Method for preparing ceramic molded body for sintering and method for producing ceramic sintered body

A method for preparing a ceramic molded body for sintering which is molded by pressing a raw material powder containing a ceramic powder which is oxide, nitride or fluoride, and a thermoplastic resin having a glass transition temperature higher than room temperature into a predetermined shape, the method comprising the steps of:

• preparing a raw material powder slurry by adding the ceramic powder and the thermoplastic resin to a solvent so that the thermoplastic resin is present in an amount of 0.5% by weight or more and 20% by weight or less based on the total weight of the ceramic powder and the thermoplastic resin, and preparing a raw material powder by drying the raw material powder slurry;
• molding an uniaxially press-molded body by uniaxially pressing the raw material powder into a predetermined shape, or filling the raw material powder into a rubber die;
• molding a first-stage press-molded body by isostatic pressing the uniaxially press-molded body or the rubber die with the raw material powder at a temperature lower than a glass transition temperature of the thermoplastic resin, wherein a pressure holding time for the first-stage isostatic press molding is from 1 to 10 minutes and the temperature of the molded body at a time of the pressing is maintained at a temperature lower than the glass transition temperature of the thermoplastic resin by 10° C. or more and an applied pressure of 40 to 400 MPa, as first-stage isostatic press molding;
• and molding a ceramic molded body by warm isostatic pressing (WIP) the first-stage press-molded body with heating its body up to a temperature equal to or higher than the glass transition temperature of the thermoplastic resin and at an applied pressure of 40 to 200 MPa, as second-stage isostatic press molding.