Ceramic-to-Metal Seal Technology.
Abstract
The major applications for glass-to-metal and ceramic-to-metal seals are found in the electrical industry where such seals serve the dual purpose of electrically isolating yet 'hermetically' sealing various portions of a device. The term 'hermetic', although widely used, is not yet capable of precise definition (ASTM Committee F-1, Sub-Committee V, is currently studying the problems of measuring and classifying leak rates in metallic-nonmetallic seals). In some applications, such as electrical feed-throughs for capacitors and transformers, a seal is merely required to be liquid or oil tight. In many more applications, such as lamps, vacuum and gas-filled electron tubes, space simulation chamber, etc., a seal must be gas-tight or, as this condition is more commonly referred to, vacuum tight. A vacuum-tight seal is generally considered to be one which, when tested on a helium-peaked mass spectrometer leak detector, shows a leakage rate of less than 10 to the -10 cc of air per second. It is this latter type of seal with which this report is primarily concerned. Although glass-to-metal seals serve admirably in many applications, there is a continually growing usage of ceramic-to-metal seals. Ceramic-to-metal seals possess a number of advantages and very few disadvantages when compared with their glass counterpart.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1966
- Accession Number
- ADA075554
Entities
People
- R. H. Bristow
Organizations
- General Electric