Compacting and Low Temperature Sintering of Ca-Doped LaCrO_3 Super-Fine Powders

Super-fine powders of calcium-doped lanthanum chromites synthesized by the aqueous organic gel method were compacted into green bodies under a series of high pressure from 400 to 1200MPa at room temperature.Then the sintering samples with high relative density were obtained by sintering at relatively low temperature of 1300℃.The sintering behaviors of super-fine powders were characterized by measuring the shrinkage and the density of the sintering bodies.SEM and Four-probe instrument were applied to analyze the fracture micrograph and electric properties of sintering samples respectively.The results show that the forming pressure is the key factor to affect the shrinkage and the density of sintering bodies.The sintered bodies with shrinkage of 14% and relative density of 94% are obtained when the forming pressure is more than 600MPa.The electrical conductivity of the sintered body also increases with increase of the forming pressure.In addition,the result shows that the crystalline grows in the growth step way.