抄録
Titanium diboride was hot-pressed at the temperature range from 1700°C to 2000°C in graphite molds with additions of 3 to 10% of binder metals-Cr, Fe, Co, Ni, Si, or Ti. Density and bending strength were measured and micro-structures were observed.
Co or Ni additions were the most effective for the densification of titanium diboride at lower hot-pressing temperatures, and Cr addition was effective at higher temperatures.
Grain growth was strongly accelerated by additions of Co or Ni especially at the surface layer of specimens, but it was hardly observed in the specimen containing Cr.
Bending strength (S) of specimens containing 6 or 10% Cr was dependent on porosity (P). The relationships between them were found to be expressed by the following equations.
S6=45e-4.0Pkg/mm2 S10=38e-5.7P
The bending strength was also affected by the rate of loading. It was reduced to half by increasing the crosshead speed of Instron Tensile Tester from 0.05 to 5cm/min.
