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Method for Coating Fixtures to Prevent Part Adhesion During Heat Treatment

IP.com Disclosure Number: IPCOM000087069D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bauman, AH: AUTHOR [+2]

Abstract

Previously, KOVAR* parts held in straightening fixtures during vacuum annealing heat treatment were dipped in a stirred solution of Al(2)O(3) and FREON**. The coating thus deposited prevented diffusion bonding or sticking of the parts to the steel fixtures when withdrawn after heat treating. The coating then had to be removed by scrubbing or ultrasonic cleaning to prevent abrasion in the following trim die operations.

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Method for Coating Fixtures to Prevent Part Adhesion During Heat Treatment

Previously, KOVAR* parts held in straightening fixtures during vacuum annealing heat treatment were dipped in a stirred solution of Al(2)O(3) and FREON**. The coating thus deposited prevented diffusion bonding or sticking of the parts to the steel fixtures when withdrawn after heat treating. The coating then had to be removed by scrubbing or ultrasonic cleaning to prevent abrasion in the following trim die operations.

In the present method, the Al(2)O(3) coating of the part is replaced by plasma flame spraying Al(2)O(3) on the fixtures. After grit blasting with #60 silicon carbide to prepare the surface for adhesion, the steel annealing fixtures were plasma flame sprayed using a METCO*** gun and METCO #105 alumina using a mixture on N(2)H(2) as the propellant and plasma. The coating was deposited in the range of .001 to .002 inch thickness.

The present coating method results in the exclusion of diffusion bonding or sticking of the parts to the fixtures and there is no apparent spalling or other degradation of the coating. Also, there is no apparent transfer of the fixture coating to the part, thus eliminating the need for post-annealing cleaning. * Trademark of Westinghouse Electric Corp. ** Trademark of E. I. du Pont de Nemours & Co. *** Trademark of Metco Company.

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