| 摘要 |
PROBLEM TO BE SOLVED: To provide a ceramic front end member for an ultrasonic horn which can exhibit excellent wear resistance and impact resistance without depending upon the material quality of a mating material and exhibits excellent durability particularly when a ferrous material is worked and the ultrasonic horn which has this member and has high durability. SOLUTION: Raw material powder is prepared by subjecting silicon nitride powder, titanium nitride powder and sintering assistants (Al2O3, MgO, ZrO2 and CeO2) to wet process mixing, then to drying and granulating and is molded by a mold press. The raw material powder is thereafter subjected to cold isostatic pressing and is subjected to prefiring at 1,550 to 1,950 deg.C in a nitrogen atmosphere of 1 MPa and is further subjected to high temperature isostatic pressing for two hours at 1,600 deg.C in a nitrogen atmosphere of 100 MPa, by which the ceramic front end member for the ultrasonic horn is obtained. The resultant ceramic front end member for the ultrasonic horn contains the silicon nitride and the nitride and/or carbide of the elements belonging to periodic table groups 4 to 6 at >=90 mass% in total and the Vickers hardness thereof is >=15 GPa and the fracture toughness thereof is >=4.5 MPam1/2. |
