Study Of Corrosion Performance And High Temperature Friction Performance Of Laser Cladding On Aluminum Bronze

The surface performance of copper and copper alloy were modified by various surface technique without altering the property of the substrate,which reinforce abrasion resistance and corrosion resistance of materials,prolong service life and improve economic efficiency. The appearance of laser cladding technique enriched the field and offered a new way to improve the surface performances.Laser cladding technique, with high energy density beams generated rapid melting, made the substrate surface form the layer of alloy which fused with substrate together and obtained the metallurgical combination with substrate, but has completely different composition and properties from the substrate.This method improved the wear-resisting, corrosion resistance,heat resistance and electrical characteristics significantly and achieved the objective of surface modification or repair, which not only satisfied the specific properties of materials,but also saved a lot of precious and rare metal materials.In this article,a Ni-Cu matrix alloy cladding layer was deposited on the QA19-4 aluminum bronze by laser cladding under aluminum-bronze surface modification technique.The laser coating which have excellent thickness and no hole and crack and have metallurgical combination with QA19-4 aluminum bronze be obtained by the experiment, optimization of process parameters.Its corrosion behavior and high temperature tribological properties have been studied on the laser coating, comparing with QA19-4 aluminum bronze.The corrosion behavior of the laser cladding layer and QA19-4 aluminum bronze in the 10% H2SO4 and 3.5% NaCl solution was studied by the electrochemical experiment, the static soak test and X-ray diffraction (XRD),scanning electron microscopy etc method the effects,and the corrosion mechanism of them were analysed.The results showed that the corrosion potentials of laser cladding layer is higher that QA19-4 aluminum-bronze in 3.5% NaCl solution, proving the laser cladding layer improve the material corrosion resistance effectively and delay the corrosion occurred.The corrosion mechanism of the QA19-4 aluminum bronze is dealuminization and that of the laser cladding is decoppering in 3.5% NaCl solution. In the 10% H2SO4 solution, the corrosion mechanism of the Ni-Cu matrix alloy cladding layer is also decoppering.In these two kinds of solutions the corrosion resistance of the laser cladding is higher than that of the QA19-4 aluminum bronze.The wear tests of Ni-Cu matrix alloy laser cladding layers and the QA19-4 aluminum bronze were carried out under the conditions of different temperatures. The results show that, at high temperature,the wear mechanism of the QA19-4 aluminum bronze is abrasive wear;the wear mechanism of the Ni-Cu matrix alloy laser cladding layer is abrasive wear and shedding loss of strengthen phase.At 550℃,the wearing capacity of the QA19-4 aluminum bronze is about 9times more than that of the Ni-Cu matrix alloy laser cladding. In this condition, high abrasion resistance of the laser cladding was attributed to the improvement of plasticity and tenacity, the degree of shedding strengthen phase decrease and smooth of the surface, thus caused slightly abrasive wear when the relative sliding,the wear capacity and wear volume of the laser cladding layer are lower than that of the QA19-4 aluminum bronze.Therefore,the laser cladding can improve the corrosion resistance and high temperature friction properties of the QA19-4 aluminum bronze.