Yamaki, Yoshio Robert2017-11-102017-11-101984http://hdl.handle.net/10919/80312Reaction sintered silicon nitride (RSSN) was studied as a substitute coating material on the carbon-carbon material (RCC) presently used as a heat shield on the space shuttle, and on advanced carbon-carbon (ACC), a later development. On RCC, RSSN showed potential in a 538°C (1000°F) screening test in which silicon carbide coated material exhibits its highest oxidation rate; RSSN afforded less protection to ACC because of a larger thermal expansion mismatch. Organosilicon densification and metallic silicon sealing methods were studied as means of further increasing the oxidation resistance of the coating, and some improvement was noted when these methods were employed.viii, 61 leavesapplication/pdfen-USIn CopyrightLD5655.V855 1984.Y352Silicon nitrideShielding (Heat)SinteringThesis