摘要
目的分析超音速火焰喷涂制备的Cr3C2-NiCr涂层在碱性环境中的腐蚀及冲蚀腐蚀磨损性能,揭示涂层腐蚀及冲蚀腐蚀磨损失效机制。方法利用超音速火焰喷涂技术在45#钢表面制备Cr3C2-NiCr金属陶瓷涂层,采用光学显微镜、显微硬度仪、碱性环境腐蚀性能试验台、电化学分析仪、冲蚀腐蚀磨损试验机、电子天平、扫描电子显微镜,分别对组织结构、显微硬度、碱性环境下耐蚀性能、耐冲蚀腐蚀磨损性能、冲蚀腐蚀磨损损失质量及表面形貌进行测试。结果Cr3C2-NiCr涂层呈典型层状结构,内部随机分布着孔隙及氧化物,涂层孔隙率及显微硬度平均值分别为1.3%和817HV0.1。在pH=11的NaOH溶液中,涂层的电化学腐蚀电位为-0.38V,腐蚀反应生成的氧化物可有效阻止腐蚀继续进行,长期浸泡过程中,腐蚀介质通过裂纹或穿透性孔隙渗入涂层内部直至基体表面,并发生腐蚀反应,形成的腐蚀产物逐渐累积并排出至涂层表面,最终形成体积较大且呈团絮状的腐蚀产物。在碱性腐蚀环境下,腐蚀介质加剧冲蚀磨损中的材料消耗。相同条件下,涂层腐蚀冲蚀磨损损失质量明显小于基体材料,涂层的冲蚀腐蚀磨损失效机制主要有腐蚀产物脱落、硬质颗粒剥落、粘结相磨耗、缺陷处因疲劳裂纹整体脱落。结论在碱性环境中,Cr3C2-NiCr涂层具有较强的耐腐蚀性能,腐蚀介质能加快涂层冲蚀磨损进程,磨损后表面为非光滑表面,使涂层具有较优的抗冲蚀磨损性能,故Cr3C2-NiCr涂层可显著改善基体表面的综合使用性能。
The work aims to analyze the corrosion resistance and erosion-corrosion wear performance of HVOF sprayed Cr3C2-NiCr coating in alkaline solution,and reveal the mechanisms of corrosion and erosion-corrosion wear.Cr3C2-NiCr ceramic coating was deposited on the surface of 45# steel by high velocity oxy-fuel spraying (HVOF).The microstructure, microhardness,corrosion resistance,erosion-corrosion wear performance in the alkaline environment,weight loss and surface morphology were tested by optical microscopy (OM),microhardness tester,corrosion performance test bench in alkaline environment,electrochemical analyzer,erosion-corrosion wear tester,electronic balance and scanning electron microscope, respectively.Cr3C2-NiCr coating exhibited a typical layered structure and pores and oxides were randomly distributed among the coating.The porosity and microhardness of the coating were 1.3% and 817HV0.1 on average,respectively.In the NaOH solution with pH=11,the electrochemical corrosion potential of Cr3C2-NiCr coating was -0.38 V.The oxides produced by the corrosion reaction could effectively prevent the corrosion from proceeding.During long-term immersion,the corrosive medium underwent a corrosion reaction with substrate after penetrating into the coating and substrate through the cracks or penetrating pores.The corrosion products formed by the corrosion reaction were gradually accumulated and discharged to the surface of the coating,thus eventually forming a bulky and flocculent corrosion product.In the alkaline corrosive environment,corrosion medium could exacerbate material consumption in erosion wear.Under the same conditions,the weight loss of erosion-corrosion wear of coating was significantly less than that of substrate material.The main failure mechanisms of erosion-corrosion wear of Cr3C2-NiCr coating were falling of corrosion products,spalling of hard particles,abrasion of binder phases,falling of the defects due to fatigue cracks.In alkaline environment,Cr3C2-NiCr coating has strong corrosion resistance. The corr
作者
王井
何冰
罗京帅
员霄
蹤雪梅
WANG Jing;HE Bing;LUO Jing-shuai;YUAN Xiao;ZONG Xue-mei(Jiangsu XCMG Construction Machinery Research Institute Co.Ltd,Xuzhou 201004,China;State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery,Xuzhou 221004,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第9期211-217,共7页
Surface Technology
基金
国家重点研发计划(2018YFB1105800)
江苏省自然科学基金(BK20170246)~~
