TiNi shape memory alloy exhibits an excellent cavitation erosion resistance. Therefore, it's an effective method for preventing cavitation erosion by applying this material as a coating. In this paper, the effect of Co element addition on cavitation erosion resistance of TiNi based coating deposited by atmospheric plasma spraying (APS) was investigated. The microstructure and microhardness were characterized. The results show that the lamellar microstructures with defects, such as porosities, microcracks and unmelted particles are presented in all TiNi based coatings. The appropriate addition of Co element is beneficial to reduce the porosity of the TiNi based coating and obtain a denser microstructure. The matrix phase of the TiNi based coatings is TiNi phase. After adding Co element, TiNiCo phase is formed in the coating. Microhardness of TiNi based coatings is slightly increased after adding Co element due to the formed TiNiCo phase and the decreased porosity. All TiNi based coatings do not show the incubation period in the initial stage of cavitation. The cavitation erosion resistance of TiNi based coating can be improved by the appropriate addition of Co element due to the formed dense microstructure with low porosity.

TiNi形状记忆合金具有出色的抗气蚀性。因此，通过将这种材料用作涂层，是防止气蚀的有效方法。本文研究了Co元素添加对大气等离子喷涂（APS）沉积的TiNi基涂层抗气蚀性的影响。表征了组织和显微硬度。结果表明，在所有基于TiNi的涂层中均出现了具有缺陷（如孔隙，微裂纹和未熔化颗粒）的层状微结构。适当添加Co元素有利于降低TiNi基涂层的孔隙率并获得致密的微观结构。TiNi基涂层的基体相为TiNi相。添加Co元素后，在涂层中形成TiNiCo相。添加Co元素后，由于形成的TiNiCo相和降低的孔隙率，TiNi基涂层的显微硬度略有提高。所有基于TiNi的涂层在空化初期均未显示出保温期。由于形成的具有低孔隙率的致密微观结构，可以通过适当添加Co元素来改善TiNi基涂层的抗气蚀性。