| 摘要 |
An object of the present invention is to provide an aluminum nitride sintered body with high optical transmissivity and which has a smooth surface in the unpolished condition after firing. The aluminum nitride sintered body of the present invention is characterized by having an oxygen concentration of 450 ppm or less, a concentration of impurity elements excluding oxygen, nitrogen, and aluminum of 350 ppm or less, and an average crystal grain diameter of between 2 µm and 20 µm, and also having an arithmetic mean surface height-Ra of 1 µm or less and a maximum height Rz of 10 µm or less in the unpolished condition after firing. |
