摘要:
Production of pore-free carbon/carbon-silicon carbide composite materials with mechanical properties making them suitable for use in such applications as the production of aircraft landing system brake components including brake discs. The method includes: providing a porous carbon-carbon composite preform; surrounding the porous carbon-carbon composite preform with silicon powder to form an intermediate construct; applying a uniaxial load to the construct; applying direct electrical current to an assembly containing the loaded construct of porous carbon-carbon preform surrounded by silicon powder, thereby melting the silicon powder and infiltrating the pores of the carbon-carbon preform with liquid silicon; and initiating a combustion-type reaction between the silicon and carbon in the preform, thereby forming silicon carbide in the preform.
摘要:
Method of improving humidity resistance in a coated article (19) comprising a carbon-carbon composite component (10), a graphite component (10), or a ceramic matrix composite component based on carbon fibers and/or graphite (10). The component (10) is preferably configured as an aircraft landing system brake disc. The method includes the steps of: (A) providing a carbon-carbon composite component (10), a graphite component (10), or a ceramic matrix composite component based on carbon fibers and/or graphite (10); (B) covering the component (10) with a phosphorus-containing antioxidant undercoating (11) having a thickness of approximately 1-10 mil; and (C) covering the resulting undercoated component (10, 11) with a boron-containing glass overcoating (12) having a thickness of approximately 1-10 mil. The overcoating includes 20-50 wt-% alkali or alkaline earth metal silicates, 3-25 wt-% alkali metal hydroxide, up to 10 wt-% boron nitride, and one or both of 5-40 wt-% elemental boron and 5-40 wt-% boron carbide. The overcoating is substantially free of phosphoric acid and phosphates. Also, articles coated with the specified undercoating/overcoating combinations.