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目的研究人工心瓣热解碳涂层与基体结合强度的影响因素,从而分析提高人工心瓣寿命的途径。方法通过改进的剪切试验法,得到人工机械心瓣热解碳涂层/石墨基体的平均界面剪切结合强度。利用有限元分析软件ANSYS建立三维模型,对人工机械心瓣热解碳涂层/石墨基体的界面剪切应力进行分析,将分析结果与试验结果进行对比。利用ANSYS验证不同涂层厚度以及不同涂层弹性模量的情况下,界面剪切应力的变化情况。结果试验所得的平均界面剪切结合强度为5.535 MPa,有限元分析得到的平均结合强度值为5.98 MPa。随着涂层厚度的增加,涂层与基体结合强度降低；随着涂层弹性模量的增加,涂层与基体结合强度增大,但弹性模量并非越大越好,应有一个合适的值。结论ANSYS分析是准确的。制备热解碳涂层时,应尽量薄一些,热解碳的弹性模量相对石墨应尽量大一些。

ABSTRACT:Objective To investigate the factors influencing the bonding strength of the coating and the substrate to figure out a method to increase the lifetime of Artificial Mechanical Heart Valves. Methods The interfacial adhesive strength of pyrolytic car-bon-graphite for Artificial Mechanical Heart Valves was tested by the improved shear test. The finite element analysis software ANSYS was used to complete a three-dimensional analysis of interfacial shear stress of pyrolytic carbon-graphite, and the results were compared with the experimental results so that the accuracy of ANSYS analysis could be verified. ANSYS was used to analyze the differences of interfacial adhesive strength with different thicknesses of coating and elasticity modulus. Results The average in-terfacial adhesive strength was 5. 535 MPa according to shear test, while the value was 5. 98 MPa as calculated by ANSYS. The in-terfacial strength decreased as the thickness of Pyrolytic coating increased, and increased as the coating elastic modulus increased, but the elastic modulus value was not the higher the better, and there should be a proper value. Conclusion The ANSYS analysis was accurate. The Pyrolytic carbon coating should be as thin as possible and the elasticity modulus should be larger than that of Graphite.