Study On The Corrosion Resistance Of High Alluminum-zinic Alloy Produced By Spray Deposition

This thesis mainly studies the ZA35 alloy. Alloying elements( Mn) is added to improve corrosion-,wear-resistance of the ZA35 alloy, which is produced by spray deposition (SD), a kind of rapid solidification (RS) technique and solid extruding. The optimally system of heat treatment is obtained through orthogonal experiments. Microstructure and pattern of fracture are observed by the optical microscope and SEM. The performance of tensile strength, corrosion, wearing are tested. The main results are summarized as follows:The microstructure of ZA35-3.5Mn alloy is homogeneous and fine. The morphology of primary phase is mainly granular or block-like. The morphology is condensation after extruding and the second-phase is dispersing on the alloying matrix. The result of orthogonal tests is that the mechanical properties are better when the parameters are: the temperature of solution heat treatment 375～385℃, holding time3.5～4.5h,aging temperature 120℃, aging time 4.5～6h, quenching medium water. The mechanical properties data are: the maximal tensile strength: 484MPa;Brinell hardness: 120～130HB; elongation percentage: 5%～7% . Both of second-phase dispersion and refined microstructure make the strength improve highly. The corrosion resistance of ZA35-3.5Mn alloy produced by spray deposition is prior to ZA35-3.5Mn alloy produced by foundry.The homogenous distribution of alloying element (Mn) on the matrix modifies electrode voltage, so that the corrosion resistance of ZA35-3.5Mn alloy is improved. The wear resistance of ZA35-3.5Mn is improved highly because of the matrix's reinforcement and deduction of its coefficient of friction.