Formation of metal composites by displacement under bubbling conditions

The present paper is aimed at studying the kinetics of copper powder deposition process onto iron—carbon alloy substrates by a ‘cementation’ type of reaction. The variables included copper sulphate concentration, reaction time, temperature, pH, rate of helium gas bubbling and the surface area of the test specimen. The properties of the composite powders were also investigated as well as the surface topography of the deposited copper powders. The properties embodied fluidity, bulk density, specific surface area, porosity and packability. The composite material — after compaction and sintering — was evaluated by both tensile and ‘Brinell’ hardness tests.It was concluded that copper deposition by cementation is controlled by the transport of the reacting species from the bulk of the solution to the test specimen. This was explained in terms of Fick's law for the rate of mass transfer by diffusion in the boundary liquid film surrounding the solid.