Ceramic heater having reduced internal stress

摘要

A ceramic heater device for use in a glow plug for a diesel engine has a gradually varying cross-sectional composition which eliminates distinct interfacial junctions between a resistive layer, an insulative layer and a highly conductive layer. The heater is manufactured by slip casting where the proportions of conductive and non-conductive ceramic particles in a slip are varied as the slip is passed through an absorbent mold.