冷喷涂Zn15Al合金涂层在NaCl溶液中的腐蚀行为和防护机制  

Corrosion Behavior of Cold Sprayed Zn15Al Alloy Coating on Q235 Carbon Steel in NaCl Aqueous Solution

作　　者：徐龙 李继文 崔传禹 卢祺 杨浩 赵聪聪 XU Long;LI Jiwen;CUI Chuanyu;LU Qi;YANG Hao;ZHAO Congcong(Materials Science and Technology Research Department,Ji Hua Laboratory,Foshan 528200,China;Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]季华实验室材料科学与技术研究部,佛山528200 [2]中国科学院金属研究所核用材料与安全评价重点实验室,沈阳110016

出　　处：《材料研究学报》2024年第3期208-220,共13页Chinese Journal of Materials Research

基　　金：广东省基础与应用基础研究基金(2020A1515110982)。

摘　　要：采用低压冷喷涂技术在Q235碳钢基材表面制备冷喷涂锌(CS-Zn)和锌铝合金涂层(CS-Zn15Al),使用SEM观察、XRD谱、测量开路电位、电化学阻抗谱和动电位极化曲线等手段对其表征,研究了涂层在NaCl溶液中的腐蚀行为和腐蚀产物影响涂层防护性能的机制。结果表明,CS-Zn涂层在NaCl溶液中浸泡期内腐蚀严重,而CS-Zn15Al涂层的腐蚀速率较低,耐蚀性能较好。CS-Zn的主要腐蚀产物是ZnO,其多孔状的结构特点和半导体属性会破坏产物层的致密结构,降低电荷转移电阻,促进涂层腐蚀反应的发生;而添加Al元素能促进保护性腐蚀产物Zn_(5)(OH)_(8)Cl_(2)·H_(2)O和层状双氢氧化物Zn_(6)Al_(2)(OH)_(16)CO_(3)·4H_(2)O的生成,显著提高对腐蚀介质的屏蔽。同时,添加Al降低了涂层的腐蚀电位、增强了对涂层的阴极保护作用,保护性腐蚀产物层的生成降低了腐蚀电流密度,延长了涂层的使用寿命。添加Al元素可实现涂层防护性能和耐久性的协同提高。Cold-sprayed coatings Zn(CS-Zn)and Zn15Al alloy(CS-Zn15Al)were prepared on Q235 carbon steel plates via low-pressure cold spraying technique.The corrosion behavior of the coatings in 3.5%NaCl aqueous solution was assessed by means of electrochemical measurement of open circuit potential,electrochemical impedance and potentiodynamic polarization curves,as well as SEM with EDS,XRD.The results indicate that the CS-Zn coating undergoes severe corrosion during immersion,while the CS-Zn15Al coating corrodes at a slower rate and exhibits superior corrosion resistance.XRD results reveal that the dominant corrosion product of CS-Zn is ZnO,which possesses porous structural characteristics that disrupt the compactness of the corrosion product layer.Furthermore,its semiconductor properties decrease the charge transfer resistance,thereby accelerating the process of corrosion.In the contrast,as for CS-Zn15Al,the incorporation of Al facilitates the formation of protective corrosion products,namely Zn_(5)(OH)_(8)Cl_(2)·H_(2)O and layered double hydroxides Zn_(6)Al_(2)(OH)_(16)CO_(3)·4H_(2)O.The shielding effect of CS-Zn15Al coating was significantly enhanced by this layer of corrosion products.Furthermore,electrochemical measurements demonstrate that the addition of Al reduces the corrosion potential of the coating,thereby enhancing its cathodic protection ability,and decreases the corrosion current density due to the generation of protective corrosion products.In conclusion,the addition of Al can synergistically enhance the anticorrosion performance and durability of the coating.

关 键 词：材料失效与保护 锌合金涂层 电化学阻抗谱 冷喷涂 

分 类 号：TG174[金属学及工艺—金属表面处理]