20CrMo钢表面喷涂有机硅改性聚脲的腐蚀行为

Corrosion Behavior of 20CrMo Steel with Polyurea Coating Modified with Organosilicone

通过在20CrMo钢试样上喷涂有机硅改性聚脲涂层,用粘结力测试仪和显微硬度计对涂层的粘结力和硬度进行测试,采用恒温井液浸泡试验和高温高压腐蚀试验测试了涂层的耐蚀性能,结合扫描电镜(SEM)观察腐蚀形貌,并计算腐蚀速率,采用慢应变速率拉伸试验(SSRT)对涂层抗应力腐蚀性能进行分析。结果表明:腐蚀后涂层与基体宏观附着良好,能有效阻止腐蚀溶液的渗透和侵蚀;20CrMo钢经过喷涂聚脲处理后,腐蚀速率减小了一个数量级,耐蚀性能提高;应力腐蚀条件下,喷涂聚脲试样的应变量和最大应力值比基体分别增加了22%和2.7%,断裂时间延长约6.5 h,延长了基材的使用寿命。

The polyurea coating modified with organosilicone on 20CrMo steel surface were prepared by spraying.The binding power and hardness of the polyurea coating were analyzed by adhesive power tester and microhardness tester.The corrosion resistance performance of the polyurea coating was tested by immersion test and corrosion experiment under the conditions filled with high temperature and pressure.By SEM observation of the corrosion surface morphologies and calculated the corrosion rate,the stress corrosion resistance performance was analyzed using the slow strain rate test（SSRT）.The results show that coating can be applied on the matrix with good adhesion after corrosion,which can prevent the penetration of corrosion and erosion solution effectively.Furthermore,the corrosion rate reduces approximately one magnitude and the corrosion resistance improves.In addition,the strain capacity and maximum stress of the steel with polyurea coating under the stress corrosion condition increases by 22% and 2.7%,respectively.The fracture time delays about 6.5 h,and the work life of the steel significantly increases.