Ceramic-to-metal seal

Absorption of hydrogen by titanium metal above 400 °C gives a solid whose stoichiometry approaches TiH2, but a true dihydride does not appear to exist. This hydride has been used for the formation of glass-to-metal and ceramic-to-metal seals.1 Thermal desorption above 600 °C provides a source of very pure hydrogen.2... 

I.W. Donald, Preparation Properties and Chemistry of Glass- and Glass-Ceramic-to-Metal Seals and Coatings , J. Mater. Sci., 28 2841-66 (1993). 

There are several possible ways of accomplishing this. These include localized cooling at the joining area, mechanical seal (such as Swagelok), ceramic-to-ceramic, ceramic-to-metal seals (cermets), gland packing, and special types of seals. 

USE Additive in powder metallurgy getter for oxygen and nitrogen in electronic tubes wetting agent for ceramic to metal seals source of pure hydrogen. 

Develop ceramic-to-metal seal for easy gas manifolding. 

The ceramic-to-metal seals for dense ceramic syngas membranes that have been suggested or demonstrated fall into one of three categories ... 

A second type of ceramic-to-metal seal patented by Air Products uses compliant, metallic, toroidial rings as the seal [40]. Figure 8.16 shows a ring in cross-section... 

Figure 8.17 Cross-section of a ceramic to metal seal from Fig. 3 of U.S. Patent 5 302 402 [40], showing the torodial ring (15) sealing between a ceramic tube (21) and a metal housing (19).

I.W. Donald, Preparation, properties and chemistry of glass and glass-ceramic-to-metal seals and coatings. Journal of Materials Science, 28 (1993) 2841-2886. 

Jiang, G., Mishler, D., Davis, R., Mobley, P., and Schulman, J. Ceramic to Metal Seal for Implantable Medical Device. Biomedical Engineering Department, USC, Los Angeles, CA. Proceedings of the 8th Annual F. Grodins Graduate Research Symposium, pp. 92-92, March 2004. 

Relative ease of hermetic sealing by having the electrical leads cast into molten glass ( glass-to-metal seal ) in ceramic ( ceramic-to-metal seal ), or embedded into thermosetting plastic ... 

J.A. (2011) Recent developments in the preparation, characterization, and applications of glass- and glass-ceramic-to-metal seals and coatings. J. Mater.. Sci., 46, 1975-2000. 

The ceramic elements used in a vacuum tube are critical elements of the device. Assembled in sections, each element builds on the previous one to form the base of the tube. The ceramic-to-metal seals are created using a material that is painted onto the ceramic and then heated in a brazing oven. After preparation in a high-temperature oven, the painted area provides a metaUic structure that is molecularly bonded to the ceramic, and provides a surface suitable for brazing. 

Mexims. Matched Expansion Insulator/ Metal Systems. These are ceramic-to-metal seals. (Trade-name English Electric Co., Stafford, England). MG-Block, MG-plank. Perforated building units, 9in x AVz x 9in (228 x 114 x 228 mm) (block) or storey-height (plank), made from fired clay. Developed by the Mellor Green Laboratories of British Ceramic Research Ltd. 

For the electrical contacts in many cases the metallic container is one pole and a glass-to-metal seal (or ceramic-to-metal seal) the other. The container may also have to be potential free then both contacts are made from the glass-to-metal seals. 

---