Preparation And Properties Of Y-PSZ/316L Stainless Steel Cermets

This study has prepared Y-PSZ/316 L composites which uses 316 L stainless steel powder and 3% mol yttrium oxide stability zirconia powder as raw materials by the method of powder injection molding. The optimum process parameters of feeding, injection molding, debinding and sintering in the process of preparation of composites have determined. The microstructure of the composites has observed and analyzed. The relative density, shrinkage rate, hardness, mechanical properties and wear resistance related with the volume fraction Y – PSZ have studied, moreover, the wear mechanism of the composites has been discussed.The results show that it can prepare composites with good organization and performance by the following processes: it uses 56vol% powder loading capacity; The injection temperature, pressure and the holding time are 150℃,50 MPa and 3 s, respectively. The degreasing solvents is n-heptane, and degreasing performs in 45 ℃ water bath pot. After 4h, open pores of the green part have got through, then thermal degreasing can be conducted; The best heating process of thermal degreasing is that average heating rates are 2 ℃ / min and 3℃/min respectively in the process of room temperature to 420 ℃and 420℃~650℃. When temperatures are at 250 ℃, 420 ℃, 550 ℃, 650 ℃,the times of heat preservation are 0.5 h, 1 h, 1 h, 1 h, respectively; The best sintering temperatures are 1320℃( 10% ~ 30%vol%Y-PSZ), 1340℃(40%vol%Y-PSZ) and 1350℃(50%vol%Y-PSZ),and the time of heat preservation is 1 h at the temperature of 900℃,respectively.When the volume fraction of Y-PSZ is more than 30 percent, the composites forms Y-PSZ matrix; and when the volume fraction of Y-PSZ is less than 25 percent, the composites forms stainless steel matrix. The relative density、the shrinkage and the hardness of the composites increase with the increasing of Y-PSZ content. The relative density of the composites is in the range from 91.5% to 95.6% in the experiment conditions.When the matrix of the composites is Y-PSZ matrix(30%~50%vol%Y-PSZ), the compressive strength increases with the increasing of Y-PSZ content, and the fracture mode is brittle fracture; and when Y-PSZ volume fraction is 20%, the compression strength is slightly high comparing with the composites of 30vol%Y-PSZ, and the composite material fracture presents small plastic fracture.The wear resistance of the composites can reach 1.2~5.3 times of 316 L stainless steel, and the characteristic that the wear resistance of the composites is superior to 316 L stainless steel is outstanding at high speed. The abrasion mechanism of Y-PSZ/316 L stainless steel composites is fatigue wear of matrix and abrasive wear.