Ceramic sintered body, insert, cutting tool, and friction stir welding tool
Provided is a ceramic sintered body having high wear resistance and chipping resistance. Also provided are an insert, a cutting tool and a friction stir welding tool, each of which uses such a high-performance ceramic sintered body. The ceramic sintered body includes Al 2 O 3 (alumina), WC (tungsten carbide) and ZrO 2 (zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the Al 2 O 3 ; and (2) a grain boundary of crystal grains of the Al 2 O and crystal grains of the WC, wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO 2 , and the balance being the Al 2 O 3 , and wherein the ZrO 2 is in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).
1. A ceramic sintered body, comprising Al 2 O 3 , WC and ZrO 2 ,
wherein Zr element is present at either one or both of: (1) a grain boundary between crystal grains of the Al 2 O 3 ; and (2) a grain boundary of crystal grains of the Al 2 O and crystal grains of the WC,
wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO 2 , and the balance being the Al 2 O 3 ,
wherein the ZrO 2 is in a phase of tetragonal structure or a mixed phase of tetragonal and monoclinic structures, and
wherein the ceramic sintered body has a value of I M /(I T +I M ) being greater than 0.52 and smaller than or equal to 0.95 where, in X-ray diffraction of the ceramic sintered body, I M is a peak intensity of (−111) plane of the monoclinic structure of the ZrO 2 ; and I T is a peak intensity of (101) plane of the tetragonal structure of the ZrO 2 .
2. The ceramic sintered body according to claim 1 ,
wherein the sintered ceramic body contains 70.0 to 80.0 vol % of the WC.
3. An insert comprising the ceramic sintered body according to claim 1 .
4. A cutting tool comprising the insert according to claim 3 .
5. A friction stir welding tool comprising the ceramic sintered body according to claim 1 .
6. The cutting tool according to claim 4 , wherein the insert comprises:
the ceramic sintered body as a substrate; and
a surface coating layer formed on a surface of the substrate and containing at least one kind selected from the group consisting of a carbide of Ti, a nitride of Ti, a carbonitride of Ti, an oxycarbide of Ti, a oxynitride of Ti and a carboxynitride of Ti.
7. The friction stir welding tool according to claim 5 , comprising:
the ceramic sintered body as a substrate; and
a surface coating layer formed on a surface of the substrate and containing at least one kind selected from the group consisting of a carbide of Ti, a nitride of Ti, a carbonitride of Ti, an oxycarbide of Ti, a oxynitride of Ti and a carboxynitride of Ti.