Hermetic glass-metal compression seal

Claim 1

In a hermetically sealed lead-in structure for an electronic device comprising a glass-metal compression seal which includes a steel outer member having an opening therethrough, a unitary glassy sealing member positioned in the opening in the steel outer member and hermetically sealed to the steel, and a metallic conductor passing through the glassy sealing member and hermetically sealed thereto, wherein the steel outer member is composed of a steel having an average linear coefficient of thermal expansion (30°-300° C.) in the range of about 120-130 × 10 -7 /° C. and the metallic conductor is composed of cobalt-nickel-iron alloy having an average linear coefficient of thermal expansion (30°-400° C.) of about 46-52 × 10 -7 /° C., the improvement wherein the glassy sealing member is composed of a material selected from the group consisting of: (a) a glass having an average linear coefficient of thermal expansion (0°-300° C.) of about 88.5 × 10 -7 /° C. and a composition consisting essentially, in parts by weight, of about 63 parts SiO 2 , 2.6 parts Al 2 O 3 , 14 parts SrO, 5.8 parts Na 2 O, 8.9 parts K 2 O and 3.0 parts B 2 O 3 , and (b) a mixture having an average linear coefficient of thermal expansion (0°-300° C.) of about 84 × 10 -7 /° C. and a composition consisting essentially of 6 parts zircon and 100 parts glass by weight, the glass consisting essentially, in parts by weight, of about 66 parts SiO 2 , 12 parts BaO, 2.7 parts Al 2 O 3 , 2.0 parts B 2 O 3 , 6.7 parts Na 2 O, 6.6 parts K 2 O, 2.0 parts ZrO 2 , 0.7 parts Li 2 O and 1.6 parts F.