Silicon nitride sintered body, wear-resistant member using the same, and method for producing silicon nitride sintered body
AssigneesKabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
InventorKai Funaki
Life of this patent
Estimating the term…
Abstract
A silicon nitride sintered body includes a silicon nitride crystal grains and grain boundary phases. Further, when D stands for width of the silicon nitride sintered body before being subjected to surface processing, relations between an average grain diameter dA and an average aspect ratio rA of the silicon nitride crystal grain in a first region from an outermost surface to a depth of 0 to 0.01D and an average grain diameter dB and an average aspect ratio rB of the silicon nitride crystal grain in a second region inside the first region satisfy the inequalities: 0.8≤dA/dB≤1.2; and 0.8≤rA/rB≤1.2.
Claims7
A silicon nitride sintered body having a shape of a sphere, the silicon nitride sintered body comprising a silicon nitride crystal grains and grain boundary phases, wherein
- the sphere before being subjected to surface processing has a diameter of 8 mm or more and 60 mm or less as the width,
- when D stands for width of the silicon nitride sintered body before being subjected to surface processing, relations between an average grain diameter dA and an average aspect ratio rA of the silicon nitride crystal grain in a first region from an outermost surface to a depth of 0 to 0.01D and an average grain diameter dB and an average aspect ratio rB of the silicon nitride crystal grain in a second region inside the first region satisfy inequalities:
- 0.8≤dA/dB≤0.97or 1.01≤dA/dB≤1.2;
- and
- 0.8≤rA/rB≤0.95or 1.05≤rA/rB≤1.2,
- and both the average grain diameter dA and the average grain diameter dB of the silicon nitride sintered body are 1.1 μm or more.
Dependencies are inferred from the claim text.