Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy

Cobalt-based alloys have been widely used in biomedical application. In this research, 11 different compositions of cobalt-chromium-nickel (Co-Cr-Ni) alloys were developed by powder metallurgy route. Scanning electron microscope (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) wa...

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Main Author: Raudhah, Othman
Format: Thesis
Language:English
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spelling my-unimap-332732014-03-31T11:01:10Z Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy Raudhah, Othman Cobalt-based alloys have been widely used in biomedical application. In this research, 11 different compositions of cobalt-chromium-nickel (Co-Cr-Ni) alloys were developed by powder metallurgy route. Scanning electron microscope (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) was used for morphology and elemental observation of the raw materials. The particle size distribution of the Co, Cr and Ni particles were characterized using Malvern particle analyzer. X-ray diffraction (XRD) was carried out to analyze the phase transformation of raw materials. The raw Co-Cr-Ni powders were first milled using planetary mill and compacted using uniaxial hand press to a pellet shape before being sintered using tube furnace under argon atmosphere. The samples were sintered at 1000°C for 2 hours. Percentage of porosity, density, shrinkage and hardness test were carried out to correlate physical and mechanical properties with composition of Co-Cr-Ni alloys. The dimensions of the samples before and after sintering were measured and the percentage of shrinkage of the samples was calculated. Density measurement was carried out by Archimedes technique while percentage of porosity was calculated based on the density data. Hardness testing was performed using Vickers hardness machine. The microstructure and the phase transformation of sintered samples were also being characterized using SEM and XRD respectively. In order to understand a relationship of corrosion resistance with composition of Co-Cr-Ni alloy, an immersion test was executed in a water bath using 0.9% sodium chloride solution while maintaining the temperature of 37°C. Weight loss measurement and corrosion rate were carried out to analyze the corrosion resistance of the immersed samples. The results showed that the percentage of porosity of the samples increased with increasing Cr content and decreased with increasing Co content. The density and the percentage of shrinkage of the alloys increased with increasing Co content and decreased with increasing Cr content. Hardness increased with increasing Co content while decreased with increasing Ni content. Sample with composition of Co4Cr5Ni was found to have the highest corrosion resistance after 30 days immersed in 0.9% sodium chloride solution. In contrary, sample with composition of Co37Cr5Ni evidenced the lowest corrosion resistance. Universiti Malaysia Perlis (UniMAP) 2011 Thesis en http://dspace.unimap.edu.my:80/dspace/handle/123456789/33273 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/33273/1/P.1-24.pdf 99d150ce970d59fffb1dc9ba4a80f718 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/33273/2/Full%20text.pdf b931d430117f2ac01942b010e1a077cb http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/33273/3/license.txt 8a4605be74aa9ea9d79846c1fba20a33 Cobalt-chromium-nickel (Co-Cr-Ni) Powder metallurgy Corrosion Alloys Biomedical materials School of Materials Engineering
institution Universiti Malaysia Perlis
collection UniMAP Institutional Repository
language English
topic Cobalt-chromium-nickel (Co-Cr-Ni)
Powder metallurgy
Corrosion
Alloys
Biomedical materials
spellingShingle Cobalt-chromium-nickel (Co-Cr-Ni)
Powder metallurgy
Corrosion
Alloys
Biomedical materials
Raudhah, Othman
Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy
description Cobalt-based alloys have been widely used in biomedical application. In this research, 11 different compositions of cobalt-chromium-nickel (Co-Cr-Ni) alloys were developed by powder metallurgy route. Scanning electron microscope (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS) was used for morphology and elemental observation of the raw materials. The particle size distribution of the Co, Cr and Ni particles were characterized using Malvern particle analyzer. X-ray diffraction (XRD) was carried out to analyze the phase transformation of raw materials. The raw Co-Cr-Ni powders were first milled using planetary mill and compacted using uniaxial hand press to a pellet shape before being sintered using tube furnace under argon atmosphere. The samples were sintered at 1000°C for 2 hours. Percentage of porosity, density, shrinkage and hardness test were carried out to correlate physical and mechanical properties with composition of Co-Cr-Ni alloys. The dimensions of the samples before and after sintering were measured and the percentage of shrinkage of the samples was calculated. Density measurement was carried out by Archimedes technique while percentage of porosity was calculated based on the density data. Hardness testing was performed using Vickers hardness machine. The microstructure and the phase transformation of sintered samples were also being characterized using SEM and XRD respectively. In order to understand a relationship of corrosion resistance with composition of Co-Cr-Ni alloy, an immersion test was executed in a water bath using 0.9% sodium chloride solution while maintaining the temperature of 37°C. Weight loss measurement and corrosion rate were carried out to analyze the corrosion resistance of the immersed samples. The results showed that the percentage of porosity of the samples increased with increasing Cr content and decreased with increasing Co content. The density and the percentage of shrinkage of the alloys increased with increasing Co content and decreased with increasing Cr content. Hardness increased with increasing Co content while decreased with increasing Ni content. Sample with composition of Co4Cr5Ni was found to have the highest corrosion resistance after 30 days immersed in 0.9% sodium chloride solution. In contrary, sample with composition of Co37Cr5Ni evidenced the lowest corrosion resistance.
format Thesis
author Raudhah, Othman
author_facet Raudhah, Othman
author_sort Raudhah, Othman
title Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy
title_short Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy
title_full Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy
title_fullStr Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy
title_full_unstemmed Physical properties and corrosion behaviour of Co-Cr-Ni alloy developed by powder metallurgy
title_sort physical properties and corrosion behaviour of co-cr-ni alloy developed by powder metallurgy
granting_institution Universiti Malaysia Perlis (UniMAP)
granting_department School of Materials Engineering
url http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/33273/1/P.1-24.pdf
http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/33273/2/Full%20text.pdf
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