Abstract. 

The effect of impurities due to the frequent melting of commercially available pure copper has been investigated on electrical (under DC and AC), mechanical and optical behavior. Three different types of copper samples are prepared, which are acquired from direct copper ingot, from melted copper, and eventually from re-melted copper. Later the pure and casted samples are cold rolled in three different steps as well as age-hardened by annealing. Then series of experiments have been conducted to measure the variation in reflectance, microhardness, resistivity along the frequency response of the materials in terms of electrical impedance, dielectric constant, and dielectric loss as a function of with and without melting impurities. Most of the electrical and optical properties are found to be altered quite remarkably by the melting impurities, mainly when the copper samples undergo both mechanical and thermal treatment. Furthermore, increased grain size and recrystallization of melted and remelted Cu samples have also influenced the mentioned properties.

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Outcome

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It was seen that with the increase of impurities by frequent melting, reflectance and electrical conductivity decreased significantly. Moreover, under alternating current, the dielectric properties of the samples have decreased with the increasing frequency. Besides, when copper samples are annealed at 100°C, they are seen to be partially crystallized as well as grain boundaries and grain size are remodeled and impurities are shifted to the intergranular region.

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However, after rolling and annealing most properties are found to be sensitive. In most cases, by doing both treatment properties can be improved and the electrical behavior of melted samples almost comes nearer to pure copper, which eventually leads to regain and control the loss in properties. The overall significance of this study is to generate a database or specification of melted and remelted Cu comparison to pure Cu as well as to characterize the operational limitations of copper with a high amount of natural melting impurities and to specify the right choice of processed copper for right application as per requirement.