SINTERED HARD MATERIAL AND MOLD COMPRISING THE SAME FOR MOLDING HIGH-PRECISION OPTICAL ELEMENT

摘要

A sintered hard material consisting mainly of a tungsten carbide phase. It is free from structural defects such as pores (voids) and abnormal phases, has a high hardness, high Young's modulus, and low coefficient of thermal expansion, and has excellent fracture toughness besides excellent processed-surface precision and surface roughness. (W,M1)<SUB>2</SUB>C<SUB>X</SUB> (0.8=X<1.0) is crystallized as a second phase in a tungsten carbide phase, the WC phase being a first phase. Thus, the fracture toughness of the tungsten carbide phase is improved. The (W,M1)<SUB>2</SUB>C<SUB>X</SUB> (0.8=X<1.0) is a solid solution of M1, which is one or more of the transition metal elements other than tungsten in Groups 4a, 5a, and 6a of the Periodic Table, in W<SUB>2</SUB>C<SUB>X</SUB> (0.8=X<1.0)