The coated ceramic bodies are then heated to cause {HEAD ~ diffusion} of {TAIL ~ the insulating substances} throughout their intergranular boundaries 
The coated ceramic bodies are then heated to cause { HEAD ~ diffusion } of { TAIL ~ the insulating substances } throughout their intergranular boundaries
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH