Copper Plating Process Of TiC Particles And Properties Of Reinforced 6101Al Composites

Ceramic particle reinforced aluminum matrix composites are compatible with the high strength and modulus of ceramics and the plasticity and toughness of aluminum alloy,and become the most potential high performance composites.However,there are often poor wettability and interfacial bonding between ceramic particles and aluminum matrix,which hinders the exertion of mechanical and electrical conductivity.In order to solve this problem,in this paper,electroless copper plating on the surface of TiC particles（TiCp）was first made,and then 6101Al（TiCp/Al）composites with different TiCp content were prepared by semi-solid stirring casting,which were hot extruded into round rods.The effects of composition,concentration,p H value and reaction temperature of copper plating solution on the deposition rate,stability and morphology of Cu layer were studied.The changes of micro-morphology,mechanics and electrical conductivity of TiCp/Al composites with heat treatment state and TiCp content were analyzed.The relationship between copper coating thickness and properties on TiCp surface was discussed,and the key factors affecting the properties of TiCp composites and their action mechanism were revealed.The main results are as follows:The effects of the concentration of main salt,complexing agent and reducing agent,p H value and copper plating temperature on the deposition rate and solution stability of electroless copper plating solution were analyzed.The preparation process parameters of Cu layer were optimized as follows:the concentration of Cu SO₄·5H₂O is 14 g/L,the concentration of complexing agent EDTA-2Na is 20.9 g/L,the concentration of formaldehyde is 12.6 ml/L,the temperature of copper plating is60℃,and the p H value is 12.5.Under this parameter,the Cu layer can be uniformly coated on the surface of TiCp,and no other phases are formed.The effect of TiCp addition on the microstructure of the composites was studied.When the addition of TiCp increased from 0 to 7 wt%,the agglomeration of TiCp increased gradually,and the number of pores and pores also increased obviously.Hot extrusion at 500℃can not only make the TiCp distribution more uniformly dispersed,but also improve the density of the composites,but can not eliminate the large-scale agglomeration with high TiCp content.With the increase of TiCp content,the tensile strength and hardness of the composites showed an upward trend,while the change of elongation was opposite;the grain size of matrix aluminum in solution aging state was finer,and the mechanical properties were higher than those in extruded and annealed state.When the content of TiCp was 7 wt%,the tensile strength and hardness were the highest,reaching 159.6MPa,74.5 HV_0.5,and the elongation was 7%.The electrical conductivity decreased with the increase of TiCp,and the electrical conductivity increased obviously after annealing,especially with the addition of 7 wt%TiCp,that is,the electrical conductivity increased from extruded 36.0%IACS and solid solution aged34.5%IACS to 48.6%IACS.After treatment at 270℃,the elongation and electrical conductivity are significantly improved.The influence of the thickness of copper layer on the surface of TiCp on the mechanical and electrical properties of the material was analyzed.When the content of TiCp is 3 wt%,when the thickness of Cu layer increases from 70 nm to 150 nm,the elongation of the composites decreases and the tensile strength increases significantly.When the theoretical thickness of Cu layer is 110 nm and 150 nm,the tensile strength of extruded state is 190.1 MPa and 237.0 MPa respectively,which is higher than that when the thickness of Cu layer is 70 nm and the content of TiCp is 7 wt%.When the thickness of Cu layer is 150 nm,the electrical conductivity of the composite is higher,and the electrical conductivity of the composite in annealed state is 52%IACS,Higher than the conductivity under the thickness of other TiCp layers when the addition of Cu is 3%.