Electroless Ni-P platings were deposited on Micro-arc Oxidation( MAO) films from TC4 alloy prepared for different time. The influence of different microstructures of the MAO films on the adhesion property between the electroless Ni-P plating and the MAO films were investigated by SEM, automatic scratch tester and thermal shock tests. The results show that with the increase of MAO time, the roughness and the radius of the microholes on the surfaces of the MAO films increases correspondly. In addition, the shape of the microholes grows open, and then closes slowly, and finally becomes a groove. With the time of MAO increasing from 3min to 15min, the adhesion property between electroless Ni-P platings and MAO films degrades, and the critical load decreases from 21. 5N to 8.5N. Besides, the typical feature of the scratch changes from cracks to flakes. Further increasing the MAO time from 15min to 60min, the adhesion property between Ni-P electroless platings and MAO films becomes better obviously, and the critical load increases from 8.5N to more than 40N. It can be seen from the thermal shock tests that after the first thermal cycle, serious peelings of Ni-P electroless plating occur, and the sequence of beginning peeling of the Ni-P electroless plating from different MAO films is MAO for Ismin, 7min and 3min. Peelings appear from MAO for 30min after 2 thermal cycles, and for MAO of 60min is 28 thermal cycles. The results from the thermal shock tests are consistent with those of the scratch tests. In addition, the models of the microstructures of the MAO films processed for different time is built, and the adhesion property between the microstructures of the MAO films and the Ni-P electroless platings is discussed as well.%在TC4钛合金上制备微弧氧化不同时间的氧化膜,然后进行化学镀Ni-P镀层,利用SEM、涂层附着力自动划痕仪和热震试验,研究不同微弧氧化膜结构对钛合金化学镀Ni-P镀层结合性能的影响.结果表明:随着微弧氧化时间的增加,微弧氧化膜表面的粗糙度增大,表面微孔逐渐变大,孔口先变成敞开形式然后慢慢缩合,最后变成凹槽状.微弧氧化时间由3min增加至15min,化学镀Ni-P镀层与微弧氧化膜的结合性能逐渐降低,临界载荷由21.5N减少至8.5N,且化学镀层表面划痕特征由裂纹向镀层剥落发展.微弧氧化时间由15min增加至60min,化学镀Ni-P镀层与微弧氧化膜的结合性能逐渐增加,临界载荷由8.5N增加至大于40N.热震试验结果表明,微弧氧化3min,7min,15min的试样热震1次时,化学镀Ni-P镀层发生严重的剥落,且在冷却过程中化学镀镍层剥落的顺序为15min,7min,3 min的试样,30min的试样热震2次剥落,60min的试样热震28次才剥落,与划痕实验的结果一致.建立了不同微弧氧化时间,TC4钛合金微弧氧化膜的结构模型,讨论了不同微弧氧化膜结构与化学镀镍层的结合强度.
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