Mechanical and thermal properties of AlN-BN-SiC (ABS) ceramics were used to calculate the R, R', and R '''' thermal shock parameters. The R parameter values ranged from similar to 400 degrees to 450 degrees C. Specimens were thermal shocked by water quenching and the critical quench temperatures (Delta T-C) were compared with those of a baseline SiC composition. The behavior of the ABS was predicted by R parameter calculations while the behavior of the baseline material was predicted by the R' calculations due to its higher thermal conductivity (87 W. (m . K)(-1)) as compared with the ABS materials (87 W. (m . K)(-1)). The highest critical quench temperature for ABS was similar to 415 degrees C with the lowest at 360 degrees C, while the critical quench temperature for the baseline material was 450 degrees C. Using temperature dependent data over an appropriate temperature range (room temperature to the predicted DTC), the R parameters of the ABS materials were within 15 degrees C of predictions. The baseline material was similar to 1.7 times higher than predicted and this was attributed to the highthermal conductivity of the material resulting in soft thermal shock during quench testing.