Al2O3对等离子喷涂Cr2O3/TiO2/Al2O3/SiO2复合陶瓷涂层性能影响研究

目的研究Al_2O_3添加量对Cr_2O_3/TiO_2/Al_2O_3/SiO_2四元复合陶瓷涂层性能的影响。方法采用等离子喷涂技术在油气管道X80管线钢基体表面制备出具有不同Al_2O_3含量的四元复合陶瓷涂层。另外,为探究基体温度对涂层性能的影响,所有涂层均在等离子喷枪预热及室温的两种基体上制备。所制涂层的气孔率、硬度、结合力及电化学腐蚀性能分别采用煮沸称重法、维氏硬度计、划痕仪、电化学工作站进行检测,并用X射线衍射仪(XRD)、扫描电镜(SEM)分析不同Al_2O_3含量涂层的物相组成和形貌特征,研究Al_2O_3含量对涂层各性能的影响。结果随着Al_2O_3含量的增加,Cr_2O_3/TiO_2/Al_2O_3/SiO_2四元复合陶瓷涂层的气孔率呈现先降低后增加的趋势,相对应的四元复合陶瓷涂层的结合力、维氏硬度则先增加后降低。当Al_2O_3质量分数为60%时,四元复合陶瓷涂层的性能最优,气孔率为3.6%,硬度为824.6HV,结合力为53.8N。电化学腐蚀测试表明,Al_2O_3能增强涂层的耐腐蚀性能,Al_2O_3质量分数为60%时,涂层自腐蚀电位最高,为-0.28 V。另外,在基体预热和不预热条件下,所制涂层性能随Al_2O_3含量的变化一致,但是基体预热比不预热更有利于涂层性能的提高。结论 Al_2O_3的添加不仅能够有效降低涂层Cr含量,还能显著提升四元复合陶瓷涂层的各项性能,特别是耐腐蚀性。此外,等离子喷涂前对基体进行预热,有利于涂层性能提高。

Effect of Al2O3 on Properties of Plasma Sprayed Cr2O3/TiO2/Al2O3/SiO2 Composite Ceramic Coating

The work aims to study the effect of Al2O3 on the properties of Cr2O3/TiO2/Al2O3/SiO2 quaternary composite ceramic coating. The composite ceramic coatings with different Al2O3 contents were deposited on the surface of X80 pipeline steel by plasma spraying. In addition, all coatings were prepared on preheated and unpreheated substrates to show the effect of substrate temperature on the coating properties. Then, the porosity, hardness, adhesion and electrochemical corrosion performance of the coatings were measured by boiling weighing method, Vickers hardness tester, scratch tester and electrochemical workstation, respectively. The phase composition and morphology characteristics of the coatings with different Al2O3 contents were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of substrate temperature and Al2O3 content on the coating properties were studied. With the increase of Al2O3 content, the porosity of Cr2O3/TiO2/Al2O3/SiO2 quaternary composite ceramic coating decreased firstly and then increased, while the adhesion and dimensional hardness of the corresponding quaternary composite ceramic coating increased firstly and then decreased. When Al2O3 mass fraction was 60%, the performance of the quaternary composite ceramic coating was the best, with porosity of 3.6%, hardness of 824.6HV and adhesion of 53.8 N. The electrochemical corrosion test showed that the corrosion resistance of the coating was improved by Al2O3. When Al2O3 mass fraction was 60%, the self corrosion potential of the coating was the highest, -0.28 V. In addition, under the preheating and unpreheating conditions, the properties of the coating varied with the Al2O3 content, but preheating was more beneficial to improving the coating properties than unpreheating. The addition of Al2O3 can not only effectively reduce the Cr content of the coating, but also significantly improve the properties of the quaternary composite ceramic coating, especially the corrosion resistance. In addition, the substrate should be preheated before plasma spraying, which is beneficial to improving the coating properties.