电弧喷涂耐海水腐蚀金属涂层的研究进展

Research Progress on Arc Sprayed Metal Coatings for Seawater Corrosion Protection

电弧喷涂金属涂层作为钢结构表面防护的一种重要措施,经过几十年的发展,已成为成熟的表面工程技术和产业。同时,随着新的喷涂工艺、设备和材料的不断研发,电弧喷涂金属涂层应用领域日益广泛。与此同时,使用电弧喷涂技术进行防腐的缺点也日益突出,尤其是喷涂过程中存在有害物质排放等问题,严重制约了其发展。电弧喷涂制备的涂层孔隙率低、微观组织致密、结合强度高且经济性好。相比于其他传统防腐技术,电弧喷涂金属涂层应用于钢结构的表面防护具有如下优势:(1)电弧喷涂沉积效率高、操作容易,便于现场施工;(2)涂层在海洋苛刻腐蚀环境中服役时间长。然而,电弧喷涂耐海水腐蚀金属涂层的服役环境介质不同,对涂层的耐蚀性能提出了更高的要求。因此,近几十年来除研究电弧喷涂工艺参数外,科研工作者们着力研发多功能、高性能的喷涂材料,并取得了丰硕成果,同时充分利用电弧喷涂技术的优势可显著提高涂层的性能。目前电弧喷涂金属涂层材料正朝着复合化、新型化方向发展。目前,用于钢结构表面防护且已取得广泛应用的喷涂材料有锌/铝及其合金、镍基合金、铁基合金和铜基合金等。其中锌、铝及其合金是使用最早且最广泛的喷涂材料;镍基合金可通过加入铬、钼等抗点蚀、缝隙腐蚀的合金元素,提高材料的耐蚀性能;铁基合金中添加少量Mo等元素,能有效抑制晶界腐蚀发生;铜基合金中加入1%的锡,能抑制合金脱锌过程并提高其力学性能。近几年的研究重点为多种合金材料复合及新型合金材料的使用,以电弧喷涂技术为手段制备耐腐蚀涂层,可实现涂层功能和性能的双提升。本文以分析钢结构在近海岸海洋环境各区域带的腐蚀规律为基础,比较了目前用于钢结构表面腐蚀防护的方法及其优缺点,阐述了电弧喷涂涂层的研究现状和防腐机理。从电弧喷涂耐海水腐蚀涂层的微观组织结构、涂层性能及防腐机理等方面,分析了电弧喷涂金属涂层防腐面临的问题并展望了其前景,以期为工业领域钢结构表面的长效防护提供参考。

Arc sprayed metal coating is an important method for the protection of steel structure.Due to development of last several decades,it has become a mature surface engineering technology and industry.Meanwhile,with the development and research of new spraying processes,equipment and materials,the application fields of it are increasingly widespread.At the same time,the shortcomings of arc spraying technology are becoming more and more prominent,especially the problems of harmful substances discharged during the spraying process,which seriously restricts its development.The coating prepared by arc spraying exhibits low porosity,compact microstructure,high bonding strength and good economy.Compared with other traditional anti-corrosion technologies,arc-sprayed metal coatings have the following advantages:(ⅰ)high efficiency of arc spray deposition,easy operation,and easy on-site construction;(ⅱ)the service life of the coatings is long.However,the coatings fabricated by arc spraying technology are used in different service environments,which puts higher requirements on the corrosion resistance of the coating.Therefore,in addition to studying the parameters of arc spraying process in recent decades,researchers have focused on the development of multi-functional,high-performance spraying materials,and have achieved fruitful results.Basing on the advantages of arc spraying technology,the performance of coating will be enhanced significantly.At present,materials employed to deposited coatings are developing in the direction of composite and new-type.Materials,such as Zn,Al and their alloys,Ni-based alloys,Fe-based alloys and Cu-based alloys,have been widely used in the protection of steel structures.Among them,Zn,Al and their alloys are the earliest and most used spraying materials;Ni-based alloys can improve the corrosion resistance of materials by adding Cr,Mo and other alloying elements,which are resistant to pitting and crevice corrosion;the addition of a small amount of Mo and other elements to the Fe-based alloy can effectively inhibit the occurrence of grain boundary corrosion;the incorporating of 1%Sn to the Cu-based alloy can inhibit the dezincification process of the alloy and improve the mechanical properties.Recently,the research focuses on the use of a variety of alloy materials and the use of new alloy materials,and the arc spray technology is used as a means to prepare corrosion-resistant coatings,which can achieve double improvement in the function and performance of coatings.Based on the analysis of the corrosion law of steel structures in various areas of the coastal marine environment,this paper compares the current methods for corrosion protection of steel structures and their advantages and disadvantages.The research status and anti-corrosion mechanism of arc spray coatings are expounded.From the aspects of microstructure,coating properties and anti-corrosion mechanism of arc sprayed mental coatings,the problems of anticorrosion of arc sprayed metal coatings are analyzed and their prospects are prospected,and ultimately as a reference to provide long-term protection for steel structures in industrial fields.