Effects of Plasma‐Sprayed Ceramic Coatings on the Strength Distribution of Silicon Carbide Materials

Sintered α‐silicon carbide and siliconized silicon carbide tubular materials were plasma‐spray coated with various ceramic oxides using conventional air plasma‐spraying technology. The strength distributions of the coated tubes were evaluated by fracturing samples at room temperature using a c‐ring test configuration. Changes in strength are explained using statistical treatments of the data, including a Weibull approach. Failure origins are characterized using fractography via scanning electron microscopy. The stength of plasma‐spray coated SiC was equivalent or superior to that of as‐received material, despite a surface pretreatment which induced surface flaws in the SiC substrate.