Mo-Cu composite powder

1. A molybdenum-copper composite powder comprising individual finite particles each having a copper phase and a molybdenum phase, the individual finite particles further having a sintered molybdenum network wherein the voids in the network are filled with copper and the molybdenum phase substantially encapsulates the copper phase.

2. The composite powder of claim 1 wherein the individual particles have a size of about 0.5 μm to about 1.5 μm.

3. The composite powder of claim 2 wherein the composite powder comprises agglomerates of the finite particles.

4. The composite powder of claim 3 wherein the agglomerates have a size of about 15 μm to about 25 μm.

5. The composite powder of claim 1 wherein the powder contains from about 2 wt. % to about 40 wt. % copper.

6. The composite powder of claim 1 , wherein the powder has the color of unalloyed molybdenum powder.

7. A method of making a Mo—Cu composite powder comprising:

(a) reducing a CuMoO 4 -based composite oxide powder in a first stage to form an intimate mixture of metallic copper and molybdenum oxides without the formation of low-melting-point cuprous molybdate phases; and

(b) reducing the intimate mixture in a second stage at a temperature and for a time sufficient to reduce the molybdenum oxides to molybdenum metal.

8. The method of claim 7 wherein the first stage reduction is performed at a temperature from about 250° C. to about 400° C.

9. The method of claim 8 wherein the second stage reduction is performed at a temperature from about 700° C. to about 950° C.

10. The method of claim 7 wherein the low-melting-point cuprous molybdate phases are Cu 6 Mo 4 O 15 and Cu 2 Mo 3 O 10 .

11. The method of claim 7 wherein the Mo—Cu composite powder is passivated in nitrogen after the second stage reduction.