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Title: Fabrication of spectrally selective solar surfaces by the thermal treatment of austenitic stainless steel aisi 321

Patent ·
OSTI ID:6254834

The spectrally selective solar surfaces have been produced after heating the austenitic stainless steel aisi 321 at a firing temperature of 843* K. And for firing times ranging from 10 to 20 minutes. The heating was carried out in a constant temperature oven under normal atmospheric conditions. The optimum values of solar absorptance alpha S and near-normal emittance epsilon S were found to be alpha S 0.92+0.02, epsilon S 0.22 + or - 0.02 respectively. The corresponding values for the unheated steel were 0.50 + or - 0.02 and 0.22 + or - 0.22. Severe temperature treatments like quenching in liquid nitrogen at 77* K. Produced no adverse visible affect on the quality of the selective surfaces. It shows that the thermal coatings so produced are very tough and durable. The value of solar absorptance and near-normal thermal emittance remained unchanged after quenching in liquod nitrogen. The thermal coatings so produced not only offer a technical advantage but also economic advantage over any of the existing techniques for the manufacture of stainless steel solar panels.

Assignee:
IFI; EDB-82-001556
Patent Number(s):
US 4268324
OSTI ID:
6254834
Resource Relation:
Patent File Date: Filed date 20 Apr 1979
Country of Publication:
United States
Language:
English