Abstract: A sintered rare earth oxyfluoride compact is composed of LnaObFc (wherein Ln is a rare earth element; and a, b, and c each independently represent a positive number, provided that they are not equal to each other) or Ca-stabilized LnOF as a primary phase and LnOF unstabilized with Ca as a secondary phase. The intensity ratio of the XRD peak of the (018) or (110) plane of the unstabilized LnOF to the highest XRD peak of LnaObFc is preferably 0.5% to 30%.

Abstract: Out of sintered metal carbides having an extremely high melting point, there is provided a sintered metal carbide which can be produced without having to perform sintering under high pressure such as hot pressing or HIP, having a high relative density and excellent mechanical strength. A sintered metal carbide of at least one metal selected from the group consisting of elements of Groups 4 and 5 of the periodic table, wherein the sintered metal carbide contains Si element of 0.1 wtppm or more and 10,000 wtppm or less.

Abstract: A sintered rare earth oxyfluoride compact is composed of LnaObFc (wherein Ln is a rare earth element; and a, b, and c each independently represent a positive number, provided that they are not equal to each other) or Ca-stabilized LnOF as a primary phase and LnOF unstabilized with Ca as a secondary phase. The intensity ratio of the XRD peak of the (018) or (110) plane of the unstabilized LnOF to the highest XRD peak of LnaObFc is preferably 0.5% to 30%.

Abstract: A sintered rare earth oxyfluoride compact is composed of LnaObFc (wherein Ln is a rare earth element; and a, b, and c each independently represent a positive number, provided that they are not equal to each other) or Ca-stabilized LnOF as a primary phase and LnOF unstabilized with Ca as a secondary phase. The intensity ratio of the XRD peak of the (018) or (110) plane of the unstabilized LnOF to the highest XRD peak of LnaObFc is preferably 0.5% to 30%.

Abstract: An yttrium oxyfluoride is represented by YOF and is stabilized by a fluoride represented by CaF2. Preferably, the number of moles of Ca with respect to 100 mol of yttrium is from 8 to 40 mol. A powder material is made of a first powder mixture including a calcium fluoride powder represented by CaF2 and an yttrium oxyfluoride powder represented by YOF, or a second powder mixture including a calcium fluoride powder represented by CaF2, an yttrium fluoride powder represented by YF3, and an yttrium oxide powder represented by Y2O3. A production method involves firing a molded product of the first or second powder mixture under predetermined conditions.

Abstract: An yttrium oxyfluoride is represented by YOF and is stabilized by a fluoride represented by CaF2. Preferably, the number of moles of Ca with respect to 100 mol of yttrium is from 8 to 40 mol. A powder material is made of a first powder mixture including a calcium fluoride powder represented by CaF2 and an yttrium oxyfluoride powder represented by YOF, or a second powder mixture including a calcium fluoride powder represented by CaF2, an yttrium fluoride powder represented by YF3, and an yttrium oxide powder represented by Y2O3. A production method involves firing a molded product of the first or second powder mixture under predetermined conditions.