Mixed powder for powder metallurgy, sintered body, and method of manufacturing sintered body

1. A mixed powder for powder metallurgy, comprising:

a partially diffusion alloyed steel powder in which Mo diffusionally adheres to a particle surface of an iron-based powder;

a Cu powder; and

a graphite powder,

wherein the mixed powder for powder metallurgy has a chemical composition containing Mo in an amount of 0.2 mass % to 1.5 mass %, Cu in an amount of 0.5 mass % to 4.0 mass %, and C in an amount of 0.1 mass % to 1.0 mass %, with the balance consisting of Fe and inevitable impurities, and

the partially diffusion alloyed steel powder has: a mean particle diameter of 30 μm to 120 μm; a specific surface area of less than 0.10 m 2 /g; and a circularity of particles thereof with a diameter in a range from 50 μm to 100 μm of 0.65 or less.

2. The mixed powder for powder metallurgy according to claim 1 ,

wherein the Cu powder has a mean particle diameter of 50 μm or less.

3. The mixed powder for powder metallurgy according to claim 1 ,

wherein the iron-based powder is at least one of an as-atomized powder and an atomized iron powder.

4. The mixed powder for powder metallurgy according to claim 2 ,

wherein the iron-based powder is at least one of an as-atomized powder and an atomized iron powder.

5. A sintered body formed by sintering a green compact that comprises the mixed powder for powder metallurgy according to claim 1 .

6. A sintered body formed by sintering a green compact that comprises the mixed powder for powder metallurgy according to claim 2 .

7. A sintered body formed by sintering a green compact that comprises the mixed powder for powder metallurgy according to claim 3 .

8. A sintered body formed by sintering a green compact that comprises the mixed powder for powder metallurgy according to claim 4 .

9. A method of producing a sintered body, comprising

sintering a green compact of a mixed powder for powder metallurgy that includes: a partially diffusion alloyed steel powder in which Mo diffusionally adheres to a particle surface of an iron-based powder; a Cu powder; and a graphite powder,

wherein the mixed powder for powder metallurgy has a chemical composition containing Mo in an amount of 0.2 mass % to 1.5 mass %, Cu in an amount of 0.5 mass % to 4.0 mass %, and C in an amount of 0.1 mass % to 1.0 mass %, with the balance consisting of Fe and inevitable impurities, and

the partially diffusion alloyed steel powder has: a mean particle diameter of 30 μm to 120 μm; a specific surface area of less than 0.10 m 2 /g; and a circularity of particles thereof with a diameter in a range from 50 μm to 100 μm of 0.65 or less.

10. The method of producing a sintered body according to claim 9 ,

wherein the Cu powder has a mean particle diameter of 50 μm or less.

11. The method of producing a sintered body according to claim 9 ,

wherein the iron-based powder is at least one of an as-atomized powder and an atomized iron powder.

12. The method of producing a sintered body according to claim 10 ,

wherein the iron-based powder is at least one of an as-atomized powder and an atomized iron powder.

13. The mixed powder for powder metallurgy according to claim 1 ,

wherein the circularity is 0.52 or more and 0.65 or less.

14. The mixed powder for powder metallurgy according to claim 2 ,

wherein the circularity is 0.52 or more and 0.65 or less.

15. The mixed powder for powder metallurgy according to claim 1 ,

wherein the Cu powder has a mean particle diameter of 30 μm or more.

16. The mixed powder for powder metallurgy according to claim 2 ,

wherein the Cu powder has a mean particle diameter of 30 μm or more.