摘要
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 is the main material used to cast large ship propellers.However,marine biofouling on the surface of the propeller alters the pH value,thereby accelerating tribocorrosion and threatening ship safety.In this study,a compact nickel aluminum bronze coating with a thickness of approximately 300 μm was deposited by cold spraying.The microstructure of the coating was observed by scanning electron microscopy and optical microscopy.The electrochemical corrosion properties and tribocorrosion behavior of the coating was determined using 3.5% Na Cl solution in different pH environments of 3,7,and 11.Results show that in a pH 3 environment,optional corrosion occurs on the nickel aluminum bronze substrate,cracks mainly containing Cu are mostly distributed on α phases,deep cannelure is observed on the wear trace of the coating,and abrasive wear occurs on the coating.In a pH 7 environment,adhesive wear occurs on the substrate,slice abrasive dust is distributed on the surface of wear trace of the substrate（because porosities on the coating absorb most of the abrasive dust and avoid three body friction）,cannelure on the coating is relative shallow.In pH 11 environment,surface fatigue occurs on the surface of the substrate and deep cannelure is observed on the wear trace of coating,which contains cracks.Generally speaking,tribocorrosion resistance of coating enhances during cold spray process in different pH environments,resulting from cold working hardening and abrasive dust entering the coating pores.
作者
孙晓峰
陈正涵
李占明
黄元林
史玉鹏
SUN Xiao-feng CHEN Zheng-han LI Zhan-ming HUANG Yuan-lin SHI Yu-peng(Department of Equipment Maintenance and Remanufacturing, Academy of Armored Forces Engineering, Beijing 100072, China)
出处
《工程科学学报》
EI
CSCD
北大核心
2017年第7期1055-1061,共7页
Chinese Journal of Engineering
基金
军内科研基金资助项目
关键词
镍铝青铜
冷喷涂
PH值
腐蚀磨损
nickel aluminum bronze
cold spray
pH value
tribocorrosion
