Preparation And Properties Of Cu-Sn-Zn-TiO₂ Nanocomposite Coating

Cu-Sn-Zn ternary alloy coatings are widely used in integrated circuits,radio frequency components and imitation of gold and silver and other fields due to their good electrical conductivity,corrosion resistance,wear resistance and decorative properties.Electrochemical deposition method is one of the most effective and convenient mothods,which has the characteristics of simple process and high environmental adaptability.In this paper,TiO₂ particle reinforced Cu-Sn-Zn nano-composite coating and TiO₂sol-reinforced Cu-Sn-Zn nano-composite coating were prepared by traditional DC plating and pulse plating,respectively,using nano-composite plating technology.The effect of TiO2content on the microstructure and properties of composite coating was studied,and the difference between traditional DC nano-composite coating and pulse composite coating was analyzed.At the same time,in order to further improve the corrosion resistance of the coating,the Cu-Sn-Zn-TiO₂/Ni multi-layer nano-composite coating was prepared,and the effect of pulse plating on the microstructure and properties of the multi-layer composite coating was studied.The results show that:?1?DC plating method:compared with the original coating,the hardness of particle-reinforced Cu-Sn-Zn-TiO2 nano-composite coating increased by¹6%and the corrosion rate decreased by²4.5%compared with the original coating.At the same time,compared with powder-reinforced Cu-Sn-Zn coating,the hardness of Cu-Sn-Zn-TiO2nano-composite coating prepared by TiO2 sol-enhanced plating technology is further improved to⁴20 HV.Compared with the original coating,the corrosion rate decreased by⁴3%,and the wear resistance also improved greatly.?2?Pulse plating:the hardness of the original Cu-Sn-Zn composite coating was increased by¹5%compared with that of the DC coating.At the same time,the hardness of particle-reinforced Cu-Sn-Zn-TiO2 nano-composite coating and sol-reinforced Cu-Sn-Zn-TiO₂ nano-composite coating increased to⁴43 HV and⁴78HV,respectively.It is also found that although the hardness and wear resistance of the pulsed coating have been greatly improved,the corrosion resistance has not changed greatly.The optimum corrosion rates of Cu-Sn-Zn-1g/L TiO₂ powder-reinforced pulsed coating and Cu-Sn-Zn-12.5mL/L TiO₂ sol-enhanced pulsed coating were maintained at⁰.09 mm/a and⁰.062 mm/a.respectively.?3?Multi-layer plating:no matter the composite coating prepared by DC or pulse power supply,the Ni pre-coating can keep the hardness of the coating better,even if too much TiO₂ is added,the hardness of the coating will not decrease greatly.In terms of hardness,the hardness of powder reinforced Cu-Sn-Zn-TiO₂/Ni DC double layer composite coating and sol reinforced Cu-Sn-Zn-TiO₂/Ni DC double layer composite coating increased to⁴00 HV and⁴27 HV,respectively.The hardness of powder reinforced Cu-Sn-Zn-TiO₂/Ni pulse double layer composite coating and sol reinforced Cu-Sn-Zn-TiO₂/Ni pulse double layer composite coating increased to⁴51 HV and⁴94HV,respectively.While maintaining good hardness and wear resistance,the corrosion resistance of Cu-Sn-Zn-TiO₂/Ni multi-layer nano-composite coating was improved obviously,and the corrosion rate of Cu-Sn-Zn-1g/L TiO₂/Ni pulse coating and Cu-Sn-Zn-12.5mL/L TiO₂/Ni pulse coating reached the minimum value.From the initial⁰.098 mm/a to⁰.044 mm/a and⁰.042 mm/a,respectively.In conclusion,compared with the traditional DC Cu-Sn-Zn composite coating,the hardness of the Cu-Sn-Zn-12.5mL/L TiO₂/Ni pulse double-layer composite coating prepared by pulse plating is increased by⁴9.5%,the wear resistance and corrosion resistance are increased by⁴1.7%and⁵7.1%respectively.Which proves that this process is the best process for preparing Cu-Sn-Zn composite coating.Based on the current research results,this process can be applied not only to the industrial production of Cu-Sn-Zn ternary alloy coating,but also to the industrial production of other Cu alloys.At the same time,according to the TiO₂ strengthening mechanism,the results can also guide the industrial production of other types of metal or alloy coatings,so as to further improve the performance and service life of coating film products.