Method for producing metal sintered body

1. A method for producing a metal sintered body, the method comprising:

(a) disposing a tungsten powder inside a chamber of a spark plasma sintering apparatus;

(b) applying an electric current to the tungsten powder to raise a temperature inside the chamber from a standby temperature to a first sintering temperature;

(c) lowering the temperature inside the chamber to a second sintering temperature lower than the first sintering temperature and performing sintering; and

(d) lowering the temperature inside the chamber from the second sintering temperature to the standby temperature,

wherein the first sintering temperature is 0.45 Tm to 0.65 Tm where Tm represents the melting point of the tungsten powder,

wherein the second sintering temperature is 0.35 Tm to 0.55 Tm where Tm represents the melting point of the tungsten powder.

2. The method of claim 1 , wherein the tungsten powder has an average particle size of about 0.2 μm to about 20 μm.

3. The method of claim 1 , wherein in step (b), a heating rate does not exceed 200° C./min.

4. The method of claim 1 , wherein prior to step (a), the tungsten powder is subjected to reduction treatment.

5. The method of claim 1 , wherein in step (b), a heating rate is 50° C./min and the first sintering temperature is 1,600° C., and in step (c), the second sintering temperature is 1,300° C. and a sintering time is 5 minutes.

6. The method of claim 1 , wherein in step (b), a heating rate is 100° C./min and the first sintering temperature is 1,700° C., and in step (c), the second sintering temperature is 1,400° C. and a sintering time is 5 minutes.