Products of Powder Metallurgy

Products of Powder Metallurgy, Engineering Manual E-64, Amplex Division, Chrysler Corp., Detroit, Mich. 

A hi mi nidcs. These are intermetalhc compounds of aluminum. The potential of these products includes uses where low weight, high-temperature strength, and oxidation resistance are required. Traditionally, these products are made by way of powder metallurgy technology. 

The time of production by CS methods is much shorter than that for conventional methods of powder metallurgy. Also, materials and articles can be produced directly in the combustion wave. Furthermore, a continuous mode of production may be realized, where reactants are fed at a rate equal to the combustion wave velocity. 

The addition of a chemical reducing agent to precipitate metals from their salt solutions has been considered for many years as an alternative to displacement reactions and electrolysis. The developments in the field of powder metallurgy in recent years have increased interest in this reduction method since the final product obtained is high-purity metal powder. The ease with which these high-purity powders can be converted into readily handled forms such as briquettes has improved their marketability to other metallurgical users. 

Chizhikov, D.M., Deyneka, S.S., Tribunsky, L.M., Gorunkov, W (1976), Application of Plasma Processes in Technology of Production of Powder Materials, in Non-Ferrous Metallurgy, Nauka (Science), Moscow,... 

For preliminary preparation of raw materials and final processing of the target products, conventional equipment of powder metallurgy (ball mills, attritors, grinders, and dry kilns) is used. It is desirable to apply up-to-date secondary machinery in order to maintain the technology efficiency and the synthesized product purity [65]. 

We also know that Wollaston had, in partnership with Smithson Tennant, invested heavily in the purchase of crude platina ore in late 1800, and from 1801 to 1805 he perfected the techniques of powder metallurgy that led to the production of malleable platinum in 1805 (28). Only when the processing of platinum became regularized about 1810 did Wollaston turn his attention again to electrochemistry, once more in connection with a small, demonstration device. 

One of the unique characteristics of powder metallurgy is the ability to produce porous parts. This has been used to produce metal filters and porous bearings. In the latter case, the sintered part is vacuum treated to remove all air and then submerged in oil to fill the pores. This produces a bearing capable of operating for the life of a product without further application of lubricant. Nonmetal powders are sometimes mixed with metal powders to produce particle metallurgy parts. 

Metal injection molding (MIM) is a form of powder metallurgy process that is ideally suited for the production of small complex parts. Its main advantage lies in its ability to produce finished parts to net-shape, requiring little or no expensive secondary operations. Hence, it is extremely attractive for hard metals and high precision or high performance parts. 

Post-Sintering Treatments. The sintering process concludes the powder metallurgy processes of production and consoHdation. However, some P/M parts may require a number of further operations. 

Metals Handbook, 9th ed. Vol. 7, Powder Metallurgy-. Production of Metal Powders, American Society of Metals, Metals Park, Ohio, 1984. 

Binders in Ceramics, Powder Metallurgy, and Water-Based Coatings of Fluorescent Lamps. In coatings and ceramics appHcations, the suspension rheology needs to be modified to obtain a uniform dispersion of fine particles in the finished product. When PEO is used as a binder in aqueous suspensions, it is possible to remove PEO completely in less than 5 min by baking at temperatures of 400°C. This property has been successfully commercialized in several ceramic appHcations, in powder metallurgy, and in water-based coatings of fluorescent lamps (164—168). 

---