Abstract: A process for preparation of a positive temperature coefficient material of the barium titanate/barium zirconate type. An aqueous feed mixture comprising a compound of barium or other suitable divalent cation and an organic compound of titanium or zirconium is introduced into an anterior zone adjacent a heated reaction zone in a rotating, inclined, tubular furnace or other useful calcining equipment. At the entrance of the reaction zone, the feed mixture forms a mass which swells in response to heat emanating from the tube wall and the reaction zone, undergoes dehydration and ignites. Particles break away from the mass and enter the reaction zone where they are calcined in an oxidizing atmosphere to produce the product material. Both these particles and the product material are milled as they pass through the reaction zone. Product material discharging from the reaction zone is collected for use in the manufacture of positive temperature coefficient elements.