目的 通过改善液相等离子喷涂制备纳米金刚石涂层的工艺参数，提高纳米金刚石涂层的显微硬度与结合强度。方法 利用 Ansys 有限元软件对纳米金刚石涂层中的残余应力进行数值模拟。建立纳米金刚石涂层的有限元分析模型与热传导方程，探讨了涂层的厚度与降温速度对纳米金刚石涂层残余应力的影响。通过扫描电子显微镜对制备的纳米金刚石涂层表面进行分析，并且利用显微硬度计和表面划痕仪测定纳米金刚石涂层的显微硬度和结合强度。结果 纳米金刚石涂层的主应力为拉应力，涂层的最大主应力随着厚度的增大而具有先增大、后减小、再增加的特点。随着涂层厚度的增加，涂层的最大剪应力由涂层表面转移到涂层界面，其值先减少，后保持稳定。涂层整体、涂层界面和涂层表面的最大主应力与最大剪应力，随涂层温度的升高而呈线性递减的趋势。纳米金刚石涂层的主应力集中在涂层的四周，而涂层的剪应力分布在涂层表面。纳米金刚石涂层表面较光滑，由大量纳米级的细小扁平颗粒紧密排布而形成。结论 采用适当的工艺参数制备出厚度为 0.1 mm 的纳米金刚石涂层，其显微硬度和结合强度分别约为 150HV 和 9 N。

The work aims to improve microhardness and bonding strength of nano-diamond coating by changing process parameters of nano-diamond coating which was prepared in the method of suspension plasma spraying. Numerical simulation was applied to residual stress of nano-diamond coating using finite element software ANSYS. Finite element analysis model and heat conduction equation were established for nano-diamond coating. The effects of coating thickness and cooling rate on residual stress of the nano-diamond coating were discussed. Surface of the nano-diamond coating was analyzed by scanning electron microscope, and microhardness and bonding strength were measured by microhardness tester and surface scratch tester. Principal stress of the nano-diamond coating was tensile stress, and the maximum principal stress first increased, then decreased and finally increased as the coating thickness increased. The maximum shear stress of the coating was transferred from coating surface to coating interface as the coating thickness increased. Moreover, the maximum shear stress first decreased and then remained stable. For the bulk coating, coating interface or coating surface, the maximum principal stress and the maximum shear stress decreased linearly with the increase of coating temperature. The maximum principal stress was concentrated around the coating while the shear stress was distributed on the coating surface. The surface of the nano-diamond coating was smooth because its smooth surface consisted of compact flat particles through a large number of nanoscale particles. The microhardness and bonding strength of the 0.1 mm thick nano-diamond coating prepared provided with proper process parameters is about 150HV and 9 N, respectively.