反応焼結によるNi_3Alへのアルミナの複合化 Incorporation of Alumina Particles into Reactively Sintered Ni_3Al
It is known that Ni and Al powders can be reactively sintered to form Ni<SUB>3</SUB>Al at around 700°C. It was attempted, in the present experiment, to incorporate alumina particles in Ni<SUB>3</SUB>Al during its formation. Alumina particles were dispersed in Ni particles by ball-milling the mixture (mechanical dispersing, MD) and then the Ni particles treated, after compacting with Al powders, were reactively sintered to form Ni<SUB>3</SUB>Al with dispersed alumina particles. As another process, NiO particles were dispersed in Ni powder particles by ball-milling (MD), and the resultant Ni powders were mixed with Al powders, compacted and heated. Curiously, the expected reactions hardly occurred (even the formation of Ni<SUB>3</SUB>Al), even though the reaction temperature was raised to 1000°C; the reason for this is considered to be due to the blocking effect of yielded alumina formed in thin wall-like barriers retarding the diffusion of Ni and Al to form Ni<SUB>3</SUB>Al. The other processes were also tried. For the processes investigated, no apparent effect of gravity, such as segregation of alumina, was observed.
粉体および粉末冶金 45(8), 749-753, 1998-08-15
Japan Society of Powder and Powder Metallurgy