Advanced surface modification agents and modification technologies for powder metallurgy

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The objective of this work is the development and testing of advanced surface modification agents and modification technologies for powder metallurgy (PM). The project will be focused on active collaboration of Rio Tinto company and McMaster University. Rio Tinto is one of the major manufacturers of high quality products by PM technologies. PM processing involves the fabrication of mixes of metal powders, containing binders and lubricants, and their compaction into specific shapes, followed by sintering. The use of fine additives is of critical importance for the final microstructure, composition and functional properties of the products. However, fine additives are prone to segregation in mixes during processing. The segregation of fine additives has detrimental effect on powder flowability, which is one of the key characteristics during compaction. Poor flow of mixes usually results in poor die cavity filling performance, which leads to density gradients, mechanical strain, composition gradients, reduced dimensional consistency after sintering, stain formation in products and lower production rates. The problem of phase segregation in the PM mixes and poor powder flowability during compaction of products before sintering will be addressed in the proposed research. Rio Tinto is interested in new surface modification technologies and materials, which are currently under development at McMaster University. The approach is based in the use of new lubricants and binders for the fabrication of PM mixes. The unique feature of new lubricants and binders is related to their strong chelating properties, which makes them universal surface modification agents for different materials. In this approach the segregation of fine particles will be avoided and enhanced flowability of the mixes will result in improved distribution of individual components, enhanced functional properties of final products and enhanced production rate. The project meets the needs of Canadian industry in advanced PM technologies. The benefits of this project will include technology transfer to Rio Tinto and Canadian HQP training in PM, materials processing, surface engineering and nanotechnology and new fundamental knowledge in PM and other fields.