On the materials and processes for additive metallurgy

This proposal consists of two parts resulting from the vast experience obtained by previous NSERC supported grants.

The first part of the proposal is an innovative approach to apply powder metallurgy in an unconventional way. Until now innovative parts made by power metallurgy are made by alloying additions. However, in cases that require different behaviour by two different metals, such as aluminum which can withstand the corrosion by glycol based coolant and magnesium which is very vulnerable to coolant, a new innovative approach is needed. Similar cases arise in the development of 3Dmetal printing additive manufacturing where the main material may be vulnerable to a fluid which is circulated through the part and the circulation pipe must be constructed from a material which is compatible with the main alloy of which the part is made and can withstand the corrosion action of the fluid. The proposed research is to address the problem of traditional powder metallurgy and the emerging 3Dmetal additive manufacturing by studying simple specimens made of the two different materials and characterize their interface by traditional characterization techniques including electrochemistry. This will lead to construction of the lighter parts composites made by two dissimilar metals such as aluminum and magnesium as they presently utilized in some automotive engine blocks.

The second part of this proposal relates to the research to develop a novel metallic filled fluoropolymer composite such as PVDF containing a metallic filler that is made of copper particles coated electrolessly with tin resulting in a core-shell structure. The novelty is related to the use of core-shell structured tin coated copper powders as metallic fillers. Copper is no more exposed to oxidation during processing. The composite will be fabricated by injection molding process where the organic polymer and tin coated copper powders are mixed followed by hot compression. The role of copper core is to create an electrical conduction path within the fabricated composite hence increasing the electrical conductivity of the fabricated material, whereas the tin coating (shell) on copper (core) protects the copper particles from oxidation during the composite fabrication. The protection from oxidation during the molding process is necessary because the copper oxide surface layer decreases the electrical conductivity of the powders. Additionally, the tin layer diffuses into the adjacent copper giving rise to environmentally stable inter-metallic phases. The core-shell structures can be beneficial to many industrial applications, for example circuit protection, antennas, automotive, and data communication. This proposal is the innovative combination of electroless plating and core-shell technique both developed previously in our laboratory.

Thus two innovative approaches by traditional techniques to produce improved products.