Sintered body, sputtering target and molding die, and process for producing sintered body employing the same

Abstract

Provided is an apparatus that includes a molding die for producing a sintered body. The molding die is configured for cold isostatic pressing and includes a knockdown mold frame comprised of plural frame members and a bottom plate provided in contact with the knockdown mold frame. An upper punch is provided to be movable along the inner surface of the knockdown mold frame. The frame members configured to be movable relative to each other to accommodate an expansion of a green body which takes place at the time of reducing the pressure after the completion of pressing.

1 . A sintered body which is a sintered body containing no carbon as a constituting element and which is characterized in that the content of carbon contained as an impurity in the sintered body is less than 0.005 wt %. 
     
     
         2 . The sintered body according to  claim 1 , wherein the thickness of the sintered body is 10 mm or more. 
     
     
         3 . The sintered body according to  claim 1 , wherein one or more flat surface areas constituting the surface of the sintered body are 600 cm 2  or more. 
     
     
         4 . The sintered body according to  claim 1 , wherein the sintered density of the entire sintered body is 90% or more, and the fluctuation in the sintered density in the sintered body is 0.2% or less. 
     
     
         5 . The sintered body according to  claim 1 , which has one or more convex portions on at least one of the upper and lower surfaces of the sintered body. 
     
     
         6 . A sintered body which is characterized in that the area of the largest surface among surfaces constituting the surface of the sintered body is 1,000 cm 2  or more, the sintered density of the entire sintered body is 90% or more, and the fluctuation in the sintered density in the sintered body is 0.2% or less. 
     
     
         7 . The sintered body according to  claim 6 , which is a sintered body having an abbreviation rectangular parallelepiped shape, wherein the ratio in length of the longest ridge to the shortest ridge is 40 or more. 
     
     
         8 . The sintered body according to  claim 6 , which has one or more convex portions on at least one of the upper and lower surfaces of the sintered body. 
     
     
         9 . A sputtering target which is characterized in that the sintered body as defined in  claim 1  is used as a target material. 
     
     
         10 . A molding die for compression molding, which is a molding die for producing a green body by filling and compressing a raw material powder in the molding die and which is characterized by having such a construction that at the time of pressure compression, pressing is applied to a filled raw material powder only in a substantially uniaxial direction, and at the time of reducing the pressure after the completion of pressing, the pressure can be released substantially isotropically with respect to the green body. 
     
     
         11 . A process for producing a sintered body, which comprises pressing a raw material powder to form a green body and then, firing the green body to form a sintered body, characterized in that the raw material powder does not contain a molding aid containing an organic substance. 
     
     
         12 . The process for producing a sintered body according to  claim 11 , wherein the raw material powder is molded directly by a cold isostatic press to obtain the green body. 
     
     
         13 . The process for producing a sintered body according to  claim 12 , wherein a molding die, for compression molding is used, wherein said molding die is a molding die for producing a green body by filling and compressing a raw material powder in the molding die and which is characterized by having such a construction that at the time of pressure compression, pressing is applied to a filled raw material powder only in a substantially uniaxial direction, and at the time of reducing the pressure after the completion of pressing, the pressure can be released substantially isotropically with respect to the green body. 
     
     
         14 . A process for producing a sintered body, which comprises pressing a raw material powder to form a green body and then, firing the green body to form a sintered body, characterized in that the process does not have a firing step intended to remove an organic substance in the green body. 
     
     
         15 . The process for producing a sintered body according to  claim 14 , wherein a raw material powder having an organic substance content of 0.6 wt % or less, is used. 
     
     
         16 . The process for producing a sintered body according to  claim 14 , wherein a molding die, for compression molding is used, wherein said molding die is a molding die for producing a green body by filling and compressing a raw material powder in the molding die and which is characterized by having such a construction that at the time of pressure compression, pressing is applied to a filled raw material powder only in a substantially uniaxial direction, and at the time of reducing the pressure after the completion of pressing, the pressure can be released substantially isotropically with respect to the green body.