Tungsten Copper Composite Powder Preparation

Tungsten copper composite powder particles produced in each phase is composed of copper phase and tungsten, wherein the tungsten coated copper in the form of phase with respect to the presence, can achieve near full density having a high thermal conductivity of the tungsten copper composite products. Oxide powders short high energy ball milling, rapid refinement oxide powder size, sintered tungsten phase and has a uniform distribution of the copper phase, and during sintering can reduce evaporation and loss of copper phase. The final sintered density of the article is not less than 99% of theoretical density

Tungsten Copper Composite Powder Preparation Step

Tungsten copper composite powder preparation includes preparation of tungsten-copper composite oxide precursors, restore energy ball milling oxide powder, sintered tungsten-copper composite powder and other steps, the specific process is as follows:
1. Preparation of tungsten-copper composite oxide precursor
The tungsten powder and copper powder in accordance with the W-2-30Cu wt% were uniformly mixed in a mixer, oxidized in air atmosphere maffei oven at 650 ℃ -700 ℃, to obtain a mixture consisting of from CuWO4 and WO3, after oxidation 0 ~ 12h milled powder mixture in energy ball mill;

Different agents milled oxide powder after milling grain size variation (W-20Cu wt%)

Milling Time(h)

Alcohol

Air

0

3.99

3.99

4

1.28

1.71

8

0.93

1.65

12

0.33

1.8

Different milling agent after milling oxide powder surface area change (W-20Cu wt%)

Milling Time(h)

Alcohol

Air

0

0.33

0.33

4

5.32

0.71

8

10.45

0.8

12

18.98

0.9

Total reduction of energy ball milling oxide powder
After milling the powder in an atmosphere of H2 reduction, reduction temperature of 650 ℃ -750 ℃, the powder after reduction by irregular shape and is in the form of a tungsten-coated copper phase relative existence. Composite powder size, the oxygen content of the oxide powder milling time varies with the following table:

Composite powder size, oxygen content changes with the oxide powder milling time (alcohol milling 10h, the reduction temperature 700 ℃)

Milling Time(h)

Composite Powder Size(um)

Surface Area (m2/g)

Composite powder oxygen content (ppm)

0

1.51

0.65

450

4

0.82

2.35

300

8

0.50

8.56

250

12

0.47

12.35

200

Tungsten Copper Mixed Powder Sintered

Restore powder is pressed to give 50% to 55% relative density of the green compacts, sintering at 1150 ℃ -1600 ℃. The present invention reduces the rate of temperature increase in the solid-phase sintering stage can obtain a high sintered density and almost completely eliminate the copper overflow. Specific final composite powder sintering temperature varies with changes in the copper content. Its final sintering temperature and sintered density as shown in following table:

Different copper content of the composite powder optimum sintering temperature and the final density (oxide alcohol wet milling 10h, sintering time 1h)

Copper Content wt%

Sintered Temperature℃

Relative Density of the Final Sintered %

20~25

1150~1200

>99.4

15~20

1200~1250

>99.1

10~15

1250~1300

>98.6

5~10

1300~1350

>98.4

2~5

1350~1600

>98.1

The above method is characterized by tungsten powder used for the reduction of tungsten powder or other relatively pure tungsten powder, copper powder used for copper or copper reduction; and as the milling media is the use of alcohol.
Tungsten-copper composite powder preparation method is to reduce the content of the final product in a variety of impurities while improving powder sintered density to obtain the final product performance. Oxide powders short high energy ball milling, rapid refinement oxide powder size, prepared highly dispersed ultrafine tungsten coated copper powder sintered tungsten phase and has a uniform distribution of the copper phase, and during sintering can reduce copper phase evaporation and loss. The powder compacts by mining reached near full density sintered tungsten copper has a high thermal conductivity properties. Another advantage of this method is that the resulting copper-clad tungsten copper powder can avoid volatilization and subsequent leak in the high-temperature liquid phase sintering process which led to the composition of organizational control are not allowed, to avoid reducing the final product performance.

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