基于冷喷涂固态增材 Al/Cu 的高压电缆铝护套高质量修复

Cold solid-state additive manufacturing is a potential solution for surface Al sheath layer connecting and repairing for the high-voltage cable due to its low processing temperature and high flexibility. However，the poor inter-particle bonding quality and high porosity makes the Al deposits present low adhesion strength and electrical conductivity. In this work，mechanically mixed Al/Cu powders are used as the feedstock powders. It is attempted to enhance the plastic deformation of the deposited Al particles through the in-situ hammering or forging of the Cu particles and thus decrease the porosity and increase the adhesion and electrical conductivity of the deposits. To study the effect of Cu content on microstructure and properties including adhesion，electrical conductivity and salt-fog corrosion resistance of the deposits，pure Al powder，Al/Cu mixed powders with Cu volumetric content of 10%，30% and 50% are cold sprayed. Results show that the deposits have more Cu particles than the corresponding feedstock powder due to the higher deposition efficiency of Cu. As the Cu content in the feedstock powders increases from 0% to 50%，the porosity of the Al/Cu composite deposits decreases from 14.4% to 0.2%，and the adhesion strength of the deposits increases from 24.2 MPa to 53.4 MPa. Significant increments in electrical conductivity of the deposits are achieved due to the inclusion of Cu and enhanced inter-particle bonding quality. However，it is found that due to galvanic corrosion between Cu particles and adjacent Al particles，the Cu-Al composite deposits experienced much more severe corrosion as compared with the pure Al deposit. To solve this problem，a bilayer deposit construction composed of Cu-Al composite bottom layer and pure Al top layer is proposed. The optimized bilayer deposit reveals comparable adhesion and electrical conductivity with the Cu-Al composite deposit while the salt-fog corrosion resistance is similar to that of the pure Al deposit.