This report summarizes the results obtained in an exploratory evaluation of ceramics for automobile thermal reactors. Potentially usable ceramic materials were evaluated in several reactor designs employing both engine-dynamometer and vehicle road tests. Silicon carbide contained in a corrugated metal support structure exhibited the best performance, lasting more than 800 h in engine dynamometer tests and for more than 15,000 miles (24,200 km) of vehicle road tests. Although reactors containing glass-ceramic components did not perform as well as silicon carbide, the glass-ceramics still offer good potential for reactor use. The results of this study are considered to be a demonstration of the potential use of ceramics in thermal reactors.