TiB₂-Ni・P系通電焼結実験

抄録

This paper describes the effects of sintering conditions such as atmosphere, temperature, amount of Ni·P binder, sintering pressure and time on the mechanical properties of the product of TiB₂-Ni·P alloys.
1) In the case of sintering in the air nitrogen and, oxygen in the air react with TiB₂ and Ni·P to produce TiB₂, TiN, TiBO₃, BN, Ni₄B₃, Ni₂P and NiP₂. It is thought that these TiN, Ti₂O₃ and BN decrease the bending strength and the hardness of the alloy sintered in the air.
2) The alloy sintered at 1300-1500°C in a vacuum has a strong bending strength. One of the reasons is that TiB₂ or the surface layer TiBO₃ of TiB₂ particle combines with Ni₄B₃. These TiB₂ or TiBO₃ becomes the surface of TiB₂ particle from 1200-1300°C and so TiB₂-Ni·P is rapidly sintered in this range.
3) The strongest bending strength of 85kg/mm² and the hardness of Hυ1560kg/mm² were obtained by the TiB₂-12%Ni·P alloy sintered at 1400°C under a die pressure of 115kg/cm² for 14 min in a vaccum.