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Making High Strength Ceramics

IP.com Disclosure Number: IPCOM000089954D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Schwartz, B: AUTHOR

Abstract

In this strengthening method, the surfaces of the ceramic are placed in compression relative to the center portions. In this method, article 10 is built up of three or more layers 11, 12, and 13 of green ceramic material. Outside layers 11 and 13 have a composition which is altered slightly in comparison to layer 12 so that they have a lower thermal coefficient of expansion than layer 12. This alteration can be achieved by the addition of chromium to alumina. The resultant layered article is then sintered. Since layers 11 and 13 have a lower thermal expansion than layer 12, the latter is placed in tension while layers 11 and 13 are placed in compression. Since ceramic material is considerably stronger in compression than in tension, layer 12 normally has a much greater thickness than the layers 11 and 13.

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Making High Strength Ceramics

In this strengthening method, the surfaces of the ceramic are placed in compression relative to the center portions. In this method, article 10 is built up of three or more layers 11, 12, and 13 of green ceramic material. Outside layers 11 and 13 have a composition which is altered slightly in comparison to layer 12 so that they have a lower thermal coefficient of expansion than layer 12. This alteration can be achieved by the addition of chromium to alumina. The resultant layered article is then sintered. Since layers 11 and 13 have a lower thermal expansion than layer 12, the latter is placed in tension while layers 11 and 13 are placed in compression. Since ceramic material is considerably stronger in compression than in tension, layer 12 normally has a much greater thickness than the layers 11 and 13. The ceramic articles so produced have a special application in serving as substrates for microelectronic devices.

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