JOHN J GRABOWSKI
Engineering in Andover, MA
License number
Massachusetts 15461
Issued Date
Mar 8, 1961
Expiration Date
Jun 30, 1986
Type
Mechanical Engineer
Address
Address
Andover, MA 01810
Professional information
Mirror And Method Of Making Same
US Patent:
4074416, Feb 21, 1978
Filed:
Sep 13, 1976
Appl. No.:
5/722844
Inventors:
Werner R. Rambauske - Carlisle MA
John J. Grabowski - Andover MA
John J. Grabowski - Andover MA
Assignee:
Raytheon Company - Lexington MA
International Classification:
B22D 1126
US Classification:
295274
Abstract:
A mirror, and method of making same, is disclosed. The mirror includes a metallic base material having a low coefficient of thermal expansion, an intermediate layer bonded to the base by a plasma spray process and a reflecting surface overlying the intermediate layer, the coefficients of thermal expansion of the materials of the intermediate layer and the reflecting surface differing from each other and from the coefficient of thermal expansion of the base material.
The disclosed method contemplates: The casting of a mirror blank from a material having a low coefficient of thermal expansion and machining the surface to a desired contour, with stress-relieving heat treatments before and after such machining; plasma spraying an intermediate coating of a material having a Rockwell hardness equal to, or greater than, 60; grinding the intermediate coating to a desired contour and lapping and cleaning such ground coating to produce an optically smooth contoured surface; and finally plating such surface to provide the desired mirror surface.