Fracture Toughness Measurements of Ba2YCu3O7-x Superconducting Oxide by Means of Indentation Technique

Abstract
Fracture toughness of polycrystalline Ba2YCu3O7-x superconducting compound was measured by means of indentation technique in air. The toughness value of the sample heat-treated at 1203 K for 28.8 ks was 0.71 MPa ·m1/2, but it became 0.87 MPa ·m1/2 through heat treatment at 1223 K for the same period and 1.37 MPa ·m1/2 by the addition of 0.1 mol of Ag2O for 1 mol of Ba2YCu3O7-x . It was demonstrated that polycrystalline Ba2YCu3O7-x can show higher fracture toughness than the single crystalline one (0.74 MPa ·m1/2) and the addition of Ag2O improves toughness.