Effect of Y and Ge addition on Mechanical properties and Corrosion

This study investigates the effect of Germanium and Yttrium as alloying element on the corrosion, wear and compressive strength behavior of CoCrMo (F75). The samples prepared by powder metallurgy approach, the powder mixture containing (62.4%Co, 28%Cr, 6%Mo, 0.5%Ni, 1%Si, 1%Mn, 0.75%Fe, 0.35%C). Each of alloying elements (Ge and Y) added with percentage of (0.5, 1and 1.5) wt. % then the additives were mixed together with 0.5%, 1% for each element at the expense of Cobalt. The elementally powders mixed for 5hr then was compacted with fixed compacting pressure of (800) MPa to obtain cylindrical samples with diameter (10) mm. The sintering process accomplished at temperature 950 C° for 5h under vacum conditions (10 torr) then the samples cooled in furnace. The addition of Ge and Y has a notable effect on the porosity of sintered CoCrMo alloys. Where, the addition of Ge to CoCrMo alloys caused decreasing in porosity .While, Y addition resulted in increasing the porosity. Also the mixture of Ge and Y has increases the porosity of samples used in CoCrMo.