The Reasrech On Electrodeposition And Electrochemical Process Of Al On The SiC Fiber In Molten Salt

Aluminum alloys has many excellent properties, such as small specific gravity, good thermal conductivity, corrosion resistance, good workability, and has been widely used in industry, agriculture and so on. Among them, the Al-Cu alloys are also known as hard aluminium alloy which has good mechanical properties. With the development of industry, more and more requirements to matirials are put forward. The excellent performance of material, and metal compatibility of SiC fiber composite based on aluminium or its alloy as matrix, is very important material in metal matrix composites. The material not only has the characteristics of aluminum alloy, but also has the advantages of high strength and modulus properties. Firstly physical vapor deposition method has been using to prepare SiC/Al matrix composites fiber, secondly the method of hot pressing used to preparation composite fiber. This material has the advantage of controlled volume fraction and well distributed, and not easy to damage. But the high price of the equipment is very high and the utilization of the metal is low. Therefore, it is very necessary to find a low cost process to prepare SiC/Al matrix composite fibers.In this paper, Al-Cu alloy were prepared in LiCl-KCl-AlCl₃?2 wt.%? molten salt system by molten salt electrolysis process. The process of electrochemical reaction was analysised. Aluminum was deposited on copper coated SiC fibers by pulse electrode position method. Aluminum matrix composite fibers were prepared and studied the electrochemical reaction process.1. Electrochemical reduction process of Al3+ on copper and molybdenum substrate were analyzed by cyclic voltammetry, square wave voltammetry and open chronopotentiometry in the molten salt system. Al-Cu intermetallic compounds based on copper substrates were deposited by electrochemical deposition method. The morphology and structure of the samples were shown by XRD and SEM. The experimental results showed that Al3+ on the copper substrate in addition to the precipitation of metallic Al had occurred three reduction reaction which mean three kinds of Al-Cu intermetallic compounds at the temperature of 648 K. Al-Cu alloys with different phase composition were prepared by the constant potential electrolysis method. XRD showed that the three compounds were Al4Cu9, Al Cu and Al2 Cu, respectively.2. Copper coating was deposited on the surface of SiC fiber by electroless plating method. The influence of different amount of sodium hydroxide on the deposition of copper layer was discussed and the surface morphology of SiC fiber was analyzed by SEM. The experimental results showed that when the amount of sodium hydroxide was 2.5g, the coating is bright and dense. The quality was best, and the electrochemical stability of the copper layer was good.3. We used cyclic voltammetry and open chronopotentiometry method to study the electrochemical reduction process of SiC fiber and compared to copper coated SiC fiber in LiCl-KCl-AlCl₃?2 wt.%? molten salt system. Comparing the electrochemical process of copper electrode and the copper coated SiC fiber. The SiC/Al matrix composite fibers were prepared by using pulse electrode position technique on copper coated SiC fibers with different current density. SEM was used to characterize the surface morphology of the SiC/Al matrix composite fibers. The experimental results showed that the conductive property of pure SiC fiber was poor and compounds with lithium. The electrochemical process of copper coated SiC fibers and copper substrate is similar and generated three intermetallic compounds. When the current is 0.6m A, the surface morphology is better, dense and more uniform.