目的 采用电化学沉积的方法在硬质合金基体上制备厚Ni-金刚石复合涂层。方法 通过引入中间复合层，改善了涂层的结合强度，并提高了其厚度。通过热震实验结合摩擦磨损实验考察加厚涂层的膜基结合强度、磨削性能。结果 从涂层的截面、微观形貌、表面裂纹分布以及金刚石微粒与基质金属间的结合状态分析可知，普通涂层的厚度在30 μm左右，多层结构涂层的厚度在50 μm左右，厚度提高了将近一倍。热震5次后，两类涂层表面均无裂纹产生。热震20次后，两类涂层中均出现了微裂纹。热震25次后，普通涂层的裂纹宽度变大，多层结构涂层的裂纹只出现在次表层，表层无裂纹。对GCr15磨削2500 m后，普通涂层中金刚石微粒与基质金属间隙增大，附近Ni层破裂；多层结构涂层中金刚石微粒与基质金属间隙仍然很小，只出现一些断续小裂纹，附近Ni层未受影响。多层结构涂层对应的材料偶件的磨损率比普通涂层高。结论 采用多层结构设计的方法降低了Ni-金刚石复合涂层的内应力，实现了涂层的加厚沉积。加厚沉积的Ni-金刚石复合涂层界面结合强度并没有降低，且上砂量更加均匀致密，磨削性能更优。

The work aims to prepare the thick Ni-diamond composite coating on hard alloy matrix by electrochemical depo-sition. The binding strength and thickness of composite coating were improved by introducing the intermediate composite layer. The bonding strength and grinding performance of thicker coating were investigated by thermal shock test and tribological test. From the analysis on section, micro morphology, surface crack distribution and the bonding state between diamond particles and matrix metals, the thickness of the normal coating was about 30 μm and the thickness of the multi-layer structure coating was about 50 μm which was nearly doubled. No cracks were found on the surface of the two types of coatings after five thermal shocks. Cracks appeared in both coatings after 20 thermal shocks. After 25 thermal shocks, the crack width of the normal coating became larger and the crack of the multi-layer structure coating only appeared in the sub-surface layer, but there was no crack in the surface layer. After GCr15 was ground for 2500 m, the gap between diamond particles and matrix metals in the normal coating increased and the nearby Ni layer broke. The gap between diamond particles and matrix metals in the multilayer structure coating was still small, with only a few intermittent small cracks and the Ni layer nearby was not affected. The wear rate of material couplers of multilayer structure coating was higher than that of normal coating. The internal stress of Ni-diamond composite coating can be reduced by multilayer structure design. Then the goal of thickening the coating is achieved. The interface bonding strength of the thickened Ni-diamond composite coating does not decrease, but the diamond particles are more uniform and compact and at the same time the coating has better grinding performance.