COATED GRAPHITE TRAY

PROBLEM TO BE SOLVED : To provide a coated graphite tray by which the number of times of repeated use in sintering cemented carbide can be increased. SOLUTION : The coated graphite tray for use in sintering cemented carbide or cermet is : (1) a coated graphite tray in which a coating film is composed of a rare-earth oxide film A having a thermal expansion coefficient β( 1/K) satisfying β≤9×10-6 and also having ≤0.105 nm ion radius and a thermal expansion coefficient α(1/K) of a substrate of the graphite tray satisfies α≥4×10-6; and (2) a coated graphite tray in which the rare-earth oxide film A of (1) is used as an inner layer and a rare-earth oxide film B having a thermal expansion coefficient γ(1/K) satisfying γ≤9×10-6 and also having >0.105 nm ion radius is used as an outer later.