White thermal control surfaces containing ZrSiO.sub.4
AssigneeMartin Marietta Corporation
InventorsHarold A. Papazian, Donald F. Shepard, Edward A. Pierson, Michael J. Gordon
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Abstract
The present invention resides in a white thermal control surface resistant to darkening due to exposure to X-rays and ultraviolet radiation. The surface comprises a substrate and a ceramic zirconium orthosilicate coating on said substrate. The zirconium orthosilicate coating is obtained by plasma-spray applying particles of zirconium orthosilicate onto the substrate. The particles of zirconium orthosilicate are doped with an oxide of a +3 valent metal. The metal ions of said +3 valent metal oxide are dispersed substantially uniformly throughout said particles.
Claims16
A white thermal control surface which is resistant to darkening due to exposure to X-rays and ultraviolet radiation comprising:
- a substrate comprising a material capable of withstanding exposure to plasma spraying;
- a ceramic zirconium orthosilicate coating plasma spray applied onto said substrate and adhered to said substrate;
- said zirconium orthosilicate being doped with a dopant which is a +3 valent metal oxide dispersed substantially uniformly throughout the zirconium orthosilicate.
A ceramic, white, thermal control surface which is resistant to darkening due to exposure to X-rays and ultraviolet radiation prepared by plasma-spray applying particles of zirconium orthosilicate onto a substrate, said substrate comprising a material capable of withstanding exposure to plasma spraying, said particles of zirconium orthosilicate being doped with a dopant which is an oxide of a +3 valent metal dispersed substantially uniformly throughout said particles, said particles being adhered to said substrate.
A ceramic, white, thermal control surface resistant to darkening due to exposure to X-rays and ultraviolet radiation prepared by plasma spray applying onto a substrate particles of zirconium orthosilicate doped with a dopant which is an oxide of a +3 valent metal dispersed substantially uniformly throughout said particles, said substrate comprising a material capable of withstanding exposure to plasma spraying and said particles being adhered to said substrate;
- said particles being prepared by the steps of:
- (a) forming a hydrosol of zirconium orthosilicate blended with said dopant;
- (b) forming microspheres of said hydrosol;
- (c) allowing said microspheres of hydrosol to gel to form microspheres of hydrogel;
- (d) drying and sintering said microspheres of hydrogel;
- and
- (e) classifying said sintered microspheres to obtain microspheres having a particle size in the range of about 50-150 microns.
Dependencies are inferred from the claim text.