| 摘要 |
The purpose of the present invention is to provide: a stishovite sintered polycrystal having high hardness and high toughness; and a method for producing the stishovite sintered polycrystal. A stishovite sintered polycrystal can be produced by heating a mass of silicon dioxide glass at 1000 to 1400°C under a pressure of 12 to 16 GPa. The stishovite sintered polycrystal produced in this manner is composed of microcrystals having an average particle diameter of 300 nm or less, and therefore the amount in grain boundaries is increased and microcrystals each having a long and thin shape are penetrated into the sintered polycrystal, whereby the toughness of the stishovite sintered polycrystal is improved. As a result, it becomes possible to produce a highly hard and highly tough stishovite sintered polycrystal having a Vickers hardness of 28 to 29 GPa and a fracture toughness of 10 to 16 MPam1/2. |
