Research On Antirust Property Of Non-copper Coated Wire And Its Rapid Evaluation

Non-copper-coated solid wire has received widespread attention from welding materials manufacturers for its environmental friendliness and energy saving. Rust resistance is an important property of Gas Shielded solid wires. Theoretically, the antirust property of non-copper-coated wire is better than that of traditional wire with copper coating defects, but still could not meet the needs for long-term storage. So the antirust property of non-copper-coated wire should be improved before realizing its industrial production. In practice, thin oil film does not affect the conductivity of wire. It is feasible to develop a kind of drawing lubricant with oil-soluble corrosion inhibitor to improve the antirust property of wire. A fast and accurate measure is needed to evaluate antirust property of non-copper-coated wire. This paper explores methods to evaluate antirust property of non-copper-oil-polished wire by analyzing link between its corrosion morphology and electrochemical responses.In this paper, four different kinds of drawing lubricants are used to draw non-copper-coated wire. The thickness of oil film is calculated by Gravimetric Method and its influencing factors are analyzed. Antirust properties of oil-coated wire are evaluated by Wire plate without packing storage, Indoor air exposure experiment and moist atmospheric corrosion experiment. By contrast investigation between corrosion morphology and oil film thickness, rust properties of thin film are dependent on oil composition. In different circumstances with different corrosion control factors, different oil-coated wire with great performance differences can achieve consistent evaluation result.The repeated cyclic voltammeter test of thick-film-coated electrode demonstrates that in the anodic polarization region of bare wire, the smaller the polarization current peak is, the better the antirust property is after enough cycle times. The appearance of oxidation peak maybe related with the adsorption of oil-soluble corrosion inhibitor in the wire surface.Polarization resistance test in micro polarization region shows that polarization resistance can be used to fast evaluate antirust property of thin-oil-coated wire. Corrosion current testing results in strong polarization region by tafel extrapolation demonstrate that the corrosion current values are scattered and can not be used to evaluate corrosion rate directly. But when deviation of corrosion potential calculated by tafel extrapolation and measured by device is small enough, corrosion current testing and moist atmospheric corrosion experiment can get consistent result.The EIS test results of the oil covered wire show that in the te low frequency region the greater the impedance modulus is, the better the antirust performance of wire is under humid atmosphere. The impedance modulus in the low frequency region reflect the polarization resistance. Therefore, the value of impedance modulus can reflect the corrosion rate of wire covered with oil film.