EFFECT OF NICKEL AND COBALT ADDITIONS ON INFILTRATION BEHAVIOR, MICROSTRUCTURE AND HARDNESS OF W-AG COMPOSITES

In this research, infiltration behavior of w-ag composite compacts with nickel and cobalt as additives hasbeen investigated. nickel and cobalt were added to tungsten powder by two distinct methods: mixing elementally andreduction of salt solution. the coated tungsten powders were compacted under controlled pressures to make porousskeleton with 32-37 vol. % porosity. infiltration process was carried out at 1100 ?c under a reducing atmosphere for1h. the effect of additives on infiltration of ag and density were evaluated by sem and archimedes methods.properties of the specimens were compared following two distinct processes namely: i) sintering simultaneously withinfiltration process and ii) sintering prior to infiltration (pre-sintering process). it was found that specimens whichwere pre-sintered and then infiltrated with molten silver represent higher hardness and finer microstructure than thespecimens infiltrated simultaneously with sintering.