Sample records for COMPUESTOS DE NIQUEL (nickel compounds)
from WorldWideScience.org

Sample records 1 - 3 shown.



1

Resistencia a la corrosión del acero revestido con Ni autocatalítico en medios alcalinos/ The Corrosion Behavior of Electroless Nickel-Coated Steel in Alkaline Solutions

Sánchez, Miguel; Orozco, Henry; Pérez, Orlando
2009-01-01

Resumen en español El niquel 200 es utilizado en la industria petroquimica, en el manejo de disoluciones causticas, en una variedad de componentes y equipos fabricados con materiales altamente resistentes a la corrosion. Sin embargo, dado su alto costo y la incidencia de fallas por corrosion, es necesario recurrir a otros materiales alternativos que puedan mitigar este fenomeno. Uno de ellos es el acero revestido mediante niquel fosforo electroless (sin paso de corriente), el cual en alguna (mas) s situaciones y bajo ciertas condiciones ofrece alta resistencia. El objetivo de este trabajo fue evaluar la resistencia a la corrosion de probetas de acero recubiertas por niquel electroless (EN), en diferentes concentraciones de sosa caustica y establecer el espesor de recubrimiento optimo correspondiente a cada concentracion de NaOH. Los resultados de los analisis quimicos realizados por EDX indicaron que la composicion de los revestimientos EN fosforo corresponde a 10,5 % de fosforo y 89,5 % de niquel con durezas promedio de 550 HV. La velocidad de Corrosion para el acero EN estuvo en el orden entre 10,0 y 13,6 ƒÊm/ano (25 oC) y 10,2 y 14,7 ƒÊm/ano (85 oC). Mientras que para el niquel 200 estuvo en el orden entre 4,7 y 5,2 ƒÊm/ano (25 oC) y 7,0 y 9,9 ƒÊm/ano (85 oC). Comparativamente, el niquel 200 resulto mas resistente a la corrosion que el acero revestido mediante EN, pero su costo es mas elevado. Resumen en inglés Nickel 200 is used in the petrochemical industry in the handling of caustic solutions using a variety of components and equipments made of materials highly resistant to corrosion. However, due to their high costs and their impact on failures by corrosion, it is necessary to resort to other alternative materials that could mitigate this phenomenon. One of them is steel coated with electroless nickel (without passing flow), which in certain situations and under certain cond (mas) itions offers high resistance. The aim of this study was to evaluate the corrosion resistance of the coated steel test coupons by electroless nickel (EN) in different concentrations of caustic soda and establish the optimal coating thickness for each concentration of NaOH. The chemical analysis conducted by EDX indicates that the composition of coatings in phosphorus compounds are phosphorus by 10.5% and 89.5% nickel with hardnesses average of 550 HV. The corrosion rate in steel EN was in the order between 10.0 and 13.6 mm/yr (25 °C) and 10.2 and 14.7 mm/yr (85 ° C). While for nickel 200 it was in the order between 4.7 and 5.2 mm/yr (25 °C) and 7.0 and 9.9 mm/yr (85 °C). Nickel 200 was comparatively more corrosion resistant than steel coated with electroless nickel, but its cost is higher.

Scientific Electronic Library Online (Spanish)

2

Nivel de níquel urinario en niños residentes en ciudades cercanas a megafuentes/ Urinary nickel in children exposed to petcoke pollution

Iglesias A, Verónica; Burgos D, Soledad; Marchetti P, Nella; Silva Z, Claudio; Pino Z, Paulina
2008-08-01

Resumen en inglés Background: Petcoke is a remmant of the oil refiningprocess that contains Ni and other heavy metáis. Undesired human exposure to these compounds may result from petcoke combustión in plants located in the vicinity ofthe cities. Aim: To compare levéis of urinary Ni in schoolchildren residing in cities exposed and not exposed to petcoke pollution. Material and methods: A cross sectional study was done in schoolchildren aged 7 to 8 years oíd in two cities in northern Chi (mas) le: Mejillones (n = 59), near to a petcoke plant and Tocopilla (n = 56) as the reference city. First, morning urinary samples were collected and urinary Ni was determined by Atomic Absorption Spectrometry. Socioeconomic and environmental exposure information of families was obtained applying a questionnaire to parents. Múltiple linear regression was performed to identify other variables that may explain urinary Ni differences among the cities. Results: Median level of Ni was higher in Mejillones (4.9 fig/L) than in Tocopilla (3.9 fig/L). Residing in the exposed city was the most important explaining factor (B = 0.26; IC 0.107 - 0.428). Additionally years of residency was associated with urinary Ni (B = 0.03; IC 0.004 - 0.060). Conclusions: Urinary Ni in schoolchildren is higher in the city exposed to petcoke emissions. The difference does not imply that there are concrete hazards for the population s health. However, it warns about the existence of a higher exposure in places where petcoke is used

Scientific Electronic Library Online (Spanish)

3

Nickel nanoparticles in hydrogen-transfer reductions: characterisation and nature of the catalyst

Alonso Valdés, Francisco; Riente Paiva, Paola; Sirvent Pérez, Juan Alberto; Yus Astiz, Miguel

Nickel nanoparticles, readily prepared by reduction of nickel(II) chloride with lithium and a catalytic amount of DTBB, have been used in the transfer hydrogenation of carbonyl compounds and have been fully characterised by different means. The reaction rate of the transfer hydrogenation was found t...

DRIVER (Spanish)