Question

1. Name some of the reasons for the commercial importance of powder metallurgy technology. 2. What are some of the disadvantages of the PM methods? 3. In the screening of powders for sizing, what is meant by the term mesh count? 4. What is the difference between open pores and closed pores in metallic powders? 5. What is meant by the term aspect ratio for a metallic particle? 6. How would one measure the angle of repose for a given amount of metallic powder? 7. Define bulk density and true density for metallic powders. 8. What are the principal methods used to produce metallic powders? 9. What are the three basic steps in the conventional powder metallurgy-shaping process? 10. What is the technical difference between mixing and blending in powder metallurgy? 11. What are some of the ingredients usually added to metallic powders during blending and/or mixing? 12. What is meant by the term green compact? 13. Describe what happens to the individual particles during compaction/ 14. Which of the following most closely typifies the usual sintering temperatures in PM? (a) 0.5 T m' (b) 0.8 T m' (c) Tm. 15. What are the three steps in the sintering cycle in PM? 16. What are some of the reasons why a controlled furnace is desirable in sintering? 17. What are the advantages of infiltration in PM? 18. What is the difference between powder injection molding and metal injection molding? 19. How is isostatic pressing distinguished from conventional pressing and sintering in PM? 20. Describe liquid phase sintering. 21. What are the two basic classes of metal powders as far as chemistry is concerned? 22. Why is PM technology so well suited to the production of gears and bearings?

Answer 1