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Abstract
Since the advent of the aerospace age, materials science has made great strides towards producing a wide array of new composites, which offer diverse properties needed for different applications. These composites include polymer-metal, ceramic-polymer, metal-metal, ceramic-metal, etc. Despite the progress made in creating new composites, the properties of some ol these composites need to be studied in relation to the conditions of their preparation in order to provide the designer with the data needed for his design calculations. The present work addresses two aspects relevant to metal composite production by the powder metallurgy technique, namely: i) study of the kinetics of the diffusion controlled production of metal powder by cementation, ii) Study of the effect of process parameters such as compaction pressure, composite composition on the properties of composites made of iron and copper powders such as hardness, electrical conductivity, thermal conductivity and corrosion behavior.
The study has revealed (hat cementation of copper on /.me particles takes place through two different mechanisms. In the early stage of cementation the rate is relatively high, and then it decreases due to coating of y.inc powder by a porous copper layer which increases the resistance to the transfer of cupric ions from the solution bulk to the surface of zinc particles. The addition of a drag reducing polymer (polyox \VSR-301) added in the form of suspension to the solution was found to reduce the rate of cementation of copper by an amount ranging from 23.308-31.092 % depending on the operating conditions.
Iron-copper composites prepared by the powder metallurgy technique under different conditions were found to have lower thermal conductivity, electrical conductivity and hardness than the parent metals. The corrosion tendency of the composite in acid solution is relatively high. Metal oxides formed during sintering seem to affect all composite properties due to the lack of perfection in performing reducing or inert atmosphere during sintering step.