Inventors:
Harry Buhay - Allison Park PA, US
James J. Finley - Pittsburgh PA, US
James P. Thiel - Pittsburgh PA, US
John P. Lehan - Silver Spring MD, US
Assignee:
PPG Industries Ohio, Inc. - Cleveland OH
International Classification:
B32B009/00
US Classification:
428432, 428428, 428433, 428434, 428446, 428697, 428698, 428699, 428701, 428702, 428704
Abstract:
An article includes a substrate, a functional coating deposited over the substrate, and a protective coating deposited over the functional coating. The functional coating and the protective coating define a coating stack. The protective coating provides the coating stack with an emissivity value higher than the emissivity value of the functional coating alone. The protective coating can have a thickness in the range of greater than 100 Å to less than or equal to 10 microns and a refractive index in the range of 1. 4 to 2. The protective coating can include a first layer formed over the functional coating and a second layer formed over the first layer. The first layer can include 50 wt. % to 100 wt. % alumina and 50 wt. % to 0 wt.