冷喷涂Ta涂层组织及腐蚀性能

Structure and corrosion properties of Ta coating prepared by cold spraying

利用冷喷涂技术在316L不锈钢表面制备Ta涂层。采用X射线衍射仪(XRD)、扫描电镜(SEM)对涂层的相结构和微观组织进行了分析,通过显微硬度计和万能力学试验机测定涂层的显微硬度和结合强度;采用电化学试验机测试了涂层和不锈钢基体的腐蚀性能。结果表明:涂层微观组织均匀致密,孔隙率为0.5%;涂层与基体结合良好,结合强度为60 MPa;涂层平均显微硬度为256 HV0.3;Ta涂层的自腐蚀电位(-0.25V)略低于316L不锈钢块体(-0.13 V),自腐蚀电流密度(2.16×10^(-7)A/cm^(2))比316L不锈钢(4.83×10^(-7)A/cm^(2))降低了一倍,钝化电位及钝化电流分别为-0.06 V和1.05×10^(-4)A/cm^(2),具有很宽的钝化区,能够有效保护316L基体。

Ta coating was prepared on 316 L stainless steel surface by cold spraying technology, and phase structure and microstructure of the coating were analyzed by means of X-ray diffractometer(XRD) and scanning electron microscopy(SEM). The microhardness and bonding strength of the coating were measured by microhardness meter and universal mechanical testing machine, the corrosion properties of the coating and stainless steel substrate were tested by electrochemical testing machine. The results show that the microstructure of the coating is uniform and dense, and the porosity is 0.5%. The coating is well bonded to the substrate, and the bonding strength is 60 MPa. The average microhardness of the coating is 256 HV0.3. The self-corrosion potential of the Ta coating(-0.25 V) is slightly lower than that of the 316 L stainless steel(-0.13 V), but the self-corrosion current density(2.16×10^(-7)A/cm^(2)) is doubled lower than that of the 316 L stainless steel(4.83×10^(-7)A/cm^(2)). The passivation potential and passivation current of the Ta coating are-0.06 V and 1.05×10^(-4) A/cm^(2), respectively, with a wide passivation zone, and can effectively protect the 316 L stainless steel substrate.