Development of high strength, high thermal conductivity cold sprayed coatings to improve thermal management in hybrid motorcycles

The deposition of thick, pore-free, high-performance copper alloy matrix composite coatings is a topic of interest for several industrial applications, including friction materials, high-strength electrical contacts, and welding electrodes, among others. This study investigates the use of cold spray to deposit CuCrZr/Al2O3 cermet coatings on aluminum alloy 6060. The objective is to integrate copper-based materials with aluminum-based materials, ensuring a high degree of mechanical and thermal contact, using a low temperature process that does not adversely affect the properties of the base materials. This technique can be used to produce integral coolers and aluminum-based bearings for automotive and motorcycle applications. Fused and crushed alumina and gas-atomized CuCrZr powder blends have been used as initial feedstocks, with compositional weight ratios of 65/35 and 80/20 (ceramic/metal). The coatings have been characterized in terms of microstructure and morphology, coating microindentation hardness, cohesion strength, and adhesion strength to the aluminum alloy substrate. Microindentation hardness greater than 200 Vickers, adhesion strength greater than 50 MPa, and cohesion strength up to 250 MPa have been obtained. Thermal conductivity up to 110 W/mK has been obtained for both as-deposited and thermally-annealed coatings.