论文部分内容阅读
镍铝青铜合金是铸造大型舰艇螺旋桨的主要材料,海洋污损生物在合金表面附着引起的pH值变化会加速镍铝青铜合金的腐蚀磨损,威胁到舰艇安全航行.采用冷喷涂技术制备了较为致密的镍铝青铜涂层,厚度约300μm,利用扫描电镜、光学显微镜观察了涂层的微观形貌,重点研究了涂层在pH值分别为3、7和11,质量分数为3.5%的Na Cl溶液中的电化学腐蚀性能和腐蚀磨损行为.实验结果表明:pH值为3的环境中,镍铝青铜基体发生了选相腐蚀,表面疲劳裂纹主要分布在富Cu的α相上,涂层上的犁削沟槽加深发生了磨粒磨损,涂层耐腐蚀性能优于基体;pH值为7的环境中,基体发生了黏着磨损,表面有片层状金属剥落,涂层中的孔隙收容了大量磨屑避免了剧烈的三体摩擦,表面犁削沟槽较浅,涂层致钝电位高于基体,耐腐蚀性能变差.pH值为11的环境中,基体发生了表面疲劳磨损,涂层磨痕上有较深的犁削沟槽,沟槽内有微裂纹,涂层耐腐蚀性能优于基体.总体来说,在不同pH值环境中,涂层由于在冷喷涂过程中发生了冷加工硬化并且涂层上的孔隙收容了磨屑,导致涂层的耐腐蚀磨损性能增强.
Nickel-aluminum bronze alloy is the main material for casting large ship propellers. The change of pH value caused by marine fouling organisms attaching to the alloy surface will accelerate the corrosion and wear of nickel-aluminum bronze alloy and threaten the safe navigation of the ships. Nickel-aluminum bronze coating with a thickness of about 300 μm. The microstructure of the coating was observed with a scanning electron microscope and a light microscope. The effects of NaCl (pH = 3, 7 and 11, 3.5% The electrochemical corrosion performance and the corrosion and wear behavior in solution were investigated.The experimental results show that phase selective corrosion occurs on the Ni-Al bronze matrix at pH 3. The surface fatigue cracks mainly distribute on the Cu-rich α phase, Of the plow groove deepened abrasive wear, corrosion resistance of the coating is better than the substrate; pH value of 7 environment, the substrate adhesive wear occurs, the surface lamellar metal spalling, the pores contained in the coating A large amount of wear debris to avoid the intense three-body friction, the surface shallow groove plow, the coating caused by blunt potential higher than the substrate, the deterioration of corrosion resistance.pH value of 11 environment, the occurrence of surface fatigue wear, coating Layer wear marks on the deeper Plow grooves, microcracks in the grooves, the corrosion resistance of the coating is better than that of the matrix.In general, in different pH environments, the coating hardens due to cold working during cold spraying and the pores in the coating Containing wear debris, resulting in corrosion resistance of the coating increased wear resistance.