Patent ID: 7041250

Claim:
A process for producing a substantially fully dense binder phase free refractory metal compact by low temperature transient liquid phase sintering and activated sintering, said process comprising: selecting a refractory metal having a melting point; selecting a metallic reagent, said metallic reagent being capable of cooperating with said refractory metal in carrying out said transient liquid phase sintering and said activated sintering, a limited amount of said metallic reagent being dissolvable in a solid phase of said refractory metal, said metallic reagent including at least two metals, a first of said metals being primarily effective in forming a low temperature transient liquid phase during said transient liquid phase sintering, and a second of said metals being primarily effective in activating said activated sintering; forming a mixture of said refractory metal and an amount of said metallic reagent that is effective to form a transient liquid phase and is less than about said limited amount; heating said mixture at a temperature that is less than approximately 80 percent of said melting point, allowing said transient liquid phase to form, and allowing a portion of said metallic reagent to dissolve in said refractory metal until said transient liquid phase substantially disappears and a solid body including at least one internal boundary and a metallic reagent residue at said boundary are formed; heating said solid body at a temperature that is less than approximately 80 percent of said melting point, allowing said metallic reagent residue to activate said activated sintering, allowing substantially all of said metallic reagent residue to diffuse away from said internal boundary into said refractory metal to form a substantially binder phase free solid refractory metal, allowing said substantially binder phase free solid refractory metal to reach a density that is greater than about 98 percent of theoretical; and, recovering said substantially fully dense binder phase free solid refractory metal compact.