Her Majesty the Queen in Right of Canada, As Represented by the Minister

Quality Hermetics Limited

John A Topping

Peter Mayer

Michael J Fairweather

M Krishna Murthy

Albert H Brooks

Corrosion-resistant, hermetic glassceramic-to-metal seals are made in a single rapid heating step by inserting a glass preform made of 25-35% by weight ZnO, 2.5-10% by weight Al.sub.2 O.sub.3 and 30-60% SiO.sub.2 together with optional nucleating and/or fluxing agents, between a metal pin and surrounding metal collar. Heating is rapid in a single step to first fluidize the glass, while avoiding excessive oxidation of the metal pin and the metal collar and to prevent excessive interaction of the glass composition at the glass/collar interface, then to ceram the seal. The resulting seals exhibit good corrosion resistance to potassium hydroxide solutions and are useful in Ni-Cd batteries.

Method of forming corrosion-resistant glassceramic-to-metal seals

Hermetic glass seals of high electrical resistivity are provided. Glass compositions suitable for use in such seals and based on lead-silica glasses are described. Glass compositions having particular efficacy in a nuclear reactor environment also are described.

Glass seal

A seal for a terminal member of a nickel-cadmium battery cell, provided with a, for example Ceramvar, terminal electrode which is first of all electroplated with nickel and is then electroplated with chromium. A ceramic ring is located between the terminal electrode and a shoulder portion of a steel collar in the battery, the shoulder portion having an axial length greater than the axial length of the ceramic ring and the ceramic ring being brazed to the central region of the shoulder portion. Glass rings, for example, which may be transparent, are provided on opposite sides of the ceramic ring and rest on ledges of the shoulder portion whereby a respective void is formed between the glass ring and the respective adjacent surface of the ceramic ring.

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Oakville, Canada

John A Topping