Kyocera Corporation

Hiroshi Yoshimitsu

Takero Fukudome

Tatsuyuki Nakaoka

Shuichi Tateno

Takashi Watanabe

A silicon nitride cutting tool comprising a sintered product is disclosed. The sintered product comprises silicon nitride, at least one rare earth element compound, and a magnesium compound. The silicon nitride cutting tool further comprises a surface region and an inside region comprising the sintered product with varying content ratios of component compounds to provide enhanced wear and fracture resistance.

Silicon nitride cutting tool

A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

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Kagoshima, Japan

Hiroshi Yoshimitsu