Transition metal-included tungsten carbide, tungsten carbide diffused cemented carbide, and process for producing same

A tungsten carbide diffused cemented carbide obtained by sintering a tungsten alloy carbide powder represented by Formula [1] which is carbonized from a tungsten alloy powder with a transition metal as a solid solution represented by Formula [2] wherein at least one transition metal element selected from the group consisting of cobalt, iron, manganese and nickel is dissolved in a tungsten grating and a peak derived from a bcc tungsten phase appears in an X-ray diffraction diagram.

• M-W—C Formula [1]:
• wherein M represents one or more selected from Co, Fe, Mn and Ni;
• M-W Formula [2]:
• wherein M represents one or more selected from Co, Fe, Mn and Ni.

A process for producing the transition metal dissolved tungsten carbide, which comprises:

• mixing an ammonium paratungstate aqueous solution containing tungsten ions with an acetate aqueous solution containing at least ions of one transition metal selected from the group consisting of cobalt, iron, manganese and nickel, wherein the mixing is performed such that the tungsten ions are 60 to 90 mol % and the transition metal ions are 40 to 10 mol %,
• drying the mixed aqueous solution by distillation or spraying,
• thermally decomposing the resulting solid, followed by hydrogen thermal reduction, to prepare a transition metal-dissolved tungsten alloy powder represented by Formula [2] of M-W wherein M represents one or more selected from Co, Fe, Ni and Fe—Mn,
• carbonizing the resulting oxide powder or transition metal-dissolved tungsten alloy powder by heating it with graphite to be mixed or gas-carburizing, to obtain a transition metal dissolved tungsten carbide represented by Formula [1] of M-W—C wherein M represents one or more selected from Co, Fe, Ni and Fe—Mn.

A process for producing the transition metal dissolved tungsten carbide diffused cemented carbide, which comprises:

• mixing an ammonium paratungstate aqueous solution containing tungsten ions with an acetate aqueous solution containing at least ions of one transition metal selected from the group consisting of cobalt, iron, manganese and nickel, wherein the mixing is performed such that the tungsten ions are 60 to 90 mol % and the transition metal ions are 40 to 10 mol %,
• drying the mixed aqueous solution by distillation or spraying,
• thermally decomposing the resulting solid, followed by hydrogen thermal reduction, to prepare a transition metal-dissolved tungsten alloy powder represented by Formula [2] of M-W wherein M represents one or more selected from Co, Fe, Ni and Fe—Mn,
• carbonizing the resulting oxide powder or transition metal-dissolved tungsten alloy powder by heating it with graphite to be mixed or gas-carburizing, to obtain a transition metal dissolved tungsten carbide represented by Formula [1] of M-W—C wherein M represents one or more selected from Co, Fe, Ni and Fe—Mn and sintering the resulting tungsten carbide with a transition metal powder.