Ceramic sintered body, insert, cutting tool, and friction stir welding tool

Abstract

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 Al2O3 (alumina), WC (tungsten carbide) and ZrO2 (zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the Al2O3; and (2) a grain boundary of crystal grains of the Al2O 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 ZrO2, and the balance being the Al2O3, and wherein the ZrO2 is in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).

Dependencies are inferred from the claim text.