion resistance. The inclusion of steel fibers into test concrete with a water-binder ratio of 0.35 resulted in a significant increase in compressive strength. This concrete also displayed better abrasion resistance and splitting tensile strength than reference concrete; in the test sample with a water-binder ratio of 0.55, the added steel fibers was unable to effectively produce cementation with the concrete. The inclusion of silica fume improved the abrasion resistance of concretes. In water abrasion testing, the abrasion resistance of concrete containing steel fiber was worse than that of concrete without steel fibers. In the water abrasion testing, the surface of steel fiber reinforced concrete was eroded by water and steel balls, and the impact caused the steel fibers to separate from the concrete and led to higher wear loss. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6460

Modeling of wear behavior of Al/B_4C composites produced by powder metallurgy

International Nuclear Information System (INIS)

Sahin, Ismail; Bektas, Asli; Guel, Ferhat; Cinci, Hanifi

2017-01-01

Wear characteristics of composites, Al matrix reinforced with B_4C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B_4C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

Fretting Wear Damage Mechanism of Uranium under Various Atmosphere and Vacuum Conditions

Directory of Open Access Journals (Sweden)

Zhengyang Li

2018-04-01

Full Text Available A fretting wear experiment with uranium has been performed on a linear reciprocating tribometer with ball-on-disk contact. This study focused on the fretting behavior of the uranium under different atmospheres (Ar, Air (21% O2 + 78% N2, and O2 and vacuum conditions (1.05 and 1 × 10−4 Pa. Evolution of friction was assessed by coefficient of friction (COF and friction-dissipated energy. The oxide of the wear surface was evaluated by Raman spectroscopy. The result shows that fretting wear behavior presents strong atmosphere and vacuum condition dependence. With increasing oxygen content, the COF decreases due to abrasive wear and formation of oxide film. The COF in the oxygen condition is at least 0.335, and it has a maximum wear volume of about 1.48 × 107 μm3. However, the COF in a high vacuum condition is maximum about 1.104, and the wear volume is 1.64 × 106 μm3. The COF in the low vacuum condition is very different: it firstly increased and then decreased rapidly to a steady value. It is caused by slight abrasive wear and the formation of tribofilm after thousands of cycles.

Tribological wear behavior of diamond reinforced composite coating

International Nuclear Information System (INIS)

Venkateswarlu, K.; Ray, Ajoy Kumar; Gunjan, Manoj Kumar; Mondal, D.P.; Pathak, L.C.

2006-01-01

In the present study, diamond reinforced composite (DRC) coating has been applied on mild steel substrate using thermal spray coating technique. The composite powder consists of diamond, tungsten carbide, and bronze, which was mixed in a ball mill prior deposition by thermal spray. The microstructure and the distribution of diamond and tungsten carbide particle in the bronze matrix were studied. The DRC-coated mild steel substrates were assessed in terms of their high stress abrasive wear and compared with that of uncoated mild steel substrates. It was observed that when sliding against steel, the DRC-coated sample initially gains weight, but then loses the transferred counter surface material. In case of abrasive wear, the wear rate was greatly reduced due to the coating; wherein the wear rate decreased with increase in diamond content

Multi technical analysis of wear mechanisms in axial piston pumps

Science.gov (United States)

Schuhler, G.; Jourani, A.; Bouvier, S.; Perrochat, J.-M.

2017-05-01

Axial piston pumps convert a motor rotation motion into hydraulic or pneumatic power. Their compactness and efficiency of approximately 0.9 make them suitable for actuation applications especially in aeronautics. However, they suffer a limited life due to the wear of their components. In the literature, studies of axial piston pumps deal with contact between its different elements under lubrication conditions. Nevertheless, they are more focused on analytic or numerical approaches. This study consists in an experimental analysis of worn pump components to highlight and understand wear mechanisms. Piston shoes are central components in the axial piston pump since they are involved in three tribological contacts. These three contacts are thereby studied: piston shoes/swashplate, piston shoes/pistons and piston shoes/shoes hold down plate (SHDP). To perform this analysis, helicopter hydraulic pumps after different operating times have been studied. The wear damage mechanisms and wear debris are analysed using SEM observations. 3D surface roughness measurements are then used to characterize worn surfaces. The observations reveal that in the contact between shoes and swashplate, the main wear mechanism is three-body abrasive wear due to coarse carbides removal. Between shoes and pistons, wear occurs in a less severe way and is mainly due to the debris generated in the first contact and conveyed by the lubricating fluid. In the third contact, the debris are also the prime cause of the abrasive wear and the generation of deep craters in the piston shoes.

Abrasive wear behaviour of bio-active glass ceramics containing ...

Indian Academy of Sciences (India)

Unknown

Technical Education Faculty, Mersin University, 33480 Tarsus, Turkey. MS received 18 October 2005; revised 22 March 2006. Abstract. In this study, abrasive ... process were used to produce bio-active ceramics. Fracture toughness of studied ...

Effect of power toothbrushing on simulated wear of dental cement margins.

Science.gov (United States)

Black, Marsha A; Bayne, Stephen C; Peterson, Charlotte A

2007-01-01

Power toothbrushes (PTBs), in combination with abrasive dentifrices, may encourage wear of dental cements at crown margins. The objective of this in vitro simulation was to control the clinical variables associated with PTB use and measure the potential side effects of PTBs with mild and abrasive dentifrices. Four PTBs ( Braun-Oral-B-Professional Care at 150 g brushing force, Sonicare-Elite at 90 g, Colgate-Actibrush at 200 g and Crest-Spinbrush-Pro at 250 g) and 2 dentifrices mixed 1:1 with tap water (Mild= Colgate-Total, Colgate-Palmolive; Abrasive= Close-up, Chesebrough-Ponds) versus tap water alone (control) were used to abrade 2 cements (Fleck's Mizzy Zinc Phosphate [ZP]; 3M-ESPE Unicem universal cement [UC]) using cement-filled slots (160 m wide) cut into wear-resistant ceramic blocks. A custom fixture controlled PTB/block alignment, PTB loads, and other testing variables. Wear was measured (3 profilometer traces/slot, 5 slots/block/group, baseline to 5-year differences) and analyzed (3-way ANOVA, p PTBs and both dentifrices. Brushing with water showed no effects (pPTBs. Pooled 5y-wear levels for ZP for both dentifrices approximately 21 microm /5y) were similar to values for current-day posterior composite materials. Combinations of PTBs with mild and abrasive dentifrices produced significant wear with ZP but not UC; thus, resin-composite cements seem to represent a better choice for wear resistance.

Modeling of wear behavior of Al/B{sub 4}C composites produced by powder metallurgy

Energy Technology Data Exchange (ETDEWEB)

Sahin, Ismail; Bektas, Asli [Gazi Univ., Ankara (Turkey). Dept. of Industrial Design Engineering; Guel, Ferhat; Cinci, Hanifi [Gazi Univ., Ankara (Turkey). Dept. of Materials and Metallurgy Engineering

2017-06-01

Wear characteristics of composites, Al matrix reinforced with B{sub 4}C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B{sub 4}C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

Crack and wear behavior of SiC particulate reinforced aluminium based metal matrix composite fabricated by direct metal laser sintering process

International Nuclear Information System (INIS)

Ghosh, Subrata Kumar; Saha, Partha

2011-01-01

In this investigation, crack density and wear performance of SiC particulate (SiCp) reinforced Al-based metal matrix composite (Al-MMC) fabricated by direct metal laser sintering (DMLS) process have been studied. Mainly, size and volume fraction of SiCp have been varied to analyze the crack and wear behavior of the composite. The study has suggested that crack density increases significantly after 15 volume percentage (vol.%) of SiCp. The paper has also suggested that when size (mesh) of reinforcement increases, wear resistance of the composite drops. Three hundred mesh of SiCp offers better wear resistance; above 300 mesh the specific wear rate increases significantly. Similarly, there has been no improvement of wear resistance after 20 vol.% of reinforcement. The scanning electron micrographs of the worn surfaces have revealed that during the wear test SiCp fragments into small pieces which act as abrasives to result in abrasive wear in the specimen.

Gear Tooth Wear Detection Algorithm

Science.gov (United States)

Delgado, Irebert R.

2015-01-01

Vibration-based condition indicators continue to be developed for Health Usage Monitoring of rotorcraft gearboxes. Testing performed at NASA Glenn Research Center have shown correlations between specific condition indicators and specific types of gear wear. To speed up the detection and analysis of gear teeth, an image detection program based on the Viola-Jones algorithm was trained to automatically detect spiral bevel gear wear pitting. The detector was tested using a training set of gear wear pictures and a blind set of gear wear pictures. The detector accuracy for the training set was 75 percent while the accuracy for the blind set was 15 percent. Further improvements on the accuracy of the detector are required but preliminary results have shown its ability to automatically detect gear tooth wear. The trained detector would be used to quickly evaluate a set of gear or pinion pictures for pits, spalls, or abrasive wear. The results could then be used to correlate with vibration or oil debris data. In general, the program could be retrained to detect features of interest from pictures of a component taken over a period of time.

Wear Resistant Thermal Sprayed Composite Coatings Based on Iron Self-Fluxing Alloy and Recycled Cermet Powders

Directory of Open Access Journals (Sweden)

Heikki SARJAS

2012-03-01

Full Text Available Thermal spray and WC-Co based coatings are widely used in areas subjected to abrasive wear. Commercial  cermet thermal spray powders for HVOF are relatively expensive. Therefore applying these powders in cost-sensitive areas like mining and agriculture are hindered. Nowadays, the use of cheap iron based self-fluxing alloy powders for thermal spray is limited. The aim of this research was to study properties of composite powders based on self-fluxing alloys and recycled cermets and to examine the properties of thermally sprayed (HVOF coatings from composite powders based on iron self-fluxing alloy and recycled cermet powders (Cr3C2-Ni and WC-Co. To estimate the properties of  recycled cermet powders, the sieving analysis, laser granulometry and morphology were conducted. For deposition of coatings High Velocity Oxy-Fuel spray was used. The structure and composition of powders and coatings were estimated by SEM and XRD methods. Abrasive wear performance of coatings was determined and compared with wear resistance of coatings from commercial powders. The wear resistance of thermal sprayed coatings from self-fluxing alloy and recycled cermet powders at abrasion is comparable with wear resistance of coatings from commercial expensive spray powders and may be an alternative in tribological applications in cost-sensitive areas.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1338

An analysis of the physiologic parameters of intraoral wear: a review

International Nuclear Information System (INIS)

Lawson, Nathaniel C; Cakir, Deniz; Burgess, John O; Janyavula, Sridhar

2013-01-01

This paper reviews the conditions of in vivo mastication and describes a novel method of measuring in vitro wear. Methods: parameters of intraoral wear are reviewed in this analysis, including chewing force, tooth sliding distance, food abrasivity, saliva lubrication, and antagonist properties. Results: clinical measurement of mastication forces indicates a range of normal forces between 20 and 140 N for a single molar. During the sliding phase of mastication, horizontal movement has been measured between 0.9 and 2.86 mm. In vivo wear occurs by three-body abrasion when food particles are interposed between teeth and by two-body abrasion after food clearance. Analysis of food particles used in wear testing reveals that food particles are softer than enamel and large enough to separate enamel and restoration surfaces and act as a solid lubricant. In two-body wear, saliva acts as a boundary lubricant with a viscosity of 3 cP. Enamel is the most relevant antagonist material for wear testing. The shape of a palatal cusp has been estimated as a 0.6 mm diameter ball and the hardest region of a tooth is its enamel surface. pH values and temperatures have been shown to range between 2–7 and 5–55 °C in intraoral fluids, respectively. These intraoral parameters have been used to modify the Alabama wear testing method. (paper)

Wear behavior of tetragonal zirconia polycrystal versus titanium and titanium alloy

International Nuclear Information System (INIS)

Kanbara, Tsunemichi; Yajima, Yasutomo; Yoshinari, Masao

2011-01-01

The aim of this study was to clarify the influence of tetragonal zirconia polycrystal (TZP) on the two-body wear behavior of titanium (Ti). Two-body wear tests were performed using TZP, two grades of cp-Ti or Ti alloy in distilled water, and the cross-sectional area of worn surfaces was measured to evaluate the wear behavior. In addition, the surface hardness and coefficient of friction were determined and an electron probe microanalysis performed to investigate the underlying mechanism of wear. The hardness of TZP was much greater than that of Ti. The coefficient of friction between Ti and Ti showed a higher value than the Ti/TZP combination. Ti was more susceptible to wear by both TZP and Ti than TZP, indicating that the mechanism of wear between TZP and Ti was abrasive wear, whereas that between Ti and Ti was adhesive wear. No remarkable difference in the amount of wear in Ti was observed between TZP and Ti as the opposite material, despite the hardness value of Ti being much smaller than that of TZP. (communication)

Air Abrasion

Science.gov (United States)

... Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air ... will perform any procedures that use air-abrasion technology. Ask your dentist if he or she uses ...

Laboratory Measurements of Particulate Matter Concentrations from Asphalt Pavement Abrasion

Directory of Open Access Journals (Sweden)

Fullová Daša

2016-12-01

Full Text Available The issue of emissions from road traffic is compounded by the fact that the number of vehicles and driven kilometres increase each year. Road traffic is one of the main sources of particulate matter and traffic volume is still increasing and has unpleasant impact on longevity of the pavements and the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The contribution deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures of wearing courses are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The contribution offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

Analysis of coarse aggregate performance based on the modified Micro Deval abrasion test

Directory of Open Access Journals (Sweden)

Jiangfeng Wu

2018-03-01

Full Text Available The anti-abrasion property of aggregate significantly affects the performance of the pavement. In this research, the quartzite and gneiss which were produced in Lincheng County, Xingtai City, Hebei Province were selected as test samples. According to the American Society for Testing and Materials standard, the Micro-Deval abrasion test was taken every 1000 rotation times until 20,000 times, and the change trend of the Micro-Deval abrasion value was obtained. Results showed that the abrasion values were in the exponential growth rate rather than linear rate. Their R-Square coefficient was 0.99142 and 0.99916 respectively. The gravel information such as area, roundness, diameter, perimeter and so on were calculated and analyzed by Image-Pro Plus software, which provided a rapid way for the 2D morphology characteristics analysis of the coarse aggregate. Keywords: Micro-Deval abrasion test, Coarse aggregate, Anti-abrasion property, Abrasion values

Processing and study of the wear and friction behaviour of discrete ...

Indian Academy of Sciences (India)

due to the increase in the braking energy, (3) at low sliding speeds (5, 10 m s−1), abrasive wear is the main wear ... tion materials, gas turbine thermal barrier coatings, armour ..... in a optimum level to balance both the wear loss and the stop-.

Simplified Abrasion Test Methodology for Candidate EVA Glove Lay-Ups

Science.gov (United States)

Rabel, Emily; Aitchison, Lindsay

2015-01-01

During the Apollo Program, space suit outer-layer fabrics were badly abraded after performing just a few extravehicular activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots that penetrated the outer-layer fabric into the thermal protection layers after less than 8 hrs of surface operations. Current plans for the exploration planetary space suits require the space suits to support hundreds of hours of EVA on a lunar or Martian surface, creating a challenge for space suit designers to utilize materials advances made over the last 40 years and improve on the space suit fabrics used in the Apollo Program. Over the past 25 years the NASA Johnson Space Center Crew and Thermal Systems Division has focused on tumble testing as means of simulating wear on the outer layer of the space suit fabric. Most recently, in 2009, testing was performed on 4 different candidate outer layers to gather baseline data for future use in design of planetary space suit outer layers. In support of the High Performance EVA Glove Element of the Next Generation Life Support Project, testing a new configuration was recently attempted in which require 10% of the fabric per replicate of that need in 2009. The smaller fabric samples allowed for reduced per sample cost and flexibility to test small samples from manufacturers without the overhead to have a production run completed. Data collected from this iteration was compared to that taken in 2009 to validate the new test method. In addition the method also evaluated the fabrics and fabric layups used in a prototype thermal micrometeoroid garment (TMG) developed for EVA gloves under the NASA High Performance EVA Glove Project. This paper provides a review of previous abrasion studies on space suit fabrics, details methodologies used for abrasion testing in this particular study, results of the validation study, and results of the TMG testing.

Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron

Directory of Open Access Journals (Sweden)

S. Pietrowski

2012-04-01

Full Text Available The current work presents the research results of abrasion wear and adhesive wear at rubbing and liquid friction of new austenitic, austenitic-ferritic (“duplex” cast steel and gray cast iron EN-GJL-250, spheroidal graphite iron EN-GJS-600-3, pearlitic with ledeburitic carbides and spheroidal graphite iron with ledeburitic carbides with a microstructure of the metal matrix: pearlitic, upper bainite, mixture of upper and lower bainite, martensitic with austenite, pearlitic-martensitic-bainitic-ausferritic obtained in the raw state. The wearing quality test was carried out on a specially designed and made bench. Resistance to abrasion wear was tested using sand paper P40. Resistance to adhesive wear was tested in interaction with steel C55 normalized, hardened and sulfonitrided. The liquid friction was obtained using CASTROL oil. It was stated that austenitic cast steel and “duplex” are characterized by a similar value of abrasion wear and adhesive wear at rubbing friction. The smallest decrease in mass was shown by the cast steel in interaction with the sulfonitrided steel C55. Austenitic cast steel and “duplex��� in different combinations of friction pairs have a higher wear quality than gray cast iron EN-GJL- 250 and spheroidal graphite iron EN-GJS-600-3. Austenitic cast steel and “duplex” are characterized by a lower wearing quality than the spheroidal graphite iron with bainitic-martensitic microstructure. In the adhesive wear test using CASTROL oil the tested cast steels and cast irons showed a small mass decrease within the range of 1÷2 mg.

Prediction of wear rates in comminution equipment

DEFF Research Database (Denmark)

Jensen, Lucas Roald Dörig; Fundal, Erling; Møller, Per

2010-01-01

-resistant high chromium white cast iron (21988/JN/HBW555XCr21), a heat-treated wear resistant steel (Hardox 400) and a plain carbon construction steel (S235). Quartz, which accounts for the largest wear loss in the cement industry, was chosen as abrasive. Other process parameters such as velocity (1–7 m...

Effects of Running Shoes with Abrasion Resistant Rubber Sole on the Exercise Capacity of the Human Body

Directory of Open Access Journals (Sweden)

Bo Wang

2017-10-01

Full Text Available With the development of industrialization, rubber has been gradually used in the manufacture of sports equipment for its favourable properties. This study involved the addition of C5 petroleum resin into brominated isobutylene-isoprene rubber (BIIR and butadiene rubber (BR while manufacturing the sole of running shoes. The effects of running shoes with abrasion resistant rubber sole on the exercise capacity of the human body were investigated by analysing the skid resistance and abrasion resistance of the running shoes, and conducting biomechanical study on naked feet and feet wearing the shoes. The results demonstrated that the rubber sole had favourable slip resistance property and mechanical properties such as stretching, abrasion resistance, and hardness. Compared to naked feet, the peak pressure intensity of the whole step of feet wearing the newly developed shoes, was significantly lower than that of feet wearing ordinary shoes. In the future, rubber can bring more comfortable experience because of its favourable properties.

Wear Characteristics of Metallic Biomaterials: A Review

Science.gov (United States)

Hussein, Mohamed A.; Mohammed, Abdul Samad; Al-Aqeeli, Naser

2015-01-01

Metals are extensively used in a variety of applications in the medical field for internal support and biological tissue replacements, such as joint replacements, dental roots, orthopedic fixation, and stents. The metals and alloys that are primarily used in biomedical applications are stainless steels, Co alloys, and Ti alloys. The service period of a metallic biomaterial is determined by its abrasion and wear resistance. A reduction in the wear resistance of the implant results in the release of incompatible metal ions into the body that loosen the implant. In addition, several reactions may occur because of the deposition of wear debris in tissue. Therefore, developing biomaterials with high wear resistance is critical to ensuring a long life for the biomaterial. The aim of this work is to review the current state of knowledge of the wear of metallic biomaterials and how wear is affected by the material properties and conditions in terms of the type of alloys developed and fabrication processes. We also present a brief evaluation of various experimental test techniques and wear characterization techniques that are used to determine the tribological performance of metallic biomaterials.

Predicting the Abrasion Resistance of Tool Steels by Means of Neurofuzzy Model

Directory of Open Access Journals (Sweden)

Dragutin Lisjak

2013-07-01

Full Text Available This work considers use neurofuzzy set theory for estimate abrasion wear resistance of steels based on chemical composition, heat treatment (austenitising temperature, quenchant and tempering temperature, hardness after hardening and different tempering temperature and volume loss of materials according to ASTM G 65-94. Testing of volume loss for the following group of materials as fuzzy data set was taken: carbon tool steels, cold work tool steels, hot work tools steels, high-speed steels. Modelled adaptive neuro fuzzy inference system (ANFIS is compared to statistical model of multivariable non-linear regression (MNLR. From the results it could be concluded that it is possible well estimate abrasion wear resistance for steel whose volume loss is unknown and thus eliminate unnecessary testing.

Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

International Nuclear Information System (INIS)

Bhushan, Bharat; Palacio, Manuel; Kwak, Kwang Joo

2008-01-01

In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions

Abrasion of Polymeric Composites on Basis of Machining Splinters from Hardfacing Alloys – Usable in Agrocomplex

Directory of Open Access Journals (Sweden)

Petr Valášek

2014-01-01

Full Text Available A paper focuses on a description of two-body and three-body abrasion wear of polymeric particle composites with fillers on a basis of machining splinters from hardfacing alloys. The abrasive wear is typical for functional surfaces of agricultural machines processing the soil. One of possibilities of the functional surface renovation is an application of resistant layers in a form of composite systems. Just the inclusion of hard inorganic particles into a polymeric matrix significantly increases its wear resistance. So long as the primary filler is replaced by the waste – by particles from the material machining – the matrix in which the filler is dispersed is a bearer of a material recyclation. This way of the recyclation is inexpensive, economic and sensitive to environment. The paper focuses on the experimental description of the two-body and three-body abrasion and the composites hardness, it describes a production of a prototype for field tests with the functional surface on the basis of the investigated composite system at the same time.

Particulate matter mass concentrations produced from pavement surface abrasion

Directory of Open Access Journals (Sweden)

Fullova Dasa

2017-01-01

Full Text Available According to the latest findings particulate matter belong to the most significant pollutants in Europe together with ground-level ozone O3 and nitrogen dioxide NO2. Road traffic is one of the main sources of particulate matter. Traffic volume has unpleasant impact on longevity of the pavements and also on the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The paper deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The paper offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

Microstructure, Wear Behavior and Corrosion Resistance of WC-FeCrAl and WC-WB-Co Coatings

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Janette Brezinová

2018-05-01

Full Text Available The paper is focused on investigating the quality of two grades of thermally sprayed coatings deposited by high-velocity oxygen fuel (HVOF technology. One grade contains WC hard particles in an environmentally progressive Ni- and Co-free FeCrAl matrix, while the second coating contains WC and WB hard particles in a cobalt matrix. The aim of the experimental work was to determine the effect of thermal cyclic loading on the coatings’ resistance to adhesive, abrasive and erosive wear. Abrasive wear was evaluated using abrasive cloth of two grit sizes, and erosive wear was evaluated by a dry-pot wear test in a pin mill at two sample angles. Adhesion wear resistance of the coatings was determined by a sliding wear test under dry friction conditions and in a 1 mol water solution of NaCl. Corrosion resistance of the coatings was evaluated using potentiodynamic polarization tests. Metallographic cross-sections were used for measurement of the microhardness and thickness and for line energy-dispersive X-ray (EDX analysis. The tests proved the excellent resistance of both coatings against adhesive, abrasive, and erosive wear, as well as the ability of the WC-WB-Co coating to withstand alternating temperatures of up to 600 °C. The “green carbide” coating (WC-FeCrAl can be recommended as an environmentally friendly replacement for Ni- and Co-containing coatings, but its operating temperature is strictly limited to 500 °C in air.

3D FEM Simulation of Flank Wear in Turning

Science.gov (United States)

Attanasio, Aldo; Ceretti, Elisabetta; Giardini, Claudio

2011-05-01

This work deals with tool wear simulation. Studying the influence of tool wear on tool life, tool substitution policy and influence on final part quality, surface integrity, cutting forces and power consumption it is important to reduce the global process costs. Adhesion, abrasion, erosion, diffusion, corrosion and fracture are some of the phenomena responsible of the tool wear depending on the selected cutting parameters: cutting velocity, feed rate, depth of cut, …. In some cases these wear mechanisms are described by analytical models as a function of process variables (temperature, pressure and sliding velocity along the cutting surface). These analytical models are suitable to be implemented in FEM codes and they can be utilized to simulate the tool wear. In the present paper a commercial 3D FEM software has been customized to simulate the tool wear during turning operations when cutting AISI 1045 carbon steel with uncoated tungsten carbide tip. The FEM software was improved by means of a suitable subroutine able to modify the tool geometry on the basis of the estimated tool wear as the simulation goes on. Since for the considered couple of tool-workpiece material the main phenomena generating wear are the abrasive and the diffusive ones, the tool wear model implemented into the subroutine was obtained as combination between the Usui's and the Takeyama and Murata's models. A comparison between experimental and simulated flank tool wear curves is reported demonstrating that it is possible to simulate the tool wear development.

Effect of distribution of striated laser hardening tracks on dry sliding wear resistance of biomimetic surface

Science.gov (United States)

Su, Wei; Zhou, Ti; Zhang, Peng; Zhou, Hong; Li, Hui

2018-01-01

Some biological surfaces were proved to have excellent anti-wear performance. Being inspired, Nd:YAG pulsed laser was used to create striated biomimetic laser hardening tracks on medium carbon steel samples. Dry sliding wear tests biomimetic samples were performed to investigate specific influence of distribution of laser hardening tracks on sliding wear resistance of biomimetic samples. After comparing wear weight loss of biomimetic samples, quenched sample and untreated sample, it can be suggested that the sample covered with dense laser tracks (3.5 mm spacing) has lower wear weight loss than the one covered with sparse laser tracks (4.5 mm spacing); samples distributed with only dense laser tracks or sparse laser tracks (even distribution) were proved to have better wear resistance than samples distributed with both dense and sparse tracks (uneven distribution). Wear mechanisms indicate that laser track and exposed substrate of biomimetic sample can be regarded as hard zone and soft zone respectively. Inconsecutive striated hard regions, on the one hand, can disperse load into small branches, on the other hand, will hinder sliding abrasives during wear. Soft regions with small range are beneficial in consuming mechanical energy and storing lubricative oxides, however, soft zone with large width (>0.5 mm) will be harmful to abrasion resistance of biomimetic sample because damages and material loss are more obvious on surface of soft phase. As for the reason why samples with even distributed bionic laser tracks have better wear resistance, it can be explained by the fact that even distributed laser hardening tracks can inhibit severe worn of local regions, thus sliding process can be more stable and wear extent can be alleviated as well.

Comparação dos valores de desgaste abrasivo e de microdureza de 13 resinas compostas usadas em odontologia através do método do disco retificado Comparing abrasive wear and microhardness of 13 dental composite resins

Directory of Open Access Journals (Sweden)

Eduardo C. Bianchi

2007-06-01

Full Text Available Atualmente tem-se buscado simplificar a tarefa de caracterização da vida útil de restaurações dentárias realizadas por resinas compostas através de métodos laboratoriais, que são mais rápidos e não sofrem influência de variáveis pessoais inerentes às análises clínicas. Com este propósito, este trabalho apresenta uma nova metodologia de ensaio laboratorial para a avaliação do desgaste abrasivo de resinas compostas através do método do disco retificado. Realizaram-se ensaios de resistência ao desgaste abrasivo com 13 resinas compostas odontológicas e buscou-se analisar o comportamento da resistência ao desgaste abrasivo em relação à microdureza dessas resinas. Com a análise dos resultados concluiu-se que o método de discos retificados é eficiente para a obtenção da resistência ao desgaste abrasivo. Notou-se também ser extremamente pequeno o nível de correlação entre microdureza e desgaste abrasivo o que indica que cada resina composta tem características próprias e que o desgaste é dependente também de outros fatores.It is now commonplace to search for methods to assess the useful lifetime of dental restorations made of resins, which are quicker and less subjective than clinical analyses. With this purpose, this work presents a new methodology based on the grinding disk for evaluating the abrasive wear of composed resins. Resistance tests to the abrasive wear were made with 13 composed resins used as dental material, and a comparison was done with the hardness of those resins. From the data analysis, we concluded that the method of rectified disks is efficient for obtaining the resistance to the abrasive wear. Furthermore, the correlation between hardness and abrasive wear was very small, which indicates that each composed resin has its own characteristics and that the wear also depends on other factors.

Abrasion Testing of Products Containing Nanomaterials, SOP-R-2: Scientific Operating Procedure Series: Release (R)

Science.gov (United States)

2016-04-01

Nanotechnologies -- Terminology and definitions for nano-objects -- Nanoparticle, nanofibre and nanoplate Definitions Abrasion - wearing away...ER D C SR -1 6- 2 Environmental Consequences of Nanotechnologies Abrasion Testing of Products Containing Nanomaterials, SOP-R-2...ERDC online library at http://acwc.sdp.sirsi.net/client/default. Environmental Consequences of Nanotechnologies ERDC SR-16-2 April 2016

Corrosive wear. Evaluation of wear and corrosive resistant materials; Noetningskorrosion. Utvaerdering av noetnings- och korrosionsbestaendiga material

Energy Technology Data Exchange (ETDEWEB)

Persson, H.; Hjertsen, D.; Waara, P.; Prakash, B.; Hardell, J.

2007-12-15

With a new purchase of a waste conveyer screw at hand, for the 'A-warehouse' at the combined power and heating plant at E.ON Norrkoeping, the request for improved construction materials was raised. The previous screw required maintenance with very short intervals due to the difficult operation conditions. With the new screw the expectation is to manage 6 months of operation without interruption. The environment for the screw has two main components that sets the demand on the materials, on one hand the corrosive products that comes along and which forms at digestion of the waste and on the other hand the abrasive content in the waste. The term of the mechanism is wear-corrosion and can give considerably higher material loss than the two mechanisms wear and corrosion separately. Combination of a strong corrosive environment together with extensive wear is something that we today have limited knowledge about. The overall objective of the project has been to establish better wear and corrosive resistant construction materials for a waste conveyer screw that will lead to reduced operational disturbance costs. The evaluation has been performed in both controlled laboratory environments and in field tests, which has given us a better understanding of what materials are more suitable in this tough environment and has given us a tool for future predictions of the wear rate of the different material. The new conveyer screw, installed in February 2007 and with which the field test have been performed, has considerably reduced the wear of the construction and the target of 6 month maintenance-free operation is met with this screw for all the evaluated materials. The wear along the screw varies very much and with a clear trend for all the materials to increase towards the feeding direction of the screw. As an example, the wear plate SS2377 (stainless duplex steel) has a useful life at the most affected areas that is calculated to be 1077 days of operation with the

Abrasion Resistance of as-Cast High-Chromium Cast Iron

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Pokusová Marcela

2014-12-01

Full Text Available High chromium cast irons are widely used as abrasion resistant materials. Their properties and wear resistance depend on carbides and on the nature of the matrix supporting these carbides. The paper presents test results of irons which contain (in wt.% 18-22 Cr and 2-5 C, and is alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve the toughness. Tests showed as-cast irons with mostly austenitic matrix achieved hardness 36-53 HRC but their relative abrasion-resistance was higher than the tool steel STN 19436 heat treated on hardness 60 HRC.

Mechanism-Based FE Simulation of Tool Wear in Diamond Drilling of SiCp/Al Composites.

Science.gov (United States)

Xiang, Junfeng; Pang, Siqin; Xie, Lijing; Gao, Feinong; Hu, Xin; Yi, Jie; Hu, Fang

2018-02-07

The aim of this work is to analyze the micro mechanisms underlying the wear of macroscale tools during diamond machining of SiC p /Al6063 composites and to develop the mechanism-based diamond wear model in relation to the dominant wear behaviors. During drilling, high volume fraction SiC p /Al6063 composites containing Cu, the dominant wear mechanisms of diamond tool involve thermodynamically activated physicochemical wear due to diamond-graphite transformation catalyzed by Cu in air atmosphere and mechanically driven abrasive wear due to high-frequency scrape of hard SiC reinforcement on tool surface. An analytical diamond wear model, coupling Usui abrasive wear model and Arrhenius extended graphitization wear model was proposed and implemented through a user-defined subroutine for tool wear estimates. Tool wear estimate in diamond drilling of SiC p /Al6063 composites was achieved by incorporating the combined abrasive-chemical tool wear subroutine into the coupled thermomechanical FE model of 3D drilling. The developed drilling FE model for reproducing diamond tool wear was validated for feasibility and reliability by comparing numerically simulated tool wear morphology and experimentally observed results after drilling a hole using brazed polycrystalline diamond (PCD) and chemical vapor deposition (CVD) diamond coated tools. A fairly good agreement of experimental and simulated results in cutting forces, chip and tool wear morphologies demonstrates that the developed 3D drilling FE model, combined with a subroutine for diamond tool wear estimate can provide a more accurate analysis not only in cutting forces and chip shape but also in tool wear behavior during drilling SiC p /Al6063 composites. Once validated and calibrated, the developed diamond tool wear model in conjunction with other machining FE models can be easily extended to the investigation of tool wear evolution with various diamond tool geometries and other machining processes in cutting different

Fretting Wear Behaviors of Aluminum Cable Steel Reinforced (ACSR Conductors in High-Voltage Transmission Line

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Xingchi Ma

2017-09-01

Full Text Available This work reports the fretting wear behavior of aluminum cable steel reinforced (ACSR conductors for use in high-voltage transmission line. Fretting wear tests of Al wires were conducted on a servo-controlled fatigue testing machine with self-made assistant apparatus, and their fretting process characteristics, friction force, wear damage, and wear surface morphology were detailed analyzed. The results show that the running regime of Al wires changes from a gross slip regime to a mixed regime more quickly as increasing contact load. With increasing amplitudes, gross slip regimes are more dominant under contact loads of lower than 30 N. The maximum friction force is relatively smaller in the NaCl solution than in a dry friction environment. The primary wear mechanisms in dry friction environments are abrasive wear and adhesive wear whereas abrasive wear and fatigue damage are dominant in NaCl solution.

Computer system for identification of tool wear model in hot forging

Directory of Open Access Journals (Sweden)

Wilkus Marek

2016-01-01

Full Text Available The aim of the research was to create a methodology that will enable effective and reliable prediction of the tool wear. The idea of the hybrid model, which accounts for various mechanisms of tool material deterioration, is proposed in the paper. The mechanisms, which were considered, include abrasive wear, adhesive wear, thermal fatigue, mechanical fatigue, oxidation and plastic deformation. Individual models of various complexity were used for separate phenomena and strategy of combination of these models in one hybrid system was developed to account for the synergy of various mechanisms. The complex hybrid model was built on the basis of these individual models for various wear mechanisms. The individual models expanded from phenomenological ones for abrasive wear to multi-scale methods for modelling micro cracks initiation and propagation utilizing virtual representations of granular microstructures. The latter have been intensively developed recently and they form potentially a powerful tool that allows modelling of thermal and mechanical fatigue, accounting explicitly for the tool material microstructure.

Performance Evaluation of Abrasive Grinding Wheel Formulated ...

African Journals Online (AJOL)

This paper presents a study on the formulation and manufacture of abrasive grinding wheel using locally formulated silicon carbide abrasive grains. Six local raw material substitutes were identified through pilot study and with the initial mix of the identified materials, a systematic search for an optimal formulation of silicon ...

Effect of Fe content on the friction and abrasion properties of copper base overlay on steel substrate by TIG welding

Institute of Scientific and Technical Information of China (English)

Lü Shixiong; Song Jianling; Liu Lei; Yang Shiqin

2009-01-01

Copper base alloy was overlaid onto 35CrMnSiA steel plate by tungsten inert gas (TIG) welding method. The heat transfer process was simulated, the microstructures of the copper base overlay were analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the friction and abrasion properties of the overlay were measured. The results show that the Fe content increases in the overlay with increasing the welding current. And with the increase of Fe content in the overlay, the friction coefficient increases and the wear mechanism changes from oxidation wear to abrasive wear and plough wear, which is related to the size and quantity of Fe grains in the overlay. While with the increase of Fe content in the overlay, the protection of oxidation layer against the oxidation wear on the melted metal decreases.

Erosive Wear of Inconel 625 Alloy Coatings Deposited by CMT Method

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Solecka M.

2016-06-01

Full Text Available The article presents the investigation results concerning the determination of the characteristics of erosive wear caused by the impact of Al2O3 solid particles on the surface of Inconel 625 alloy after plastic working and the same material after weld cladding process using the CMT method. Erosion wear tests were performed at two temperatures: 20°C and 650°C. The erosion tests were conducted using the standard ASTM G76. A jet with a specified abrasive waight was directed to the surface of the tested material at an α impingement angle varied in the range of 30-90° at a velocity imparted to the abrasive by the medium, which was compressed air. The eroded surface was examined using a scanning electron microscope (SEM, while the depths of craters caused by the erosion tests were measured with an optical profilometer. The predominant mechanisms of the formation of mass losses during solid particle erosion were microcutting and microfissuring.

Effect of pressing temperature on the wear resistance of a Co-based Cr-Mo powder alloy produced by hot pressing

Energy Technology Data Exchange (ETDEWEB)

Somunkiran, Ilyas [Firat Univ., Elazig (Turkey). Metallurgical and Materials Engineering Dept.; Balin, Ahmet [Siirt Univ. (Turkey). Dept. of Vocational High School

2016-02-01

In this study, Co-based Cr-Mo powder alloy was produced at different pressing temperatures by using hot pressing technique and abrasive wear behaviors of the produced specimens were examined. Produced specimens were exposed to abrasive wear experiment using block on disc wear test device by applying a load of 50 N with 100-mesh SiC abrasive paper. Each specimen was investigated at 25, 50, 75 and 100 m. At the end of the experiment, abrasive wear results of the specimens were determined by calculating their mass losses. Microstructural properties of the specimens which were produced at different pressing temperatures were investigated by optical and SEM examinations and their wear resistances were examined by abrasive wear experiments. Consequently, it was observed that in Co-based Cr-Mo powder alloy produced by hot pressing technique; as sintering temperature increased, size of neck formations between the powder grains increased, porosity decreased and abrasive wear resistance increased. [German] In diesem Beitrag zugrunde liegenden Studie wurde eine Co-basierte Cr-Mo-Legierung mittels Heisspressens hergestellt und der Abrasivverschleisswiderstand dieser Proben untersucht. Die hergestellten Proben wurden dem Abrasivverschleissversuch durch einen Block-Scheibe-Versuchsaufbau unterzogen, wobei eine Kraft von 50 N mit einem SiC-Papier (100 mesh) verwendet wurde. Jede Probe wurde ueber eine Distanz von 25, 50, 75 und 100 m untersucht. Am Ende der jeweiligen Experimente wurden die Abrasivverschleissergebnisse ermittelt, indem die Massenverluste berechnet wurden. Die mikrostrukturellen Eigenschaften der Proben, die bei verschiedenen Presstemperaturen hergestellt wurden, wurden mittels optischer und Rasterelektronenmikroskopie bestimmt und ihr Verschleisswiderstand anhand der Verschleissversuche ermittelt. Schliesslich wurde beobachtet, dass bei steigender Sintertemperatur der heissgespressten Co-basierten Cr-Mo-Pulverlegierung die Groesse der Einschnuerungen zwischen den

Wear performance of laser processed tantalum coatings

Energy Technology Data Exchange (ETDEWEB)

Dittrick, Stanley; Balla, Vamsi Krishna; Bose, Susmita; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

2011-12-01

This first generation investigation evaluates the in vitro tribological performance of laser-processed Ta coatings on Ti for load-bearing implant applications. Linear reciprocating wear tests in simulated body fluid showed one order of magnitude less wear rate, of the order of 10{sup -4} mm{sup 3}(N.m){sup -1}, for Ta coatings compared to Ti. Our results demonstrate that Ta coatings can potentially minimize the early-stage bone-implant interface micro-motion induced wear debris generation due to their excellent bioactivity comparable to that of hydroxyapatite (HA), high wear resistance and toughness compared to popular HA coatings. Highlights: {yields} In vitro wear performance of laser processed Ta coatings on Ti was evaluated. {yields} Wear tests in SBF showed one order of magnitude less wear for Ta coatings than Ti. {yields} Ta coatings can minimize early-stage micro-motion induced wear debris generation.

Performance evaluation of PCBN, coated carbide and mixed ceramic inserts in finish-turning of AISI D2 steel

Directory of Open Access Journals (Sweden)

M. Junaid Mir

2017-09-01

Full Text Available The present study compares the performance of three different cutting tools, viz., PCBN, mixed ceramic and coated carbide tool in finish turning of hardened D2 tool steel in terms of tool wear, surface roughness, and economic feasibility under dry cutting conditions. Results showed that tool life of PCBN inserts was better than mixed ceramic and coated carbide inserts. The flank wear of PCBN tools was observed to be lower than mixed ceramic and coated carbide inserts. The surface roughness achieved under all cutting conditions for mixed ceramic and coated-carbide inserts was comparable with that achieved with PCBN inserts and was below 1.6μm. Experimental results showed that the wear mechanism of ceramic tool is pre-dominantly abrasive wear at lower speeds and abrasive wear followed by adhesive wear at medium and higher speeds and for PCBN tools the dominant wear mechanism is abrasive wear and cratering at lower speeds followed by adhesive wear at higher speeds. For carbide tool the dominant wear mechanism was abrasive wear and cratering at lower speeds followed by adhesion and chipping at higher speeds. Obtained results revealed that PCBN tools can outperform both ceramic and carbide tools in terms of tool life under different machinability criteria used.

Plasma immersion ion implantation on 15-5PH stainless steel: influence on fatigue strength and wear resistance

Science.gov (United States)

Bonora, R.; Cioffi, M. O. H.; Voorwald, H. J. C.

2017-05-01

Surface improvement in steels is of great interest for applications in industry. The aim of this investigation is to study the effect of nitrogen ion implantation on the axial fatigue strength and wear resistance of 15-5 PH stainless steel. It is well know that electroplated coatings, which are used to improve abrasive wear and corrosion properties, affects negatively the fatigue strength. It is also important to consider requirements to reduce the use of coated materials with electroplated chromium and cadmium, that produce waste, which is harmful to health and environment. The HVOF (High velocity oxygen fuel) process provides hardness, wear strength and higher fatigue resistance in comparison to electroplated chromium. Plasma immersion ion implantation has been used to enhance the hardness, wear, fatigue and corrosion properties of metals and alloys. In the present research the fatigue life increased twice for 15-5 PH three hours PIII treated in comparison to base material. From the abrasive wear tests a lower pin mass reduction was observed, associated to the superficial treatments. The improvement of fatigue and mechanical performance is attributed to a combination of nitrides phase structure and compressive residual stresses during the PIII treatment.

Plasma immersion ion implantation on 15-5PH stainless steel: influence on fatigue strength and wear resistance

International Nuclear Information System (INIS)

Bonora, R; Cioffi, M O H; Voorwald, H J C

2017-01-01

Surface improvement in steels is of great interest for applications in industry. The aim of this investigation is to study the effect of nitrogen ion implantation on the axial fatigue strength and wear resistance of 15-5 PH stainless steel. It is well know that electroplated coatings, which are used to improve abrasive wear and corrosion properties, affects negatively the fatigue strength. It is also important to consider requirements to reduce the use of coated materials with electroplated chromium and cadmium, that produce waste, which is harmful to health and environment. The HVOF (High velocity oxygen fuel) process provides hardness, wear strength and higher fatigue resistance in comparison to electroplated chromium. Plasma immersion ion implantation has been used to enhance the hardness, wear, fatigue and corrosion properties of metals and alloys. In the present research the fatigue life increased twice for 15-5 PH three hours PIII treated in comparison to base material. From the abrasive wear tests a lower pin mass reduction was observed, associated to the superficial treatments. The improvement of fatigue and mechanical performance is attributed to a combination of nitrides phase structure and compressive residual stresses during the PIII treatment. (paper)

How wear affects road surface texture and its impact on tire/road noise

OpenAIRE

Siebert, Doreen

2017-01-01

Mechanical pavement wear in the Nordic countries is essentially influenced by the use of studded tires during long winter seasons. The abrasive effect of the studded tires is the cause of significant damage on the pavement and a contributor to rutting. In addition, the mechanical aggregate removal due to the studded tires is the reason for significant changes in the road surface texture. At traditional dense asphalt pavements, the mechanical wear is initiated by the abrasion of the mortar, wh...

Optical tools for high-throughput screening of abrasion resistance of combinatorial libraries of organic coatings

Science.gov (United States)

Potyrailo, Radislav A.; Chisholm, Bret J.; Olson, Daniel R.; Brennan, Michael J.; Molaison, Chris A.

2002-02-01

Design, validation, and implementation of an optical spectroscopic system for high-throughput analysis of combinatorially developed protective organic coatings are reported. Our approach replaces labor-intensive coating evaluation steps with an automated system that rapidly analyzes 8x6 arrays of coating elements that are deposited on a plastic substrate. Each coating element of the library is 10 mm in diameter and 2 to 5 micrometers thick. Performance of coatings is evaluated with respect to their resistance to wear abrasion because this parameter is one of the primary considerations in end-use applications. Upon testing, the organic coatings undergo changes that are impossible to quantitatively predict using existing knowledge. Coatings are abraded using industry-accepted abrasion test methods at single-or multiple-abrasion conditions, followed by high- throughput analysis of abrasion-induced light scatter. The developed automated system is optimized for the analysis of diffusively scattered light that corresponds to 0 to 30% haze. System precision of 0.1 to 2.5% relative standard deviation provides capability for the reliable ranking of coatings performance. While the system was implemented for high-throughput screening of combinatorially developed organic protective coatings for automotive applications, it can be applied to a variety of other applications where materials ranking can be achieved using optical spectroscopic tools.

Comparative analyses of tooth wear in free-ranging and captive wild equids.

Science.gov (United States)

Taylor, L A; Müller, D W H; Schwitzer, C; Kaiser, T M; Castell, J C; Clauss, M; Schulz-Kornas, E

2016-03-01

Captive breeding has played a crucial role in the conservation of threatened equid species. Grazing ruminants and rhinoceros in captivity have less abrasion-dominated tooth wear than their free-ranging conspecifics, with potential negative consequences for their health. However, a similar study on wild equids in captivity is missing. The aim was to establish if different tooth wear patterns are exhibited by free-ranging and captive equids. Cross-sectional study of museum specimens comparing free-ranging and captive equids. Dental casts of maxillary cheek teeth of 228 museum specimens (122 from free-ranging and 106 from captive individuals) of 7 wild equid species were analysed using the extended mesowear method. Although teeth showing specific abnormalities were not scored, the presence of focal overgrowths (hooks) of the rostral premolars (106, 206) was recorded. Captive Equus ferus przewalskii, E. grevyi, E. hemionus, E. quagga boehmi and E. zebra hartmannae have less abrasion-dominated tooth wear on their premolars than their free-ranging conspecifics (P<0.001). Fewer differences were exhibited between populations in the molars. No differences were exhibited in the distal cusp of the molars (110, 210) between populations, except in a small sample of E. kiang. Captive equids exhibited more homogeneous wear along the tooth row whereas free-ranging equids exhibited a tooth wear gradient, with more abrasion on premolars than molars. There were more rostral hooks on the premolars (106, 206) in the captive than the free-ranging population (P = 0.02). Captive equids did experience less abrasion-dominated tooth wear than their free-ranging conspecifics, but the differences in tooth wear were less pronounced than those between captive and free-ranging wild ruminant and rhinoceros species. This indicates that feeding regimes for captive equids deviate less from natural diets than those for captive ruminants and rhinoceros but that factors leading to hook

Wear behavior of Al-7%Si-0.3%Mg/melon shell ash particulate composites.

Science.gov (United States)

Abdulwahab, M; Dodo, R M; Suleiman, I Y; Gebi, A I; Umar, I

2017-08-01

The present study examined wear characteristics of A356/melon shell ash particulate composites. Dry-sliding the stainless steel ball against specimen disc revealed the abrasive wear behavior of the composites under loads of 2 and 5N. The composite showed lower wear rate of 2.182 × 10 -4 mm 3 /Nm at 20 wt% reinforced material under load of 5N. Results showed that wear rate decreased significantly with increasing weight percentage of melon shell ash particles. Microstructural analyses of worn surfaces of the composites reveal evidence of plastic deformation of matrix phase. The wear resistance of A356 increased considerably with percentage reinforcement. In other words, the abrasive mass loss decreased with increasing percentage of reinforcement addition at the both applied loads. The control sample suffered a highest mass loss at 5 N applied load.

Justification of parameters artificial soil for laboratory research of cutting edge wear

Directory of Open Access Journals (Sweden)

I. V. Liskin

2017-01-01

Full Text Available For soil cultivation with the cutting tools of agricultural machines we can allocate three main types of shavings: shift, separation and continuous chip. The shift is most accurately expressed on sandy soils, a separation - on clay and loamy, continuous chip - on humid soils with the high content of clay particles. In field conditions researches of regularities of cutting edges wear are complicated because of heterogeneity of physic and mechanical properties of the soil and the changing climatic conditions. At laboratory modeling of soil conditions we can make experiments independent of weather and season. For development of the artificial soil and depend modeling of edges wear we considered conditions of creation of model with use mechanics of abrasive wear. Have allocated The major factors defining character and intensity of wear were allocated. The wearing-out ability of abrasive particles is defined by the radius of the curve of their sharp ledges. This radius depends on the particle size. The hardness of the soil influences wear of the cutting details and characterizes penetration into it of the cutting elements, and degree of fixedness of abrasive particles defines shaving type. We conseeder the soil as the abrasive environment with the particles which are in a condition of non-rigid fixing and have an opportunity to move relatively each other or to turn on itself under the influence of normal and tangential stress. Type of shaving when soil layer destruction depends on a ratio of the normal and tangential stress characterizing degree of fixedness of firm particles. We conducted researches of physic and mechanical properties of the artificial soil on the basis of quartz sand and paraffin. Injection of the petrolatum into structure of the artificial soil reduces the hardness and degree of fixedness of firm particles, but the ceresin increases these indicators. The mechanical structure was changed due to introduction of dust-like cement and

Wear Behavior and Microstructure of Mg-Sn Alloy Processed by Equal Channel Angular Extrusion.

Science.gov (United States)

Chen, Jung-Hsuan; Shen, Yen-Chen; Chao, Chuen-Guang; Liu, Tzeng-Feng

2017-11-16

Mg-5wt.% Sn alloy is often used in portable electronic devices and automobiles. In this study, mechanical properties of Mg-5wt.% Sn alloy processed by Equal Channel Angular Extrusion (ECAE) were characterized. More precisely, its hardness and wear behavior were measured using Vickers hardness test and a pin-on-disc wear test. The microstructures of ECAE-processed Mg-Sn alloys were investigated by scanning electron microscope and X-ray diffraction. ECAE process refined the grain sizes of the Mg-Sn alloy from 117.6 μm (as-cast) to 88.0 μm (one pass), 49.5 μm (two passes) and 24.4 μm (four passes), respectively. Meanwhile, the hardness of the alloy improved significantly. The maximum wear resistance achieved in the present work was around 73.77 m/mm³, which was obtained from the Mg-Sn alloy treated with a one-pass ECAE process with a grain size of 88.0 μm. The wear resistance improvement was caused by the grain size refinement and the precipitate of the second phase, Mg₂Sn against the oxidation of the processed alloy. The as-cast Mg-Sn alloy with the larger grain size, i.e., 117.6 μm, underwent wear mechanisms, mainly adhesive wear and abrasive wear. In ECAE-processed Mg-Sn alloy, high internal energy occurred due to the high dislocation density and the stress field produced by the plastic deformation, which led to an increased oxidation rate of the processed alloy during sliding. Therefore, the oxidative wear and a three-body abrasive wear in which the oxide debris acted as the three-body abrasive components became the dominant factors in the wear behavior, and as a result, reduced the wear resistance in the multi-pass ECAE-processed alloy.

Dentifrice fluoride and abrasivity interplay on artificial caries lesions.

Science.gov (United States)

Nassar, Hani M; Lippert, Frank; Eckert, George J; Hara, Anderson T

2014-01-01

Incipient caries lesions on smooth surfaces may be subjected to toothbrushing, potentially leading to remineralization and/or abrasive wear. The interplay of dentifrice abrasivity and fluoride on this process is largely unknown and was investigated on three artificially created lesions with different mineral content/distribution. 120 bovine enamel specimens were randomly allocated to 12 groups (n = 10), resulting from the association of (1) lesion type [methylcellulose acid gel (MeC); carboxymethylcellulose solution (CMC); hydroxyethylcellulose gel (HEC)], (2) slurry abrasive level [low (REA 4/ RDA 69); high (REA 7/RDA 208)], and (3) fluoride concentration [0/275 ppm (14.5 mM) F as NaF]. After lesion creation, specimens were brushed in an automated brushing machine with the test slurries (50 strokes 2×/day). Specimens were kept in artificial saliva in between brushings and overnight. Enamel surface loss (SL) was determined by optical profilometry after lesion creation, 1, 3 and 5 days. Two enamel sections (from baseline and post-brushing areas) were obtained and analyzed microradiographically. Data were analyzed by analysis of variance and Tukey's tests (α = 5%). Brushing with high-abrasive slurry caused more SL than brushing with low-abrasive slurry. For MeC and CMC lesions, fluoride had a protective effect on SL from day 3 on. Furthermore, for MeC and CMC, there was a significant mineral gain in the remaining lesions except when brushed with high-abrasive slurries and 0 ppm F. For HEC, a significant mineral gain took place when low-abrasive slurry was used with fluoride. The tested lesions responded differently to the toothbrushing procedures. Both slurry fluoride content and abrasivity directly impacted SL and mineral gain of enamel caries lesions.

Tooth wear

OpenAIRE

Tušek Ivan; Tušek Jasmina

2014-01-01

Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction), which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to toot...

Abrasive wear based predictive maintenance for systems operating in sandy conditions

NARCIS (Netherlands)

Woldman, M.; Tinga, T.; Heide, E. van der; Masen, M.A.

2015-01-01

Machines operating in sandy environments are damaged by the abrasive action of sand particles that enter the machine and become entrapped between components and contacting surfaces. In the case of the military services the combination of a sandy environment and the wide range of tasks to be

Effect of Volume Fraction of Particle on Wear Resistance of Al2O3/Steel Composites at Elevated Temperature

Institute of Scientific and Technical Information of China (English)

BAO Chong-gao; WANG En-ze; GAO Yi-min; XING Jian-dong

2005-01-01

Based on previous work,abrasive wear resistance of Al2 O3/steel composites with different Al2 O3 parti cle volume fraction (VOF) at 900 C was investigated.The experimental results showed that a suitable particle VOF is important to protect the metal matrix from wear at elevated temperature.Both too high and too low particle VOF lead to a poor abrasive wear because a bulk matrix is easily worn off by grits when it exceeds the suitable VOF and also because when VOF is low,the Al2O3 particles are easily dug out by grits during wearing as well.When the particle VOF is 39%,the wear resistance of tested composites is excellent.

Wear characteristics of current aesthetic dental restorative CAD/CAM materials: two-body wear, gloss retention, roughness and Martens hardness.

Science.gov (United States)

Mörmann, Werner H; Stawarczyk, Bogna; Ender, Andreas; Sener, Beatrice; Attin, Thomas; Mehl, Albert

2013-04-01

This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance). Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well. All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD

Wear of semi-solid rheocast SiCp/Al metal matrix composites

CSIR Research Space (South Africa)

Curle, UA

2010-09-01

Full Text Available ). Hardness increases as the volume fractions of SiC increases. Wear rates of the MMCs in the F and T6 heat treatment conditions were assessed with a metallographic preparation machine. It is found that the 11% SiC MMC wear rate is higher on SiC abrasives...

Effect of dried sunflower seeds on incisal edge abrasion: A rare case report.

Science.gov (United States)

Rath, Avita; Ramamurthy, Priyadarshini H; Fernandes, Bennete Aloysius; Sidhu, Preena

2017-01-01

Tooth surface loss (TSL) is a complex phenomenon characterized by the loss of hard tooth structure at various locations of the teeth, usually due to more than one factor. TSL due to abrasion can be significant in patients consuming coarse, abrasive diet. The present case reports an interesting incisal edge abrasion in a female patient, attributed to a particular dietary behavior of long-term consumption of sunflower seeds. All her family members and most of the people from her native place were also reported to have similar lesions by the patient. Larger epidemiological studies to assess the prevalence and severity of such abrasive lesions in geographic areas with this particular dietary habit need to be carried out so that people may be made aware and educated about alternative ways of eating sunflower seeds that will not cause any form of tooth wear.

Baking soda as an abrasive in toothpastes: Mechanism of action and safety and effectiveness considerations.

Science.gov (United States)

Hara, Anderson T; Turssi, Cecilia P

2017-11-01

Toothpastes can be formulated with different abrasive systems, depending on their intended clinical application. This formulation potentially affects their effectiveness and safety and, therefore, requires proper understanding. In this article, the authors focused on abrasive aspects of toothpastes containing sodium bicarbonate (baking soda), which have gained considerable attention because of their low abrasivity and good compatibility, while providing clinical effectiveness (further detailed in the other articles of this special issue). The authors first appraised the role of toothpaste abrasivity on tooth wear, exploring some underlying processes and the existing methods to determine toothpaste abrasivity. The authors reviewed the available data on the abrasivity of toothpastes containing baking soda and reported a summary of findings highlighting the clinical implications. On the basis of the collected evidence, baking soda has an intrinsic low-abrasive nature because of its comparatively lower hardness in relation to enamel and dentin. Baking soda toothpastes also may contain other ingredients, which can increase their stain removal effectiveness and, consequently, abrasivity. Even those formulations have abrasivity well within the safety limit regulatory agencies have established and, therefore, can be considered safe. Copyright © 2017 American Dental Association. Published by Elsevier Inc. All rights reserved.

Structurally Integrated Coatings for Wear and Corrosion

Energy Technology Data Exchange (ETDEWEB)

Beardsley, M. Brad; Sebright, Jason L.

2008-11-18

Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

Comparison of sliding friction and wear behaviour of overhead conveyor steels tested under dry and lubrication conditions

International Nuclear Information System (INIS)

Castro-Regal, G.; Fernandez-Vicente, A.; Martinez, M. A.

2005-01-01

The sliding friction and wear behaviour of different steel qualities were investigated with and without lubrication conditions. Steel qualities tested are normally used in the overhead conveyor system of many industrial fields, like the automotive sector. Sliding wear tests have been conducted by means of a pin-on-disk machine. A 100Cr6 steel similar to that used within the overhead conveyor trolleys has been employed as a pin. Friction coefficient values obtained under lubrication conditions were three times smaller than those obtained without lubrication. The mechanism that controls wear behaviour under lubrication conditions is an abrasive one and the wear values obtained are almost worthless. On the other hand, mechanism controlling wear during non lubrication tests, was a combination of abrasion and adhesion. (Author) 20 refs

Wear Mechanism of Chemical Vapor Deposition (CVD) Carbide Insert in Orthogonal Cutting Ti-6Al-4V ELI at High Cutting Speed

International Nuclear Information System (INIS)

Gusri, A. I.; Che Hassan, C. H.; Jaharah, A. G.

2011-01-01

The performance of Chemical Vapor Deposition (CVD) carbide insert with ISO designation of CCMT 12 04 04 LF, when turning titanium alloys was investigated. There were four layers of coating materials for this insert i.e.TiN-Al2O3-TiCN-TiN. The insert performance was evaluated based on the insert's edge resistant towards the machining parameters used at high cutting speed range of machining Ti-6Al-4V ELI. Detailed study on the wear mechanism at the cutting edge of CVD carbide tools was carried out at cutting speed of 55-95 m/min, feed rate of 0.15-0.35 mm/rev and depth of cut of 0.10-0.20 mm. Wear mechanisms such as abrasive and adhesive were observed on the flank face. Crater wear due to diffusion was also observed on the rake race. The abrasive wear occurred more at nose radius and the fracture on tool were found at the feed rate of 0.35 mm/rev and the depth of cut of 0.20 mm. The adhesion wear takes place after the removal of the coating or coating delaminating. Therefore, adhesion or welding of titanium alloy onto the flank and rake faces demonstrates a strong bond at the workpiece-tool interface.

Wear resistance of cast iron

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-10-01

Full Text Available In this paper investigations of abrasive and adhesive wear resistance of different cast iron grades have been presented. Examinations showed, that the most advantageous pair of materials is the cast iron – the hardened steel with low-tempered martensite. It was found, that martensitic nodular cast iron with carbides is the most resistant material.

Effects of toothbrush hardness on in vitro wear and roughness of composite resins.

Science.gov (United States)

Kyoizumi, Hideaki; Yamada, Junji; Suzuki, Toshimitsu; Kanehira, Masafumi; Finger, Werner J; Sasaki, Keiichi

2013-11-01

To investigate and compare the effects of toothbrushes with different hardness on abrasion and surface roughness of composite resins. Toothbrushes (DENT. EX Slimhead II 33, Lion Dental Products Co. Ltd., Tokyo, Japan) marked as soft, medium and hard, were used to brush 10 beam-shaped specimens of each of three composites resins (Venus [VEN], Venus Diamond [VED] and Venus Pearl [VEP]; HeraeusKulzer) with standardized calcium carbonate slurry in a multistation testing machine (2N load, 60 Hz). After each of five cycles with 10k brushing strokes the wear depth and surface roughness of the specimens were determined. After completion of 50k strokes representative samples were inspected by SEM. Data were treated with ANOVA and regression analyses (p composite resins increased linearly with increasing number of brushing cycles (r² > 0.9). Highest wear was recorded for VEN, lowest for VED. Hard brushes produced significantly higher wear on VEN and VEP, whereas no difference in wear by toothbrush type was detected for VED. Significantly highest surface roughness was found on VED specimens (Ra > 1.5 µm), the lowest one on VEN (Ra composite resins produced by toothbrushing with dentifrice depend mainly on the type of restorative resin. Hardness grades of toothbrushes have minor effects only on abrasion and surface roughness of composite resins. No relationship was found between abrasion and surface roughness. The grade of the toothbrush used has minor effect on wear, texture and roughness of the composite resin.

Dental wear, wear rate, and dental disease in the African apes.

Science.gov (United States)

Elgart, Alison A

2010-06-01

The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

Preparation, characterization and wear behavior of carbon coated magnesium alloy with electroless plating nickel interlayer

International Nuclear Information System (INIS)

Mao, Yan; Li, Zhuguo; Feng, Kai; Guo, Xingwu; Zhou, Zhifeng; Dong, Jie; Wu, Yixiong

2015-01-01

Highlights: • The carbon film with nickel interlayer (Ni + C coating) is deposited on GW83. • In Ni + C composite coating the carbon coating has good adhesion with the nickel interlayer. • The wear track of Ni + C coating is narrower compared to the bare one. • The wear resistance of GW83 is greatly improved by the Ni + C coating. - Abstract: Poor wear resistance of rare earth magnesium alloys has prevented them from wider application. In this study, composite coating (PVD carbon coating deposited on electroless plating nickel interlayer) is prepared to protect GW83 magnesium alloys against wear. The Ni + C composite coating has a dense microstructure, improved adhesion strength and hardness due to the effective support of Ni interlayer. The wear test result shows that the Ni + C composite coating can greatly prolong the wear life of the magnesium alloy. The wear track of the Ni + C coated magnesium alloy is obviously narrower and shows less abrasive particles as compared with the bare one. Abrasive wear is the wear mechanism of the coatings at the room temperature. In conclusion, the wear resistance of the GW83 magnesium alloy can be greatly improved by the Ni + C composite coating

Combating wear in bulk solids handling plants

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

A total of five papers presented at a seminar on problems of wear caused by abrasive effects of materials in bulk handling. Topics of papers cover the designer viewpoint, practical experience from the steel, coal, cement and quarry industries to create an awareness of possible solutions.

Synthesis CNTs Particle Based Abrasive Media for Abrasive Flow Machining Process

International Nuclear Information System (INIS)

Kumar, Sonu; Walia, R.S; Dhull, S.; Murtaza, Q.; Tyagi, P. K.

2016-01-01

Abrasive flow machining (AFM) is a modem fine finishing process used for intricate and internal finishing of components or parts. It is based on flowing of viscoelastic abrasive media over the surface to be fine finished. The abrasive media is the important parameter in the AFM process because of its ability to accurately abrade the predefined area along it flow path. In this study, an attempt is made to develop a new abrasive, alumina with Carbon nanotubes (CNTs) in viscoelastic medium. CNT s in house produced through chemical vapour deposition technique and characterize through TEM. Performance evaluation of the new abrasive media is carried out by increasing content of CNT s with fixed extrusion pressure, viscosity of media and media flow rate as process parameters and surface finish improvement and material removal as process responses in AFM setup. Significantly improvement has been observed in material removal and maximum improvement of 100% has been observed in the surface finish on the inner cylindrical surface of the cast iron work piece. (paper)

Prepolishing on a CNC platform with bound abrasive contour tools

Science.gov (United States)

Schoeffler, Adrienne E.; Gregg, Leslie L.; Schoen, John M.; Fess, Edward M.; Hakiel, Michael; Jacobs, Stephen D.

2003-05-01

Deterministic microgrinding (DMG) of optical glasses and ceramics is the commercial manufacturing process of choice to shape glass surfaces prior to final finishing. This process employs rigid bound matrix diamond tooling resulting in surface roughness values of 3-5μm peak to valley and 100-400nm rms, as well as mid-spatial frequency tool marks that require subsequent removal in secondary finishing steps. The ability to pre-polish optical surfaces within the grinding platform would reduce final finishing process times. Bound abrasive contour wheels containing cerium oxide, alumina or zirconia abrasives were constructed with an epoxy matrix. The effects of abrasive type, composition, and erosion promoters were examined for tool hardness (Shore D), and tested with commercial optical glasses in an Optipro CNC grinding platform. Metrology protocols were developed to examine tool wear and subsequent surface roughness. Work is directed to demonstrating effective material removal, improved surface roughness and cutter mark removal.

On the abrasion of heat-treated 2.8C21Cr1Mo white cast iron

Energy Technology Data Exchange (ETDEWEB)

Al-Rubaie, Kassim S.; Preti, Orlando [Centro Universitario SOCIESC, Joinville (Brazil). Engenharia Mecanica; Pohl, Michael [Bochum Univ. (Germany). Inst. fuer Werkstoffe

2016-09-15

The abrasion behaviour of heat-treated 2.8C21Cr1Mo cast iron was studied. The specimens were destabilised at two temperatures, 980 and 1050 C, for 4 h, air hardened, and then tempered at five temperatures, 220, 320, 400, 500, and 620 C, for 2 h followed by air cooling. Using a pin-on-plate abrasion apparatus, the specimens were abraded on four types of bonded abrasives (silicon carbide, corundum, flint, and glass). The effect of work hardening on the abrasion resistance was investigated. It was found that the increase in alloy hardness produced by heat treatment had little effect on the abrasion resistance against silicon carbide or corundum; the inverse was true against flint or glass. The as-hardened structure containing 40% retained austenite gave the best abrasion resistance, whereas the hardened and tempered at 620 C showed the worst. Both bulk hardness and matrix hardness before wear correlated poorly with the abrasion resistance. Therefore, a general model ''equivalent hardness'' was developed, in which the hardness of the abraded matrix was considered. With this model, the abrasion behaviour can be clearly analysed.

Wear Resistance of Piston Sleeve Made of Layered Material Structure: MMC A356R, Anti-Abrasion Layer and FGM Interface

Directory of Open Access Journals (Sweden)

Hernik Szymon

2016-09-01

Full Text Available The aim of this paper is the numerical analysis of the one of main part of car engine – piston sleeve. The first example is for piston sleeve made of metal matrix composite (MMC A356R. The second improved material structure is layered. Both of them are comparison to the classical structure of piston sleeve made of Cr-Ni stainless steel. The layered material structure contains the anti-abrasion layer at the inner surface of piston sleeve, where the contact and friction is highest, FGM (functionally graded material interface and the layer of virgin material on the outer surface made of A356R. The complex thermo-elastic model with Archard's condition as a wear law is proposed. The piston sleeve is modelling as a thin walled cylindrical axisymmetric shell. The coupled between the formulation of thermo-elasticity of cylindrical axisymmetric shell and the Archard’s law with functionally changes of local hardness is proposed.

THE COURSE IN TESTING THE WEARING OUT OF MUD PUMPS PARTS

Directory of Open Access Journals (Sweden)

Davorin Matanović

1989-12-01

Full Text Available Piston and cylinder are such parts in the mud pumps which cause the greatest expences due to the work stoppage of drilling rig. To reduce so caused expences it is necessary to produce spare parts of better quality. In determining the abrasion wear resistance for chosen materials, so called dry sand/rubber wheel abrasion test as an ASTM standard has been used (the paper is published in Croatian.

Friction and wear of stainless steel, titanium and aluminium with various surface treatments, ion implantation and overlay hard coatings

International Nuclear Information System (INIS)

Bunshah, R.F.

1979-01-01

This paper deals with the evaluation of the wear properties of 304 stainless steel, commercial grade titanium and commercial grade aluminium without and with different surface treatments, i.e., ion implantation of boron and nitrogen, and overlay coating of superhard materials, titanium carbide and nitride by the Biased Activated Reactive Evaporation (BARE) process. Wear properties were evaluated in adhesive, erosive and abrasive modes of wear. In the case of adhesive wear, ion implantation resulted in an improved wear behaviour in lubricated conditions but had no beneficial effect in dry wear conditions. Overlay coatings on the other hand resulted in improved wear behaviour for both the dry and lubricating conditions. In the case of erosive wear with SiC particles at high velocities, overlay coatings showed higher erosion rates (typical of brittle materials in normal impingement) whereas ion implanted materials behaved similarly as untreated materials; i.e., a lower wear rate than the specimens with overlay coatings. In the case of abrasive wear, it was again observed that the wear rates of overlay coatings is far lower than the wear rates of untreated or ion implanted materials. (author)

Wear Assessment of Fe-TiC/ZrC Hardfacing Produced from Oxides

Directory of Open Access Journals (Sweden)

S. Corujeira-Gallo

2015-03-01

Full Text Available The direct conversion of oxides into carbides during plasma transferred arc welding is a promising processing route to produce wear resistant overlays at low cost. In the present study, Fe-TiC and Fe-ZrC composite overlays were produced by carbothermic reduction of TiO2 and ZrO2 during plasma transferred arc deposition. The overlays were characterised by optical microscopy, electron microscopy and X-ray diffraction. The microstructure consisted of small TiC and ZrC evenly dispersed in a pearlitic matrix. The Vickers microhardness was measured and low-stress abrasion tests were conducted. The results showed increased hardness and promising wear resistance under low-stress abrasion conditions.

WEAR OF THE FRICTION SURFACES PARTS IN THE PRESENSE OF SOLID PARTICLES CONTACTING ZONE

Directory of Open Access Journals (Sweden)

B. M. Musaibov

2015-01-01

Full Text Available The problems of intensity of wear of details of the cars working in the oil polluted by abrasive particles, depending on mechanical properties of material of details and abrasive particles, their sizes, a form and concentration, loading, temperature of a surface of friction, speed of sliding, quality of lubricant are considered. 

Recent developments in the use of plastic optical fiber for an embedded wear sensor

Science.gov (United States)

Cohen, Edward I.; Mastro, Stephen A.; Nemarich, Christopher P.; Korczynski, Joseph F., Jr.; Jarrett, Andrew W.; Jones, Wayne C.

1999-05-01

This paper describes recent developments of a practical, low cost embedded plastic optical fiber (POF) wear sensor system for the condition based maintenance of external outboard water lubricated bearings aboard U.S. Navy Ships. The benefit of this measurement system over the status quo is the ability to remotely monitor bearing wear. The Embedded Wear Sensor system (Navy invention disclosure #78,570) features a sacrificial wear fiber embedded into the nitrile rubber bearing. This fiber may also act as a conduit for the transmission of pressure and temperature data that may be resolved into alignment data. The authors selected a commercially-off-the- shelf plastic fiber for the sensor because of its material compatibility with the nitrile rubber bearing staves in terms of flexural modulus and wear properties. Presented herein is a description of the system concept, the results of non-linear finite element analysis, market survey of POF, mold studies, small scale prototyping and abrasive wear testing. A description of the sensor concept and the results of the preliminary finite element analysis of the bearing stave geometry are presented. Preliminary results of molding and glue bonding POF in nitrile rubber and then abrasive wear testing indicate that this is a viable concept.

Effect of low temperature annealing on the wear properties of NITINOL

International Nuclear Information System (INIS)

Mukunda, Sriram; Nath S, Narendra; Herbert, Mervin A.; Mukunda, P. G.

2016-01-01

NiTi shape memory alloy is a wonder material that is a solution looking for problems. The material finds wide biomedical applications like endodontic files for root canal treatment and cardiovascular stents. This material has rendered the surgical procedure simple compared to that with the existing Stainless Steel (SS) or titanium ones. NiTi as an endodontic file would cause less discomfort to the patients in comparison to that with far stiffer SS or titanium ones. Here nearly equi-atomic 50:50 commercial NiTi rods were subjected to low temperature aging at 300 to 450°C. The wear resistance of the as-received and the heat-treated samples was studied using adhesive wear tests on hardened steel counter face. Abrasive wear tests were run against Alumina disc to simulate the working of endodontic drills and files against dental hard and soft tissues. The abrasive wear resistance is expected to be proportional to the Vickers Hardness of the material and is high for the 450°C heat-treated sample. A correlation between the mechanical properties and microstructures of this material is attempted (paper)

Investigation of machining damage and tool wear resulting from drilling powder metal aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Fell, H.A. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)

1997-05-01

This report documents the cutting of aluminum powder metallurgy (PM) parts for the North Carolina Manufacturing Extension Partnership. The parts, an aluminum powder metal formulation, were supplied by Sinter Metals Inc., of Conover, North Carolina. The intended use of the alloy is for automotive components. Machining tests were conducted at Y-12 in the machine shop of the Skills Demonstration Center in Building 9737. Testing was done on June 2 and June 3, 1997. The powder metal alloy tested is very abrasive and tends to wear craters and produce erosion effects on the chip washed face of the drills used. It also resulted in huge amounts of flank wear and degraded performance on the part of most drills. Anti-wear coatings on drills seemed to have an effect. Drills with the coating showed less wear for the same amount of cutting. The usefulness of coolants and lubricants in reducing tool wear and chipping/breakout was not investigated.

Pre-polishing on a CNC platform with bound abrasive contour tools

Science.gov (United States)

Schoeffer, Adrienne E.

2003-05-01

Deterministic micorgrinding (DMG) of optical glasses and ceramics is the commercial manufacturing process of choice to shape glass surfaces prior to final finishing. This process employs rigid bound matrix diamond tooling resulting in surface roughness values of 3-51.tm peak to valley and 100-400nm rms, as well as mid-spatial frequency tool marks that require subsequent removal in secondary finishing steps. The ability to pre-polish optical surfaces within the grinding platform would reduce final finishing process times. Bound abrasive contour wheels containing cerium oxide, alumina or zirconia abrasives were constructed with an epoxy matrix. The effects of abrasive type, composition, and erosion promoters were examined for tool hardness (Shore D), and tested with commercial optical glasses in an OptiproTM CNC grinding platform. Metrology protocols were developed to examine tool wear and subsequent surface roughness. Work is directed to demonstrating effective material removal, improved surface roughness and cutter mark removal.

An in vitro study of dental enamel wear by restorative materials using radiometric method

International Nuclear Information System (INIS)

Adachi, Lena Katekawa

2000-01-01

There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains.

Directory of Open Access Journals (Sweden)

Jie Min

Full Text Available The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains.Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of artificial saliva at 37°C. The friction coefficients were recorded by the testing system. The microstructure features, wear volume, and damage morphologies were recorded and analyzed with a confocal laser scanning microscope and a scanning electron microscope. The wear mechanism was then elucidated.The friction coefficients of the five veneering porcelains differ significantly. No significant correlation between hardness and wear volume was found for these veneering porcelains. Under lubrication of artificial saliva, the porcelain with higher leucite crystal content exhibited greater wear resistance. Additionally, leucite crystal size and distribution in glass matrix influenced wear behavior. The wear mechanisms for these porcelains were similar: abrasive wear dominates the early stage, whereas delamination was the main damage mode at the later stage. Furthermore, delamination was more prominent for porcelains with larger crystal sizes.Wear compatibility between porcelain and natural teeth is important for dental restorative materials. Investigation on crystal content, size, and distribution in glass matrix can provide insight for the selection of dental porcelains in clinical settings.

Wear mechanisms of Al2O3/TiC/Mo/Ni ceramic wire-drawing dies

International Nuclear Information System (INIS)

Deng Jianxin; Yang Xuefeng; Wang Jinghai

2006-01-01

Al 2 O 3 /TiC/Mo/Ni ceramic composites were produced by hot-pressing for the use of wire drawing dies. The fundamental properties of these ceramic die materials were examined. Wire drawing tests were carried out on the 65Mn steel wire with these ceramic dies. Finite element method (FEM) was used as a means of numerically evaluating stress and its distribution inside the ceramic drawing dies. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy (SEM). The wear mechanisms of the ceramic drawing dies were investigated. Detailed observations and analyses of the die wear surface have revealed that the most common failure of the ceramic drawing die is the wear at its approach zone. FEM analysis showed that the compressive stresses on both sides of the corners at the approach zone are higher than those of other parts of the ceramic drawing die. Abrasive and adhesive wear were found to be the predominant wear mechanisms through the whole approach zone owing to the greater compressive stresses. Examination of the center bore surface at the die bearing zone of the ceramic drawing dies demonstrated that the wear occurred by light abrasive, no adhesion wear was observed

Control of erosive tooth wear: possibilities and rationale

Directory of Open Access Journals (Sweden)

Mônica Campos Serra

2009-06-01

Full Text Available Dental erosion is a type of wear caused by non bacterial acids or chelation. There is evidence of a significant increase in the prevalence of dental wear in the deciduous and permanent teeth as a consequence of the frequent intake of acidic foods and drinks, or due to gastric acid which may reach the oral cavity following reflux or vomiting episodes. The presence of acids is a prerequisite for dental erosion, but the erosive wear is complex and depends on the interaction of biological, chemical and behavioral factors. Even though erosion may be defined or described as an isolated process, in clinical situations other wear phenomena are expected to occur concomitantly, such as abrasive wear (which occurs, e.g, due to tooth brushing or mastication. In order to control dental loss due to erosive wear it is crucial to take into account its multifactorial nature, which predisposes some individuals to the condition.

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

Energy Technology Data Exchange (ETDEWEB)

Blau, Peter Julian [ORNL

2009-11-01

The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats

Microstructure and wear resistance of spray-formed supermartensitic stainless steel

Directory of Open Access Journals (Sweden)

Guilherme Zepon

2013-06-01

Full Text Available Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance1,2. The addition of boron to iron-based alloys promotes the formation of hard boride particles (M2B type which improve their wear resistances3-9. This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (% and 0.7 wt. (% processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively. These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS.

Performance Enhancement of Abrasive Waterjet Cutting

NARCIS (Netherlands)

2008-01-01

Abrasive Waterjet (AWJ) Machining is a recent non-traditional machining process. This technology is widely used in industry for cutting difficult-to-machine-materials, milling slots, polishing hard materials etc. AWJ machining has many advantages, e.g. it can cut net-shape parts, no heat is

Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

Directory of Open Access Journals (Sweden)

Eitvydas GRUZDYS

2011-07-01

Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

Influence of quartz particles on wear in vertical roller mills

DEFF Research Database (Denmark)

Jensen, Lucas R.D.; Friis, Henrik; Fundal, Erling

2010-01-01

The standard closed circuit comminution process commonly employed in industrial vertical roller mills has been analyzed to determine the influence of typical abrasive minerals on wear rates. With the main focus on raw mixes used in cement plants, synthetic mixtures imitating were prepared. Using...

Corrosion and wear resistant metallic layers produced by electrochemical methods

DEFF Research Database (Denmark)

Christoffersen, Lasse; Maahn, Ernst Emanuel

1999-01-01

Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods....... Determination of polarisation resistance during 100 hours followed by stepwise anodic polarisation seems to be a promising technique to obtain steady state data on slowly corroding coatings with transient kinetics. A slurry test enables determination of simultaneous corrosion and abrasive wear. Comparison...... of AISI 316, hard chromium and hardened Ni-P shows that there is no universal correlation between surface hardness and wear-corrosion loss. The possible relation between questionable passivity of Ni-P coatings and their high wear-corrosion loss rate compared to hard chromium is discussed....

Dental Wear: A Scanning Electron Microscope Study

Directory of Open Access Journals (Sweden)

Luca Levrini

2014-01-01

Full Text Available Dental wear can be differentiated into different types on the basis of morphological and etiological factors. The present research was carried out on twelve extracted human teeth with dental wear (three teeth showing each type of wear: erosion, attrition, abrasion, and abfraction studied by scanning electron microscopy (SEM. The study aimed, through analysis of the macro- and micromorphological features of the lesions (considering the enamel, dentin, enamel prisms, dentinal tubules, and pulp, to clarify the different clinical and diagnostic presentations of dental wear and their possible significance. Our results, which confirm current knowledge, provide a complete overview of the distinctive morphology of each lesion type. It is important to identify the type of dental wear lesion in order to recognize the contributing etiological factors and, consequently, identify other more complex, nondental disorders (such as gastroesophageal reflux, eating disorders. It is clear that each type of lesion has a specific morphology and mechanism, and further clinical studies are needed to clarify the etiological processes, particularly those underlying the onset of abfraction.

Binder extrusion of sliding wear of WC-Co alloys

International Nuclear Information System (INIS)

Larsen-Basse, J.

1985-01-01

It has previously been proposed that preferential removal of the cobalt binder is an important mechanism in the abrasive wear of cemented carbides in the WC-Co family. It is here demonstrated that binder extrusion occurs also in metal-to-metal sliding wear contacts. The wear scar generated by sliding a hardened steel ball repeatedly over a polished WC-Co surface was studied by SEM. The extruded cobalt fragments accumulate by surface defects, such as cracks caused by the sliding loaded ball, and gradual microfragmentation of the carbide grains follows. The energy required to extrude the cobalt and cause the gradual change in surface layer microstructure is provided by the frictional forces

Impact Capacity Reduction in Railway Prestressed Concrete Sleepers with Surface Abrasions

Science.gov (United States)

Ngamkhanong, Chayut; Li, Dan; Kaewunruen, Sakdirat

2017-10-01

Railway sleepers (also called ‘railroad tie’ in North America) embedded in ballasted railway tracks are a main part of railway track structures. Its important role is to transfer the loads evenly from the rails to a wider area of ballast bed and to secure rail gauge and enable safe passages of rolling stocks. By nature, railway infrastructure is nonlinear, evidenced by its behaviours, geometry and alignment, wheel-rail contact and operational parameters such as tractive efforts. Based on our critical review, the dynamic behaviour of railway sleepers has not been fully investigated, especially when the sleepers are deteriorated by excessive wears. In fact, the ballast angularity causes differential abrasions on the soffit or bottom surface of sleepers (especially at railseat zone). Furthermore, in sharp curves and rapid gradient change, longitudinal and lateral dynamics of rails increase the likelihood of railseat abrasions in concrete sleepers due to the unbalanced loading conditions. This paper presents a structural capacity of concrete sleepers under dynamic transient loading. The modified compression field theory for ultimate strength design of concrete sleepers under impact loading will be highlighted in this study. The influences of surface abrasions, including surface abrasion and soffit abrasion, on the dynamic behaviour of prestressed concrete sleepers, are firstly highlighted. The outcome of this study will improve the rail maintenance and inspection criteria in order to establish appropriate and sensible remote track condition monitoring network in practice. Moreover, this study will also improve the understanding of the fundamental dynamic behaviour of prestressed concrete sleepers with surface abrasions. The insight into these behaviours will not only improve safety and reliability of railway infrastructure but will enhance the structural safety of other concrete structures.

Advanced Wear-resistant Nanocomposites for Increased Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

Cook, B. A.; Harringa, J. L.; Russel, A. M.

2012-12-01

This report summarizes the work performed by an Ames-led project team under a 4-year DOE-ITP sponsored project titled, 'Advanced Wear-resistant Nanocomposites for Increased Energy Efficiency.' The Report serves as the project deliverable for the CPS agreement number 15015. The purpose of this project was to develop and commercialize a family of lightweight, bulk composite materials that are highly resistant to degradation by erosive and abrasive wear. These materials, based on AlMgB{sub 14}, are projected to save over 30 TBtu of energy per year when fully implemented in industrial applications, with the associated environmental benefits of eliminating the burning of 1.5 M tons/yr of coal and averting the release of 4.2 M tons/yr of CO{sub 2} into the air. This program targeted applications in the mining, drilling, machining, and dry erosion applications as key platforms for initial commercialization, which includes some of the most severe wear conditions in industry. Production-scale manufacturing of this technology has begun through a start-up company, NewTech Ceramics (NTC). This project included providing technical support to NTC in order to facilitate cost-effective mass production of the wear-resistant boride components. Resolution of issues related to processing scale-up, reduction in energy intensity during processing, and improving the quality and performance of the composites, without adding to the cost of processing were among the primary technical focus areas of this program. Compositional refinements were also investigated in order to achieve the maximum wear resistance. In addition, synthesis of large-scale, single-phase AlMgB{sub 14} powder was conducted for use as PVD sputtering targets for nanocoating applications.

Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

International Nuclear Information System (INIS)

Ebrahimi, Mansoureh; Mahboubi, Farzad; Naimi-Jamal, M. Reza

2016-01-01

Highlights: • Effect of pulsed DC PACVD deposition temperature, duty cycle, hydrogen flow and argon/CH4 flow ratio on the wear rate and durability of DLC films was studied. • Results show that wear rate of the DLC films, reduced from 14×E-4 mm3/Nm to 1×E-6 mm3/Nm with increasing the duty cycle from 50% to 80%. • In low duty cycle (around 50%), wear rate increases with increasing in Argon/CH4 flow ratio. • Oxidation, fatigue, abrasion and graphitization are main wear mechanisms in the DLC film. - Abstract: The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH_4 flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH_4 ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH_4 flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

Energy Technology Data Exchange (ETDEWEB)

Ebrahimi, Mansoureh [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, P.O. Box 1875-4413, Tehran (Iran, Islamic Republic of); Mahboubi, Farzad, E-mail: mahboubi@aut.ac.ir [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, P.O. Box 1875-4413, Tehran (Iran, Islamic Republic of); Naimi-Jamal, M. Reza [Research Laboratory of Green Organic Synthesis and Polymers, Department of Chemistry, Iran University of Science and Technology, P.O. Box 16846, Tehran (Iran, Islamic Republic of)

2016-12-15

Highlights: • Effect of pulsed DC PACVD deposition temperature, duty cycle, hydrogen flow and argon/CH4 flow ratio on the wear rate and durability of DLC films was studied. • Results show that wear rate of the DLC films, reduced from 14×E-4 mm3/Nm to 1×E-6 mm3/Nm with increasing the duty cycle from 50% to 80%. • In low duty cycle (around 50%), wear rate increases with increasing in Argon/CH4 flow ratio. • Oxidation, fatigue, abrasion and graphitization are main wear mechanisms in the DLC film. - Abstract: The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH{sub 4} flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH{sub 4} ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH{sub 4} flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

Abrasion behavior of graphite pebble in lifting pipe of pebble-bed HTR

Energy Technology Data Exchange (ETDEWEB)

Shen, Ke; Su, Jiageng [Institute of Nuclear and New Energy Technology, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 10084 (China); Zhou, Hongbo [Institute of Nuclear and New Energy Technology, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 10084 (China); Chinergy Co., LTD., Beijing 100193 (China); Peng, Wei; Liu, Bing [Institute of Nuclear and New Energy Technology, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 10084 (China); Yu, Suyun, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, The Key Laboratory for Thermal Science and Power Engineering, Ministry of Educations, Tsinghua University, Beijing 10084 (China)

2015-11-15

Highlights: • Quantitative determination of abrasion rate of graphite pebbles in different lifting velocities. • Abrasion behavior of graphite pebble in helium, air and nitrogen. • In helium, intensive collisions caused by oscillatory motion result in more graphite dust production. - Abstract: A pebble-bed high-temperature gas-cooled reactor (pebble-bed HTR) uses a helium coolant, graphite core structure, and spherical fuel elements. The pebble-bed design enables on-line refueling, avoiding refueling shutdowns. During circulation process, the pebbles are lifted pneumatically via a stainless steel lifting pipe and reinserted into the reactor. Inevitably, the movement of the fuel elements as they recirculate in the reactor produces graphite dust. Mechanical wear is the primary source of graphite dust production. Specifically, the sources are mechanisms of pebble–pebble contact, pebble–wall (structural graphite) contact, and fuel handling (pebble–metal abrasion). The key contribution to graphite dust production is from the fuel handling system, particularly from the lifting pipe. During pneumatic lift, graphite pebbles undergo multiple collisions with the stainless steel lifting pipe, thereby causing abrasion of the graphite pebbles and producing graphite dust. The present work explored the abrasion behavior of graphite pebble in the lifting pipe by measuring the abrasion rate at different lifting velocities. The abrasion rate of the graphite pebble in helium was found much higher than those in air and nitrogen. This gas environment effect could be explained by either tribology behavior or dynamic behavior. Friction testing excluded the possibility of tribology reason. The dynamic behavior of the graphite pebble was captured by analysis of the audio waveforms during pneumatic lift. The analysis results revealed unique dynamic behavior of the graphite pebble in helium. Oscillation and consequently intensive collisions occur during pneumatic lift, causing

Scanning electron microscopy of dentition: methodology and ultrastructural morphology of tooth wear.

Science.gov (United States)

Shkurkin, G V; Almquist, A J; Pfeihofer, A A; Stoddard, E L

1975-01-01

Scanning electron micrographs were taken of sets of human molars-those of paleo-Indians used in mastication of, ostensibly, a highly abrasive diet, and those of contemporary Americans. Different ultrastructural patterns of enamel wear were observed between the groups.

Combined Corrosion and Wear of Aluminium Alloy 7075-T6

NARCIS (Netherlands)

Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.

2016-01-01

The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

Performance tests of an abrasive cut-off systems for the finishing of high-precision casts

Directory of Open Access Journals (Sweden)

A. Fedoryszyn

2008-10-01

Full Text Available The paper summarizes the performance data of a newly designed and engineered grinding and cut-off system. The machine is used forseparation of models manufactured by the investment casting method. The machine comprises the following units:- base supporting other assemblies and elements: abrasive disc holder and drives; this solution enables an easy replacement and access toholding elements while a belt transmission allows the disc rpm to be varied,- mechanism moving the spindle in the horizontal, hence the abrasive disc position with respect to the batch can be precisely controlled,depending on the cast position and their shape,- holding and positioning-control of the batch to enable the fore and aft movements and rotations,- guide systems ensuring the travel of the batch in the specified direction and adjusting the travel speed to the required cutting rate,- centering, control, exhaust system, housing.Extensive tests were performed, including the tests of operating parameters of abrasive discs depending on the cast material, cyclograms ofthe applied treatment are obtained accordingly.

Performance tests of an abrasive cut-off systems for the finishing of high-precision casts

Directory of Open Access Journals (Sweden)

A. Fedoryszyn

2008-07-01

Full Text Available The paper summarizes the performance data of a newly designed and engineered grinding and cut-off system. The machine is used for separation of models manufactured by the investment casting method. The machine comprises the following units:- base supporting other assemblies and elements: abrasive disc holder and drives; this solution enables an easy replacement and access to holding elements while a belt transmission allows the disc rpm to be varied,- mechanism moving the spindle in the horizontal, hence the abrasive disc position with respect to the batch can be precisely controlled, depending on the cast position and their shape,- holding and positioning-control of the batch to enable the fore and aft movements and rotations,- guide systems ensuring the travel of the batch in the specified direction and adjusting the travel speed to the required cutting rate,- centering, control, exhaust system, housingExtensive tests were performed, including the tests of operating parameters of abrasive discs depending on the cast material, cyclograms of the applied treatment are obtained accordingly.

Influence of silicon content and heat treatment on wear resistance of white chromium cast irons under high speed solidification conditions; Influencia del contenido de silicio y el tratamiento termico en la resistencia al desgaste de fundiciones blancas al cromo en condiciones de rapida solidificacion

Energy Technology Data Exchange (ETDEWEB)

Goyo, L.; Varela, A.; Verhaege, M.; Garcia, A.; Mier, J.; Moors, M.

2012-11-01

The influence of silicon content and heat treatment on microstructure, abrasive and dry friction wear resistance of a 3 % C, 12 % Cr cast iron, under fast solidification conditions is studied. The fast solidification condition diminishes the carbide volume and the silicon content increases their dispersion and finesses. All matrixes obtained were perlitics, whit different finesses. No intermediate transformation products were noticed. Hardness had little variation. Austenization treatment show little effectivity, with tendency to increase wear in reference to as cast and maintenance treatments. Behavior under dry friction and abrasive wear were similar under test conditions applied whit more influence of carbide morphology in the abrasive wear conditions. (Author) 32 refs.

Assessment of abrasiveness for research of rock cutting

Directory of Open Access Journals (Sweden)

Milan Labaš

2012-12-01

Full Text Available Rock abrasiveness is ability of rock to wear down the working tool during the mutual interaction between the working indentorand the rock in the mechanical rock cutting process. The cutting indentor is worn down during the interaction, which changes itsgeometric dimensions causing the enlargement of a contact area between the tool and the rock surface. The changes in these dimensionsconsequently alter the rate of advance of the drilling machine and the specific cutting energy. We have determined the abrasivenessaccording to the norm ON 44 1121 (1982 on the testing device constructed at the Institute of Geotechnics SAS.

Wear behavior of Cu-Ag-Cr alloy wire under electrical sliding

International Nuclear Information System (INIS)

Jia, S.G.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zheng, M.S.; Zhou, G.S.

2005-01-01

The wear behavior of a Cu-Ag-Cr alloy contact wire against a copper-base sintered alloy strip was investigated. Wear tests were conducted under laboratory conditions with a special sliding wear apparatus that simulated train motion under electrical current conditions. The initial microstructure of the Cu-Ag-Cr alloy contact wire was analyzed by transmission electron microscopy. Worn surfaces of the Cu-Ag-Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results indicate that the wear rate of the Cu-Ag-Cr wire increased with increasing electrical current and sliding. Within the studied range of electrical current, the wear rate increases with increasing electrical current and sliding speed. Compared with the Cu-Ag contact wire under the same testing conditions, the Cu-Ag-Cr alloy wire has much better wear resistance. Adhesive, abrasive, and electrical erosion wear are the dominant mechanisms during the electrical sliding processes

Backside wear in modern total knee designs.

Science.gov (United States)

Jayabalan, Prakash; Furman, Bridgette D; Cottrell, Jocelyn M; Wright, Timothy M

2007-02-01

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II (IB II), Optetrak, and Advance. A random sample of 71 inserts were obtained from our institution's retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0-10%, 2 = 10-50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance and IB II polyethylene inserts showed significantly higher scores for backside wear than the Optetrak inserts. All IB II and Advance implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.

Wear resistance of TiB/sub 2/-Fe cermets

International Nuclear Information System (INIS)

Champagne, B.; Dallaire, S.

1985-01-01

A material which consists of TiB/sub 2/ dispersed in an iron matrix was synthesized by the exothermic reaction of ferrotitanium and boron. The as-reacted products were hot isostatically pressed to produce TiB/sub 2/-Fe cermets. The influence of HIP variables on the density and total fractional porosity of specimens is presented. Density above 95% is obtained by HIPping at temperatures below 1300 0 C. Increasing the temperature and the time of HIPping enhance the mechanical properties and wear resistance of TiB/sub 2/-Fe cermets by reducing their residual porosity. Relations obtained by regression analysis showed that the porosity strongly affects the properties of parts. Regression analysis point out that the wear loss of a 5% porosity TiB/sub 2/-Fe cermet is 270% higher than a dense HIPped cermet. Low stress and high stress abrasion resistance tests utilizing various abrasive media were carried out on dense HIPped cermets and results were compared with those obtained from WC-Co cermets and 1020 steel

Properties, structure and machnining capabilities sintered corundum abrasives

Directory of Open Access Journals (Sweden)

Cz.J. Niżankowski

2010-07-01

Full Text Available The diversity of sintered corundum abrasives used in both bonded and in the embankment of abrasive tools currently poses substantialproblems for their choice of technology to specific tasks. Therefore performed a comparative study of ownership structures and capacitiesof elected representatives machnining sintered corundum abrasives of different generations, and this is normal sintered alumina,submicrocrystalline alumina sintered and nanocrystalline alumina sintered. Were studied some properties of a set of abrasive particles,physicochemical properties and structural and mechanical and technological properties. The studies used the method of microscopicmeasurement to determine the shape of abrasive particles, the pycnometer to determine the density of abrasive, a spectrometer todetermine the chemical composition of the magnetic analyzer for determining the magnetic fraction, scanning electron microscope toanalysis of abrasive grains and a special position to designate the machining capacity abrasive grains. The results showed a significantincrease in machining capacity sintered corundum abrasives with increasing degree of fragmentation of the crystallites sintered corundum abrasives and distinctive bands in the emerging microchip. The originality of the development provides a comparative summary ofproperties of sintered corundum abrasives of different generations and functions obtained by the author making the change in value indexof machininhcapacity grit from cutting speeds for different generations of sintered corundum.

Disc cutter wear and rock texture in hard rock TBM tunneling

International Nuclear Information System (INIS)

Koizumi, Yu; Tsusaka, Kimikazu; Tanimoto, Chikaosa; Nakagawa, Shigeo; Fujita, Naoya

2008-01-01

Disc cutter wear in TBM tunneling is caused by initial fragmentation of a solid rock face (the primary fragmentation) and fragmentation of residual rock pieces between a cutterhead and the face (the secondary fragmentation). In two projects through sedimentary and granitic rocks, the authors investigated the relationships between the rate of cutter wear caused by the primary fragmentation, point load index and the grain size and contents of abrasive minerals. As a result, it was found that the tensile strength and the mineral contents of rocks significantly influenced the cutter wear in both projects and thus it is necessary to take into account of rock type. (author)

The inter-relationship between dietary and environmental properties and tooth wear: comparisons of mesowear, molar wear rate, and hypsodonty index of extant Sika deer populations.

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Mugino Ozaki Kubo

Full Text Available In reference to the evolutionary trend of increasing cheek tooth height in herbivorous ungulates, the causes of dental abrasion have long been debated. Interspecific comparisons of extant ungulates have revealed that both phytoliths in grass and external abrasive matter may play important roles. Using analysis of extant sika deer living in various environments and showing continuous latitudinal variation in food habits from northern grazing to southern browsing, we quantitatively evaluated the influence of dietary and environmental properties on three dental variables: mesowear score (MS, molar wear rate, and M3 hypsodonty index. We used 547 skulls and 740 mandibles from 16 populations of sika deer to obtain the dental measurements. We found that only graminoid proportion in diet correlated with MS and the molar wear rate, implying that phytoliths in grass abrade dental tissues. In contrast, annual precipitation in habitat was not correlated with any of the dental variables. We also found a significant correlation between the molar wear rate (selective pressure for high-crowned molars and the M3 hypsodonty index of extant sika deer, implying an evolutionary increment in molar height corresponding to the molar wear rate. Our intraspecific comparative analyses provide further support for use of mesowear analysis as a paleodiet estimation method; it not only reveals staple food types (graminoids or dicots but also implies regional or seasonal variation in the diet of the species.

Effects of sintering temperature on the microstructural evolution and wear behavior of WCp reinforced Ni-based coatings

Science.gov (United States)

Chen, Chuan-hui; Bai, Yang; Ye, Xu-chu

2014-12-01

This article focuses on the microstructural evolution and wear behavior of 50wt%WC reinforced Ni-based composites prepared onto 304 stainless steel substrates by vacuum sintering at different sintering temperatures. The microstructure and chemical composition of the coatings were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning and transmission electron microscopy (SEM and TEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The wear resistance of the coatings was tested by thrust washer testing. The mechanisms of the decomposition, dissolution, and precipitation of primary carbides, and their influences on the wear resistance have been discussed. The results indicate that the coating sintered at 1175°C is composed of fine WC particles, coarse M6C (M=Ni, Fe, Co, etc.) carbides, and discrete borides dispersed in solid solution. Upon increasing the sintering temperature to 1225°C, the microstructure reveals few incompletely dissolved WC particles trapped in larger M6C, Cr-rich lamellar M23C6, and M3C2 in the austenite matrix. M23C6 and M3C2 precipitates are formed in both the γ/M6C grain boundary and the matrix. These large-sized and lamellar brittle phases tend to weaken the wear resistance of the composite coatings. The wear behavior is controlled simultaneously by both abrasive wear and adhesive wear. Among them, abrasive wear plays a major role in the wear process of the coating sintered at 1175°C, while the effect of adhesive wear is predominant in the coating sintered at 1225°C.

Friction and wear behaviour of hypereutectic Al-Si alloy/steel tribopair under dry and lubricated conditions

Directory of Open Access Journals (Sweden)

Parveen Kumar

2017-12-01

Full Text Available Dry and lubricated sliding tribological tests on hypereutectic Al-25Si alloy was performed using a ball- on- disk configuration at room temperature. Hypereutectic Al-25Si alloy were prepared by rapid solidification process under T6 condition. Friction coefficient (COF and wear rate of the alloy were measured under different applied loads ranging from 5–100 N. It is found that the friction coefficient varies with load, first declines (from 5-50 N, then increases (from 50-80 N and then again decreases (80-100 N. The wear rate of the samples of hypereutectic Al-25Si alloy, first increases and then decreases with increasing the applied normal load. Hypereutectic Al-25Si alloy presents higher wear rate at 50 N due to the participation of a large amount of needle-like precipitates, but shows low wear rate under high load of 100 N because of the work hardening layer. Worn surface morphologies were analyzed using optical and scanning electron microscope (SEM coupled with an energy dispersive spectrometer (EDS. The improvements in COF and wear rate were mainly attributed to morphology, size and distribution of Si particles due to its fabrication process. The dominant wear mechanism for hypereutectic Al-25Si alloy was adhesive wear, abrasive wear and plastic deformation.

Development of in-situ ZrC reinforced iron based composites for wear resistance applications

International Nuclear Information System (INIS)

Bandyopadhyay, T.K.; Das, K.

2002-01-01

A common objective behind the processing of iron-based composites is to improve the wear resistance of steels by incorporating some reinforcing phases, e.g., carbides and oxides. In the present investigation, iron-based zirconium carbide reinforced composite is produced by the aluminothermic reduction of zircon sand (ZrSiO 4 ) and blue dust (Fe 2 O 3 ) in the presence of carbon. Aluminothermic reduction of blue dust and zircon sand, being highly exothermic in nature, essentially leads to a self-propagating high-temperature synthesis (SHS) of the Fe-ZrC composite. The as-cast composite is characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical properties of the composite and the effect of heat treatment on the microstructure are evaluated. The composite possess sufficient hardness and promising abrasive wear resistance property. The abrasive wear resistance property of the Fe-ZrC composite is compared with that of a M2 grade tool material and it is found to be better than the tool material. The composite also possess good high temperature stability. (author)

Evolution of metal-metal wear mechanisms in martensitic steel deposits for recharging

International Nuclear Information System (INIS)

Gualco, Agustin; Svoboda, Hernan G; Surian, Estela S; De Vedia, Luis A

2008-01-01

This work studied metal recharged by welding with a martensitic steel (Cr, Mn, Mo, V and W alloy), deposited with a metal filled tubular wire on a low carbon steel, using semi-automatic welding with a contributing heat of 2 kJ/mm and under a gaseous protection of Ar-2%CO 2 . Transverse cuts were extracted from the welded sample for microstructural characterization, hardness measurement, determination of chemical composition and wear tests. The microstructural characterization was performed using light microscopy (LM) and scanning electron microscopy (SEM), X-Ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The wear tests (metal-metal) were carried out on an Amsler machine in natural flow condition, with 500, 1250 and 2000 N of applied charge. The reference material was SAE 1020 steel. The weight loss curves were determined as a function of the distance run up to 5000 meters for all conditions. Then the test's wear surfaces and debris were analyzed. The microstructure consisted mostly of martensite and a fraction of retained austenite. A pattern of dendritic segregation was observed. The hardness on the wear surface averaged 670 HV 1 . The wear behavior showed a lineal variation between the loss of weight and the distance run, for the different loads applied. The rates of wear for each condition were obtained. The observed wear mechanisms were abrasion and adhesion, with plastic deformation. At low charges, the predominant mechanism was mild oxidative wear and at bigger loads heavy oxidative wear with the presence of zones with adhesion. The oxides formed on the surface of the eroded plate were identified

Study of corrosive-erosive wear behaviour of Al6061/albite composites

International Nuclear Information System (INIS)

Sharma, S.C.; Krishna, M.; Murthy, H.N. Narasimha; Tarachandra, R.; Satyamoorthy, M.; Bhattacharyya, D.

2006-01-01

This investigation analyses the influence of dispersed alumina particles on the wear behaviour of the Al/albite composites in a corrosive environment. The composites were prepared by modified pressure die-casting technique. The corrosive-erosive wear experiments were carried out on a proprietary corrosion-erosion wear tester to study the wear characteristics of the composites. The slurry was made up of water and alumina (size: 90-150 μm, proportion: 0-30 wt.%), while H 2 SO 4 (0.01, 0.1 and 1N) was added to create the corrosive conditions. Experiments were arranged to test the relationships among the corrosive-erosive wear rate, concentrations of H 2 SO 4 and alumina in the slurry, weight percent of albite in the composite, erosion speed and distance. Wear rate varies marginally at low speeds but sharply increases at higher speeds. The corrosive wear rate logarithmically increased with the increasing concentration of the corrosive medium. The effect of abrasive particles and corrosion medium on the wear behaviour of the composite is explained experimentally, theoretically and using scanning electron microscopy

A comparative study of tribological behavior of plasma and D-gun sprayed coatings under different wear modes

International Nuclear Information System (INIS)

Sundararajan, G.; Rao, D.S.; Prasad, K.U.M.; Joshi, S.V.

1998-01-01

In recent years, thermal sprayed protective coatings have gained widespread acceptance for a variety of industrial applications. A vast majority of these applications involve the use of thermal sprayed coatings to combat wear. While plasma spraying is the most versatile variant of all the thermal spray processes, the detonation gun (D-gun) coatings have been a novelty until recently because of their proprietary nature. The present study is aimed at comparing the tribological behavior of coatings deposited using the two above techniques by focusing on some popular coating materials that are widely adopted for wear resistant applications, namely, WC-12% Co, Al 2 O 3 , and Cr 3 C 2 -NiCr. To enable a comprehensive comparison of the above indicated thermal spray techniques as well as coating materials, the deposited coatings were extensively characterized employing microstructural evaluation, microhardness measurements, and XRD analysis for phase constitution. The behavior of these coatings under different wear modes was also evaluated by determining their tribological performance when subjected to solid particle erosion tests, rubber wheel sand abrasion tests, and pin-on-disk sliding wear tests. Among all the coating materials studied, D-gun sprayed WC-12% Co, in general, yields the best performance under different modes of wear, whereas plasma sprayed Al 2 O 3 shows least wear resistance to every wear mode

Study on torsional fretting wear behavior of a ball-on-socket contact configuration simulating an artificial cervical disk

International Nuclear Information System (INIS)

Wang, Song; Wang, Fei; Liao, Zhenhua; Wang, Qingliang; Liu, Yuhong; Liu, Weiqiang

2015-01-01

A ball-on-socket contact configuration was designed to simulate an artificial cervical disk in structure. UHMWPE (ultra high molecular weight polyethylene) hot pressed by powders and Ti6Al4V alloy were selected as the material combination of ball and socket. The socket surface was coated by a ~ 500 nm C-DLC (carbon ion implantation-diamond like carbon) mixed layer to improve its surface nano hardness and wear resistance. The torsional fretting wear behavior of the ball-on-socket model was tested at different angular displacements under 25% bovine serum lubrication with an axial force of 100 N to obtain more realistic results with that in vivo. The fretting running regimes and wear damage characteristics as well as wear mechanisms for both ball and socket were studied based on 2D (two dimension) optical microscope, SEM (scanning electron microscope) and 3D (three dimension) profiles. With the increase of angular displacement amplitude from 1° to 7°, three types of T-θ (Torsional torque-angular displacement amplitude) curves (i.e., linear, elliptical and parallelogram loops) corresponding to running regimes of PSR (partial slip regime), MR (mixed regime) and SR (slip regime) were observed and analyzed. Both the central region and the edge zone of the ball and socket were damaged. The worn surfaces were characterized by wear scratches and wear debris. In addition, more severe wear damage and more wear debris appeared on the central region of the socket at higher angular displacement amplitude. The dominant damage mechanism was a mix of surface scratch, adhesive wear and abrasive wear for the UHMWPE ball while that for the coated socket was abrasive wear by PE particles and some polishing and rolling process on the raised overgrown DLC grains. The frictional kinetic behavior, wear type, damage region and damage mechanism for the ball-on-socket model revealed significant differences with those of a ball-on-flat contact while showing better consistency with that of in

Study on torsional fretting wear behavior of a ball-on-socket contact configuration simulating an artificial cervical disk

Energy Technology Data Exchange (ETDEWEB)

Wang, Song [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Wang, Fei [School of Material Science and Engineering, China University of Mining and Technology, Xuzhou 221116 (China); Liao, Zhenhua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Wang, Qingliang [School of Material Science and Engineering, China University of Mining and Technology, Xuzhou 221116 (China); Liu, Yuhong [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

2015-10-01

A ball-on-socket contact configuration was designed to simulate an artificial cervical disk in structure. UHMWPE (ultra high molecular weight polyethylene) hot pressed by powders and Ti6Al4V alloy were selected as the material combination of ball and socket. The socket surface was coated by a ~ 500 nm C-DLC (carbon ion implantation-diamond like carbon) mixed layer to improve its surface nano hardness and wear resistance. The torsional fretting wear behavior of the ball-on-socket model was tested at different angular displacements under 25% bovine serum lubrication with an axial force of 100 N to obtain more realistic results with that in vivo. The fretting running regimes and wear damage characteristics as well as wear mechanisms for both ball and socket were studied based on 2D (two dimension) optical microscope, SEM (scanning electron microscope) and 3D (three dimension) profiles. With the increase of angular displacement amplitude from 1° to 7°, three types of T-θ (Torsional torque-angular displacement amplitude) curves (i.e., linear, elliptical and parallelogram loops) corresponding to running regimes of PSR (partial slip regime), MR (mixed regime) and SR (slip regime) were observed and analyzed. Both the central region and the edge zone of the ball and socket were damaged. The worn surfaces were characterized by wear scratches and wear debris. In addition, more severe wear damage and more wear debris appeared on the central region of the socket at higher angular displacement amplitude. The dominant damage mechanism was a mix of surface scratch, adhesive wear and abrasive wear for the UHMWPE ball while that for the coated socket was abrasive wear by PE particles and some polishing and rolling process on the raised overgrown DLC grains. The frictional kinetic behavior, wear type, damage region and damage mechanism for the ball-on-socket model revealed significant differences with those of a ball-on-flat contact while showing better consistency with that of in

A new mathematical model of the surface degradation causing wear on the cutting tool`s flank land

OpenAIRE

Pаlmai, Z.

2011-01-01

Having reviewed the extensive literature on the wear of the cutting tool, we chose the theoretical description of flank wear as the subject matter of this paper. Based on the optical electron-optical and morphological studies of the physical characteristics of wear processes we came to the conclusion that the cutting distance need not only be taken into consideration in abrasive, adhesive processes but also in thermally activated diffusion, oxidation processes. Consequently, we propose the ap...

Numerical modelling of tool wear in turning with cemented carbide cutting tools

Science.gov (United States)

Franco, P.; Estrems, M.; Faura, F.

2007-04-01

A numerical model is proposed for analysing the flank and crater wear resulting from the loss of material on cutting tool surface in turning processes due to wear mechanisms of adhesion, abrasion and fracture. By means of this model, the material loss along cutting tool surface can be analysed, and the worn surface shape during the workpiece machining can be determined. The proposed model analyses the gradual degradation of cutting tool during turning operation, and tool wear can be estimated as a function of cutting time. Wear-land width (VB) and crater depth (KT) can be obtained for description of material loss on cutting tool surface, and the effects of the distinct wear mechanisms on surface shape can be studied. The parameters required for the tool wear model are obtained from bibliography and experimental observation for AISI 4340 steel turning with WC-Co cutting tools.

Numerical modelling of tool wear in turning with cemented carbide cutting tools

International Nuclear Information System (INIS)

Franco, P.; Estrems, M.; Faura, F.

2007-01-01

A numerical model is proposed for analysing the flank and crater wear resulting from the loss of material on cutting tool surface in turning processes due to wear mechanisms of adhesion, abrasion and fracture. By means of this model, the material loss along cutting tool surface can be analysed, and the worn surface shape during the workpiece machining can be determined. The proposed model analyses the gradual degradation of cutting tool during turning operation, and tool wear can be estimated as a function of cutting time. Wear-land width (VB) and crater depth (KT) can be obtained for description of material loss on cutting tool surface, and the effects of the distinct wear mechanisms on surface shape can be studied. The parameters required for the tool wear model are obtained from bibliography and experimental observation for AISI 4340 steel turning with WC-Co cutting tools

Risk factors for tooth wear lesions among patients attending the dental clinic of a Nigerian Teaching Hospital, Benin City: A pilot study

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Okeigbemen A Sunny

2015-01-01

Full Text Available Aims: This study was to evaluate the risk factors associated with tooth wear lesions in patients attending a dental clinic. Context: Tooth wear lesions entail the loss of dental hard tissues in the absence of caries or trauma. They include abrasion, attrition, and erosion. The etiology is often related to habits leading to insidious symptoms with similar presentations in both community and hospital patients. Materials and Methods: This cross-sectional study involved patients attending the outpatient dental clinic of a Nigerian Teaching Hospital over a 3-month period. A semi-structured questionnaire was used to elicit information from the respondents. Results: A total of 152 respondents aged 17–80 years and above, comprising 86 males (56.6%, and 66 females (43.3% constituted the study population. The Binis were the most represented 34.2%, followed by the Esans 21.1%, while the least represented were the Yorubas (6.6%. The occupations represented in this study include civil servants (30.3%, unskilled workers (23.7%, and non-medical professionals (7.9%. Tooth wear lesions were present in 55.3% of the respondents. Attrition accounted for 29.6%, Abrasion (11.8%, combination of attrition and abrasion (4.6%, and abfraction (2.0%. There was a statistically significant association between tooth wear lesions and age, occupation, sensitivity or pain, tooth cleaning aids, toothbrush texture brushing technique, intake of carbonated beverages, and method of intake. Conclusion: Tooth wear lesions such as attrition and abrasion were prevalent among the respondents in this hospital setting and, therefore, represent an important group of dental problems among this population. It is, therefore, important to direct the appropriate oral health awareness program for the prevention, early detection, and management of these conditions.

Resistance to wear and microstructure of martensitic welds deposits for recharge

International Nuclear Information System (INIS)

Gualco, Agustin; Svoboda, Hernan G; Surian, Estela S; Vedia, Luis A

2006-01-01

This work studied the welding metal for a martensitic steel (alloyed to Cr, Mn, Mo, V and W), deposited with a tubular metal-cored wire with gaseous protection of 82%Ar-18%Co 2 on a low carbon steel using the semi-automatic welding process. Transverse pieces were cut from the welded coupon for microstructural characterization, measurement of hardness profiles, determination of the chemical composition and wear trials. The microstructural characterization was done using optic and scanning electronic microscopes, X-rays diffraction and energy-dispersive X-ray spectroscopy and Vicker microhardness (1 kg.) was measured. The wear trials (metal-metal) were performed in an Amsler machine under pure flow conditions. Different loads were used and the reference material was a SAE 1020 steel. The temperatures for each case were measured and the weight loss curves were defined as a function of the distance run and of the load. After testing the wear surfaces and the debris were measured. The microstructure of the welded deposit mostly consists of martensite and some retained austenite, with a pattern of dendritic segregation, and a hardness on the surface of 612 HVI. A lineal variation between the weight loss and the load applied was obtained as a response to the wear. The following phenomena were observed: abrasion, plastic deformation, oxidation and adhesion to the wear surfaces, as well as a tempering effect in the condition of the biggest load. The wear mechanisms acting on both surfaces were identified (CW)

Association between Severity of Tooth Wear and Dentinal Hypersensitivity

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Ashok Ayer

2016-11-01

Full Text Available Background & Objectives: Tooth wear (attrition, abrasion, erosion, and abfraction is perceived globally as ever increasing problem. Several outcome of the tooth wear are hypersensitivity, esthetic problems, functional impairment, annoyance to the patient, and fracture of the tooth. Among these, the measurable and more commonly reported outcome is hypersensitivity to stimuli. Although dentin hypersensitivity is a common clinical condition and is generally reported by the patient after experiencing a sharp, short pain caused by one of the several different external stimuli, it is often inadequately understood. None of the scientific literature available till date attempted to establish the relationship between tooth wear and dentin hypersensitivity which could be a key factor in monitoring those patients.  The aim of the study was to estimate the association between severity of teeth wear and sensitivity in the patients with reported dentinal hypersensitivity.Materials & Methods: Fifty patients with dentin hypersensitivity were investigated for tooth wear. Tooth wear measured using exact tooth wear index and level of sensitivity to stimuli was recorded using a numerical rating scale. Results: Enamel wear at cervical region of teeth showed a positive correlation (p=.010, similarly, dentin wear at cervical region of teeth showed positive correlation and significant association (p<.001 with dentinal hypersensitivity.Conclusion: The observation supports a significant association between severities of tooth surface wear and dentinal hypersensitivity.

Abrasive wear behaviour of Al-Cu-Mg/palm kernel shell ash particulate composite

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Gambo Anthony VICTOR

2017-12-01

Full Text Available This paper presents a systematic approach to develop a wear model of Al-Cu-Mg/Palm kernel shell ash particulate composites (PKSAp produced by double stir-casting method. Four factors, five levels, central composite, rotatable design matrix was used to optimize the number of experiments. The factors considered were sliding velocity, sliding distance, normal load and mass fraction of PKSA reinforcement in the matrix. Response surface methodology (RSM was employed to develop the mathematical model. The developed regression model was validated by statistical software MINITAB and statistical tool such as analysis of variance (ANOVA. It was found that the developed regression model could be effectively used to predict the wear rate at 95% confidence level. The regression model indicated that the wear rate of cast Al-Cu-Mg/PKSAp composite decreased with an increase in the mass fraction of PKSA and increased with an increase of the sliding velocity, sliding distance and normal load acting on the composite specimen.

Wear behavior of niobium carbide coated AISI 52100 steel

International Nuclear Information System (INIS)

Fernandes, Frederico Augusto Pires; Casteletti, Luiz Carlos; Oliveira, Carlos Kleber Nascimento de; Lombardi Neto, Amadeu; Totten, George Edward

2010-01-01

Bearing steels must have high hardness, good wear resistance and dimensional stability. The aim of this work was to study the effect of NbC coating, produced using the thermo-reactive deposition (TRD) process, on the wear resistance of the AISI 52100 steel. Untreated AISI 52100 samples were ground up to 600 mesh emery paper. The bath was composed of 5wt.% ferroniobium (65 wt.% Nb), 3wt.% aluminum and (Na2B4O7) to 100%. Samples were treated at 1000 deg C for 4h and quenched in oil directly from the bath. The resulting layer was characterized by X-ray diffraction, scanning electron microscopy and a micro-abrasive wear testing. The thermo-reactive deposition process in molten borax produced a hard and homogeneous layer composed by NbC, which was confirmed by X-ray diffraction. The NbC coating produced a great increase in the wear resistance of the AISI 52100 steel, decreasing the wear rate by an order of magnitude in relation to the substrate. For coated and uncoated samples the worn volume and wear rate increases with the load. (author)

Abrasion Resistance of Nano Silica Modified Roller Compacted Rubbercrete: Cantabro Loss Method and Response Surface Methodology Approach

Science.gov (United States)

Adamu, Musa; Mohammed, Bashar S.; Shafiq, Nasir

2018-04-01

Roller compacted concrete (RCC) when used for pavement is subjected to skidding/rubbing by wheels of moving vehicles, this causes pavement surface to wear out and abrade. Therefore, abrasion resistance is one of the most important properties of concern for RCC pavement. In this study, response surface methodology was used to design, evaluate and analyze the effect of partial replacement of fine aggregate with crumb rubber, and addition of nano silica on the abrasion resistance of roller compacted rubbercrete (RCR). RCR is the terminology used for RCC pavement where crumb rubber was used as partial replacement to fine aggregate. The Box-Behnken design method was used to develop the mixtures combinations using 10%, 20%, and 30% crumb rubber with 0%, 1%, and 2% nano silica. The Cantabro loss method was used to measure the abrasion resistance. The results showed that the abrasion resistance of RCR decreases with increase in crumb rubber content, and increases with increase in addition of nano silica. The analysis of variance shows that the model developed using response surface methodology (RSM) has a very good degree of correlation, and can be used to predict the abrasion resistance of RCR with a percentage error of 5.44%. The combination of 10.76% crumb rubber and 1.59% nano silica yielded the best combinations of RCR in terms of abrasion resistance of RCR.

Development of a new inexpensive green thermoplastic composite and evaluation of its physico-mechanical and wear properties

International Nuclear Information System (INIS)

Syed, Murtuza Ali; Syed, Akheel Ahmed

2012-01-01

Highlights: ► Turmeric spent (TS) incorporated polypropylene (PP) green composites were fabricated. ► Addition of TS into PP matrix improved tensile modulus and flexural properties of composites. ► The water absorption characteristics of composites were determined. ► Wear volume loss and specific wear rate as a function of abrading distance and load were determined. ► Surface morphology of composites was examined using scanning electron microscope. -- Abstract: In the present study an attempt has been made to use turmeric spent (TS) as reinforcing filler to fabricate polypropylene (PP) green composite for load bearing and tribological applications. PP/TS composites were fabricated using varying amounts of TS viz, 10%, 20%, 30% and 40% (w/w) by twin screw extrusion method. The fabricated PP green composites were evaluated for physico-mechanical and tribological properties. Experimentally obtained tensile values were compared with theoretically predicted values using different theoretical models. Tensile modulus of composites increased from 1041 to 1771 MPa with the increase in filler addition from 0 to 40 wt.%. Flexural strength and flexural modulus of composites were improved after incorporation of TS into PP matrix. The water absorption characteristics of composites were determined. The effect of abrading distances viz., 150, 300, 450, and 600 m and different loads of 23.54 and 33.54 N at 200 rpm on the abrasive wear behaviour were studied using dry sand/rubber wheel abrasive test rig. The TS filler lowered the abrasion resistance of PP/TS composites. The wear volume loss and specific wear rate as a function of abrading distance and load were determined. The surface morphology of tensile fractured green composites and their worn surface features were examined under scanning electron microscope.

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

Directory of Open Access Journals (Sweden)

Anders E. W. Jarfors

2016-12-01

Full Text Available The current paper aims to review tooling life span, failure modes and models in cold microforming processes. As there is nearly no information available on tool-life for microforming the starting point was conventional cold forming. In cold forming common failures are (1 over stressing of the tool; (2 abrasive wear; (3 galling or adhesive wear, and (4 fatigue failure. The large variation in tool life observed in production and how to predict this was reviewed as this is important to the viability of microforming based on that the tooling cost takes a higher portion of the part cost. Anisotropic properties of the tool materials affect tool life span and depend on both the as-received and in-service conditions. It was concluded that preconditioning of the tool surface, and coating are important to control wear and fatigue. Properly managed, the detrimental effects from surface particles can be reduced. Under high stress low-cycle fatigue conditions, fatigue failure form internal microstructures and inclusions are common. To improve abrasive wear resistance larger carbides are commonly the solution which will have a negative impact on tooling life as these tend to be the root cause of fatigue failures. This has significant impact on cold microforming.

Tool wear of a single-crystal diamond tool in nano-groove machining of a quartz glass plate

International Nuclear Information System (INIS)

Yoshino, Masahiko; Nakajima, Satoshi; Terano, Motoki

2015-01-01

Tool wear characteristics of a diamond tool in ductile mode machining are presented in this paper. Nano-groove machining of a quartz glass plate was conducted to examine the tool wear rate of a single-crystal diamond tool. Effects of lubrication on the tool wear rate were also evaluated. A numerical simulation technique was developed to evaluate the tool temperature and normal stress acting on the wear surface. From the simulation results it was found that the tool temperature does not increase during the machining experiment. It is also demonstrated that tool wear is attributed to the abrasive wear mechanism, but the effect of the adhesion wear mechanism is minor in nano-groove machining. It is found that the tool wear rate is reduced by using water or kerosene as a lubricant. (paper)

Investigation on hard coating of pivot-jewel bearing and wearing performance

International Nuclear Information System (INIS)

Han Kun; Dai Xingjian

2014-01-01

The reliability of high speed rotating machine is related to the anti-wear properties of pivot jewel bearing used in the system. To reduce its wearing process, hard coating method is used on the steel pivot. Through the wearing test on specialized facilities, its founded that the TiN coating shows better performance than DLC coating, and multi-layer TiN coating can slow down the pivot's wearing process obviously compared to other methods. (authors)

Study of the rheological properties and the finishing behavior of abrasive gels in abrasive flow machining

Energy Technology Data Exchange (ETDEWEB)

Wang, A. C.; Liu, C. H.; Liang, K. Z.; Pai, S. H. [Ching Yun University, Taipei (China)

2007-10-15

Abrasive flow machining (AFM) is an effective method to finish the smooth surface in the complex holes. Abrasive media are key elements which dominate the polished results in AFM. But it is hard to develop the machining model of these abrasive gels because of its complicated mechanism. In this research, a non-Newtonian flow is used to set up the abrasive mechanism of the abrasive media in AFM. Power law is a main equation of the non-Newtonian flow to describe the motion of the abrasive media. Viscosities vs. shear rates of different abrasive gels are used to establish the power law in CFD-ACE{sup +} software first. And the working parameters of AFM were applied as input to study the properties of the abrasive gels in AFM. Finally, the relationships between the simulations and the experiments were found. And the abrasive mechanism of the abrasive gels was set up in AFM. The simulated results show that the abrasive gel with high viscosity can entirely deform in the complex hole than the abrasive gel with low viscosity. And the abrasive gel with high viscosity generates a larger shear force than the abrasive gel with low viscosity in the same area. Moreover, the strain rate is seriously changed when the abrasive gel cross over the narrow cross-section of the complex hole. It also means that abrasive gel will produce large finish force in that area. And these results indeed consist with the experiments in AFM.

Evaluation of planarization performance for a novel alkaline copper slurry under a low abrasive concentration

International Nuclear Information System (INIS)

Jiang Mengting; Liu Yuling; Yuan Haobo; Chen Guodong; Liu Weijuan

2014-01-01

A novel alkaline copper slurry that possesses a relatively high planarization performance is investigated under a low abrasive concentration. Based on the action mechanism of CMP, the feasibility of using one type of slurry in copper bulk elimination process and residual copper elimination process, with different process parameters, was analyzed. In addition, we investigated the regular change of abrasive concentration effect on copper and tantalum removal rate and within wafer non-uniformity (WIWNU) in CMP process. When the abrasive concentration is 3 wt%, in bulk elimination process, the copper removal rate achieves 6125 Å/min, while WIWNU is 3.5%, simultaneously. In residual copper elimination process, the copper removal rate is approximately 2700 Å/min, while WIWNU is 2.8%. Nevertheless, the tantalum removal rate is 0 Å/min, which indicates that barrier layer isn't eliminated in residual copper elimination process. The planarization experimental results show that an excellent planarization performance is obtained with a relatively high copper removal rate in bulk elimination process. Meanwhile, after residual copper elimination process, the dishing value increased inconspicuously, in a controllable range, and the wafer surface roughness is only 0.326 nm (sq < 1 nm) after polishing. By comparison, the planarization performance and surface quality of alkaline slurry show almost no major differences with two kinds of commercial acid slurries after polishing. All experimental results are conducive to research and improvement of alkaline slurry in the future. (semiconductor technology)

Effect of heat treatment on strength and abrasive wear behaviour of ...

Indian Academy of Sciences (India)

In the present investigation Al6061–SiCp composites was fabricated by liquid metallurgy route with percentages of SiCp varying from 4 wt% to 10 wt% in steps of 2 ... However, under identical heat treatment conditions, adopted Al6061–SiCp composites exhibited better microhardness and tensile strength reduced wear loss ...

Wear resistance of layers hard faced by the high-alloyed filler metal

OpenAIRE

Dušan Arsić; Vukić Lazić; Ruzica R. Nikolic; Milan Mutavdžić; Srbislav Aleksandrović; Milan Djordjević

2016-01-01

The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by ...

Surface engineering for enhanced performance against wear

CERN Document Server

2013-01-01

Surface Engineering constitutes a variety of processes and sub processes. Each chapter of this work covers specific processes by experts working in the area. Included for each topic are tribological performances for each process as well as results of recent research. The reader also will benefit from in-depth studies of diffusion coatings, nanocomposite films for wear resistance, surfaces for biotribological applications, thin-film wear, tribology of thermal sprayed coatings, hardfacing, plating for tribology and high energy beam surface modifications. Material scientists as well as engineers working with surface engineering for tribology will be particularly interested in this work.

Wear Resistance Increase by Friction Stir Processing for Partial Magnesium Replacement in Aluminium Alloys

Science.gov (United States)

Balos, Sebastian; Labus Zlatanovic, Danka; Janjatovic, Petar; Dramicanin, Miroslav; Rajnovic, Dragan; Sidjanin, Leposava

2018-03-01

In this paper, the influence of friction stir processing (FSP) was evaluated as a way of increasing mechanical properties and a way of replacing the magnesium content in aluminium alloys. FSP was done on AA5754 H111 aluminium alloy, containing 3 % Mg, by using various types of tools and different welding speeds, rotational speeds and tilt angles. Wear test was done against SiC abrasive papers. SiC was used to simulate extreme abrasive wear conditions. The wear test was done on untreated AA5754 specimens, processed AA5754 specimens and untreated AA5083 H111 specimens, the latter containing 4.5 % Mg. AA5083 was chosen as an alternative to AA5754, but with a significantly higher Mg content. Base material microhardness was 60 HV1 and 80 HV1 for AA5754 and AA5083 alloys respectively. To find the effect of FSP on AA5754 alloy, microstructures were studied, mainly grain size in the stir zone. It was found, that an elevated processing and rotational speed, without tilt angle and the tool without a reservoir resulted in an increase in hardness of the AA5754 to 70 HV1, but with the occurrence of tunneling defect and the wear rate of 79.3 mg. Lower FSP parameters and a tilted tool with a reservoir resulted in microhardness of 68 HV1 and wear rate of 68.2 mg without tunneling. These wear values are lower than those obtained with unmodified Al-alloys: AA5754 97.2 mg and AA5083 86.3 mg. An increased wear resistance can be attributed to the combined effect of grain boundary strengthening mechanism and solid solution strengthening, versus only the latter in untreated alloys.

Influence of pulsed plasma streams processing on wear behavior of steels in different friction conditions

International Nuclear Information System (INIS)

Bandura, A.N.; Byrka, O.V.; Tereshin, V.I.; Bovda, A.M.; Tortika, A.S.

2000-01-01

Pulsed plasma streams processing was applied for surface modification of industrial steel samples. Different types of wear tests (pin-on-disk,flat-on-flat, abrasive,cavitation) were carried out for samples irradiated by pulsed nitrogen plasma streams. There was achieved essential decrease of wear and tear of processed surfaces of all kinds of steels including previously thermally quenched ones. Obtained results are of importance for both determination of optimal regimes of plasma streams processing and the most resulting use of pulsed plasma streams for technology purpose, i.e. for identification of wear modes and optimal friction conditions for steels processed by plasma streams

Influence of Rock Properties on Wear of M and SR Grade Rubber with Varying Normal Load and Sliding Speed

Directory of Open Access Journals (Sweden)

Pal Samir Kumar

2017-09-01

Full Text Available Rubbers are interesting materials and are extensively used in many mining industries for material transportation. Wear of rubber is a very complex phenomenon to understand. The present study aims to explain the influence of rock properties on wear of M and SR grade rubber used in top cover of conveyor belts. Extensive laboratory experiments were conducted under four combinations of normal load and sliding speed. The wear of both the rubber types were analyzed based on the rock properties like shear strength, abrasivity index and fractal dimension. A fully instrumented testing set up was used to study the wear of rubber samples under different operating conditions. In general, wear was higher for M grade rubber compared to SR grade rubber. Increase in shear strength of rocks depicts decreasing trend for the wear of M and SR grade rubber at lower load conditions. Moreover, a higher load combination displays no definite trend in both the rubbers. The strong correlation between the wear of rubber and frictional power for all rubber-rock combinations has given rise to the parameter A, which reflects the relative compatibility between the rubber and rock. Increase of Cerchar’s Abrasivity Index of rocks shows gradual enhancement in wear for M grade rubber in all the load and speed combinations whereas, it fails in SR grade rubber due to its higher strength. The wear of rubber tends to decrease marginally with the surface roughness of rocks at highest normal load and sliding speed in M grade rubber. However, the wear of M and SR grade rubber is influenced by the surface roughness of rocks.

Radioactive wear measurements of cutting tools made of metal in cutting aluminium alloys

International Nuclear Information System (INIS)

Frevert, E.

1977-01-01

The possibility of making quick checkings of the inhomogeneities of turning materials with radioactive wear measurements has been tested. After activation analysis of the long-lived radioisotopes of cutting tools made of hard metal a method for loss-free collection of the turnings has been developed. The detection limit of the abrasion is about 10 -8 g, the measuring times are 5-10 minutes. Special radiation protection measures are not necessary. An analysis of the abrasion showed that at the beginning of cutting the amount of cobalt is 6 times higher than in the normal composition of the used cutting tools. (author)

Wear- and heat resistance of vacuum-arc TiN and TiAlN based coatings with Si and Y additives

International Nuclear Information System (INIS)

Aksenov, I.I.; Belous, V.A.; Grigor'ev, A.N.; Ermolenko, I.G.; Zadneprovskij, Yu.A.; Kovalenko, V.I.; Lomino, N.S.; Marinin, V.G.; Tolmacheva, G.N.; Sobol', O.V.

2011-01-01

It is shown, that insertion of silicon additives into TiN coatings and of yttrium into TiAlN coatings in explored limits (to a few wht. %) leads to increasing of resistance against abrasive friction wear. At the same time silicon or yttrium presence in the coatings leads to loos of their columnar structure and demonstrate decrease in the cavitation resistance. It is supposed, that such distinction in behaviour of the given working performances is a consequence of that mechanisms of the coating surface fracture at action of cavitation and abrasive friction are different. All explored coatings of (Ti-Si)N composition are not oxidised up to 600 o C, and of (Ti-Al-Y)N coatings - up to 800 o C.

Mechanical and wear properties of pre-alloyed molybdenum P/M steels with nickel addition

Directory of Open Access Journals (Sweden)

Yamanoglu R.

2012-01-01

Full Text Available The aim of this study is to understand the effect of nickel addition on mechanical and wear properties of molybdenum and copper alloyed P/M steel. Specimens with three different nickel contents were pressed under 400 MPa and sintered at 1120ºC for 30 minutes then rapidly cooled. Microstructures and mechanical properties (bending strength, hardness and wear properties of the sintered specimens were investigated in detail. Metallographical investigations showed that the microstructures of consolidated specimens consist of tempered martensite, bainite, retained austenite and pores. It is also reported that the amount of pores varies depending on the nickel concentration of the alloys. Hardness of the alloys increases with increasing nickel content. Specimens containing 2% nickel showed minimum pore quantity and maximum wear resistance. The wear mechanism changed from abrasive wear at low nickel content to adhesive wear at higher nickel content.

Effects of Rare Earth Metal Addition on Wear Resistance of Chromium-Molybdenum Cast Steel

Directory of Open Access Journals (Sweden)

Kasinska J.

2017-09-01

Full Text Available This paper discusses changes in the microstructure and abrasive wear resistance of G17CrMo5-5 cast steel modified with rare earth metals (REM. The changes were assessed using scanning microscopy. The wear response was determined in the Miller test to ASTM G75. Abrasion tests were supplemented with the surface profile measurements of non-modified and modified cast steel using a Talysurf CCI optical profilometer. It was demonstrated that the modification substantially affected the microstructure of the alloy, leading to grain size reduction and changed morphology of non-metallic inclusions. The observed changes in the microstructure resulted in a three times higher impact strength (from 33 to 99 kJ/cm2 and more than two times higher resistance to cracking (from 116 to 250 MPa. The following surface parameters were computed: Sa: Arithmetic mean deviation of the surface, Sq: Root-mean-square deviation of the surface, Sp: Maximum height of the peak Sv: Maximum depth of the valley, Sz: Ten Point Average, Ssk: Asymmetry of the surface, Sku: Kurtosis of the surface. The findings also indicated that the addition of rare earth metals had a positive effect on the abrasion behaviour of G17CrMo5-5 cast steel.

The friction and wear of γ-irradiated polytetrafluoroethylene

International Nuclear Information System (INIS)

Briscoe, B.J.; Ni, Z.

1984-01-01

The exposure of polytetrafluoroethylene (PTFE) to γ radiation significantly reduces the molecular weight but below the gross softening temperature suppresses the overall molecular domain mobility. The shear modulus and creep resistance increase but the toughness is reduced. Data are presented to substantiate these trends and to interpret their influence on the friction and wear of γ-damaged PTFE. The sliding friction on smooth rigid counterfaces increases but the wear in this configuration is decreased. The rate of abrasion on rough rigid counterfaces is increased. There is also an improvement in the ultimate load-bearing capacity. All the changes produced are a function of the exposure but most of the effects are fully manifested by 20 Mrad. The general conclusion is that the extent of the molecular mobility or migration induced by mechanical stresses, imposed in both the interface and the bulk of the polymer, has a critical effect on the friction and wear processes. (Auth.)

Reduced abrasion drilling fluid

NARCIS (Netherlands)

2010-01-01

A reduced abrasion drilling fluid system and method of drilling a borehole by circulating the reduced abrasion drilling fluid through the borehole is disclosed. The reduced abrasion drilling fluid comprises a drilling fluid, a first additive and a weighting agent, wherein the weighting agent has a

Reduced abrasion drilling fluid

NARCIS (Netherlands)

2012-01-01

A reduced abrasion drilling fluid system and method of drilling a borehole by circulating the reduced abrasion drilling fluid through the borehole is disclosed. The reduced abrasion drilling fluid comprises a drilling fluid, a first additive and a weighting agent, wherein the weighting agent has a

Cleaning power and abrasivity of European toothpastes.

Science.gov (United States)

Wülknitz, P

1997-11-01

For 41 toothpastes available to European consumers in 1995, the cleaning efficacy was evaluated in comparison with abrasivity on dentin (RDA value). For cleaning power assessment, a modified pellicle cleaning ratio (PCR) measurement method was developed. The method is characterized by a five-day tea-staining procedure on bovine front teeth slabs on a rotating wheel, standardized brushing of the slabs in a V8 cross-brushing machine, and brightness measurement by a chromametric technique. All tested products were in accordance with the new DIN/ISO standard 11,609 for toothpastes in terms of dentin abrasivity. Not a single product exceeded an RDA value of 200. The majority of toothpastes (80%) had an RDA value below 100. Only three products surpassed the reference in cleaning power. Most products (73%) had a cleaning power (PCR value) between 20 and 80. The correlation between cleaning power and dentin abrasion was low (r = 0.66), which can be explained with the different influence on dentin and stains by factors like abrasive type, particle surface and size, as well as the chemical influence of other toothpaste ingredients. Some major trends could be shown on the basis of abrasive types. The ratio PCR to RDA was rather good in most silica-based toothpastes. A lower ratio was found in some products containing calcium carbonate or aluminum trihydrate as the only abrasive. The addition of other abrasives, such as polishing alumina, showed improved cleaning power. Some active ingredients, especially sequenstrants such as sodium tripolyphosphate or AHBP, also improve the PCR/RDA ratio by stain-dissolving action without being abrasive. The data for some special anti-stain products did not differ significantly from standard products. Compared with data measured in 1988, a general trend toward reduced abrasivity without loss of cleaning efficacy could be noticed on the European toothpaste market. This may be mostly due to the increased use of high-performance abrasives such

Metallurgical/Alloy Optimization of High Strength and Wear Resistant Structural Quench and Tempered Steels

Science.gov (United States)

Stalheim, Douglas G.; Peimao, Fu; Linhao, Gu; Yongqing, Zhang

Structural steels with yield strength requirements greater or equal to 690 MPa can be produced through controlled recrystallization hot rolling coupled with precipitation strengthening or purposeful heat treatment through quench and tempering (Q&T). High strength structural steel and wear/abrasion resistant requirements greater or equal to 360 Brinell hardness (BHN) are produced by the development of microstructures of tempered lower bainite and/or martensite through the Q&T process. While these Q&T microstructures can produce very high strengths and hardness levels making them ideal for 690 MPa plus yield strength or wear/abrasion resistant applications, they lack toughness/ductility and hence are very brittle and prone to cracking. While tempering the microstructures helps in improving the toughness/ductility and reducing the brittleness, strength and hardness can be sacrificed. In addition, these steels typically consist of alloy designs containing boron with carbon equivalents (CE) greater than 0.50 to achieve the desired microstructures. The higher CE has a negative influence on weldability.

Experimental study and effect of particulate interference on the microhardness, wear and microstructural properties of ternary doped coating

Energy Technology Data Exchange (ETDEWEB)

Fayomi, O. S. I., E-mail: ojosundayfayomi3@gmail.com [Department of Chemical, Metallurgical & Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Mechanical Engineering, Covenant University, P.M.B. 1023, Canaanland, Ota (Nigeria); Popoola, A. P. I. [Department of Chemical, Metallurgical & Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Joseph, O. O.; Inegbenebor, A. O. [Department of Mechanical Engineering, Covenant University, P.M.B. 1023, Canaanland, Ota (Nigeria); Olukanni, D. O. [Department of Civil Engineering, Covenant University, P.M.B. 1023, Ota, Ogun State (Nigeria)

2016-07-25

This paper studies effects of the composite particle infringement of ZnO/Cr{sub 2}O{sub 3} on zinc rich ternary based coating. The corrosion-degradation property in 3.5% NaCl was investigatedusing polarization technique. The structural characteristics of the multilayer produce coatings were evaluated by scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS). The mechanical response of the coated samples was studied using a diamond base Dura –Scan) micro-hardness tester and a MTR-300 dry abrasive wear tester. The combined effect of the coatings gave highly-improved performance on microhardness, corrosion and wear damage. This also implies that protection of wind-energy structures in marine environments can be achieved by composite strengthening capacity.

Wear monitoring of protective nitride coatings using image processing

DEFF Research Database (Denmark)

Rasmussen, Inge Lise; Guibert, M.; Belin, M.

2010-01-01

-meter with up to 105 19 repetitive cycles, eventually leaving the embedded TiN signal layer uncovered at the bottom the wear scar. 20 The worn surface was characterized by subsequent image processing. A color detection of the wear scar with 21 the exposed TiN layer by a simple optical imaging system showed......A double-layer model system, consisting of a thin layer of tribological titanium aluminum nitride (TiAlN) on 17 top of titanium nitride (TiN), was deposited on polished 100Cr6 steel substrates. The TiAlN top-coatings 18 were exposed to abrasive wear by a reciprocating wear process in a linear tribo...... a significant increase up to a factor of 2 of 22 the relative color values from the TiAlN top layers to the embedded TiN signal layers. This behavior agrees 23 well with the results of reflectance detection experiment with a red laser optical system on the same system. 24 Thus we have demonstrated that image...

Modeling and Tool Wear in Routing of CFRP

International Nuclear Information System (INIS)

Iliescu, D.; Fernandez, A.; Gutierrez-Orrantia, M. E.; Lopez de Lacalle, L. N.; Girot, F.

2011-01-01

This paper presents the prediction and evaluation of feed force in routing of carbon composite material. In order to extend tool life and improve quality of the machined surface, a better understanding of uncoated and coated tool behaviors is required. This work describes (1) the optimization of the geometry of multiple teeth tools minimizing the tool wear and the feed force, (2) the optimization of tool coating and (3) the development of a phenomenological model between the feed force, the routing parameters and the tool wear. The experimental results indicate that the feed rate, the cutting speed and the tool wear are the most significant factors affecting the feed force. In the case of multiple teeth tools, a particular geometry with 14 teeth right helix right cut and 11 teeth left helix right cut gives the best results. A thick AlTiN coating or a diamond coating can dramatically improve the tool life while minimizing the axial force, roughness and delamination. A wear model has then been developed based on an abrasive behavior of the tool. The model links the feed rate to the tool geometry parameters (tool diameter), to the process parameters (feed rate, cutting speed and depth of cut) and to the wear. The model presented has been verified by experimental tests.

Study on wear resistance of vanadium alloying compacted/vermicular graphite cast iron

International Nuclear Information System (INIS)

Park, Yoon Woo

1987-01-01

Wear resistance of the Compacted/Vermicular graphite cast irons was studied by changing the vanadium content in the cast irons. The results obtained in this work are summarized as follows. 1. When the same amount of vanadium was added to the flake graphite cast iron, spheroidal graphitecast iron and Compacted/Vermicular graphite cast iron, spheroidal graphite cast iron and Compacted/Vermicular graphite cast iron wear resistance decreased in following sequence, that is, flake graphite cast iron> spheroidal graphite cast iron>Compacted/Vermicular graphite cast iron. 2. Addition of vanadium to the Compacted/Vermicular cast iron leaded to a remarkable increase in hardness because it made the amount of pearlite in matrix increase. 3. Addition of vanadium to the compacted/Vermicular graphite cast iron significantly enhanced wear resistance and the maximum resistance was achieved at about 0.36% vanadium. 4. The maximum amount of wear apppeared at sliding speed of about 1.4m/sec and wear mode was considered to be oxidation abrasion from the observation of wear tracks. (Author)

Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

International Nuclear Information System (INIS)

Raab, A. E.; Berger, E.; Freudenthaler, J.; Leomann, F.; Walch, C.

2011-01-01

Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesive and abrasive tool wear.First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test.All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.

Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

Science.gov (United States)

Raab, A. E.; Berger, E.; Freudenthaler, J.; Leomann, F.; Walch, C.

2011-05-01

Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry1,2,3. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago1. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesive and abrasive tool wear. First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test. All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.

Effect of Laser Remelting on Friction-Wear Behaviors of Cold Sprayed Al Coatings in 3.5% NaCl Solution

Directory of Open Access Journals (Sweden)

Zhang Jing

2018-02-01

Full Text Available A cold sprayed Al coating on S355 structural steel was processed using a laser remelting (LR. The surface and cross-section morphologies, chemical compositions, and phases of as-obtained Al coating before and after LR were analyzed using a scanning electronic microscope (SEM, energy dispersive spectrometer (EDS, and X-ray diffractometer (XRD, respectively, and their hardness was measured using a micro-hardness tester. The friction-wear behaviors of Al coating before and after LR in 3.5% NaCl solution were conducted to simulate the sand and gravel scouring on its surface in seawater, the effects of wear loads and speeds on the tribological properties of Al coating were analyzed, and the wear mechanisms under different wear loads and speeds were also discussed. The results show that the Al coating after LR is primarily composed of an Al phase and its hardness is 104.66 HV, increasing 54.70 HV than the cold sprayed Al coating. The average coefficient of friction (COF of cold sprayed Al coating at the wear load of 0.5, 1.0 and 1.5 N is 0.285, 0.239, and 0.435, respectively, while that after LR is 0.243, 0.227, and 0.327, respectively, decreased by 14.73%, 5.02% and 24.83% compared to the cold sprayed Al coating. The wear rate of cold sprayed Al coating at the wear load of 0.5, 1.0 and 1.5 N is 1.60 × 10−4, 2.36 × 10−4, and 2.40 × 10−4 mm3/m·N, respectively, while that after LR is 1.59 × 10−4, 1.70 × 10−4, and 1.94 × 10–4 mm3/m·N, respectively, decreased by 1%, 32%, and 23%, respectively, indicating that LR has high anti-friction performance. Under the wear load action of 1.0 N, the average COF of laser remelted Al coating at the wear speeds of 300, 400 and 500 times/min is 0.294, 0.279, and 0.239, respectively, and the corresponding wear rate is 1.06 × 10−4, 1.24 × 10−4, and 1.70 × 10−4 mm3/m·N, respectively. The wear mechanism of cold sprayed Al coating is primarily corrosion wear at the loads of 0.5 and 1.0 N, and

Machining with abrasives

CERN Document Server

Jackson, Mark J

2011-01-01

Abrasive machining is key to obtaining the desired geometry and surface quality in manufacturing. This book discusses the fundamentals and advances in the abrasive machining processes. It provides a complete overview of developing areas in the field.

CONTROL SYSTEM EVALUATION AND IMPLEMENTATION FOR THE ABRASIVE MACHINING PROCESS ON WOOD

Directory of Open Access Journals (Sweden)

Stephen Jackson

2011-06-01

Full Text Available Continuous process improvement and automation have proven to be powerful tools for the wood processing industries in order to obtain better final product quality and thus increase profits. Abrasive machining represents an important and relevant process in the manufacturing and processing of wood products, which also implies high cost of materials and labor; therefore, special attention to this process is necessary. The objective of this work was to evaluate and demonstrate a process control system for use in the abrasive machining of wood and wood-based products. A control system was created on LabView® to integrate the monitoring process and the actions required, depending on the abrasive machining process conditions. The system acquires information from the optical sensor to detect loading and activate the cleaning system. The system continuously monitors the condition of the abrasive belt (tool wear by using an acoustic emission sensor and alerts the operator of the status of the belt (green, yellow, and red lights indicating satisfactory, medium, and poor belt condition. The system also incorporates an additional safety device, which helps prevent permanent damage to the belt, equipment, or workpiece by alerting the operator when an excessive temperature has been reached. The process control system proved that automation permits enhancement in the consistency of the belt cleaning technique by the elimination of the human errors. Furthermore, this improvement also affects the cost by extending the life of the belt, which reduces setup time, belt cost, operation cost, as well as others.

Influence of thermal oxidation duration on the microstructure and fretting wear behavior of Ti6Al4V alloy

Energy Technology Data Exchange (ETDEWEB)

Wang, Song [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liao, Zhenhua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Liu, Yuhong [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

2015-06-01

Thermal oxidation under water oxidizing atmosphere was performed on Ti6Al4V alloy under different durations from 2 h to 8 h. Surface characterizations were performed using X-ray diffractometery (XRD), scanning electron microscopy (SEM), Raman spectroscopy, nanoindentation and nano scratch testing. Fretting wear behaviors of untreated and oxidized samples were also examined. The formed oxide coating mainly included rutile TiO{sub 2} as well as a little alumina. The weight gain with respect to the oxidation duration obeyed the linear oxidation kinetics law. The growth of oxide grains was in inadequate growth state of incomplete scale coverage from 2nd to 4th hour duration, in normal growth state from 4th to 6th hour duration while in excessive growth state of oxide particle agglomeration and surface roughening from 6th to 8th (or more than 8th) hour duration. The coating thickness increased from 5 μm to 12 μm as oxidation duration increased from 2 h to 8 h. The increase in duration also increased surface roughness and nano hardness as well as adhesion strength of the film/substrate for oxidized samples. The nano hardness value was 10.06 ± 2.15 GPa and the critical load of failure during nano scratch testing was 554.3 ± 6.44 mN for 4 h treated sample. The untreated and oxidized samples showed a same fretting running status and fretting regime with a displacement amplitude of 200 μm while revealing different fretting failure mechanisms. It was mainly abrasive and adhesive wear under ploughing force for untreated sample, while a mix of 3-body abrasion by rolling oxide particles and severe plastic deformation under high contact stress between two ceramic materials for the oxidized samples. The oxide coating was not worn out and improved the fretting wear resistance of titanium alloy. - Highlights: • A thickness of 5–12 μm rutile TiO{sub 2} coating formed under different oxidation durations. • Weight gain with respect to oxidation duration obeyed linear

Wear Resistance of TiC Reinforced Cast Steel Matrix Composite

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Sobula S.

2017-03-01

Full Text Available Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g for base steel.

Sliding wear of steels (used in polished rods of oil pump jack) against polyurethane; Desgaste de deslizamento de acos (usados em hastes de unidade de bombeio de petroleo) contra poliuretano

Energy Technology Data Exchange (ETDEWEB)

Gois, Gelsoneide da Silva [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Engenharia de Materiais; Farias, Aline Cristina Mendes; Lima da Silva, Ruthilene Catarina; Medeiros, Joao Telesforo Nobrega [Universidade Federal do Rio Grande do Norte (PPGEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia de Materiais], e-mail: gelsoneidegg@yahoo.com.br, e-mail: alineastro@yahoo.com.br, e-mail: ruthilene@ufrnet.br, e-mail: medeirosj2@asme.org

2008-07-01

Accelerated sliding tests were carried out in the steels AISI 316, AISI 4140, AISI 1045 coated and AISI 4142 coated, in the dry and lubricated with contaminated oil with 10% SiO{sub 2} conditions. Each cylindrical counterbody with angular generatrix of polyurethane slid against a stationary metallic specimen. The contact pressure changed by increment of normal loads of 10,0 and 2,3 N, velocity of 0,91 m/s and distance of 12 km. The wear rates were calculated through of the mass variation from specimens after each test. The wear morphology was characterized by Optical and Scanning Electron Microscopy, where identified damages by abrasion at two and three bodies. The contaminated lubricant increase the wear rate due to action of the abrasive particles. (author)

Morphology and Performance of 5Cr5MoV Casting Die Steel in the Process of Surfacing

Science.gov (United States)

Song, Yulai; Kong, Xiangrui; Yang, Pengcong; Fu, Hongde; Wang, Xuezhu

2017-12-01

To investigate the microstructures and mechanical properties of the deposited metal on surface of die steel, two layer of weld-seam were prepared on the surface of 5Cr5MoV die steel by arc surfacing. The surface microstructures and microhardness were characterized by scanning electron microscopy, energy dispersive spectrometer and Vickers microhardness tester, respectively. The effect of load on the abrasion resistance and wear mechanism of the base metal and surfacing metal was studied by pin-on-disk tribometer. The results showed that martensite and retained austenite exist in weld-seam, both of them grow up in the form of dendrites and equiaxed grains and microhardness reach 774.2HV. The microstructures of the quenching zone mainly consist of martensite and retained austenite, while tempered martensite is the dominant phase in partial quenching zone. The abrasion resistance of the surfacing metal is superior to the base metal based on the results of wear test. The wear rates of surfacing metal and base metal raise with the increase of load. The wear rates of base metal raise extremely when the load reach 210N. Both of two kinds of materials have the similar wear mechanism, namely, abrasive wear at low load, oxidative wear and adhesive wear at high load.

Abrasives and possibilities of increase in efficiency of abrasive waterjets

Czech Academy of Sciences Publication Activity Database

Sitek, Libor; Martinec, Petr

2016-01-01

Roč. 9, March 2016 (2016), s. 877-881 ISSN 1805-0476 R&D Projects: GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : high-speed waterjets * abrasive waterjets * abrasives * garnet * zirconia Subject RIV: JQ - Machines ; Tools http://www.mmscience.eu/content/file/archives/MM_Science_201603.pdf

Research on operation mode of abrasive grain during grinding

Science.gov (United States)

Ivanova, T. N.; Dement’ev, V. B.; Nikitina, O. V.

2018-03-01

The processing of materials by cutting with an abrasive tool is carried out by means of thousands of grains bonded together as a single whole. The quality of the abrasive tool is defined by cutting properties of abrasive grains and depends on features of spreading the temperature field in time and in the abrasive grain volume. Grains are exposed to heating and cooling during work. It leads to undesired effects such as a decrease of durability of grain retention in the binder, hardness, intensification of diffusion and oxidation processes between the binder and the grain, the occurrence of considerable temperature stresses in the grain itself. The obtained equation which allows calculation of temperature field of grain for one rotation of grinding wheel shows that the temperature of the wheel depends on grinding modes and thermophysical properties of abrasive material. Thus, as the time of contact of grain with processed material increases, the temperature in the cutting area rises. As thermophysical properties increase, the temperature in cutting area decreases. Thermal working conditions are determined to be different from each other depending on contact time of the grain and the material. For example, in case of creep-feed grinding, the peak value of temperature is higher than during multistep grinding; the depth of expansion is greater. While the speed of the thermal process in creep-feed grinding is 2-3 times lower than in multistep grinding, the gradient reduces 3-4 times. The analysis of machining methods shows that creep-feed grinding ensures greater depth of grain heating, a smaller heating rate and a reduced velocity gradient. It causes a decrease of probable allotropic modifications and prevents from occurring of heat strokes - cracking of grains due to high temperature falls. Consequently, it is necessary to employ creep-feed grinding to increase the efficiency of abrasive tool employing. Three operation modes of grinding wheel including blunting, full

Three-dimensional in vitro measurements of tooth wear using fluoridated dentifrices.

Science.gov (United States)

Al-Mashhadani, A; Plygkos, I; Bozec, L; Rodriguez, J M

2016-09-01

The aim of this study was to compare differences in wear of human enamel and dentine in vitro using a 3D measurement method comparing silica versus non-silica containing fluoridated dentifrices (Colgate Total(™) [CT] or Fluor Protector Gel(™) [FPG]). Mounted native enamel (n = 36) and polished dentine (n = 36) samples were subjected to 10 wear cycles. Each cycle consisted of: (1) 1 hour remineralization in artificial saliva (AS); (2) 10 minute erosion (0.3% citric acid; pH = 2.8); (3) 2 minute toothbrush abrasion in AS (G1, control) or a slurry of 3:1 by weight of AS:dentifrice (G2 = CT; G3 = FPG) under a load of 2 N. Each group contained 12 enamel and 12 dentine samples. Paired pre- and post-wear scans made with a contacting scanner were digitally superimposed using ball bearings as datum. Mean and (SD) enamel wear was G1 = 21.9 μm (6.4); G2 = 15.2 μm (2.8); G3 = 16.9 μm (3.2). Enamel wear was not different between dentifrices (p = 0.99). Both dentifrices resulted in less enamel wear compared to the control (p Dental Association.

Wear resistance of layers hard faced by the high-alloyed filler metal

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Dušan Arsić

2016-10-01

Full Text Available The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by high hardness and wear resistance. In experiments, the sliding speed and the normal loading were varied and the wear scar was monitored, based on which the volume of the worn material was calculated analytically. The contact duration time was monitored over the sliding path of 300 mm. The most intensive wear was established for the loading force of 100 N and the sliding speed of 1 m.s-1, though the significant wear was also noticed in conditions of the small loading and speed of 0.25 m.s-1, which was even greater that at larger speeds.

Corrosion and wear behavior of functionally graded Al2024/SiC composites produced by hot pressing and consolidation

Energy Technology Data Exchange (ETDEWEB)

Erdemir, Fatih; Canakci, Aykut, E-mail: aykut@ktu.edu.tr; Varol, Temel; Ozkaya, Serdar

2015-09-25

Highlights: • Functionally graded Al2024/SiC composites were produced by hot pressing. • Effect of the number of graded layers was investigated on the corrosion behavior. • Functionally graded composites has the most corrosion resistant than composites. • Wear mechanisms of Al2024/SiC composites were explained. - Abstract: Functionally graded Al2024/SiC composites (FGMs) with varying percentage of SiC (30–60%) were produced by hot pressing and consolidation method. The effects of SiC content and number of layers of Al2024/SiC FGMs on the corrosion and wear behaviors were investigated. The microstructures of these composites were characterized by a scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). The corrosion performances of composites were evaluated by potentiodynamic polarization scans in 3.5% NaCl solution. Corrosion experiments shows that corrosion rate (1109 mpy) of two layered FGMs which containing 50 wt.% SiC were much higher than Al2024 matrix (2569 mpy) and Al2024/50 wt.% SiC composite (2201 mpy). Mechanical properties of these composites were evaluated by microhardness measurements and ball-on-disk wear tests. As the applied load change from 15 to 20 N, the wear rates of the Al2024 increased significantly and wear mechanism transformed from mild to severe wear regime. It has been shown that Al2024/40 wt.% SiC composite has lower wear rate where adhesive and abrasive wear mechanisms play a major role.

Abrasive Wear of AlSi12-Al2O3 Composite Materials Manufactured by Pressure Infiltration

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Kremzer M.

2016-09-01

Full Text Available The aim of this study is to investigate tribological properties of EN AC-AlSi12 alloy composite materials matrix manufactured by pressure infiltration of Al2O3 porous preforms. In the paper, a technique of manufacturing composite materials was described in detail as well as wear resistance made on pin on disc was tested. Metallographic observations of wear traces of tested materials using stereoscopic and confocal microscopy were made. Studies allow concluding that obtained composite materials have much better wear resistance than the matrix alloy AlSi12. It was further proved that the developed technology of their preparation consisting of pressure infiltration of porous ceramic preforms can find a practical application.

Friction and wear performance of bearing ball sliding against diamond-like carbon coatings

Science.gov (United States)

Wu, Shenjiang; Kousaka, Hiroyuki; Kar, Satyananda; Li, Dangjuan; Su, Junhong

2017-01-01

We have studied the tribological properties of bearing steel ball (Japan standard, SUJ2) sliding against tetrahedral amorphous carbon (ta-C) coatings and amorphous hydrogenated carbon (a-C:H) coatings. The reciprocating sliding testes are performed with ball-on-plate friction tester in ambient air condition. Analysis of friction coefficient, wear volume and microstructure in wear scar are carried out using optical microscopy, atom force morphology (AFM) and Raman spectroscopy. The results show the SUJ2 on ta-C coating has low friction coefficient (around 0.15) but high wear loss. In contrast, the low wear loss of SUJ2 on a-C:H coating with high (around 0.4) and unsteady friction coefficient. Some Fe2O3, FeO and graphitization have been found on the wear scar of SUJ2 sliding against ta-C coating. Nearly no oxide materials exist on the wear scar of SUJ2 against a-C:H coating. The mechanism and hypothesis of the wear behavior have been investigated according to the measurement results. This study will contribute to proper selection and understand the tribological performance of bearing steels against DLC coatings.

Improvement of finishing antifriction treatment without abrasive of the rubbing parts surfaces of agricultural machineries

Directory of Open Access Journals (Sweden)

I.V. Shepelenk

2014-06-01

Full Text Available The wear of machines and mechanisms after rubbing is a major concern. The costs of manufacturing and restoration parts for agricultural machinery are enormous such as the trunnions pinions of hydraulic pumps. Finishing treatment antifriction without abrasive (FTAA is the existing method of manufacturing and restoration, but it has disadvantages like low work efficiency and the frequent replacement of the instrument. That is why a new method of FTAA parts type ''tree'' has been developed called vibratory finishing treatment antifriction without abrasive, (VFTAA method. The study was conducted at the laboratory of the State Technical University of Kirovograd (Ukraine where turn 16K20, the profilograph-profilometer "Talysurf-5", the scanning electron microscope REM-106I, friction machine MI-1M and the stand KI-28097-02M were used respectively for machining, study of micro relief before and after the VFTAA, microstructure, wear resistance and the determination of the break-in period of parts. The results showed that the VFTAA helped reduce the roughness Ra of the samples studied by half compared to the samples processed by polishing and 1.3 times compared to those treated with the FTAA, the break-in period has been reduced four times , this leads to an increase in the life of the hydraulic pump. This technology can be recommended for manufacturing and repair of hydraulic units of agricultural machineries.

Metal nitride coatings by physical vapor deposition (PVD) for a wear resistant aluminum extrusion die.

Science.gov (United States)

Lee, Su Young; Kim, Sang Ho

2014-12-01

The purpose of this study is to investigate the friction and wear behaviors of CrN, TiN, CrAlN, and TiAIN coated onto SKD61 for application to Al 7000 series extrusion dies. On the wear test, the experimental parameters are the load and the counter material's temperature. The results showed that the friction coefficient increased with load but decreased with the counter material's temperature, and the friction coefficients of CrN and CrAIN were lower than the friction coefficients of TiAIN and TIN, especially at a higher temperature. The wear track with different coatings identified different wear behaviors; the wear behavior of CrAIN was found to be abrasive, but the wear behavior of TiN, CrN, and TiAIN was adhesive. Therefore, CrAIN showed the least wear loss with a lower friction coefficient and less adhesion with counter materials at the highest range of wear load and temperature. This resulted in the easy formation of aluminum oxide in the wear track and less Al adhesion; moreover during the hard second phase, AIN dispersed in the film during deposition.

Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

Science.gov (United States)

Ebrahimi, Mansoureh; Mahboubi, Farzad; Naimi-Jamal, M. Reza

2016-12-01

The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH4 flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH4 ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH4 flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

Nano-crystallization of steel wire and its wear behavior

Energy Technology Data Exchange (ETDEWEB)

Xu, Y.H. [School of Electromechanical Engineering, Xian University of Architecture and Technology, Xian 716000 (China) and School of Materials Science and Engineering, Northwestern Polytecnical University, Xian 710072 (China)], E-mail: xuyunhua@vip.163.com; Peng, J.H. [School of Electromechanical Engineering, Xian University of Architecture and Technology, Xian 716000 (China); Fang, L. [State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, Xian 710049 (China)

2008-06-15

As carbon steel wire is widely used in civil engineering and industry, it is quite important to increase its strength. In the present paper, a severe cold drawing approach is applied to increase strength and is shown to produce nano grains. With increasing true strain, the tensile strength increases continuously and the cementite flake thickness decreases correspondingly. It is observed by transmission electron microscopy that a significant amount of cementite flakes have been fragmented and dissolved at true strains. Finally, the grains are transformed to nano-sized crystals. Additionally, the cold drawn nano-sized steel wire has been knitted and filled with polyurethane to produce a composite material. Three-body abrasive wear tests show that the wear resistance of the test material is even better than that of high-Cr white cast irons.

Nano-crystallization of steel wire and its wear behavior

International Nuclear Information System (INIS)

Xu, Y.H.; Peng, J.H.; Fang, L.

2008-01-01

As carbon steel wire is widely used in civil engineering and industry, it is quite important to increase its strength. In the present paper, a severe cold drawing approach is applied to increase strength and is shown to produce nano grains. With increasing true strain, the tensile strength increases continuously and the cementite flake thickness decreases correspondingly. It is observed by transmission electron microscopy that a significant amount of cementite flakes have been fragmented and dissolved at true strains. Finally, the grains are transformed to nano-sized crystals. Additionally, the cold drawn nano-sized steel wire has been knitted and filled with polyurethane to produce a composite material. Three-body abrasive wear tests show that the wear resistance of the test material is even better than that of high-Cr white cast irons

Wear behaviors of pure aluminum and extruded aluminum alloy (AA2024-T4) under variable vertical loads and linear speeds

Science.gov (United States)

Jung, Jeki; Oak, Jeong-Jung; Kim, Yong-Hwan; Cho, Yi Je; Park, Yong Ho

2017-11-01

The aim of this study was to investigate the transition of wear behavior for pure aluminum and extruded aluminum alloy 2024-T4 (AA2024-T4). The wear test was carried using a ball-on-disc wear testing machine at various vertical loads and linear speeds. The transition of wear behaviors was analyzed based on the microstructure, wear tracks, wear cross-section, and wear debris. The critical wear rates for each material are occurred at lower linear speed for each vertical load. The transition of wear behavior was observed in which abrasion wears with the generation of an oxide layer, fracture of oxide layer, adhesion wear, severe adhesion wear, and the generation of seizure occurred in sequence. In case of the pure aluminum, the change of wear debris occurred in the order of blocky, flake, and needle-like debris. Cutting chip, flake-like, and coarse flake-like debris was occurred in sequence for the extruded AA2024-T4. The transition in the wear behavior of extruded AA2024-T4 occurred slower than in pure aluminum.

Preparation and Properties of Superamphiphobic Wear-resistance PPS-based Coating

Directory of Open Access Journals (Sweden)

WANG Huai-yuan

2017-01-01

Full Text Available Superamphiphobic wear-resistance PPS-based coatings were prepared by a simple spraying method with a pore-forming reagent of NH4HCO3 and nano-filler of carbon nanotubes (CNTs.The surface morphology and the hydrophobicity,oleophobicity of the coating were analyzed by scanning electron microscope (SEM and contact angle meter.The wear-resistance of the coating was verified by sanding method with given load.The results indicate that a rough surface is obtained after pore-forming,and the porous structures in combination with the CNTs construct the special micro/nano-scale network structures.When the mass fraction of NH4HCO3 is 5%,the contact angles of the coating for water,glycerine and ethylene glycol are 162°,158° and 152°,showing superamphiphobic property.After polished 10000 times by abrasive paper,the coating shows slight friction marks and remains high hydrophobicity,exhibiting excellent wear-resistance.

An in vitro study of dental enamel wear by restorative materials using radiometric method; Estudo in vitro do desgaste do esmalte dental pelos materiais restauradores utilizando metodo radiometrico

Energy Technology Data Exchange (ETDEWEB)

Adachi, Lena Katekawa

2000-07-01

There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of {sup 32}P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

Cutting concrete with abrasion jet

International Nuclear Information System (INIS)

Yie, G.G.

1982-01-01

Fluidyne Corporation has developed a unique process and apparatus that allow selected abrasives to be introduced into high-speed waterjet to produce abrasive-entrained waterjet that has high material-cutting capabilities, which is termed by Fluidyne as the Abrasion Jet. Such Abrasion Jet has demonstrated capability in cutting hard rock and concrete at a modest pressure of less than 1360 bars (20,000 psi) and a power input of less than 45 kW (60 horsepower). Abrasion Jet cutting of concrete is characterized by its high rate of cutting, flexible operation, good cut quality, and relatively low costs. This paper presents a general description of this technology together with discussions of recent test results and how it could be applied to nuclear decontamination and decommissioning work. 8 references

Study of surface roughness and flank wear in hard turning of AISI 4140 steel with coated ceramic inserts

Energy Technology Data Exchange (ETDEWEB)

Das, Sudhansu Ranjan; Kuma, Amaresh [National Institute of Technology, Jamshedpur (India); Dhupal, Debabrata [Veer Surendra Sai University of Technology, Burla (India)

2015-10-15

This experimental investigation deals with dry hard turning of AISI 4140 steel using PVD-TiN coated Al{sub 2}O{sub 3}+TiCN mixed ceramic inserts. The combined effect of cutting parameters (cutting speed, feed and depth of cut) on performance characteristics such as surface roughness and flank wear is explored by Full factorial design (FFD) and analysis of variance (ANOVA). The results show that feed is the principal cutting parameter influencing surface roughness, followed by cutting speed. However, flank wear is affected by the cutting speed and interaction of feed-depth of cut, although depth of cut has not been found statistically significant, but flank wear is an increasing function of depth of cut. Observations are made on the machined surface, and worn tool by Scanning electron microscope (SEM) to establish the process. Abrasion was the major wear mechanism found during hard turning within the studied range. The effect of tool wear on surface roughness was also studied. The experimental data were analyzed to predict the optimal range of surface roughness and flank wear. Based on Response surface methodology (RSM), mathematical models were developed for surface roughness (Ra) and flank wear (VB) with 95% confidence level. Finally, under optimum cutting conditions (obtained by response optimization technique), tool life was evaluated to perform cost analysis for justifying the economic viability of coated ceramic inserts in hard turning. The estimated machining cost per part for TiN coated ceramic was found to be lower (Rs. 12.31) because of higher tool life (51 min), which results in the reduction of downtime and increase in savings.

Study of surface roughness and flank wear in hard turning of AISI 4140 steel with coated ceramic inserts

International Nuclear Information System (INIS)

Das, Sudhansu Ranjan; Kuma, Amaresh; Dhupal, Debabrata

2015-01-01

This experimental investigation deals with dry hard turning of AISI 4140 steel using PVD-TiN coated Al_2O_3+TiCN mixed ceramic inserts. The combined effect of cutting parameters (cutting speed, feed and depth of cut) on performance characteristics such as surface roughness and flank wear is explored by Full factorial design (FFD) and analysis of variance (ANOVA). The results show that feed is the principal cutting parameter influencing surface roughness, followed by cutting speed. However, flank wear is affected by the cutting speed and interaction of feed-depth of cut, although depth of cut has not been found statistically significant, but flank wear is an increasing function of depth of cut. Observations are made on the machined surface, and worn tool by Scanning electron microscope (SEM) to establish the process. Abrasion was the major wear mechanism found during hard turning within the studied range. The effect of tool wear on surface roughness was also studied. The experimental data were analyzed to predict the optimal range of surface roughness and flank wear. Based on Response surface methodology (RSM), mathematical models were developed for surface roughness (Ra) and flank wear (VB) with 95% confidence level. Finally, under optimum cutting conditions (obtained by response optimization technique), tool life was evaluated to perform cost analysis for justifying the economic viability of coated ceramic inserts in hard turning. The estimated machining cost per part for TiN coated ceramic was found to be lower (Rs. 12.31) because of higher tool life (51 min), which results in the reduction of downtime and increase in savings.

Study on the wear of TiN/Ti duplex and multilayer coatings in microabrasion tests

International Nuclear Information System (INIS)

Flores, M; De Las Heras, E; Ruelas, R; Rodriguez, E; Bautista, A; Pazos, L; Corengia, P

2008-01-01

Ionic nitriding, on steels, is used to harden the surface of components improving resistance to corrosion and wear and increasing the stress life. Duplex treatments are an alternative for resolving the limitations of very hard coatings on less hard substrates. In this case the duplex treatment consists of an ionic nitriding treatment followed by a single or multilayer coatings deposited by means of the PVD technique. This work presents the influence of the variation in the severity of contact on the kind of wear present in the microabrasion test used to measure the wear coefficient of duplex coatings, consisting of a layer nitrided by DC-pulsed plasma plus TiN coatings and multilayers of TiN/Ti deposited on non-nitrided and nitrided AISI 316L stainless steel and H13 steel. The severity of contact was modified by varying the charge (0.25 to 1 N). The abrasives used were a suspension of 0.1μm diameter diamond particles and a suspension of an average 5 μm diameter aluminum particles. The influence of the presence of relatively soft metallic layers on the determination of the wear coefficient was analyzed in the metal-ceramic multilayers. Two sphere revolving speeds of de 0.05 and 0.154 m/s were used on two microabrasion machines: one commercial and the other built in the UdeG laboratory. The wear marks were photographed and measured with an optic microscope. The value of the critical charge at which the transition occurs between the methods of wear of the substrates and the nitrited samples was determined. Resistance to the AISI 316L steel's microabrasive wear increases with the ionic nitriding treatment. The duplex coatings increase resistance to the wear from the nitrited samples. The wear resistance of the samples with multilayer coatings surpassed that of the duplex samples with multilayer coatings. The greater resistance of the multilayers may be explained by an increase in the resistance to the fracture and not by a increase in surface hardness. The transition

On the performances and wear of WC-diamond like carbon coated tools in drilling of CFRP/Titanium stacks

Science.gov (United States)

Boccarusso, L.; Durante, M.; Impero, F.; Minutolo, F. Memola Capece; Scherillo, F.; Squillace, A.

2016-10-01

The use of hybrid structures made of CFRP and titanium alloys is growing more and more in the last years in the aerospace industry due to the high strength to weight ratio. Because of their very different characteristics, the mechanical fastening represent the most effective joining technique for these materials. As a consequence, drilling process plays a key role in the assembly. The one shot drilling, i.e. the contemporary drilling of the stack of the two materials, seems to be the best option both in terms of time saving and assembly accuracy. Nevertheless, due to the considerable different machinability of fiber reinforced plastics and metallic materials, the one shot drilling is a critical process both for the holes quality and for the tools wear. This research was carried out to study the effectiveness of new generation tools in the drilling of CFRP/Titanium stacks. The tools are made of sintered grains of tungsten carbide (WC) in a binder of cobalt and coated with Diamond like carbon (DLC), and are characterized by a patented geometry; they mainly differ in parent WC grain size and binder percentage. Both the cutting forces and the wear phenomena were accurately investigated and the results were analyzed as a function of number of holes and their quality. The results show a clear increase of the cutting forces with the number of holes for all the used drilling tools. Moreover, abrasive wear phenomena that affect initially the tools coating layer were observed.

Scratch Hardness and Wear Performance of Laser-Melted Steels : Effects of Anisotropy

NARCIS (Netherlands)

Beurs, H. de; Minholts, G.; Hosson, J.Th.M. De

Effects of the orientation of dendrites on the scratch hardness and wear performance of laser-melted steels have been investigated. Scratch experiments have been carried out with a Vickers indenter and wear experiments with a pin-on-disk tester. The deformed structure is investigated, using

Tooth wear and feeding ecology in mountain gorillas from Volcanoes National Park, Rwanda.

Science.gov (United States)

Galbany, Jordi; Imanizabayo, Olive; Romero, Alejandro; Vecellio, Veronica; Glowacka, Halszka; Cranfield, Michael R; Bromage, Timothy G; Mudakikwa, Antoine; Stoinski, Tara S; McFarlin, Shannon C

2016-03-01

Ecological factors have a dramatic effect on tooth wear in primates, although it remains unclear how individual age contributes to functional crown morphology. The aim of this study is to determine how age and individual diet are related to tooth wear in wild mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. We calculated the percent of dentine exposure (PDE) for all permanent molars (M1-M3) of known-age mountain gorillas (N = 23), to test whether PDE varied with age using regression analysis. For each molar position, we also performed stepwise multiple linear regression to test the effects of age and percentage of time spent feeding on different food categories on PDE, for individuals subject to long-term observational studies by the Dian Fossey Gorilla Fund International's Karisoke Research Center. PDE increased significantly with age for both sexes in all molars. Moreover, a significant effect of gritty plant root consumption on PDE was found among individuals. Our results support prior reports indicating reduced tooth wear in mountain gorillas compared to western gorillas, and compared to other known-aged samples of primate taxa from forest and savanna habitats. Our findings corroborate that mountain gorillas present very low molar wear, and support the hypothesis that age and the consumption of particular food types, namely roots, are significant determinants of tooth wear variation in mountain gorillas. Future research should characterize the mineral composition of the soil in the Virunga habitat, to test the hypothesis that the physical and abrasive properties of gritty foods such as roots influence intra- and interspecific patterns of tooth wear. © 2015 Wiley Periodicals, Inc.

Wear Resistance Analysis of A359/SiC/20p Advanced Composite Joints Welded by Friction Stir Welding

Directory of Open Access Journals (Sweden)

O. Cuevas Mata

Full Text Available Abstract Advancement in automotive part development demands new cost-effective materials with higher mechanical properties and improved wear resistance as compared to existing materials. For instance, Aluminum Matrix Composites (AMC shows improved mechanical properties as wear and abrasion resistance, high strength, chemical and dimensional stability. Automotive industry has focused in AMC for a variety of applications in automotive parts in order to improve the fuel economy, minimize vehicle emissions, improve design options, and increase the performance. Wear resistance is one of the most important factors in useful life of the automotive components, overall in those components submitted to mechanical systems like automotive brakes and suspensions. Friction Stir Welding (FSW rises as the most capable process to joining AMC, principally for the capacity to weld without compromising their ceramic reinforcement. The aim of this study is focused on the analysis of wear characteristics of the friction-stir welded joint of aluminum matrix reinforced with 20 percent in weight silicon carbide composite (A359/SiC/20p. The experimental procedure consisted in cut samples into small plates and perform three welds on these with a FSW machine using a tool with 20 mm shoulder diameter and 8 mm pin diameter. The wear features of the three welded joints and parent metal were analyzed at constant load applying 5 N and a rotational speed of 100 rpm employing a Pin-on - Disk wear testing apparatus, using a sapphire steel ball with 6 mm diameter. The experimental results indicate that the three welded joints had low friction coefficient compared with the parent metal. The results determine that the FSW process parameters affect the wear resistance of the welded joints owing to different microstructural modifications during welding that causes a low wear resistance on the welded zone.

Is clinical performance adversely affected by wearing gloves during paediatric peripheral intravenous cannulation?

Science.gov (United States)

Zhang, Michael; Lee, Mark; Knott, Susan

2014-10-01

To investigate if wearing protective gloves during paediatric intravenous cannulation affects performance of the procedure. This was a prospective observational study. Peripheral intravenous cannulation (PIVC) performed within the Paediatric ED was observed and recorded over a 12 month period. Data were compared between those clinicians wearing gloves and those not wearing gloves during PIVC. One thousand and twenty paediatric cannulations were recorded during the observed period. The mean age of the children was 5.79 years. The overall success rate of cannulation was 86.18% and first attempt success rate 76.08%. Overall, gloves were used by 54.31% of clinicians to establish vascular access; glove use was lowest in the registrar group (41.11% compliance rate). The glove-wearing group had comparable overall success rate of 85.74% (475/554) to the no-gloves group of 86.70% (404/466). The difference was not statistically significant (P > 0.05). Higher incidence of significant blood spillage during the procedure was observed among clinicians wearing no gloves (16.74%) in comparison with their glove-wearing counterparts (9.03%, P glove-wearing group and no-gloves group (3.94% vs 3.76%, P > 0.05). The present study shows that the use of protective gloves was not associated with adverse outcomes of clinical performance during paediatric cannulation. The low compliance rate of gloves use is alarming, and many clinicians might be exposed to potential blood-borne infections. Clinicians should be encouraged and supported to use gloves for paediatric cannulation. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Fabrication and wear protection performance of superhydrophobic surface on zinc

Energy Technology Data Exchange (ETDEWEB)

Wan Yong, E-mail: wanyong@qtech.edu.cn [School of Mechanical Engineering, Qingdao Technological University, 11 Fushun Road, Qingdao 266033 (China); Wang Zhongqian; Xu Zhen; Liu Changsong [School of Mechanical Engineering, Qingdao Technological University, 11 Fushun Road, Qingdao 266033 (China); Zhang Junyan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Lanzhou 730000 (China)

2011-06-15

A simple two-step process has been developed to render zinc surface superhydrophobic, resulting in low friction coefficient and long wear resistance performance. The ZnO film with uniform and packed nanorod structure was firstly created by immersing the zinc substrates into 4% N,N-dimethylformamide solution. The as-fabricated surface was then coated a layer of fluoroalkylsilane (FAS) by gas phase deposition. Scanning electron microscopy (SEM) and water contact angle (WCA) measurement have been performed to characterize the morphological feature, chemical composition and superhydrophobicity of the surface. The resulting surfaces have a WCA as high as 156 deg. and provide effective friction-reducing and wear protection for zinc substrate.

Fabrication and wear protection performance of superhydrophobic surface on zinc

International Nuclear Information System (INIS)

Wan Yong; Wang Zhongqian; Xu Zhen; Liu Changsong; Zhang Junyan

2011-01-01

A simple two-step process has been developed to render zinc surface superhydrophobic, resulting in low friction coefficient and long wear resistance performance. The ZnO film with uniform and packed nanorod structure was firstly created by immersing the zinc substrates into 4% N,N-dimethylformamide solution. The as-fabricated surface was then coated a layer of fluoroalkylsilane (FAS) by gas phase deposition. Scanning electron microscopy (SEM) and water contact angle (WCA) measurement have been performed to characterize the morphological feature, chemical composition and superhydrophobicity of the surface. The resulting surfaces have a WCA as high as 156 deg. and provide effective friction-reducing and wear protection for zinc substrate.

Microstructure and wear of in-situ Ti/(TiN + TiB) hybrid composite layers produced using liquid phase process

Energy Technology Data Exchange (ETDEWEB)

Yazdi, R., E-mail: ryazdi@ut.ac.ir; Kashani-Bozorg, S.F.

2015-02-15

Tungsten inert gas (TIG) technique was conducted on commercially pure (CP)-Ti substrate, which was coated with h-BN-based powder mixture prior to the treatment. The treated surfaces were evaluated and characterized by means of scanning electron microscope (SEM), X-ray diffraction analysis, and electron dispersive spectrometry (EDS). The microhardness and wear experiment were also performed by using a microhardness machine and pin-on-disk tribometer. As h-BN reacted with titanium, an in-situ hybrid composite layer was formed showing near stoichiometric dendrites of TiN, platelets of TiB and interdendritic regions of α′-Ti martensite crystal structures. The population level of TiN and TiB regions were found to increase using a pre-placed powder mixture with greater h-BN content. However, the fabricated layers exhibited cracking and porosity; these were minimized by adjusting arc energy density and h-BN content of powder mixture. The microhardness value of the fabricated hybrid composite layers was found to be in the range of ∼650 HV{sub 0.2}–1000 HV{sub 0.2}; this is three to five times higher than that of the untreated CP-Ti substrate. In addition, the in-situ hybrid composite layers exhibited superior wear behavior over CP-Ti substrate; this is attributed to the formation of newly formed ceramic phases in the solidified surface layers and good coherent interface between the composite layer and CP-substrate. Meanwhile, severe adhesive wear mechanism of CP-titanium surface changed to mild abrasive one as a result of surface treatment. - Highlights: • In-situ Ti/(TiN + TiB) hybrid composite layers were synthesized by TIG processing on commercially pure titanium. • The microstructure features were characterized by several methods. • Microhardness enhanced three to five times higher than that of the CP-Ti substrate after surface modification. • The fabricated composite layers improved wear resistance of CP-titanium. • Severe adhesive wear mechanism of

Wear and corrosion performance of metallurgical coatings in sodium

International Nuclear Information System (INIS)

Johnson, R.N.; Farwick, D.G.

1980-01-01

The friction, wear, and corrosion performance of several metallurgical coatings in 200 to 650 0 C sodium are reviewed. Emphasis is placed on those coatings which have successfully passed the qualification tests necessary for acceptance in breeder reactor environments. Tests include friction, wear, corrosion, thermal cycling, self-welding, and irradiation exposure under as-prototypic-as-possible service conditions. Materials tested were coatings of various refractory metal carbides in metallic binders, nickel-base and cobalt-base alloys and intermetallic compounds such as the aluminides and borides. Coating processes evaluated included plasma spray, detonation gun, sputtering, spark-deposition, and solid-state diffusion

Friction, adhesion and wear properties of PDMS films on silicon sidewalls

International Nuclear Information System (INIS)

Penskiy, I; Gerratt, A P; Bergbreiter, S

2011-01-01

This paper demonstrates the first tests of friction, adhesion and wear properties of thin poly(dimethylsiloxane) (PDMS) films on the sidewalls of silicon-on-insulator structures. The test devices were individually calibrated using a simple method that included optical and electrical measurements. The static coefficient of friction versus normal pressure curves were obtained for PDMS–PDMS, PDMS–silicon and silicon–silicon sidewall interfaces. The effects of aging on friction and adhesion properties of PDMS were also evaluated. The results of friction tests showed that the static coefficient of friction follows the JKR contact model, which means that the friction force depends on the apparent area of contact. The wear tests showed high resistance of PDMS to abrasion over millions of cycles.

Influence of applied load on wear behavior of C/C-Cu composites under electric current

Directory of Open Access Journals (Sweden)

Jian Yin

2017-04-01

Full Text Available Using carbon fiber needled fabrics with Cu-mesh and graphite powder as the preform, Cu mesh modified carbon/carbon(C/C-Cu composites were prepared by chemical vapor deposition (CVD with C3H6 and impregnation-carbonization (I/C with furan resin. C/C composites, as a comparison, were also prepared. Their microstructures and wear morphologies were observed by optical microscopy (OM and scanning electron microscope (SEM, respectively. Wear behavior of C/C and C/C-Cu composites under different applied loads were investigated on a pin-on-disc wear tester. The results show that Cu meshes are well dispersed and pyrolytic carbon is in rough laminar structure. Both C/C and C/C-Cu composites had good wear properties. The current-carrying capacity of C/C-Cu composites increases and the arc discharge is hindered as the applied load increases from 40 N to 80 N. Both C/C and C/C-Cu composites had good wear properties. The mass wear rate of C/C-Cu composites under 80 N was only 4.2% of that under 60 N. In addition, C/C-Cu composites represent different wear behaviors because wear mechanisms of arc erosion, abrasive wear, adhesive wear, and oxidative wear are changing under different applied loads.

[Influences of composition on brush wear of composite resins. Influences of particle size and content of filler].

Science.gov (United States)

Yuasa, S

1990-07-01

The influences of the composition on abrasion resistance of composite resins were examined using various experimental composite resins which had various matrix resin, filler size and content. The abrasion test was conducted by the experimental toothbrush abrasion testing machine developed in our laboratory. Three series of heat-curing composite resins were tested. One series was made from a Bis-MPEPP or UDMA monomer, and a silica filler with an average particle size of 0.04, 1.9, 3.8, 4.3, 7.5, 13.8 and 14.1 microns. The filler content of this series was constant at 45 wt%. The second series contained a silica filler of 4.3 microns in a content ranging from 35 to 75 wt%. The third series contained a microfiller (0.04 microns) and macrofiller (4.3 microns) in total content of 45 wt%. In this series, the microfiller was gradually replaced by 5, 15, 25 and 45 wt% of the macrofiller. The results obtained for these three series indicated that the abrasion resistance of composite resins was controlled by the inorganic filler, mainly filler size and content. The abrasion loss did not vary with the difference of matrix resin. When the particle size of the filler was below about 5 microns, the abrasion resistance decreased markedly with the decrease in filler size. The composite resin which contained a 0.04 or 1.9 micron filler was less resistant to toothbrush wear than the unfilled matrix resin. However, the microfiller also contributed to abrasion resistance when used in combination with the macrofiller, although abrasion resistance decreased with the increase in the microfiller concentration. The increase of filler content clearly improved the abrasion resistance when used the macrofiller. The analysis of these results and SEM observations of the brushed surfaces of samples suggested that the toothbrush abrasion was three-body abrasion caused by the abrasive in the toothpaste, and affected by the difference in the particle size between abrasive and filler, and between

Fissure sealant materials: Wear resistance of flowable composite resins.

Science.gov (United States)

Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

2016-01-01

Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

Experimental Research into Technology of Abrasive Flow Machining Nonlinear Tube Runner

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Junye Li

2014-06-01

Full Text Available In the fields of military and civil uses, some special passages exist in many major parts, such as non-linear tubes. The overall performance is usually decided by the surface quality. Abrasive flow machining (AFM technology can effectively improve the surface quality of the parts. In order to discuss the mechanism and technology of abrasive flow machining nonlinear tube, the nozzle is picked up as the researching object, and the self-designed polishing liquid is employed to make research on the key technological parameters of abrasive flow machining linear tube. Technological parameters’ impact on surface quality of the parts through the nozzle surface topography and scanning electron microscopy (SEM map is explored. It is experimentally confirmed that abrasive flow machining can significantly improve surface quality of nonlinear runner, and experimental results can provide technical reference to optimizing study of abrasive flow machining theory.

Sustainability of abrasive processes

DEFF Research Database (Denmark)

Aurich, J.C.; Linke, B.; Hauschild, Michael Zwicky

2013-01-01

, the content of technical presentations in STC G, and the results of a comprehensive literature study. The approach to sustainability includes environmental, social, and economic sustainability in accordance with the definition proposed in the Brundtland Report of the United Nations [156]. The main focus......This paper presents an overview of research on sustainability of abrasive processes. It incorporates results from a round robin study on ‘‘energy-efficiency of abrasive processes’’ which has been carried out within the scientific technical committee ‘‘abrasive processes’’ (STC G) of CIRP...... is on environmental and social sustainability. Economic sustainability will be considered as manufacturing productivity. © 2013 CIRP....

Wear of Polished Steel Surfaces in Dry Friction Linear Contact on Polimer Composites with Glass Fibres

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D. Rus

2013-12-01

Full Text Available It is generally known that the friction and wear between polymers and polished steel surfaces has a special character, the behaviour to friction and wear of a certain polymer might not be valid for a different polymer, moreover in dry friction conditions. In this paper, we study the reaction to wear of certain polymers with short glass fibres on different steel surfaces, considering the linear friction contact, observing the friction influence over the metallic surfaces wear. The paper includes also its analysis over the steel’s wear from different points of view: the reinforcement content influence and tribological parameters (load, contact pressure, sliding speed, contact temperature, etc.. Thus, we present our findings related to the fact that the abrasive component of the friction force is more significant than the adhesive component, which generally is specific to the polymers’ friction. Our detections also state that, in the case of the polyamide with 30% glass fibres, the steel surface linear wear rate order are of 10-4 mm/h, respectively the order of volumetric wear rate is of 10-6 cm3 /h. The resulting volumetric wear coefficients are of the order (10-11 – 10-12 cm3/cm and respectively linear wear coefficients of 10-9 mm/cm.

Sliding-wear resistance of pure near fully-dense B4C under lubrication with water, diesel fuel, and paraffin oil

DEFF Research Database (Denmark)

Ortiz, Angel L.; Leal, Victor Manuel Candelario; Borrero-López, Oscar

2017-01-01

The sliding-wear resistance of pure near fully-dense B4C is investigated, and the wear mode/mechanisms identified, under lubrication with water, diesel fuel, and paraffin oil. It is found that the wear is mild in the three cases, with specific wear rates (SWRs) of 10−16–10−17 m3/N m. Nonetheless......, the wear resistance of the B4C ceramic is one order of magnitude greater under oil lubrication (1016 N m/m3) than under water lubrication (1015 N m/m3), and twice as great for the specific case of paraffin oil than diesel fuel, attributable to the lubricant’s viscosity. It is also found that the wear mode...... is always abrasion, and that the wear mechanisms are plastic deformation and localized fracture with grain pullout. However, in agreement with the macro-wear data, the severity of the wear damage is lower under lubrication with paraffin oil, followed by diesel fuel, and lastly water. Finally...

Progress in abrasive and grinding technology

CERN Document Server

Xu, Xipeng

2009-01-01

The grinding and abrasive processing of materials are machining techniques which use bonded or loose abrasives to remove material from workpieces. Due to the well-known advantages of grinding and abrasive processes, advances in abrasive and grinding technology are always of great import in enhancing both productivity and component quality. In order to highlight the recent progress made in this field, the editor invited 21 world-wide contributions with the aim of gathering together all of the achievements of leading researchers into a single publication. The authors of the 21 invited papers, of

A Review on Parametric Analysis of Magnetic Abrasive Machining Process

Science.gov (United States)

Khattri, Krishna; Choudhary, Gulshan; Bhuyan, B. K.; Selokar, Ashish

2018-03-01

The magnetic abrasive machining (MAM) process is a highly developed unconventional machining process. It is frequently used in manufacturing industries for nanometer range surface finishing of workpiece with the help of Magnetic abrasive particles (MAPs) and magnetic force applied in the machining zone. It is precise and faster than conventional methods and able to produce defect free finished components. This paper provides a comprehensive review on the recent advancement of MAM process carried out by different researcher till date. The effect of different input parameters such as rotational speed of electromagnet, voltage, magnetic flux density, abrasive particles size and working gap on the performances of Material Removal Rate (MRR) and surface roughness (Ra) have been discussed. On the basis of review, it is observed that the rotational speed of electromagnet, voltage and mesh size of abrasive particles have significant impact on MAM process.

A quasi-stationary approach to particle concentration and distribution in gear oil for wear mode estimation

DEFF Research Database (Denmark)

Henneberg, Morten; Eriksen, René Lynge; Jørgensen, Bent

2015-01-01

that particles less than 14 μm dominate the wear. Hence, it is concluded that abrasion dominate the wear, for the gear in operation, and it is concluded to be in quasi-stationary mode. The distribution of the particles is observed in conjunction with the particle quantity to determine a basis for normal...... operation. Limitations to the model in lack of fitting to large and frequent signal spikes are suggested to be caused by measurement equipment and/or model constraints. Predicting the transition from quasi-stationary (normal) mode to break-down mode is made possible by particle quantity detection as well......Suspension of wear particles in gear oil with respect to the diversity of particle size combined with filter mechanisms has been analyzed. Coupling of wear modes from tribology is combined with particle size bins to show how a mathematical model can be expanded to include information gained from...

INTRODUCTION TO THE ANALYSIS OF THE MECHANICS OF THE DIAMOND GRINDING PROCESS WITH THE ACCOUNT OF WEAR OF WHEEL GRAINS

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Feodor NOVIKOV

2017-12-01

Full Text Available The work is devoted to the theoretical analysis of the mechanics of the diamond grinding process, taking into account the wear of the wheel grains for scientifically based choice of optimal processing conditions. A multiplicative probabilistic approach to the generalization of the cutting profile of a diamond grinding wheel in its consideration in a state of some steady wear during processing is considered. This is achieved by working the wheel in a mode of properly established self-sharpening or with the use of effective dressing methods. In this case, the linear wear of individual grains of diamond abrasive located on the working surface of the grinding wheel and opened to mechanical contact with the material being processed is assumed to proportionally to the depth of the introduction of grain into it. The analytical dependence of the maximum thickness of the cut is presented, and the relationship between the maximum grain wear and the accepted universal relative characteristic of the steady wear with the operational parameters of the tool and the grinding mode is shown. The obtained results can be used in the development of analytical models of processing productivity and microgeometric engineering of the treated surface, new approaches to increasing the efficiency of diamond grinding. The research is based on modern technical possibilities of controlling the state of the cutting relief of diamond-abrasive tools, especially in electro-physical-mechanical grinding technologies, for example, using the diamond-spark method developed at the Kharkov Polytechnic Institute.

Study of wear mechanism of chopped fiber reinforced epoxy composite filled with graphite and bronze

Science.gov (United States)

Patil, Nitinchand; Prasad, Krishna

2018-04-01

The combined effect of graphite and sintered bronze with a short glass fiber reinforced epoxy composites was investigated in this work. A pin on disc wear test was carried out to study the wear behaviour and mechanism of the composites. The objective of this work is to develop an alternate friction resistance material for the application of sliding bearing. It was observed that the addition of sintered bronze improved mechanical and thermal stability of the composites as bronze has low contact resistance with graphite and has high thermal conductivity. It was observed from the test results that increased volume percentage of graphite and presence of bronze are play significant role in wear mechanism of the composites. It was observed from the scanning electronic microscopes (SEM) that the abrasive and adhesive wear mechanism was prominent in this study. It was also evident from the result that the frictional force remains stable irrespective of the applied normal load.

Wear performance of garnet aluminium composites at high contact pressure

Science.gov (United States)

Sharma, Anju; Arora, Rama; Kumar, Suresh; Singh, Gurmel; Pandey, O. P.

2016-05-01

To satisfy the needs of the engineering sector, researchers and material scientists in this area adopted the development of composites with tailor made properties to enhance efficiency and cost savings in the manufacturing sector. The technology of the mineral industry is shaping the supply and demand of minerals derived materials. The composites are best classified as high performance materials have high strength-to-weight ratios, and require controlled manufacturing environments for optimum performance. Natural mineral garnet was used as the reinforcement of composite because of satisfactory mechanical properties as well as an attractive ecological alternative to others ceramics. For this purpose, samples have been prepared with different sizesof the garnet reinforcement using the mechanical stirring method to achieve the homogeneously dispersed strengthening phase. A systematic study of the effect of high contact pressure on the sliding wear behaviour of garnet reinforced LM13 alloy composites is presented in this paper. The SEM analysis of the worn samples and debris reveals the clues about the wear mechanism. The drastic improvement in the wear resistance of the composites at high contact pressure shows the high potential of the material to be used in engineering 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.

Quantification of in vitro wear of a synthetic meniscus implant using gravimetric and micro-CT measurements.

Science.gov (United States)

Elsner, Jonathan J; Shemesh, Maoz; Shefy-Peleg, Adaya; Gabet, Yankel; Zylberberg, Eyal; Linder-Ganz, Eran

2015-09-01

A synthetic meniscus implant was recently developed for the treatment of patients with mild to moderate osteoarthritis with knee pain associated with medial joint overload. The implant is distinctively different from most orthopedic implants in its pliable construction, and non-anchored design, which enables implantation through a mini-arthrotomy without disruption to the bone, cartilage, and ligaments. Due to these features, it is important to show that the material and design can withstand knee joint conditions. This study evaluated the long-term performance of this device by simulating loading for a total of 5 million gait cycles (Mc), corresponding to approximately five years of service in-vivo. All five implants remained in good condition and did not dislodge from the joint space during the simulation. Mild abrasion was detected by electron microscopy, but µ-CT scans of the implants confirmed that the damage was confined to the superficial surfaces. The average gravimetric wear rate was 14.5 mg/Mc, whereas volumetric changes in reconstructed µ-CT scans point to an average wear rate of 15.76 mm(3)/Mc (18.8 mg/Mc). Particles isolated from the lubricant had average diameter of 15 µm. The wear performance of this polycarbonate-urethane meniscus implant concept under ISO-14243 loading conditions is encouraging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Single layer and multilayer wear resistant coatings of (Ti,Al)N: a review

International Nuclear Information System (INIS)

PalDey, S.; Deevi, S.C.

2003-01-01

We review the status of (Ti,Al)N based coatings obtained by various physical vapor deposition (PVD) techniques and compare their properties. PVD techniques based on sputtering and cathodic arc methods are widely used to deposit wear resistant (Ti,Al)N coatings. These techniques were further modified to improve the metal ionization rate and to eliminate macrodroplets from plasma streams. We summarize manufacture of target/cathode, substrate materials for deposition of coatings, deposition parameters, and the effect of deposition parameters on the physical and mechanical properties of (Ti,Al)N coatings. It is shown that (Ti,Al)N coatings by PVD enhance the wear, thermal, and oxidation resistance of a wide variety of tool materials. We discuss the wear resistant properties of (Ti,Al)N for various machining applications as compared with coatings such as TiN, Ti(C,N) and (Ti,Zr)N. High hardness (∼28-32 GPa), relatively low residual stress (∼5 GPa), superior oxidation resistance, high hot hardness, and low thermal conductivity make (Ti,Al)N coatings most desirable in dry machining and machining of abrasive alloys at high speeds. Multicomponent coatings based on different metallic and nonmetallic elements combine the benefit of individual components leading to a further refinement of coating properties. Alloying additions such as Cr and Y drastically improve the oxidation resistance, Zr and V improve the wear resistance, whereas, Si increases the hardness and resistance to chemical reactivity of the film. Addition of boron improves the abrasive wear behavior of Ti-Al based coatings due to the formation of TiB 2 and BN phases depending on the deposition conditions. Hafnium based nitrides and carbides have potential for resistance to flank and crater wear. The presence of a large number of interfaces between individual layers of a multilayered structure results in a drastic increase in hardness and strength. (Ti,Al)N multilayer super lattice coatings with lattice

Modeling of Micro Deval abrasion loss based on some rock properties

Science.gov (United States)

Capik, Mehmet; Yilmaz, Ali Osman

2017-10-01

Aggregate is one of the most widely used construction material. The quality of the aggregate is determined using some testing methods. Among these methods, the Micro Deval Abrasion Loss (MDAL) test is commonly used for the determination of the quality and the abrasion resistance of aggregate. The main objective of this study is to develop models for the prediction of MDAL from rock properties, including uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness, apparent porosity, void ratio Cerchar abrasivity index and Bohme abrasion test are examined. Additionally, the MDAL is modeled using simple regression analysis and multiple linear regression analysis based on the rock properties. The study shows that the MDAL decreases with the increase of uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness and Cerchar abrasivity index. It is also concluded that the MDAL increases with the increase of apparent porosity, void ratio and Bohme abrasion test. The modeling results show that the models based on Bohme abrasion test and L type Schmidt rebound hardness give the better forecasting performances for the MDAL. More models, including the uniaxial compressive strength, the apparent porosity and Cerchar abrasivity index, are developed for the rapid estimation of the MDAL of the rocks. The developed models were verified by statistical tests. Additionally, it can be stated that the proposed models can be used as a forecasting for aggregate quality.

The application of metal cutting technologies in tasks performed in radioactive environments

International Nuclear Information System (INIS)

Fogle, R.F.; Younkins, R.M.

1997-01-01

The design and use of equipment to perform work in radioactive environments is uniquely challenging. Some tasks require that the equipment be operated by a person wearing a plastic suit or full face respirator and donning several pairs of rubber gloves. Other applications may require that the equipment be remotely controlled. Other important, design considerations include material compatibility, mixed waste issues, tolerance to ionizing radiation, size constraints and weight capacities. As always, there is the ''We need it ASAP'' design criteria. This paper describes four applications where different types of metal cutting technologies were used to successfully perform tasks in radioactive environments. The technologies include a plasma cutting torch, a grinder with an abrasive disk, a hydraulic shear, and a high pressure abrasive water jet cutter

Microstructural evolution during dry wear test in magnesium and Mg-Y alloy

Energy Technology Data Exchange (ETDEWEB)

Somekawa, Hidetoshi, E-mail: SOMEKAWA.Hidetoshi@nims.go.jp [Research Center for Strategic Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Maeda, Shunsuke; Hirayama, Tomoko; Matsuoka, Takashi [Department of Mechanical Engineering, Doshisha University, 1-3 Miyakodani, Tatara, Kyotanabe 610-0321 (Japan); Inoue, Tadanobu [Research Center for Strategic Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Mukai, Toshiji [Department of Mechanical Engineering, Kobe University, 1-1 Rokkodai, Kobe, 657-8501 (Japan)

2013-01-20

The friction and wear properties of pure magnesium and the Mg-Y alloy were investigated using the pin-on-disk configuration. The friction and wear resistance of the Mg-Y alloy was superior to those of pure magnesium. The wear mechanism was abrasion under all the conditions. The deformed microstructural evolutions near the surface region were observed by transmission electron microscopy and electron backscatter diffraction. The stress and strain states were also evaluated by finite element analysis (FEA). The deformed microstructures of both alloys consisted of the {l_brace}10-12{r_brace} twinning formation and the FEA results showed the occurrence of plastic deformation even at the beginning of the test. The formation of low angle grain boundaries was also confirmed with an increase in the applied load in the Mg-Y alloy. On the other hand, grain refinement due to dynamic recrystallization was observed in pure magnesium as the wear test progressed. The different microstructures resulted from difference in the surface temperature during the wear test, which was estimated to be around 393 K and 363 K for pure magnesium and the Mg-Y alloy, respectively. The high increment temperature in the fine-grained alloys brought about the occurrence of grain boundary sliding, i.e., material softening, which led to a decrease in the friction and wear properties. The present results indicated that one of the methods for enhancing the friction and wear properties is to increase the dynamic recrystallization temperature.

Wear of Flame-Sprayed Ni-Cr-B-Si Powder Coating on Journal for Seal Contact

Directory of Open Access Journals (Sweden)

Hu Sheng-Yen

2016-01-01

Full Text Available Flame-sprayed techniques is used in this paper to coat Ni-Cr-B-Si powder on low-carbon steel or bearing steel materials of the journal surface. The wear tester is used to explore material properties of the binding capability, surface hardness, wear and friction within each layer depth. The normal force is applied in addition to the cladding layer by not only using bearing ball but also oil seal pieces, to explore rubber material of oil seal contact journal. In experiments to explore the material and processing conditions affect the microstructure and hardness of the cladding layer, and at the same hardness, surface roughness to affect the performance of the mill run.The results showed that spraying Ni-Cr-B-Si alloy powder in mild steel sheet to melt and run, cladding layer and the substrate has a uniform distribution of fine abrasive particles and binding effect, causing the substrate surface hardness (HRC about promotion 10 times. While, if sprayed Ni-Cr-B-Si alloy powder to steel panels bearing surface because the surface coated compact structure, can reduce the surface roughness and the coefficient of friction, and more improve the wear resistance of the cladding layer.

Corrosion and Wear Behaviors of Cr-Doped Diamond-Like Carbon Coatings

Science.gov (United States)

Viswanathan, S.; Mohan, L.; Bera, Parthasarathi; Kumar, V. Praveen; Barshilia, Harish C.; Anandan, C.

2017-08-01

A combination of plasma-enhanced chemical vapor deposition and magnetron sputtering techniques has been employed to deposit chromium-doped diamond-like carbon (DLC) coatings on stainless steel, silicon and glass substrates. The concentrations of Cr in the coatings are varied by changing the parameters of the bipolar pulsed power supply and the argon/acetylene gas composition. The coatings have been studied for composition, morphology, surface nature, nanohardness, corrosion resistance and wear resistance properties. The changes in I D / I G ratio with Cr concentrations have been obtained from Raman spectroscopy studies. Ratio decreases with an increase in Cr concentration, and it has been found to increase at higher Cr concentration, indicating the disorder in the coating. Carbide is formed in Cr-doped DLC coatings as observed from XPS studies. There is a decrease in sp 3/ sp 2 ratios with an increase in Cr concentration, and it increases again at higher Cr concentration. Nanohardness studies show no clear dependence of hardness on Cr concentration. DLC coatings with lower Cr contents have demonstrated better corrosion resistance with better passive behavior in 3.5% NaCl solution, and corrosion potential is observed to move toward nobler (more positive) values. A low coefficient of friction (0.15) at different loads is observed from reciprocating wear studies. Lower wear volume is found at all loads on the Cr-doped DLC coatings. Wear mechanism changes from abrasive wear on the substrate to adhesive wear on the coating.

CR TKA UHMWPE Wear Tested after Artificial Aging of the Vitamin E Treated Gliding Component by Simulating Daily Patient Activities

Directory of Open Access Journals (Sweden)

Jens Schwiesau

2014-01-01

Full Text Available The wear behaviour of total knee arthroplasty (TKA is dominated by two wear mechanisms: the abrasive wear and the delamination of the gliding components, where the second is strongly linked to aging processes and stress concentration in the material. The addition of vitamin E to the bulk material is a potential way to reduce the aging processes. This study evaluates the wear behaviour and delamination susceptibility of the gliding components of a vitamin E blended, ultra-high molecular weight polyethylene (UHMWPE cruciate retaining (CR total knee arthroplasty. Daily activities such as level walking, ascending and descending stairs, bending of the knee, and sitting and rising from a chair were simulated with a data set received from an instrumented knee prosthesis. After 5 million test cycles no structural failure of the gliding components was observed. The wear rate was with 5.62±0.53 mg/million cycles falling within the limit of previous reports for established wear test methods.

CR TKA UHMWPE wear tested after artificial aging of the vitamin E treated gliding component by simulating daily patient activities.

Science.gov (United States)

Schwiesau, Jens; Fritz, Bernhard; Kutzner, Ines; Bergmann, Georg; Grupp, Thomas M

2014-01-01

The wear behaviour of total knee arthroplasty (TKA) is dominated by two wear mechanisms: the abrasive wear and the delamination of the gliding components, where the second is strongly linked to aging processes and stress concentration in the material. The addition of vitamin E to the bulk material is a potential way to reduce the aging processes. This study evaluates the wear behaviour and delamination susceptibility of the gliding components of a vitamin E blended, ultra-high molecular weight polyethylene (UHMWPE) cruciate retaining (CR) total knee arthroplasty. Daily activities such as level walking, ascending and descending stairs, bending of the knee, and sitting and rising from a chair were simulated with a data set received from an instrumented knee prosthesis. After 5 million test cycles no structural failure of the gliding components was observed. The wear rate was with 5.62 ± 0.53 mg/million cycles falling within the limit of previous reports for established wear test methods.

Demonstration experience with an abrasive blasting technique for decontaminating concrete pads

International Nuclear Information System (INIS)

Devgun, J.S.; Land, R.R.; Doane, R.W.

1990-01-01

A demonstration was performed for decontaminating a radioactivity contaminated concrete pad with a portable abrasive blasting system. The system utilizes a rotating blast wheel that scours the concrete surface with metal abrasive. The metal abrasive, pulverized concrete dust, and contaminants rebound into a separator chamber. The reusable metal abrasive is recycled, and the pulverized media are removed to an integral dust collection system. The exhaust is HEPA filtered to minimize release of airborne contaminants. However, the technique had limited success in reducing contamination around the cracks and seams in the concrete where the higher activity levels of contamination were detected during the radiological survey before the cleanup. The technique can be successful and cost-effective in decontaminating large areas of low contamination; however, careful characterization and planning are necessary. 3 refs., 3 figs., 1 tabs

Effect of Cobalt on Microstructure and Wear Resistance of Ni-Based Alloy Coating Fabricated by Laser Cladding

Directory of Open Access Journals (Sweden)

Kaiming Wang

2017-12-01

Full Text Available Ni-based alloy powders with different contents of cobalt (Co have been deposited on a 42CrMo steel substrate surface using a fiber laser. The effects of Co content on the microstructure, composition, hardness, and wear properties of the claddings were studied by scanning electron microscopy (SEM, an electron probe microanalyzer (EPMA, X-ray diffraction (XRD, a hardness tester, and a wear tester. The results show that the phases in the cladding layers are mainly γ, M7(C, B3, M23(C, B6, and M2B. With the increase in Co content, the amounts of M7(C, B3, M23(C, B6, and M2B gradually decrease, and the width of the eutectic structure in the cladding layer also gradually decreases. The microhardness decreases but the wear resistance of the cladding layer gradually improves with the increase of Co content. The wear resistance of the NiCo30 cladding layer is 3.6 times that of the NiCo00 cladding layer. With the increase of Co content, the wear mechanism of the cladding layer is changed from abrasive wear to adhesive wear.

Performance evaluation of thin wearing courses through scaled accelerated trafficking.

Science.gov (United States)

2014-01-01

The primary objective of this study was to evaluate the permanent deformation (rutting) and fatigue performance of : several thin asphalt concrete wearing courses using a scaled-down accelerated pavement testing device. The accelerated testing : was ...

Wear studies on diamond layers; Verschleissuntersuchungen an Diamantschichten

Energy Technology Data Exchange (ETDEWEB)

Deuerler, F. [Wuppertal Univ. (Gesamthochschule) (Germany). Fachgebiet Materialkunde; Pohl, M.; Tikana, L. [Bochum Univ. (Germany). Inst. fuer Werkstoffe

2000-08-01

Wear studies were carried out on thin CVD diamond layers on WC/Co hard metal substrate. The diamond and hard metal system was exposed to abrasive particles, and the time to initial failure and the size of the wear crater were recorded. In the cavitation test, vibrational cavitation is induced by a sonotrode immersed in a liquid and excited by ultrasonic waves. The wear damage on the surface are recorded by quantitative image analysis as percent surface damage. The mechanism of layer failure (adhesive, cohesive) can be assessed qualitatively by means of SEM pilctures. The effects of surface pretreatment on the adhesive strength of the coating are investigated as well. [German] Das Verhalten von duennen CVD-Diamantschichten auf WC/Co-Hartmetallsubstraten unter Verschleissbeanspruchung wird beschrieben. Dabei wird der Schichtverbund Diamant-Hartmetall im Strahlverschleisstest abrasiven Partikeln ausgesetzt und die Zeit bis zum ersten Schichtversagen sowie die Groesse des Verschleisskraters registriert. Beim Kavitationstest erzeugt eine durch Ultraschall angeregte Sonotrode, die in eine Fluessigkeit eintaucht, Schwingungskavitation. Die durch Oberflaechenzerruettung verursachten Verschleissschaeden an der Schichtoberflaeche werden ueber quantitative Bildanalyse als prozentuale Flaechenschaedigung erfasst. Der Mechanismus des Schichtversagens (adhaesiv, kohaesiv) kann anhand von REM-Aufnahmen qualitativ beurteilt werden. Die Auswirkungen einer Vorbehandlung der Oberflaeche des Hartmetalls auf die fuer die Anwendung massgebliche Haftfestigkeit der Beschichtung werden betrachtet. (orig.)

Performance tests of an abrasive cut-off systems for the finishing of high-precision casts

OpenAIRE

A. Fedoryszyn; W. T. Meksa; G. Woźnicki

2008-01-01

The paper summarizes the performance data of a newly designed and engineered grinding and cut-off system. The machine is used for separation of models manufactured by the investment casting method. The machine comprises the following units:- base supporting other assemblies and elements: abrasive disc holder and drives; this solution enables an easy replacement and access to holding elements while a belt transmission allows the disc rpm to be varied,- mechanism moving the spindle in the horiz...

Friction and Wear of Metals With a Single-Crystal Abrasive Grit of Silicon Carbide - Effect of Shear Strength of Metal

National Research Council Canada - National Science Library

Miyoshi, Kazuhisa

1978-01-01

An investigation was conducted to examine the removal and plastic deformation of metal as a function of the metal properties when the metal is in sliding contact with a single-crystal abrasive grit of silicon carbide...

Study of Effect of Impacting Direction on Abrasive Nanometric Cutting Process with Molecular Dynamics.

Science.gov (United States)

Li, Junye; Meng, Wenqing; Dong, Kun; Zhang, Xinming; Zhao, Weihong

2018-01-11

Abrasive flow polishing plays an important part in modern ultra-precision machining. Ultrafine particles suspended in the medium of abrasive flow removes the material in nanoscale. In this paper, three-dimensional molecular dynamics (MD) simulations are performed to investigate the effect of impacting direction on abrasive cutting process during abrasive flow polishing. The molecular dynamics simulation software Lammps was used to simulate the cutting of single crystal copper with SiC abrasive grains at different cutting angles (0 o -45 o ). At a constant friction coefficient, we found a direct relation between cutting angle and cutting force, which ultimately increases the number of dislocation during abrasive flow machining. Our theoretical study reveal that a small cutting angle is beneficial for improving surface quality and reducing internal defects in the workpiece. However, there is no obvious relationship between cutting angle and friction coefficient.

Standard test method for wear testing with a pin-on-disk apparatus

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

1.1 This test method covers a laboratory procedure for determining the wear of materials during sliding using a pin-on-disk apparatus. Materials are tested in pairs under nominally non-abrasive conditions. The principal areas of experimental attention in using this type of apparatus to measure wear are described. The coefficient of friction may also be determined. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Wear Characteristics of Ceramic Coating Materials by Plasma Spray under the Lubricative Environment

International Nuclear Information System (INIS)

Kim, Chang Ho

2001-02-01

This paper is to investigate the wear behaviors of two types of ceramics, Al 2 O 3 and TiO 2 , by coated plasma thermal spray method under the lubricative environment. The lubricative environments are grease fluids, a general hydraulic fluids, and bearing fluids. The wear testing machine used a pin on disk type. Wear characteristics, which were friction force, friction coefficient and the specific wear rate, according to the lubricative environments were obtained at the four kinds of load, and the sliding velocity is 0.2m/sec. After the wear experiments, the wear surfaces of the each test specimen were observed by a scanning electronic microscope. The obtained results are as follows. : 1. The friction coefficients of TiO 2 coating materials are 0.11 ∼ 0.16 range and those of Al 2 O 3 are 0.24 ∼ 0.39. The friction coefficient of two coating materials is relative to the hardness of these materials. 2. The friction coefficient of TiO 2 coating materials in three lubricative environments is almost same to each other in spite of changing of applied loads. 3. The friction coefficient of Al 2 O 3 coating materials is more large in low load than high load. And the friction coefficient in grease is more large than a general hydraulic and bearing fluids had almost same friction coefficient. 4. The specific wear rate in TiO 2 is greatly increasing according to change the applied loads, but that in Al 2 O 3 is slightly. And the wear in grease is the least among three lubricating environments. 5. On the wear mechanism by SEM image observation, the wear of Al 2 O 3 is adhesive wear and TiO 3 is abrasive wear

Wear behavior of human enamel against lithium disilicate glass ceramic and type III gold.

Science.gov (United States)

Lee, Ahreum; Swain, Michael; He, Lihong; Lyons, Karl

2014-12-01

The wear behavior of human enamel that opposes different prosthetic materials is still not clear. The purpose of this in vitro study was to investigate and compare the friction and wear behavior of human tooth enamel that opposes 2 indirect restorative materials: lithium disilicate glass ceramic and Type III gold. Friction-wear tests on human enamel (n=5) that opposes lithium disilicate glass ceramic (n=5) and Type III gold (n=5) were conducted in a ball-on-flat configuration with a reciprocating wear testing apparatus. The wear pairs were subjected to a normal load of 9.8 N, a reciprocating amplitude of approximately 200 μm, and a reciprocating frequency of approximately 1.6 Hz for up to 1100 cycles per test under distilled water lubrication. The frictional force of each cycle was recorded, and the corresponding friction coefficient for different wear pairs was calculated. After wear testing, the wear scars on the enamel specimens were examined under a scanning electron microscope. Type III gold had a significantly lower steady-state friction coefficient (P=.009) and caused less wear damage on enamel than lithium disilicate glass ceramic. Enamel that opposed lithium disilicate glass ceramic exhibited cracks, plow furrows, and surface loss, which indicated abrasive wear as the prominent wear mechanism. In comparison, the enamel wear scar that opposed Type III gold had small patches of gold smear adhered to the surface, which indicated a predominantly adhesive wear mechanism. A lower friction coefficient and better wear resistance were observed when human enamel was opposed by Type III gold than by lithium disilicate glass ceramic in vitro. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Study on design of light-weight super-abrasive wheel

Science.gov (United States)

Nohara, K.; Yanagihara, K.; Ogawa, M.

2018-01-01

Fixed-abrasive tool, also called a grinding wheel, is produced by furnacing abrasive compound which contains abrasive grains and binding powder such as vitrified materials or resins. Fixed-abrasive tool is installed on spindle of grinding machine. And it is given 1,800-2,000 min-1 of spindle rotation for the usage. The centrifugal fracture of the compound of fixed- abrasive tool is one of the careful respects in designing. In recent years, however, super-abrasive wheel as a fixed-abrasive tool has been developed and applied widely. One of the most characteristic respects is that metal is applied for the body of grinding-wheel. The strength to hold abrasive grain and the rigidity of wheel become stronger than those of general grinding wheel, also the lifespan of fixed-abrasive tool becomes longer. The weight of fixed-abrasive tool, however, becomes heavier. Therefore, when the super-abrasive wheel is used, the power consumption of spindle motor becomes larger. It also becomes difficult for the grinding-wheel to respond to sudden acceleration or deceleration. Thus, in order to reduce power consumption in grinding and to obtain quicker frequency response of super-abrasive wheel, the new wheel design is proposed. The design accomplishes 46% weight reduction. Acceleration that is one second quicker than that of conventional grinding wheel is obtained.

Innovative decontamination technology by abrasion in vibratory vessels

International Nuclear Information System (INIS)

Fabbri, Silvio; Ilarri, Sergio

2007-01-01

Available in abstract form only. Full text of publication follows: The possibility of using conventional vibratory vessel technology as a decontamination technique is the motivation for the development of this project. The objective is to explore the feasibility of applying the vibratory vessel technology for decontamination of radioactively-contaminated materials such as pipes and metal structures. The research and development of this technology was granted by the U.S. Department of Energy (DOE). Abrasion processes in vibratory vessels are widely used in the manufacture of metals, ceramics, and plastics. Samples to be treated, solid abrasive media and liquid media are set up into a vessel. Erosion results from the repeated impact of the abrasive particles on the surface of the body being treated. A liquid media, generally detergents or surfactants aid the abrasive action. The amount of material removed increases with the time of treatment. The design and construction of the machine were provided by Vibro, Argentina private company. Tests with radioactively-contaminated aluminum tubes and a stainless steel bar, were performed at laboratory level. Tests showed that it is possible to clean both the external and the internal surface of contaminated tubes. Results show a decontamination factor around 10 after the first 30 minutes of the cleaning time. (authors)

Chemical mechanical polishing of hard disk substrate with {alpha}-alumina-g-polystyrene sulfonic acid composite abrasive

Energy Technology Data Exchange (ETDEWEB)

Lei Hong, E-mail: hong_lei2005@yahoo.com.c [Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Bu Naijing; Chen Ruling; Hao Ping [Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Neng Sima; Tu Xifu; Yuen Kwok [Shenzhen Kaifa Magnetic Recording Co., LTD, Shenzhen, 518035 (China)

2010-05-03

{alpha}-Alumina-g-polystyrene sulfonic acid ({alpha}-Al{sub 2}O{sub 3}-g-PSS) composite abrasive was prepared by surface activation, graft polymerization and sulfonation, successively. The composition, dispersibility and morphology of the product were characterized by Fourier transformed infrared spectroscopy, laser particle size analysis and scanning electron microscopy, respectively. The chemical mechanical polishing (CMP) performances of the composite abrasive on hard disk substrate with nickel-phosphorous plating were investigated. The microscopy images of the polished surfaces show that {alpha}-Al{sub 2}O{sub 3}-g-PSS composite abrasive results in improved CMP and post-CMP cleaning performances than pure {alpha}-alumina abrasive under the same testing conditions.

Submerged cutting of steel by abrasive water jets

International Nuclear Information System (INIS)

Haferkamp, H.; Louis, H.; Meier, G.

1990-01-01

A special cutting head for underwater use was designed and built. Tests were carried out to find out useful parameters for submerged cutting. With regard to the production of secondary waste the abrasive flow rate had to be minimized. This was achieved by using a small water jet nozzle (up to 0.4 mm diameter) and a high pressure (up to 4000 bar) with an optimal abrasive flow rate of about 5 g/s. In the case of a higher ambient pressure a decrease of the cutting performance was measured. But this decrease is not important regarding decommissioning because the ambient pressure is less than 2 bar. An air mantle nozzle was adapted to the cutting head to improve the working distance under water. The air mantle surrounding the abrasive jet lowers the friction between jet and surrounding water and increases the cutting efficiency in the case of greater working distances. (author)

The influence of nominal stress on wear factors of carbon fibre-reinforced polyetheretherketone (PEEK-OPTIMA® Wear Performance) against zirconia toughened alumina (Biolox® delta ceramic).

Science.gov (United States)

Evans, Andrew; Horton, Henrietta; Unsworth, Anthony; Briscoe, Adam

2014-06-01

Carbon fibre-reinforced polyetheretherketone is an attractive alternative to ultra-high-molecular-weight polyethylene in artificial joints, but little has been published on the influence of stress on the wear factor. We know that in ultra-high-molecular-weight polyethylene, the wear factor reduces as the normal stress increases, which is counter-intuitive but very helpful in the case of non-conforming contacts. In this study, carbon fibre-reinforced polyetheretherketone (PEEK-OPTIMA ® Wear Performance) has been investigated in a pin-on-plate machine under steady loads and under stresses typical of hip and knee joints. At stresses below about 6 MPa, wear factors are between 10 and a 100 times lower than for ultra-high-molecular-weight polyethylene but at higher stresses the wear factors increase substantially. © IMechE 2014.

Abrasive water jets for controlled demolition and dismantling

International Nuclear Information System (INIS)

Abudaka, M.; Crofton, P.S.J.

1988-01-01

Abrasive water jets offer an efficient high speed cutting tool for hard materials such as reinforced concrete, tool steel and armour plate. Cutting by abrasive water jets is often described as a cold cutting operation since no heat is developed and any increase in local temperature is immediately cooled by the water jet. Moreover no sparks are generated to ignite a potentially inflammable atmosphere. Mass flow rates of water and abrasive are small (typically 4 litres/min.water and 1 kg/min abrasive) and hence are easy to collect and to dispose of. For these reasons abrasive water jets offer certain advantages in cutting difficult materials in hazardous environments such as in the nuclear industry, offshore oil rigs and petrochemical plant. Available portable cutting systems are described and the advantages of using abrasive water jets are discussed as well as some of the parameters involved in the cutting operation. Finally a description is presented of some typical applications of abrasive water jet cutting. (author)

Study of wear performance of deep drawing tooling

Science.gov (United States)

Naranje, Vishal G.; Karthikeyan, Ram; Nair, Vipin

2017-09-01

One of the most common challenges for many of the mechanical engineers and also in the field of materials science is the issue of occurrences of wear of the material parts which is used in certain applications that involves such surface interactions. In this paper, wear behaviour of particular grade High Carbon High Chromium Steel and many most famously D2, H13, O1 known as the Viking steel has been studied, evaluated and analyzed under certain processing parameters such as speed, load, track diameter and time required for deep drawing process to know it’s the wear rate and coefficient of friction. Also, the significance of the processing parameters which is used for wear testing analysis is also examined.

Wear rate quantifying in real-time using the charged particle surface activation

Science.gov (United States)

Alexandreanu, B.; Popa-Simil, L.; Voiculescu, D.; Racolta, P. M.

1997-02-01

Surface activation, commonly known as Thin Layer Activation (TLA), is currently employed in over 30 accelerator laboratories around the world for wear and/or corrosion monitoring in industrial plants [1-6]. TLA was primarily designed and developed to meet requirements of potential industrial partners, in order to transfer this technique from research to industry. The method consists of accelerated ion bombardment of a surface of interest, e.g., a machine part subjected to wear. Loss of material owing to wear, erosive corrosion or abrasion is characterized by monitoring the resultant changes in radioactivity. In principle, depending upon the case at hand, one may choose to measure either the remnant activity of the component of interest or to monitor the activity of the debris. For applications of the second type, especially when a lubricating agent is involved, dedicated installations have been constructed and adapted to an engine or a tribological testing stand in order to assure oil circulation around an externally placed detection gauge. This way, the wear particles suspended in the lubricant can be detected and the material loss rates quantified in real time. Moreover, in specific cases, such as the one presented in this paper, remnant activity measurements prove to be useful tools for complementary results. This paper provides a detailed presentation of such a case: in situ resistance-to-wear testing of two types of piston rings.

Design and tailoring of Ni-Sn-W composites for bonded abrasive applications

Energy Technology Data Exchange (ETDEWEB)

Kourtoukova, G.L.; Demetry, C.; Biederman, R.R. [Worcester Polytechnic Inst., MA (United States). Materials Science and Engineering Program; Ramanath, S.; Andrews, R.M.; Jacobs, D.S. [Saint-Gobain/Norton Company, Worcester, MA (United States)

2000-01-15

The combination of properties ideal for metal bonds in abrasive products can rarely be achieved in a monolithic material. This research demonstrates a successful approach for producing a composite bond with higher elastic modulus without a significant increase in wear resistance, by taking advantage of the reaction between matrix and reinforcement to produce intermetallics. Composites comprised of a Ni-Sn matrix with continuous W fiber and/or W powder dispersoid were prepared by powder metallurgy methods. Composite specimens densified by hot pressing were characterized with a combination of scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses, measurements of wear resistance, and measurements of Young's modulus and hardness by both bulk and nanoindentation methods. A significant stiffening effect was observed; the elastic modulus of the composites was up to 30% greater than that predicted by a rule of mixtures based on the moduli of the unreacted fiber and matrix constituents alone. As desired, the wear resistance of the composite was approximately equal to that of the Ni-Sn matrix. One contribution to this combination of properties is believed to be the high elastic moduli and likely low fracture toughness of the Ni-W and Ni-Sn intermetallics that are formed. Properties of the Ni-Sn-W composites are contrasted with those of a Ni-Sn matrix reinforced with WC particulate, where no reaction occurs at the interface. (orig.)

Ceramic-bonded abrasive grinding tools

Science.gov (United States)

Holcombe, Jr., Cressie E.; Gorin, Andrew H.; Seals, Roland D.

1994-01-01

Abrasive grains such as boron carbide, silicon carbide, alumina, diamond, cubic boron nitride, and mullite are combined with a cement primarily comprised of zinc oxide and a reactive liquid setting agent and solidified into abrasive grinding tools. Such grinding tools are particularly suitable for grinding and polishing stone, such as marble and granite.

Ceramic-bonded abrasive grinding tools

Science.gov (United States)

Holcombe, C.E. Jr.; Gorin, A.H.; Seals, R.D.

1994-11-22

Abrasive grains such as boron carbide, silicon carbide, alumina, diamond, cubic boron nitride, and mullite are combined with a cement primarily comprised of zinc oxide and a reactive liquid setting agent and solidified into abrasive grinding tools. Such grinding tools are particularly suitable for grinding and polishing stone, such as marble and granite.

Determination of vibration frequency depending on abrasive mass flow rate during abrasive water jet cutting

Czech Academy of Sciences Publication Activity Database

Hreha, P.; Radvanská, A.; Hloch, Sergej; Peržel, V.; Krolczyk, G.; Monková, K.

2014-01-01

Roč. 77, 1-4 (2014), s. 763-774 ISSN 0268-3768 Institutional support: RVO:68145535 Keywords : Abrasive water jet * Abrasive mass flow rate * Vibration Subject RIV: JQ - Machines ; Tools Impact factor: 1.458, year: 2014 http://link.springer.com/article/10.1007%2Fs00170-014-6497-9#page-1

Dry sliding wear behaviour of Al-12Si-4Mg alloy with cerium addition

International Nuclear Information System (INIS)

Anasyida, A.S.; Daud, A.R.; Ghazali, M.J.

2010-01-01

The purpose of this work is to understand the effect of cerium addition on wear resistance behaviour of as-cast alloys. Al-12Si-4 Mg alloys with 1-5 wt% cerium addition were prepared using the casting technique. A sliding wear test was carried out under applied loads of 10 N, 30 N and 50 N at a fixed sliding speed of 1 m/s using a pin-on-disc configuration. The wear test was conducted in dry conditions at room temperature of ∼25 o C. Detailed analysis of the microstructure, worn surface, collected debris and microhardness was undertaken in order to investigate the differences between the as-cast alloys with different levels of cerium addition. The addition of 1-5 wt% cerium was found to lead to the precipitation of intermetallic phases (Al-Ce), resulting a needle-like structures. Increasing cerium content up to 2 wt% improved both wear resistance and microhardness of as-cast alloys. Addition of more than 2 wt% cerium, however, led to a decrease in microhardness, resulting in lower wear resistance of the alloys. Moderate wear was observed at all loads, with specific wear rates (K') ranging from 6.82 x 10 -5 with 2 wt% Ce at applied load of 50 N to 21.48 x 10 -5 mm 3 /N m without added Ce at an applied load of 10 N. Based on K' ranges, the as-cast alloys exhibited moderate wear regimes, and the mechanism of wear is a combination of abrasion and adhesion. Alloy containing 2 wt% Ce, with the highest hardness and lowest K' value, showed the greatest wear resistance.

Cerium Addition Improved the Dry Sliding Wear Resistance of Surface Welding AZ91 Alloy

Directory of Open Access Journals (Sweden)

Qingqiang Chen

2018-02-01

Full Text Available In this study, the effects of cerium (Ce addition on the friction and wear properties of surface welding AZ91 magnesium alloys were evaluated by pin-on-disk dry sliding friction and wear tests at normal temperature. The results show that both the friction coefficient and wear rate of surfacing magnesium alloys decreased with the decrease in load and increase in sliding speed. The surfacing AZ91 alloy with 1.5% Ce had the lowest friction coefficient and wear rate. The alloy without Ce had the worst wear resistance, mainly because it contained a lot of irregularly shaped and coarse β-Mg17Al12 phases. During friction, the β phase readily caused stress concentration and thus formed cracks at the interface between β phase and α-Mg matrix. The addition of Ce reduced the size and amount of Mg17Al12, while generating Al4Ce phase with a higher thermal stability. The Al-Ce phase could hinder the grain-boundary sliding and migration and reduced the degree of plastic deformation of subsurface metal. Scanning electron microscopy observation showed that the surfacing AZ91 alloy with 1.5% Ce had a total of four types of wear mechanism: abrasion, oxidation, and severe plastic deformation were the primary mechanisms; delamination was the secondary mechanism.

Influence of deep cryogenic treatment on structure and wear resistance of materials of hydraulic breaker chisels

Science.gov (United States)

Bolobov, V. I.; BinhLe, Thanh

2018-03-01

It is shown that shallow cryogenic treatment at -75°C (SCT) of the materials of hydraulic breaker chisels - P20, 1080 and D2 steels leads to a decrease (44 ÷ 82%) in the amount of retained austenite and an increase (26 ÷ 99%) in the amount of carbides in the structure of hardened steel, which is accompanied by an increase in its hardness (1.4 ÷ 2.1%) and abrasive wear resistance (10 ÷ 31%) with a simultaneous decrease in impact toughness (19 ÷ 24%). Deep cryogenic treatment at -196°C (DCT) and subsequent low-temperature tempering of D2 steel leads to a significant increase in its wear resistance (98%) and impact toughness (32%).

Early stages of sliding wear behaviour of Al2O3 and SiC reinforced aluminium

International Nuclear Information System (INIS)

Bonollo, F.; Ceschini, L.; Garagnani, G.L.; Palombarini, G.; Tangerini, I.; Zambon, A.

1993-01-01

Al matrix composites reinforced by 10 vol.% Al 2 O 3 and SiC particles were subjected to dry sliding tests against steel using a slider-on-cylinder tribometer. Damage mechanisms were 'micro-machining' of the steel carried out by ceramic particles, plastic deformation and oxidation of the metal matrix, as well as abrasion. The results were discussed on the basis of the third-body wear model. (orig.)

Ion implantation and ion assisted coatings for wear resistance in metals

International Nuclear Information System (INIS)

Dearnaley, G.

1986-01-01

The implantation of electrically accelerated ions of chosen elements into the surface of material provides a method for improving surface properties such as wear resistance. High concentrations of nitrogen implanted into metals create obstacles to dislocation movement, and certain combinations of metallic and non-metallic species will also strengthen the surface. The process is best applied to situations involving mild abrasive wear and operating temperatures that are not too high. Some dramatic increases in life have been reported under such favourable conditions. A more recent development has been the combination of a thin coating with reactive ion bombardment designed to enhance adhesion by ion mixing at the interface and so provide hardness by the formation of finely dispersed nitrides, including cubic boron nitride. These coatings often possess vivid and decorative colours as an added benefit. Developments in the equipment for industrial ion implantation now offer more attractive costs per unit area and a potentially greater throughput of work. A versatile group of related hard vacuum treatments is now emerging, involving the use of intense beams of nitrogen ions for the purpose of tailoring metal surfaces to resist wear. (author)

Friction and Wear Behavior of Several Hard Materials

NARCIS (Netherlands)

Quercia Bianchi, G.; Grigorescu, I.C.; Di Rauso, C.; Contreras, H.; Gutierrez, D.

2001-01-01

Sliding friction, abrasion and erosion tests were performed on several materials: cemented carbides, partially stabilized zirconia (Mg–PSZ), electroless Ni–P coatings and SAE 4140 steel as reference material. Sliding friction test was carried out in a pin-on-disk system. A micro-abrasion test was

Evaluation of refractory lining wear of Companhia Siderurgica Nacional (CSN) blast furnaces

International Nuclear Information System (INIS)

Santos, N.J. dos; Mello, A.H.B. de; Pereira, C.L.; Paula Sarkis, D. de; Martins Filho, D.I.; Banados Perez, H.E.; Carvalho, G.; Daltro, T.F.L.

1984-01-01

The blast furnace refractory linings are submitted to unfavourable conditions such as alkalis attack, temperature, top pressure, abrasion and so forth... After studies on distribution and installation of radioactive sources with low activities in the refractory lining, it was possible to develop a new technique of thickness evaluation and attendance of wearing in the furnace lining. The viability analysis, simulated laboratory tests, localization, identification, installations and periodical measurements of the radioactive sources are described, as well the results obtained on the present campaign of CSN Blast Furnaces. (Author) [pt

Ultrasonic Abrasive Removal Of EDM Recast

Science.gov (United States)

Mandel, Johnny L.; Jacobson, Marlowe S.

1990-01-01

Ultrasonic abrasive process removes layer of recast material generated during electrical-discharge machining (EDM) of damper pocket on turbine blade. Form-fitted tool vibrated ultrasonically in damper pocket from which material removed. Vibrations activate abrasive in pocket. Amount of material removed controlled precisely.

Laser cladding of copper with molybdenum for wear resistance enhancement in electrical contacts

International Nuclear Information System (INIS)

Ng, K.W.; Man, H.C.; Cheng, F.T.; Yue, T.M.

2007-01-01

Laser cladding of Mo on Cu has been attempted with the aim of enhancing the wear resistance and hence increasing the service life of electrical contacts made of Cu. In order to overcome the difficulties arising from the large difference in thermal properties and the low mutual solubility between Cu and Mo, Ni was introduced as an intermediate layer between Mo and Cu. The Ni and Mo layers were laser clad one after the other to form a sandwich layer of Mo/Ni/Cu. Excellent bonding between the clad layer and the Cu substrate was ensured by strong metallurgical bonding. The hardness of the surface of the clad layer is seven times higher than that of the Cu substrate. Pin-on-disc wear tests consistently showed that the abrasive wear resistance of the clad layer was also improved by a factor of seven as compared with untreated Cu substrate. The specific electrical contact resistance of the clad surface was about 5.6 x 10 -7 Ω cm 2

Synthesis and wear behavior of aluminum 6061 alloy reinforced with carbon nanotubes

Science.gov (United States)

Khalil, Abdullah

In the present work, Al6061 alloy was uniformly reinforced with 0.5, 0.75, 1 and 2 wt. % Carbon Nanotubes (CNTs) using two way dispersion method. For consolidation, Spark Plasma Sintering (SPS) was used which resulted in very high densification for the matrix as well as composite. Results showed that addition of CNTs lead to increased hardness of the material and maximum hardness was found for 1 wt. % CNTs. So this composition was selected for detailed wear analysis. Pin-on-disk wear tests were conducted for the monolithic Al6061 and the composite at a constant speed of 0.5 m/s with varying load from 5 N to 30 N under dry sliding conditions using AISI 4140 steel disk as a counterface. The composite displayed lower wear rate and friction coefficient at lower levels of applied stress (0.175 to 0.525 MPa). Under higher stresses (0.700 to 1.050 MPa), the increased brittleness and porosity of the composite caused severe fracturing and delamination resulting in excessive wear rate and friction coefficient for the composite as compared to monolithic Al6061. The transition from mild to severe wear regime in composite occurred also at lower stress as compared to monolith. Analysis of the worn surfaces revealed abrasion as the dominant wear mechanism for both the materials at lower stresses. At higher stress levels, adhesion was found to be dominant in monolithic Al6061 whereas in composite, excessive sub-surface fracturing and delamination was mainly observed.

Wear studies on ZrO2-filled PEEK as coating bearing materials for artificial cervical discs of Ti6Al4V

International Nuclear Information System (INIS)

Song, Jian; Liu, Yuhong; Liao, Zhenhua; Wang, Song; Tyagi, Rajnesh; Liu, Weiqiang

2016-01-01

Polyetheretherketone (PEEK) and its composite coatings are believed to be the potential candidates' bio-implant materials. However, these coatings have not yet been used on the surface of titanium-based orthopedics and joint products and very few investigations on the tribological characteristics could be found in the published literature till date. In this study, the wettabilities, composition and micro-hardness were characterized using contact angle measurement, scanning electron microscopy (SEM) and hardness tester. The tribological tests were conducted using a ball-on-disc contact pair under 25% newborn calf serum (NCS) lubricated condition. For comparison, bare Ti6Al4V was studied. The obtained results revealed that those PEEK/ZrO 2 composite coatings could improve the tribological properties of Ti6Al4V significantly. Adhesive wear and mild abrasive wear might be the dominant wear and failure mechanisms for PEEK/ZrO 2 composite coatings in NCS lubricated condition. After comprehensive evaluation in the present study, 5 wt.% ZrO 2 nanoparticles filled PEEK coating displayed the optimum tribological characteristics and could be taken as a potential candidate for the bearing material of artificial cervical disc. - Graphical abstract: Polyetheretherketone (PEEK) is a type of biomaterial which might be used in surface modification. In this study, the wettabilities, composition, hardness, friction and wear characteristics of PEEK/ZrO 2 coatings were investigated, compared with bare Ti6Al4V sample. After comprehensive evaluation, 5 wt.% ZrO 2 nanoparticles filled PEEK coating displayed the optimum tribological characteristics and could be taken as a potential candidate for the bearing material of artificial cervical disc. - Highlights: • PEEK coating were filled by ZrO 2 nanoparticles with different weight percentage. • The lubrication regime of all the tested samples are boundary lubrication. • Adhesive wear and mild abrasive wear were the dominant wear

Microstructural changes and strain hardening effects in abrasive contacts at different relative velocities and temperatures

Energy Technology Data Exchange (ETDEWEB)

Rojacz, H., E-mail: rojacz@ac2t.at [AC2T research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt (Austria); Mozdzen, G. [Aerospace & Advanced Composites GmbH, Viktor-Kaplan-Straße 2F, 2700 Wiener Neustadt (Austria); Weigel, F.; Varga, M. [AC2T research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt (Austria)

2016-08-15

Strain hardening is commonly used to reach the full potential of materials and can be beneficial in tribological contacts. 2-body abrasive wear was simulated in a scratch test, aimed at strain hardening effects in various steels. Different working conditions were examined at various temperatures and velocities. Strain hardening effects and microstructural changes were analysed with high resolution scanning electron microscopy (HRSEM), electron backscatter diffraction (EBSD), micro hardness measurements and nanoindentation. Statistical analysing was performed quantifying the influence of different parameters on microstructures. Results show a crucial influence of temperature and velocity on the strain hardening in tribological contacts. Increased velocity leads to higher deformed microstructures and higher increased surface hardness at a lower depth of the deformed zones at all materials investigated. An optimised surface hardness can be achieved knowing the influence of velocity (strain rate) and temperature for a “tailor-made” surface hardening in tribological systems aimed at increased wear resistance. - Highlights: •Hardening mechanisms and their intensity in tribological contacts are dependent on relative velocity and temperature. •Beneficial surface hardened zones are formed at certain running-in conditions; the scientific background is presented here. •Ferritic-pearlitic steels strain hardens via grain size reduction and decreasing interlamellar distances in pearlite. •Austenitic steels show excellent surface hardening (120% hardness increase) by twinning and martensitic transformation. •Ferritic steels with hard phases harden in the ferrite phase as per Hall-Petch equation and degree of deformation.

Microstructural changes and strain hardening effects in abrasive contacts at different relative velocities and temperatures

International Nuclear Information System (INIS)

Rojacz, H.; Mozdzen, G.; Weigel, F.; Varga, M.

2016-01-01

Strain hardening is commonly used to reach the full potential of materials and can be beneficial in tribological contacts. 2-body abrasive wear was simulated in a scratch test, aimed at strain hardening effects in various steels. Different working conditions were examined at various temperatures and velocities. Strain hardening effects and microstructural changes were analysed with high resolution scanning electron microscopy (HRSEM), electron backscatter diffraction (EBSD), micro hardness measurements and nanoindentation. Statistical analysing was performed quantifying the influence of different parameters on microstructures. Results show a crucial influence of temperature and velocity on the strain hardening in tribological contacts. Increased velocity leads to higher deformed microstructures and higher increased surface hardness at a lower depth of the deformed zones at all materials investigated. An optimised surface hardness can be achieved knowing the influence of velocity (strain rate) and temperature for a “tailor-made” surface hardening in tribological systems aimed at increased wear resistance. - Highlights: •Hardening mechanisms and their intensity in tribological contacts are dependent on relative velocity and temperature. •Beneficial surface hardened zones are formed at certain running-in conditions; the scientific background is presented here. •Ferritic-pearlitic steels strain hardens via grain size reduction and decreasing interlamellar distances in pearlite. •Austenitic steels show excellent surface hardening (120% hardness increase) by twinning and martensitic transformation. •Ferritic steels with hard phases harden in the ferrite phase as per Hall-Petch equation and degree of deformation.

Wear Performance of Bionic Dimpled-Shape Pistons of Mud Pump

Directory of Open Access Journals (Sweden)

Xuejing Cheng

2017-01-01

Full Text Available The piston is one of the parts that most easily become worn out and experience failure in mud pumps for well drilling. By imitating the body surface morphology of the dung beetle, this paper proposed a new type (BW-160 of mud pump piston that had a dimpled shape in the regular layout on the piston leather cup surface and carried out a performance test on the self-built test rig. Firstly, the influence of different dimple diameters on the service life of the piston was analyzed. Secondly, the analysis of the influence of the dimple central included angle on the service life of the piston under the same dimple area density was obtained. Thirdly, the wear of the new type of piston under the same wear time was analyzed. The experimental results indicated that the service life of the piston with dimples on the surface was longer than that of L-Standard pistons, and the maximum increase in the value of service life was 92.06%. Finally, the Workbench module of the software ANSYS was used to discuss the wear-resisting mechanism of the new type of piston.

Recent Developments in Abrasive Hybrid Manufacturing Processes

Directory of Open Access Journals (Sweden)

Ruszaj Adam

2017-06-01

Full Text Available Recent dynamic development of abrasive hybrid manufacturing processes results from application of a new difficult for machining materials and improvement of technological indicators of manufacturing processes already applied in practice. This tendency also occurs in abrasive machining processes which are often supported by ultrasonic vibrations, electrochemical dissolution or by electrical discharges. In the paper we present the review of new results of investigations and new practical applications of Abrasive Electrodischarge (AEDM and Electrochemical (AECM Machining.

Sandstone Turning by Abrasive Waterjet

Czech Academy of Sciences Publication Activity Database

Hlaváček, Petr; Cárach, J.; Hloch, Sergej; Vasilko, K.; Klichová, Dagmar; Klich, Jiří; Lehocká, D.

2015-01-01

Roč. 48, č. 6 (2015), s. 2489-2493 ISSN 0723-2632 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : turning away from the jet * conventional turning towards the jet * sandstone * abrasive water jet Subject RIV: JQ - Machines ; Tools Impact factor: 2.386, year: 2015 http://www.springerprofessional.de/sandstone-turning-by-abrasive-waterjet/6038028.html

The Effects of Rare Earth Pr and Heat Treatment on the Wear Properties of AZ91 Alloy

Directory of Open Access Journals (Sweden)

Ning Li

2018-06-01

Full Text Available This paper investigated the influences of Pr addition and heat treatment (T6 on the dry sliding wear behavior of AZ91 alloy. The wear rates and friction coefficients were measured by using a pin-on-disc tribometer under loads of 30, 60 and 90 N at dry sliding speeds of 100 rpm, over a sliding time of 15 min. The worn surfaces were examined using a scanning electron microscope and was analyzed with an energy dispersive spectrometer. The experimental results revealed that AZ91-1.0%Pr magnesium alloy exhibited lower wear rate and friction coefficient than the other investigated alloys. As the applied load increased, the wear rate and friction coefficient increased. Compared with the as-cast AZ91-1.0%Pr magnesium alloy, the hardness and wear resistance of the alloy after solution treatment were reduced, and through the subsequent aging, the hardness and wear resistance of the alloy were improved and the hardness was 101.1 HB (compared to as-cast AZ91 magnesium alloy, it increased by 45%. The AZ91-1.0%Pr with T6 magnesium alloy exhibited best wear resistance. Abrasion was dominant at load of 30 N, delamination was dominant at load of 60 N and plastic deformation was dominant at load of 90 N. Oxidation was observed at all loads.

Wear studies on ZrO{sub 2}-filled PEEK as coating bearing materials for artificial cervical discs of Ti6Al4V

Energy Technology Data Exchange (ETDEWEB)

Song, Jian [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liu, Yuhong, E-mail: liuyuhong@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liao, Zhenhua; Wang, Song [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Tyagi, Rajnesh [Department of Mechanical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi 221005 (India); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

2016-12-01

Polyetheretherketone (PEEK) and its composite coatings are believed to be the potential candidates' bio-implant materials. However, these coatings have not yet been used on the surface of titanium-based orthopedics and joint products and very few investigations on the tribological characteristics could be found in the published literature till date. In this study, the wettabilities, composition and micro-hardness were characterized using contact angle measurement, scanning electron microscopy (SEM) and hardness tester. The tribological tests were conducted using a ball-on-disc contact pair under 25% newborn calf serum (NCS) lubricated condition. For comparison, bare Ti6Al4V was studied. The obtained results revealed that those PEEK/ZrO{sub 2} composite coatings could improve the tribological properties of Ti6Al4V significantly. Adhesive wear and mild abrasive wear might be the dominant wear and failure mechanisms for PEEK/ZrO{sub 2} composite coatings in NCS lubricated condition. After comprehensive evaluation in the present study, 5 wt.% ZrO{sub 2} nanoparticles filled PEEK coating displayed the optimum tribological characteristics and could be taken as a potential candidate for the bearing material of artificial cervical disc. - Graphical abstract: Polyetheretherketone (PEEK) is a type of biomaterial which might be used in surface modification. In this study, the wettabilities, composition, hardness, friction and wear characteristics of PEEK/ZrO{sub 2} coatings were investigated, compared with bare Ti6Al4V sample. After comprehensive evaluation, 5 wt.% ZrO{sub 2} nanoparticles filled PEEK coating displayed the optimum tribological characteristics and could be taken as a potential candidate for the bearing material of artificial cervical disc. - Highlights: • PEEK coating were filled by ZrO{sub 2} nanoparticles with different weight percentage. • The lubrication regime of all the tested samples are boundary lubrication. • Adhesive wear and mild abrasive

Comparing the Air Abrasion Cutting Efficacy of Dentine Using a Fluoride-Containing Bioactive Glass versus an Alumina Abrasive: An In Vitro Study

Directory of Open Access Journals (Sweden)

Melissa H. X. Tan

2015-01-01

Full Text Available Air abrasion as a caries removal technique is less aggressive than conventional techniques and is compatible for use with adhesive restorative materials. Alumina, while being currently the most common abrasive used for cutting, has controversial health and safety issues and no remineralisation properties. The alternative, a bioactive glass, 45S5, has the advantage of promoting hard tissue remineralisation. However, 45S5 is slow as a cutting abrasive and lacks fluoride in its formulation. The aim of this study was to compare the cutting efficacy of dentine using a customised fluoride-containing bioactive glass Na0SR (38–80 μm versus the conventional alumina abrasive (29 μm in an air abrasion set-up. Fluoride was incorporated into Na0SR to enhance its remineralisation properties while strontium was included to increase its radiopacity. Powder outflow rate was recorded prior to the cutting tests. Principal air abrasion cutting tests were carried out on pristine ivory dentine. The abrasion depths were quantified and compared using X-ray microtomography. Na0SR was found to create deeper cavities than alumina (p<0.05 despite its lower powder outflow rate and predictably reduced hardness. The sharper edges of the Na0SR glass particles might improve the cutting efficiency. In conclusion, Na0SR was more efficacious than alumina for air abrasion cutting of dentine.

Corrosion-wear of β-Ti alloy TMZF (Ti-12Mo-6Zr-2Fe) in simulated body fluid.

Science.gov (United States)

Yang, Xueyuan; Hutchinson, Christopher R

2016-09-15

Titanium alloys are popular metallic implant materials for use in total hip replacements. Although, α+β titanium alloys such as Ti-6Al-4V have been the most commonly used alloys, the high Young's modulus (∼110GPa) leads to an undesirable stress shielding effect. An alternative is to use β titanium alloys that exhibit a significantly lower Young's modulus (∼70GPa). Femoral stems made of a β titanium alloy known as TMZF (Ti-12Mo-6Zr-2Fe (wt.%)) have been used as part of modular hip replacements since the early 2000's but these were recalled in 2011 by the US Food & Drug Administration (FDA) due to unacceptable levels of 'wear debris'. The wear was caused by small relative movement of the stem and neck at the junction where they fit together in the modular hip replacement design. In this study, the corrosion and wear properties of the TMZF alloy were investigated in simulated body fluid to identify the reason for the wear debris generation. Ti64 was used as a control for comparison. It is shown that the interaction between the surfaces of Ti64 and TMZF with simulated body fluid is very similar, both from the point of view of the products formed and the kinetics of the reaction. The dry wear behaviour of TMZF is also close to that of Ti64 and consistent with expectations based on Archard's law for abrasive wear. However, wear of Ti64 and TMZF in simulated body fluid show contrasting behaviours. A type of time-dependent wear test is used to examine the synergy between corrosion and wear of TMZF and Ti64. It is shown that the wear of TMZF accelerated rapidly in SBF whereas that of Ti64 is reduced. The critical role of the strain hardening capacity of the two materials and its role in helping the surface resist abrasion by hydroxyapatite particles formed as a result of the reaction with the SBF is discussed and recommendations are made for modifications that could be made to the TMZF alloy to improve the corrosion-wear response. TMZF is a low modulus β-Ti alloy

Investigation of anti-wear performance of automobile lubricants using thin layer activation analysis technique

Energy Technology Data Exchange (ETDEWEB)

Biswal, Jayashree [Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Thakre, G.D. [Tribology and Combustion Division, Indian Institute of Petroleum, Dehradun 248005, Uttarakhand (India); Pant, H.J., E-mail: hjpant@barc.gov.in [Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Samantray, J.S. [Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Arya, P.K. [Tribology and Combustion Division, Indian Institute of Petroleum, Dehradun 248005, Uttarakhand (India); Sharma, S.C.; Gupta, A.K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2017-05-15

An investigation was carried out to examine the anti-wear behavior of automobile lubricants using thin layer activation analysis technique. For this study disc gears made of EN 31 steel were labeled with a small amount of radioactivity by irradiating with 13 MeV proton beam from a particle accelerator. Experiments on wear rate measurement of the gear were carried out by mounting the irradiated disc gear on a twin-disc tribometer under lubricated condition. The activity loss was monitored by using a NaI(Tl) scintillation detector integrated with a multichannel analyzer. The relative remnant activity was correlated with thickness loss by generating a calibration curve. The wear measurements were carried out for four different types of lubricants, named as, L1, L2, L3 and L4. At lower load L1 and L4 were found to exhibit better anti-wear properties than L2 and L3, whereas, L4 exhibited the best anti-wear performance behavior than other three lubricants at all the loads and speeds investigated.

Microhardness and wear resistance of PEO-coated 5754 aluminum alloy

Science.gov (United States)

Vyaliy, I. E.; Egorkin, V. S.; Sinebryukhov, S. L.; Minaev, A. N.; Gnedenkov, S. V.

2017-09-01

We present results of the study aimed at assessing the effect of duty cycle (D) during plasma electrolytic oxidation (PEO) on protective properties of the coatings produced on 5754 aluminum alloy. It is shown that increasing the duty cycle of a microsecond current pulses leads to increased hardness and reduced abrasive wear of the PEO-layers, improving mechanical properties. The obtained data allowed confirming, that increasing the amount of energy consumed for coating growth leads to the formation of thicker PEO-layers with improved tribological properties. The effect of duty cycle during plasma electrolytic oxidation on protective properties of the produced coatings was assessed.

Life cycle and sustainability of abrasive tools

CERN Document Server

Linke, Barbara

2016-01-01

This monograph focuses on abrasive tools for grinding, polishing, honing, and lapping operations. The book describes the life cycle of abrasive tools from raw material processing of abrasive grits and bonding, manufacturing of monolithic or multi-layered tools, tool use to tool end-of-life. Moreover, this work highlights sustainability challenges including economic, environmental, social and technological aspects. The target audience primarily comprises research and industry experts in the field of manufacturing, but the book may also be beneficial for graduate students.

Assessment of wear facets produced by the ACTA wear machine

DEFF Research Database (Denmark)

Benetti, Ana R; Larsen, Liselotte; Dowling, Adam H

2016-01-01

. The mean wear depth was measured using the traditionally employed 2D and compared with the 3D profilometric (digital) techniques. Data were submitted to analyses of variance, Tukey's post hoc tests and Independent Samples Student's t-tests (where appropriate) at p...OBJECTIVE: To investigate the use of a three-dimensional (3D) digital scanning method in determining the accuracy of the wear performance parameters of resin-based composites (RBCs) determined using a two-dimensional (2D) analogue methodology following in-vitro testing in an Academisch Centrum...... for Tandheelkunde Amsterdam (ACTA) wear machine. METHODS: Specimens compatible with the compartments of the ACTA wear machine specimen wheel (n=10) were prepared from one commercial and four experimental RBCs. The RBC specimens were rotated against an antagonist wheel in a food-like slurry for 220,000 wear cycles...

Wear Characteristics According of Heat Treatment of Si3N4 with Different Amounts of SiO2 Nano-Colloid

International Nuclear Information System (INIS)

Ahn, Seok Hwan; Nam, Ki Woo

2014-01-01

This study sintered Si 3 N 4 with different amounts of SiO 2 nano-colloid. The surface of a mirror-polished specimen was coated with SiO 2 nano-colloid, and cracks were healed when the specimen was treated at a temperature of 1273 K for 1 h in air. Wear specimen experiments were conducted after heat treatments for 10 min at 1073, 1273, and 1573 K. The heat-treated surface that was coated with the SiO 2 nano-colloid was slightly rougher than the noncoated surface. The oxidation state of the surface according to the heat treatment temperature showed no correlation with the surface roughness. Moreover, the friction coefficient, wear loss, and bending strength were not related to the surface roughness. Si 3 N 4 exhibited an abrasive wear behavior when SKD11 was used as an opponent material. The friction coefficient was proportional to the wear loss, and the bending strength was inversely proportional to the friction coefficient and wear loss. The friction coefficient and wear loss increased with increasing amounts of the SiO 2 nanocolloid. In addition, the friction coefficient was slightly increased by increasing the heat treatment temperature

Study of Surface Wear and Damage Induced by Dry Sliding of Tempered AISI 4140 Steel against Hardened AISI 1055 Steel

Directory of Open Access Journals (Sweden)

A. Elhadi

2016-12-01

Full Text Available In industry, the sliding mechanical systems are subject to friction and wear phenomena. These phenomena can be the origin of a reduction of the efficiency of the mechanical system even to be responsible for its incapacity. Generally, the materials of the parts which are moving relative (tribological couple of these systems are low alloy steels and carbon steels, thanks to their good mechanical and tribological properties. The present work aimed to study, the surface wear and damage induced by dry sliding of hard carbon steel AISI 1055 (disc against tempered low alloy steel AISI 4140 (pin with different hardness and applied loads was investigated. The results revealed that the interaction between the applied load and pin hardness result in complex thermo-mechanical behaviour of the worn surfaces. When a lower hardness pin is used, the main wear mechanisms observed on the discs were abrasion, adhesion, and oxidation. When a higher hardness pin is used, the wear of the discs is governed by delamination, oxidation, and plastic deformation. In particular, third-body wear occurs at high applied load resulting in higher wear rate of high hardness pins compared to low hardness pins.

Development of dynamic models of wagons on models 18-9810 and 18-9855 bogies taking into account wheel wear research

Directory of Open Access Journals (Sweden)

A. V. Saidova

2013-04-01

Full Text Available Purpose. Wear parameters clarification in wear simulation is an actual goal because of absence of corresponding data for freight cars in condition of using them on Russian railways. Research is devoted to development of dynamic models of wagons on three-peace two-axle models 18-9810 and 18-9855 bogies with maximum axle-loads 23,5 ts and 25 ts, and to choice of factors, with varying which parameters in the model of wheel wear can be identified. Methodology. The problem is solved by method of mathematic simulation in «MEDYNA» software. Wear calculation is based on abrasive wear theory (Archard’s theory. Findings. Clarification of wheels’ wear model may be done with varying of friction coefficient between wheel and rail for different wheel profile areas (flange and tread, wear coefficient in Archard’s model for mild and heavy wear and transition between them. Originality. Dynamic models of universal gondola on models 18-9810 and 18-9855 bogies are developed. It is established, that rail treads irregularities size effect wheel wear insignificantly, when car is running on circle track of constant radius. Practical value. Developed dynamic models of wagons on models 18-9810 and 18-9855 bogies may be used in wear simulation, determination of car running characteristics, interaction of car and rail of different type, construction, condition and etc. Research results of some factors influence on freight car wheel wear may be interesting for people, who study this problem.

Radiation tagging measures wear at speed

International Nuclear Information System (INIS)

Barrett, Jon.

1994-01-01

A new non-invasive technique for performing accelerated wear and corrosion analysis is particularly relevant to power transmission systems. Wear tests that would normally take days or weeks to complete can now be performed in hours. A tiny patch of the wearing component is made mildly radioactive and the drop in activity as material is worn away is monitored. Known as Thin Layer Activation (TLA), the technology was originally developed and pioneered in-house by the Atomic Energy Authority. Since then, the dominant partner has been the automotive sector where TLA has been used extensively for engine wear and lubrication performance analysis. However, TLA could be used in any wear or corrosion environment. Applications include wear analysis of machine tool cutting surfaces, pump impellers and brake linings to the corrosion monitoring of process plant and pipelines. (author)

In Vivo Wear Performance of Cobalt-Chromium Versus Oxidized Zirconium Femoral Total Knee Replacements.

Science.gov (United States)

Gascoyne, Trevor C; Teeter, Matthew G; Guenther, Leah E; Burnell, Colin D; Bohm, Eric R; Naudie, Douglas R

2016-01-01

This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design. Copyright © 2016 Elsevier Inc. All rights reserved.

Abrasive water jet: a complementary tool

International Nuclear Information System (INIS)

Duarte, J.P.; Pecas, P.; Nunes, E.; Gouveia, H.

1998-01-01

The abrasive water jet is a powerful cutting tool, whose main advantages lie in the absence of thermal effects and the capability of cutting highly thick materials. Compared with Laser, the abrasive water jet allows the cutting of a larger range of thicknesses and a wider variety of materials such as: ornamental stones, metals, polymers, composites, wood, glass ceramics. The application of this technology has suffered and extensive growth, with successful applications in varied industrial sectors like the automotive, aerospace, textile, metalworking, ornamental stones, etc. The present communication aims at introducing the abrasive water jet as a complementary tool to laser cutting, presenting its advantages by showing some documented examples of pieces cut for different industries. (Author) 5 refs

Wear Behavior of Cold Pressed and Sintered Al2O3/TiC/CaF2Al2O3/TiC Laminated Ceramic Composite

Institute of Scientific and Technical Information of China (English)

Xuefeng YANG; Jian CHENG; Peilong SONG; Shouren WANG; Liying YANG; Yanjun WANG; Ken MAO

2013-01-01

A novel laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite was fabricated through cold pressing and sintering to achieve better anti-wear performance,such as low friction coefficient and low wear rate.Al2O3/TiC/CaF2 and Al2O3/TiC composites were alternatively built layer-by-layer to obtain a sandwich structure.Solid lubricant CaF2 was added evenly into the Al2O3/TiC/CaF2 layer to reduce the friction and wear.Al2O3/TiC ceramic was also cold pressed and sintered for comparison.Friction analysis of the two ceramics was then conducted via a wear-and-tear machine.Worn surface and surface compositions were examined by scanning electron microscopy and energy dispersion spectrum,respectively.Results showed that the laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite has lower friction coefficient and lower wear rate than those of Al2O3/TiC ceramic alone because of the addition of CaF2 into the laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite.Under the friction load,the tiny CaF2 particles were scraped from the Al2O3/TiC/CaF2 layer and spread on friction pairs before falling off into micropits.This process formed a smooth,self-lubricating film,which led to better anti-wear properties.Adhesive wear is the main wear mechanism of Al2O3/TiC/CaF2 layer and abrasive wear is the main wear mechanism of Al2O3/TiC layer.

Micro-Structures and High-Temperature Friction-Wear Performances of Laser Cladded Cr–Ni Coatings

Directory of Open Access Journals (Sweden)

Li Jiahong

2018-01-01

Full Text Available Cr–Ni coatings with the mass ratios of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni were fabricated on H13 hot work mould steel using a laser cladding (LC. The surface–interface morphologies, chemical elements, surface roughness and phase composition of the obtained Cr–Ni coatings were analysed using a scanning electron microscope (SEM, energy disperse spectroscopy (EDS, atomic force microscope (AFM and X–ray diffractometer (XRD, respectively. The friction–wear properties and wear rates of Cr–Ni coatings with the different mass ratios of Cr and Ni at 600 °C were investigated, and the worn morphologies and wear mechanism of Cr–Ni coatings were analysed. The results show that the phases of Cr–Ni coatings with mass ratios of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni are composed of Cr + Ni single-phases and their compounds at the different stoichiometry, the porosities on the Cr–Ni coatings increase with the Cr content increasing. The average coefficient of friction (COF of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% coatings are 1.10, 0.33 and 0.87, respectively, in which the average COF of 20% Cr–80% Ni coating is the lowest, exhibiting the better anti-friction performance. The wear rate of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni coatings is 4.533 × 10−6, 5.433 × 10−6, and 1.761 × 10−6 N−1·s−1, respectively, showing the wear resistance of Cr–Ni coatings at a high temperature increases with the Cr content, in which the wear rate is 24% Cr–76% Ni coating with the better reducing wear. The wear mechanism of 17% Cr–83% Ni and 20% Cr–80% Ni and 24% Cr–76% coatings at 600 °C is primarily adhesive wear, and that of 24% Cr–76% coating is also accompanied by oxidative wear.

Investigation of the Effect of Residual Stress Gradient on the Wear Behavior of PVD Thin Films

Science.gov (United States)

Tlili, B.; Nouveau, C.; Guillemot, G.; Besnard, A.; Barkaoui, A.

2018-02-01

The control of residual stresses has been seldom investigated in multilayer coatings dedicated to improvement of wear behavior. Here, we report the preparation and characterization of superposed structures composed of Cr, CrN and CrAlN layers. Nano-multilayers CrN/CrAlN and Cr/CrN/CrAlN were deposited by Physical Vapor Deposition (PVD) onto Si (100) and AISI4140 steel substrates. The Cr, CrN and CrAlN monolayers were developed with an innovative approach in PVD coatings technologies corresponding to deposition with different residual stresses levels. Composition and wear tracks morphologies of the coatings were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction and 3D-surface analyzer. The mechanical properties (hardness, residual stresses and wear) were investigated by nanoindentation, interferometry and micro-tribometry (fretting-wear tests). Observations suggest that multilayer coatings are composed mostly of nanocrystalline. The residual stresses level in the films has practically affected all the physicochemical and mechanical properties as well as the wear behavior. Consequently, it is demonstrated that the coating containing moderate stresses has a better wear behavior compared to the coating developed with higher residual stresses. The friction contact between coated samples and alumina balls shows also a large variety of wear mechanisms. In particular, the abrasive wear of the coatings was a combination of plastic deformation, fine microcracking and microspallation. The application of these multilayers will be wood machining of green wood.

Grading technologies for the manufacture of innovative cutting blades

Science.gov (United States)

Rostek, Tim; Homberg, Werner

2018-05-01

Cutting blades for harvesting applications are used in a variety of agricultural machines. These parts are in contact with highly abrasive lawn clippings and often wear out within hours which results in high expensive re-sharpening maintenance. This paper relates to manufacturing techniques enhancing the durability of cutting blades based on a structural analysis of the prevailing wear mechanisms containing chipping and abrasive wear. Each mechanism results in specific demands on the cutting edge's mechanical characteristics. The design of evaluation methods respectively is one issue of the paper. This is basis for approaches to improve the cutting edge performance on purpose. On option to improve abrasive wear resistance and, thus, service life is the application of locally graded steel materials as semi-finished products for self-sharpening cutting blades. These materials comprise a layered structure consisting of a hard, wear resistant layer and a relatively softer layer which is lesser wear resistant. As the cutting blade is subjected to wear conditions, the less wear resistant layer wears faster than the relatively more wear resistant harder layer revealing a durable cross section of the cutting edge and, thus, cutting performance. Anyways, chipping is another key issue on the cutting edge's lifetime. Here, the cutting edges cross section by means of geometry and grind respectively as well as its mechanical properties matter. FEM analysis reveal innovative options to optimize the cross section of the blade as well as thermomechanical strengthening add further strength to reduce chipping. This paper contains a comprehensive strategy to improve cutting blades with use of innovative manufacturing technologies which apply application-specific graded mechanical characteristics and, thus, significantly improved performance characteristics.

Fretting wear behaviour of TiC/Ti(C,N)/TiN multi-layer coatings at elevated temperature in gross slip regime

International Nuclear Information System (INIS)

Liu Hanwei; Huang Kunpeng; Zhu Minhao; Zhou Zhongrong

2005-01-01

Tic/Ti(C,N)/TiN multi-layer coatings are prepared on the 1Cr13 stainless steel substrate by the technique of Chemical Vapour Deposition, and the fretting wear behaviour of 1Cr13 stainless steel and TiC/Ti(C,N)/TiN coatings are investigated and studied controversially from 25 degree C to 400 degree C in the gross slip regime. It shows that the temperature has great influence on the fretting wear in the gross slip regime for the 1Cr13 stainless steel but little for Ti/C/Ti(C,N)/TiN multi-layer coatings. With the temperature increasing, the friction coefficient and the wear volume of the 1Cr13 alloy decreases and the wear volume of TiC/Ti(C, N)/TiN multi-layer coatings is invariant. TiC/Ti(C,N)/TiN multi-layer coatings have better wear-resistant capability than the 1Cr13 stainless steel, but the wear volume of the substrate increases greatly because of the grain-abrasion resulted from hard debris when TiC/Ti(C,N)/TiN multi-layer coatings are ground off. (authors)

Friction and wear properties of novel HDPE--HAp--Al2O3 biocomposites against alumina counterface.

Science.gov (United States)

Bodhak, Subhadip; Nath, Shekhar; Basu, Bikramjit

2009-03-01

In an effort to enhance physical properties of biopolymers (high-density polyethylene, HDPE) in terms of elastic modulus and hardness, various ceramic fillers, like alumina (Al2O3) and hydroxyapatite (HAp) are added, and therefore it is essential to assess the friction and wear resistance properties of HDPE biocomposites. In this perspective, HDPE composites with varying ceramic filler content (upto 40 vol%) were fabricated under the optimal compression molding conditions and their friction and wear properties were evaluated against Al2O3 at fretting contacts. All the experiments were conducted at a load of 10 N for duration of 100,000 cycles in both dry as well as simulated body fluid (SBF). Such planned set of experiments has been designed to address three important issues: (a) whether the improvement in physical properties (hardness, E-modulus) will lead to corresponding improvement in friction and wear properties; (b) whether the fretting in SBF will provide sufficient lubrication in order to considerably enhance the tribological properties, as compared to that in ambient conditions; and (c) whether the generation of wear debris particles be reduced for various compositionally modified polymer composites, in comparison to unreinforced HDPE. The experimental results indicate the possibility of achieving extremely low coefficient of friction (COF approximately 0.047) as well as higher wear resistance (wear rate in the order of approximately 10(-7) mm3 N(-1) m(-1)) with the newly developed composites in SBF. A low wear depth of 3.5-4 microm is recorded, irrespective of fretting environment. Much effort has been put forward to correlate the friction and wear mechanisms with abrasion, adhesion, and wear debris formation.

Release of carbon nanotubes from an epoxy-based nanocomposite during an abrasion process.

Science.gov (United States)

Schlagenhauf, Lukas; Chu, Bryan T T; Buha, Jelena; Nüesch, Frank; Wang, Jing

2012-07-03

The abrasion behavior of an epoxy/carbon nanotube (CNT) nanocomposite was investigated. An experimental setup has been established to perform abrasion, particle measurement, and collection all in one. The abraded particles were characterized by particle size distribution and by electron microscopy. The abrasion process was carried out with a Taber Abraser, and the released particles were collected by a tube for further investigation. The particle size distributions were measured with a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS) and revealed four size modes for all measured samples. The mode corresponding to the smallest particle sizes of 300-400 nm was measured with the SMPS and showed a trend of increasing size with increasing nanofiller content. The three measured modes with particle sizes from 0.6 to 2.5 μm, measured with the APS, were similar for all samples. The measured particle concentrations were between 8000 and 20,000 particles/cm(3) for measurements with the SMPS and between 1000 and 3000 particles/cm(3) for measurements with the APS. Imaging by transmission electron microscopy (TEM) revealed that free-standing individual CNTs and agglomerates were emitted during abrasion.

WEAR PERFORMANCE OPTIMIZATION OF SILICON NITRIDE USING GENETIC AND SIMULATED ANNEALING ALGORITHM

Directory of Open Access Journals (Sweden)

SACHIN GHALME

2017-12-01

Full Text Available Replacing damaged joint with the suitable alternative material is a prime requirement in a patient who has arthritis. Generation of wear particles in the artificial joint during action or movement is a serious issue and leads to aseptic loosening of joint. Research in the field of bio-tribology is trying to evaluate materials with minimum wear volume loss so as to extend joint life. Silicon nitride (Si3N4 is non-oxide ceramic suggested as a new alternative for hip/knee joint replacement. Hexagonal Boron Nitride (hBN is recommended as a solid additive lubricant to improve the wear performance of Si3N4 . In this paper, an attempt has been made to evaluate the optimum combination of load and % volume of hBN in Si3N4 to minimize wear volume loss (WVL. The experiments were conducted according to Design of Experiments (DoE – Taguchi method and a mathematical model is developed. Further, this model is processed with Genetic Algorithm (GA and Simulated Annealing (SA to find out the optimum percentage of hBN in Si3N4 to minimize wear volume loss against Alumina (Al2O3 counterface. Taguchi method presents 15 N load and 8% volume of hBN to minimize WVL of Si3N4 . While GA and SA optimization offer 11.08 N load, 12.115% volume of hBN and 11.0789 N load, 12.128% volume of hBN respectively to minimize WVL in Si3N4. .

21 CFR 872.6030 - Oral cavity abrasive polishing agent.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or powder form...

The Tribological Performance of Hardfaced/ Thermal Sprayed Coatings for Increasing the Wear Resistance of Ventilation Mill Working Parts

Directory of Open Access Journals (Sweden)

A. Vencl

2015-09-01

Full Text Available During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings. The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC.

Microstructural Evolution of AlCoCrFeNiSi High-Entropy Alloy Powder during Mechanical Alloying and Its Coating Performance.

Science.gov (United States)

Tian, Lihui; Fu, Ming; Xiong, Wei

2018-02-23

High-entropy alloys (HEAs) are promising structural materials due to their excellent comprehensive performances. The use of mechanically alloyed powders to deposit HEA coatings through atmospheric plasma spraying (APS) is an effective approach that can broaden the application areas of the HEAs. In this paper, a ductility-brittleness AlCoCrFeNiSi system was chosen as an object of study, and the detailed evolution of the surface morphology, particle size distribution, and microstructure of the powder during mechanical alloying was investigated. An AlCoCrFeNiSi HEA coating was deposited using powder milled for 10 h, which can be used as an ideal feedstock for APS. The surface morphology, microstructure, microhardness, and wear behavior of the coating at room temperature were investigated. The results showed that as the milling time increased, the particle size first increased, and then decreased. At the milling time of 10 h, simple body-centered cubic (BCC) and face-centered cubic (FCC) solid solution phases were formed. After spraying, the lamellar structure inside a single particle disappeared. An ordered BCC phase was detected, and the diffraction peaks of the Si element also disappeared, which indicates that phase transformation occurred during plasma spraying. A transmission electron microscopy analysis showed that nanometer crystalline grains with a grain size of about 30 nm existed in the APS coating. For the coating, an average microhardness of 612 ± 41 HV was obtained. Adhesive wear, tribo-oxidation wear, and slight abrasion wear took place during the wear test. The coating showed good wear resistance, with a volume wear rate of 0.38 ± 0.08 × 10 -4 mm³·N -1 ·m -1 , which makes it a promising coating for use in abrasive environments.

Numerical study of agglomerate abrasion in a tumbling mixer

NARCIS (Netherlands)

Thanh Nguyen, [No Value; Willemsz, Tofan; Frijlink, Henderik; Maarschalk, Kees van der Voort

2014-01-01

A numerical simulation using the Discrete Element Method (DEM) was performed to investigate the phenomena concerning the abrasion and breakage of agglomerates in a diffusion powder mixer. Agglomerates were created by defining a single structure of particles with bonds of different strengths using

Abrasion of 6 dentifrices measured by vertical scanning interference microscopy.

Science.gov (United States)

Pascaretti-Grizon, Florence; Mabilleau, Guillaume; Chappard, Daniel

2013-01-01

The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders) and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI). Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate) were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra) and illustrated in 3D the abraded areas. Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix® produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials.

Basics of cutting and abrasive processes

CERN Document Server

Toenshoff, Hans Kurt

2013-01-01

Manufacturing is the basic industrial activity generating real value. Cutting and abrasive technologies are the backbone of precision production in machine, automotive and aircraft building as well as of production of consumer goods. We present the knowledge of modern manufacturing in these technologies on the basis of scientific research. The theory of cutting and abrasive processes and the knowledge about their application in industrial practice are a prerequisite for the studies of manufacturing science and an important part of the curriculum of the master study in German mechanical engineering. The basis of this book is our lecture “Basics of cutting and abrasive processes” (4 semester hours/3 credit hours) at the Leibniz University Hannover, which we offer to the diploma and master students specializing in manufacturing science.

Structural changes and tribological performance of thermosetting polyimide induced by proton and electron irradiation

International Nuclear Information System (INIS)

Lv, Mei; Wang, Yanming; Wang, Qihua; Wang, Tingmei; Liang, Yongmin

2015-01-01

The structural changes and tribological performance of thermosetting polyimide were investigated by electron, proton or both combined irradiations at 25 keV in a ground-based simulation facility. Three forms of irradiations could lead to the formation of the carbonized layer on the polymer surface that could increase the hardness and adhesive force of the material. Proton irradiation induced more extensive changes in structure and friction behavior than electron irradiation by reason of the higher linear energy transfer value, and combined irradiation resulted in the largest impact, but which was less than the sum of the radiation effects of electron and proton. Moreover, the experimental results indicated that the changes in friction behavior are closely related with the carbonized layer, which was easily worn out in friction process and could introduce a shift from adhesion wear to three-body abrasive wear that reduced the wear rate and the friction coefficient. The friction process of irradiated samples could be divided into the initial stage and the steady stage. Three forms of irradiations all induced the high friction coefficient in the initial stage and the low friction coefficient in the steady stage, and the wear rate of the irradiated samples decreased in the order: electron irradiation>proton irradiation>combined irradiation. - Highlights: • Proton irradiation induced more extensive changes in structure and friction behavior than electron irradiation. • The effect of combined irradiation was less than that of the sum of electron and proton irradiation. • Three forms of irradiations all induced the high initial friction coefficient and the low steady-stage friction coefficient. • The initial friction stage means a fast-wearing adhesive process while the steady-state of the system is a three-body abrasion

Review of Artificial Abrasion Test Methods for PV Module Technology

Energy Technology Data Exchange (ETDEWEB)

Miller, David C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Muller, Matt T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simpson, Lin J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-08-01

This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended to provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.

Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives: Synthesis and the effects on chemical mechanical polishing (CMP) performances of sapphire wafers

Energy Technology Data Exchange (ETDEWEB)

Liu, Tingting; Lei, Hong, E-mail: hong_lei2005@aliyun.com

2017-08-15

Highlights: • The novel Nd{sup 3+}-doped colloidal SiO{sub 2} abrasives were synthesized by seed-introduced method. • The Nd{sup 3+}-doped colloidal SiO{sub 2} abrasives exhibited lower Ra and higher MRR on sapphire during CMP. • The cores SiO{sub 2} were coated by the shells (SiO{sub 2}, Nd{sub 2}Si{sub 2}O{sub 7} and Nd(OH){sub 3}) via chemical bonds and hydrogen bonds. • XPS analysis revealed the solid-state chemical reaction between Nd{sup 3+}-doped colloidal SiO{sub 2} abrasives and sapphire during CMP. - Abstract: Abrasive is one of the most important factors in chemical mechanical polishing (CMP). In order to improve the polishing qualities of sapphire substrates, the novel Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives were prepared by seed-induced growth method. In this work, there were a series of condensation reactions during the synthesis process of Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives and the silica cores were coated by shells (which contains SiO{sub 2}, Nd{sub 2}Si{sub 2}O{sub 7} and Nd(OH){sub 3}) via chemical bonds and hydrogen bonds in the Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives, which made the composite abrasives’ core-shell structure more sTable Scanning electron microscopy (SEM) showed that Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives were spherical and uniform in size. And the acting mechanisms of Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives on sapphire in CMP were investigated. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the solid-state chemical reactions between the shells (which contained SiO{sub 2}, Nd{sub 2}Si{sub 2}O{sub 7} and Nd(OH){sub 3}) of Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives and the sapphire occurred during the CMP process. Furthermore, Nd{sup 3+}-doped colloidal SiO{sub 2} composite abrasives exhibited lower surface roughness and

Research on the effect of wear-ring clearances to the axial and radial force of a centrifugal pump

International Nuclear Information System (INIS)

Zhao, W G; Qi, C X; Li, Y B; He, M Y

2013-01-01

Varying of the wear-ring clearance not only has a distinct effect on the volumetric loss of the centrifugal pump, but also on the performance of the centrifugal pump including the axial and radial forces. Comparing with the experimental studies, numerical simulation methods have some special advantages, such as the low cost, fast and high efficiency, and convenient to get the detailed structure of the internal flow characteristics, so it has been widely used in the fluid machinery study in recent years. In order to study the effect of wear-ring clearance on the force performance of the centrifugal pump, based on the Reynolds Time-Averaged N-S equations and RNG k-ε turbulence model, a centrifugal pump with three variable styles of the wear-rings was simulated: Only the clearance of the front wear-ring was changed, only the clearance of the back wear-ring was changed and both were changed. Comparing with the experiment, numerical results show a good agreement. In the three changing styles of the clearance, the variable of the clearance of front wear-ring has the most influence on the axial force of the centrifugal pump, while has tiny effect on the radial force for all the conditions

Coating of Ultra-Small Micro End Mills: Analysis of Performance and Suitability of Eight Different Hard-Coatings

Directory of Open Access Journals (Sweden)

Martin Bohley

2018-03-01

Full Text Available Due to the constant need for better functionalized surfaces or smaller, function integrated components, precise and efficient manufacturing processes have to be established. Micro milling with micro end mills is one of the most promising processes for this task as it combines a high geometric flexibility in a wide range of machinable materials with low set-up costs. A downside of this process is the wear of the micro end mills. Due to size effects and the relatively low cutting speed, the cutting edge is especially subjected to massive abrasive wear. One possibility to minimize this wear is coating of micro end mills. This research paper describes the performance of eight different hard coatings for micro end mills with a diameter <40 µm and discusses some properties for the best performing coating type. With this research, it is therefore possible to boost the possibilities of micro milling for the manufacture of next generation products.

Design of a new abrasive slurry jet generator

Science.gov (United States)

Wang, F. C.; Shi, L. L.; Guo, C. W.

2017-12-01

With the advantages of a low system working pressure, good jet convergence and high cutting quality, abrasive slurry jet (ASJ) has broad application prospects in material cutting and equipment cleaning. Considering that the generator plays a crucial role in ASJ system, the paper designed a new type ASJ generator using an electric oil pump, a separate plunger cylinder, and a spring energized seal. According to the determining of structure shape, size and seal type, a new ASJ generator has been manufactured out and tested by a series of experiments. The new generator separates the abrasive slurry from the dynamic hydraulic oil, which can improve the service life of the ASJ system. And the new ASJ system can reach 40 MPa and has good performance in jet convergence, which deserves to popularization and application in materials machining.

Laser engineered net shaping of quasi-continuous network microstructural TiB reinforced titanium matrix bulk composites: Microstructure and wear performance

Science.gov (United States)

Hu, Yingbin; Ning, Fuda; Wang, Hui; Cong, Weilong; Zhao, Bo

2018-02-01

Titanium (Ti) and its alloys have been successfully applied to the aeronautical and biomedical industries. However, their poor tribological properties restrict their fields of applications under severe wear conditions. Facing to these challenges, this study investigated TiB reinforced Ti matrix composites (TiB-TMCs), fabricated by in-situ laser engineered net shaping (LENS) process, through analyzing parts quality, microstructure formation mechanisms, microstructure characterizations, and workpiece wear performance. At high B content areas (original B particle locations), reaction between Ti and B particles took place, generating flower-like microstructure. At low B content areas, eutectic TiB nanofibers contacted with each other with the formation of crosslinking microstructure. The crosslinking microstructural TiB aggregated and connected at the boundaries of Ti grains, forming a three-dimensional quasi-continuous network microstructure. The results show that compared with commercially pure Ti bulk parts, the TiB-TMCs exhibited superior wear performance (i.e. indentation wear resistance and friction wear resistance) due to the present of TiB reinforcement and the innovative microstructures formed inside TiB-TMCs. In addition, the qualities of the fabricated parts were improved with fewer interior defects by optimizing laser power, thus rendering better wear performance.

Effect of deep cryogenic treatment on the microstructure and wear performance of Cr-Mn-Cu white cast iron grinding media

Science.gov (United States)

Vidyarthi, M. K.; Ghose, A. K.; Chakrabarty, I.

2013-12-01

The phase transformation and grinding wear behavior of Cr-Mn-Cu white cast irons subjected to destabilization treatment followed by air cooling or deep cryogenic treatment were studied as a part of the development program of substitute alloys for existing costly wear resistant alloys. The microstructural evolution during heat treatment and the consequent improvement in grinding wear performance were evaluated with optical and scanning electron microscopy, X-ray diffraction analysis, bulk hardness, impact toughness and corrosion rate measurements, laboratory ball mill grinding wear test etc. The deep cryogenic treatment has a significant effect in minimizing the retained austenite content and converts it to martensite embedded with fine M7C3 alloy carbides. The cumulative wear losses in cryotreated alloys are lesser than those with conventionally destabilized alloys followed by air cooling both in wet and dry grinding conditions. The cryotreated Cr-Mn-Cu irons exhibit comparable wear performance to high chromium irons.

Use of new ceramic linings in coal preparation plants

Energy Technology Data Exchange (ETDEWEB)

Fedorchenko, V.E.; Rudenko, V.A.; Bondarev, A.Ya.

1984-01-01

This article evaluates several materials used as liners in coal preparation equipment. The evaluations concentrate on liners used under conditions of intensive temperature fluctuations, e.g. liners of coal chutes for coal transport from coal dryers. Two aspects of wear are analyzed: abrasion by friction and effects of temperature fluctuations. Abrasive wear is tested using magnetite suspension with a density of 400 g/l. Tests show that abrasive wear of liners on an alumina basis is 3 times lower than abrasive wear of high quality steel, from 13 to 24 times lower than that of iron and from 6 to 8 times lower than that of steels used in coal preparation plants. Effects of temperature fluctuations from 20 to 840 C on abrasive wear of liners of steels, iron, slag glass ceramics, mullite-corundum material and corundum is shown in a table. The test show that mullite-corundum material on the basis of alumina is characterized by a high resistance to abrasive wear after 30 cycles of temperature increase from 20 to 840 C and decrease to 20 C. Using mullite-corundum as liners of equipment and installations operating under conditions of temperature fluctuations is recommended.

29 CFR 1910.215 - Abrasive wheel machinery.

Science.gov (United States)

2010-07-01

... be securely fastened to the spindle and the bearing surface shall run true. When more than one wheel... 29 Labor 5 2010-07-01 2010-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a...

Effects of hardness of abrasive grains on surface roughness of work piece in PVA bonded grinding wheel

International Nuclear Information System (INIS)

Nitta, S.; Takata, A.; Ishizaki, K.

2000-01-01

The purpose of this study is to clarify relation between hardness of abrasive grains and surface roughness of work piece in the case of PVA (Polyvinyl alcohol) bonded grinding wheels. Two PVA bonded grinding wheels; with diamond or silicon carbide as abrasive grains and grinding of glass and aluminum alloy was performed. The PVA bonded grinding wheels The PVA bonded grinding wheel with silicon carbide could not grind the glass. Because insufficiency in hardness, the PVA bonded grinding wheel with the diamond abrasive grains caused deep scratch on the aluminum alloy. It was found that the final surface roughness of the work piece was not proportional to the hardness of abrasive grains. The suitable hardness of abrasive grains will be obtained by the hardness of work piece. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

Influence of Workpiece Material on Tool Wear Performance and Tribofilm Formation in Machining Hardened Steel

Directory of Open Access Journals (Sweden)

Junfeng Yuan

2016-04-01

Full Text Available In addition to the bulk properties of a workpiece material, characteristics of the tribofilms formed as a result of workpiece material mass transfer to the friction surface play a significant role in friction control. This is especially true in cutting of hardened materials, where it is very difficult to use liquid based lubricants. To better understand wear performance and the formation of beneficial tribofilms, this study presents an assessment of uncoated mixed alumina ceramic tools (Al2O3+TiC in the turning of two grades of steel, AISI T1 and AISI D2. Both workpiece materials were hardened to 59 HRC then machined under identical cutting conditions. Comprehensive characterization of the resulting wear patterns and the tribofilms formed at the tool/workpiece interface were made using X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy. Metallographic studies on the workpiece material were performed before the machining process and the surface integrity of the machined part was investigated after machining. Tool life was 23% higher when turning D2 than T1. This improvement in cutting tool life and wear behaviour was attributed to a difference in: (1 tribofilm generation on the friction surface and (2 the amount and distribution of carbide phases in the workpiece materials. The results show that wear performance depends both on properties of the workpiece material and characteristics of the tribofilms formed on the friction surface.

Using stamping punch force variation for the identification of changes in lubrication and wear mechanism

Science.gov (United States)

Voss, B. M.; Pereira, M. P.; Rolfe, B. F.; Doolan, M. C.

2017-09-01

The growth in use of Advanced High Strength Steels in the automotive industry for light-weighting and safety has increased the rates of tool wear in sheet metal stamping. This is an issue that adds significant costs to production in terms of manual inspection and part refinishing. To reduce these costs, a tool condition monitoring system is required and a firm understanding of process signal variation must form the foundation for any such monitoring system. Punch force is a stamping process signal that is widely collected by industrial presses and has been linked closely to part quality and tool condition, making it an ideal candidate as a tool condition monitoring signal. In this preliminary investigation, the variation of punch force due to different lubrication conditions and progressive wear are examined. Linking specific punch force signature changes to developing lubrication and wear events is valuable for die wear and stamping condition monitoring. A series of semi-industrial channel forming trials were conducted under different lubrication regimes and progressive die wear. Punch force signatures were captured for each part and Principal Component Analysis (PCA) was applied to determine the key Principal Components of the signature data sets. These Principal Components were linked to the evolution of friction conditions over the course of the stroke for the different lubrication regimes and mechanism of galling wear. As a result, variation in punch force signatures were correlated to the current mechanism of wear dominant on the formed part; either abrasion or adhesion, and to changes in lubrication mechanism. The outcomes of this study provide important insights into punch force signature variation, that will provide a foundation for future work into the development of die wear and lubrication monitoring systems for sheet metal stamping.

Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

Directory of Open Access Journals (Sweden)

I. Sudhakar

2015-03-01

Full Text Available Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

International Nuclear Information System (INIS)

Zhang Shitang; Zhou Jiansong; Guo Baogang; Zhou Huidi; Pu Yuping; Chen Jianmin

2008-01-01

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si 3 N 4 from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

Energy Technology Data Exchange (ETDEWEB)

Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

2008-09-15

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si{sub 3}N{sub 4} from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C.

Maintenance and preservation of concrete structures. Report 3: Abrasion-erosion resistance of concrete

Science.gov (United States)

Liu, T. C.

1980-07-01

This report describes a laboratory test program on abrasion-erosion resistance of concrete, including the development of a new underwater abrasion-erosion test method. This program was designed to evaluate the relative abrasion-erosion resistance of various materials considered for use in the repair of erosion-damaged concrete structures. The test program encompassed three concrete types (conventional concrete, fiber-reinforced concrete, and polymer concrete); seven aggregate types (limestone, chert, trap rock, quartzite, granite, siliceous gravel, and slag); three principal water-cement rations (0.72, 0.54, and 0.40); and six types of surface treatment (vacuum, polyurethane coating, acrylic mortar coating, epoxy mortar coating, furan resin mortar coating, and iron aggregate topping). A total of 114 specimens made from 41 batches of concrete was tested. Based on the test data obtained, a comprehensive evaluation of the effects of various parameters on the abrasion-erosion resistance of concrete was presented. Materials suitable for use in the repair of erosion-damaged concrete structures were recommended. Additional work to correlate the reported findings with field performance was formulated.

Transition metal carbide and boride abrasive particles

International Nuclear Information System (INIS)

Valdsaar, H.

1978-01-01

Abrasive particles and their preparation are discussed. The particles consist essentially of a matrix of titanium carbide and zirconium carbide, at least partially in solid solution form, and grains of crystalline titanium diboride dispersed throughout the carbide matrix. These abrasive particles are particularly useful as components of grinding wheels for abrading steel. 1 figure, 6 tables

A new approach for assessing the wear resistance of soft ductile materials

International Nuclear Information System (INIS)

Zaid, A.I.O.; Banna, M.A.E.

2007-01-01

Aluminum and its alloys are the most versatile and attractive metallic materials which have been used for many decades in many engineering applications specially in the automobile and airspace industries due to their high strength-to- weight ratio, thermal conductivity, electrical conductivity, corrosion and wear resistances. Wear is the loss of material from a surface caused by interaction with another material. The main mechanisms of interaction are applied loads and relative motion, which can cause adhesion or/and abrasion, all of which leads to material loss. Therefore, most of the suggested methods, theoretical and empirical, for estimating the wear resistance of material is based on the mass loss, irrespective of the material or type of existing wear. Experimental observations reveal that in some situations, especially for soft and ductile materials, the tested specimen showed little or no mass loss while its dimensions and shape have suffered from plastic deformation which causes more damage than mass loss. Similar phenomenon was observed during electric spot welding of aluminum and zinc coated steels at the area beneath the electrode where plastic deformation takes place, causing increase in area which reduces the current density, will be also discussed in the paper. The amount of the plastic deformation, even when mentioned in some publications, was neglected in assessing wear resistance. In this paper, a model based on the plastic deformation at the worn end together with the mass loss is forwarded and discussed. The model was tested qualitatively using commercially pure aluminum of 99.97% purity in the as supplied condition and in grain refined conditions by some rare earth materials e.g. titanium and titanium plus boron, which are normally used in industry for improving its hardness and mechanical behavior. The wear tests were carried out under different loads and speeds (the main parameters in assessing wear resistance) and the data was used for

Abrasive water jet: a complementary tool

OpenAIRE

Duarte, J. P.; Peças, P.; Nunes, E.; Gouveia, H.

1998-01-01

The abrasive water jet is a powerful cutting tool, whose main advantages lie in the absence of thermal effects and the capability of cutting highly thick materials. Compared with Laser, the abrasive water jet allows the cutting of a larger range of thicknesses and a wider variety of materials such as: ornamental stones, metals, polymers, composites, wood, glass and ceramics. The application of this technology has suffered an extensive growth, with successful applications in varied industrial ...

Polishability and wear resistance of splint material for oral appliances produced with conventional, subtractive, and additive manufacturing.

Science.gov (United States)

Huettig, Fabian; Kustermann, Achim; Kuscu, Ebru; Geis-Gerstorfer, Jürgen; Spintzyk, Sebastian

2017-11-01

Occlusal splints to treat bruxism are commonly made from polymethylmethacrylate (PMMA) in a manual workflow (powder-liquid technique). Today digitalization allows a machine-based manufacturing in subtractive (milling) and additive (printing) means using industrial-made PMMA or comparable resins. An in-vitro study should assess the surface finish and screen the wear resistance of conventional and industrial materials. Therefore, a total of 30 specimens made from conventionally PMMA (group C; powder-liquid, Palapress), polycarbonate ingots (group S; innoBlanc splint plus), and light-curing resin (group A; VarseoWax splint) were polished to examine the surface roughness (Ra) by profilometry and further analyzed by SEM. The specimens were loaded with a steatite ball moving 5000 times along 1cm with 5N of surface pressure under constant wetting (artificial saliva). The total height of profile (Pt) was calculated by further profilometry of the specimens. All specimen showed initially comparable Ra values ranging between 0.06 and 0.05µm (SD = 0.01) after polishing. SEM investigations revealed no visual cues for scratches or irregularities in any group. After abrasion test, the comparison of the wear depths, revealed mean Pt values of 111.4µm (SD = 18.5) in C, 85.7µm (SD = 21.5) in S, and 99.1µm (SD = 21.5) in A, whereas the mean of S was statistically different from C (p = 0.025). No signs of abrasion were found on the steatite balls. All materials showed comparable polished surfaces and a similar scale of wear. It remains questionable if the detected statistical differences are of clinical relevance, but indicates the need for tests of novel materials, especially in additive manufacturing. Copyright © 2017 Elsevier Ltd. All rights reserved.