Patent ID: 6884467

Claim:
A method of protecting a component made of carbon fiber or carbon-carbon composite simultaneously against catalytic oxidation and high temperature non-catalytic oxidation, which method comprises: covering said composite with an undercoating comprising ions formed from 10-80 wt % H 2 O, 20-70 wt % H 3 PO 4 , 0.1-25 wt % alkali metal mono-, di-, or tri-basic phosphate, 0-2 wt % B 2 O 3 , and 0-25 wt % MnHPO 4 .1.6H 2 O, 0-30 wt % AlPO 4 , and 0-10 wt % Zn 3 (PO 4 ) 2 , provided that at least one of AlPO 4 , MnHPO 4 .1.6H 2 O, and Zn 3 (PO 4 ) 2 is present, said undercoating having a thickness of approximately 1-10 mil, and subsequently covering the undercoating with a boron-containing glass overcoating comprising boron nitride, said overcoating having a thickness of approximately 1-10 mil.