"Ceramic surface finish: its influence on heat transfer in thermal shock tests"

A. G. TOMBA MARTINEZ; A.L. CAVALIERI

MATERIALS LETTERS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2000 vol. 42 p. 240 - 245

0167-577X

Disks of a commercial alumina were fabricated by slip casting, precalcined, sintered and machined using two different conditions, with a diamond wheel (70 grit) and SiC papers (120 and 320 grit). Finally, they were tested in thermal shock conditions. The specimens were suddenly cooled from elevated temperatures using a high-velocity air jet at room temperature. The temperature differential between the disk and the air jet was incremented in 10°C until crack propagation was detected. During each test, the temperature was recorded at two points on the lower specimen surface. The temperature distributions during air impinging were calculated using a finite element analysis. Heat transfer coefficients were estimated by fitting of the calculated temperature profiles with those measured.