JOINING MATERIAL FOR SILICON NITRIDE SINTERED BODY AND JOINING METHOD

摘要

PURPOSE:To lower joining temp. and to obtain high joining strength at high temp. by constituting the joining material of the mixture of CaO, SiO2 and Ta2O3. CONSTITUTION:Joining material for a silicon nitride sintered body is obtained by incorporating three components of A) CaO, B) SiO2 and C) Ta2O3 or four components obtained by adding D) Si3N4 powder thereto according to circumstances. As the blending rate of the respective components, B/A by weight ratio is 0.2-5.0 preferably 0.5-2.0 and component C is 0.1-80wt.% preferably 5-40wt.% of the whole body and component P is 0.01-80wt.% preferably 10-50%. Amount of nitrogen contained in the joining material is increased by addition of component D and thereby strength of the joint phase is enhanced and also thermal expansion coefficient is lowered and thermal stress at a time for joining to Si3N4 is lowered. In the case of utilizing this joining material and joining an Si3N4 sintered body, this joining material is applied to the surface of the sintered body, melted and coated by performing heat-treatment in the nonoxidative atmosphere and thereafter the Si3N4 sintered body is joined thereto.