Metal-ceramic composite body and a method of manufacturing the same

A metal-ceramic composite body comprising:

• a ceramic member having a large diameter portion with a front surface and a back surface and an integral small diameter portion extending from said back surface thereof;
• and
• a metallic member including a main body portion and an insertion edge portion, said main body portion having recess means, said insertion edge portion including an insertion edge surface having a thickness which is not greater than 0.2 times the diameter of the small diameter portion of the ceramic member, said insertion edge portion having a length which is not less than 0.5 times the diameter of the small diameter portion of the ceramic member and a thickness which gradually increases from said insertion edge surface toward said main body portion such that said increase in thickness has an outer radius of curvature of not less than 0.4 times as large as the small diameter portion of the ceramic member, said insertion edge portion forming an outer opening of said recess means such that said small diameter portion of the ceramic member is fitted into said recess means and a space of not less than the diameter of the small diameter portion of the ceramic member is provided between the insertion edge surface of the metallic member and the back surface of the large diameter portion of the ceramic member.

A method of manufacturing a metal-ceramic composite body comprising:

• fitting a ceramic member having a large diameter portion with a front surface and a back surface and an integral small diameter portion extending from said back surface together with a metallic member including a main body portion and an insertion edge portion, said main body portion having recess means, said insertion edge portion including an insertion edge surface, said insertion edge portion being made by machining said metallic member to result in said insertion edge portion having a thickness which gradually increases from said insertion edge surface toward said main body portion such that said increase in thickness has an outer radius of curvature of not less than 0.4 times as large as the small diameter portion of the ceramic member, said insertion edge portion forming an outer opening of said recess means such that said small diameter portion is fitted into said recess feature and a space of not less than the diameter of the small diameter portion of the ceramic member is provided between the insertion edge surface of the metallic member and the back surface of the large diameter portion of the ceramic member.