. . . "Joining ceramic materials such as zirconia, alumina, or steatite to metallic materials such as steel or Inconel??? requires sealing glasses to possess a relatively wide range of coefficient of thermal expansion, i.e. in the range of about 45???10-7 /??? C. to about 95???10-7 /??? C., more closely matching the coefficients of thermal expansion of the ceramic material in order to minimize the risk o" .