碳化硅晶须骨架结构增强聚四氟乙烯复合涂层力学及摩擦学性能

Mechanical and tribological properties of poly(tetrafluoroethylene) composite coatings reinforced with silicon carbide whisker skeleton structure

  • 摘要: 纤维填充是增强聚四氟乙烯(PTFE)复合涂层耐磨性和力学性能的常用手段。目前PTFE复合涂层中纤维含量通常在10%左右,若要实现更高的纤维含量则面临着纤维分散的难题。本研究通过优化晶须分散工艺,使用PTFE乳液,以硅树脂乳液为粘结剂,实现了高质量分数(17%-50%)且均匀分布的碳化硅晶须增强PTFE复合涂层制备。研究结果表明:当碳化硅晶须添加量较高时,均匀分散的晶须能够通过无序堆垛在复合涂层中形成自相似的连续骨架结构,有效抑制涂层中的裂纹扩展,复合涂层的冲击韧性提高了10倍、结合力提高了1倍以上。此外,晶须骨架为复合涂层提供了一个界面载荷支撑机制,增强了PTFE复合涂层对轴向力的抵抗,减小了磨损率。当加入的碳化硅晶须质量分数为17%时,复合涂层的综合性能最佳,抗冲击强度为50 kg·cm,磨损率为1.456×10−4 mm3·N−1·m−1,维氏硬度HV为54.82,摩擦系数为0.12。该晶须骨架结构为高性能树脂基复合涂层的设计提供了参考。

     

    Abstract: Fiber reinforcement is a commonly used method to enhance the wear resistance and mechanical properties of polytetrafluoroethylene (PTFE) composite coatings. The fiber content in PTFE composite coatings is typically around 10%, and achieving a higher fiber content presents challenges in fiber dispersion. This study optimizes the whisker dispersion process by utilizing PTFE emulsion and silicon resin emulsion as a binder to fabricate PTFE composite coatings reinforced with silicon carbide whiskers at high volume fractions (17%-50%) and uniform distribution. The results indicate that, when the silicon carbide whisker content is high, the uniformly dispersed whiskers can form a self-similar continuous skeletal structure through disordered stacking in the composite coating, effectively inhibiting crack propagation. The impact toughness of the composite coating increased by 10 times, and the adhesion strength improved by over 1 time. Furthermore, the whisker skeleton provides an interface load-bearing mechanism, enhancing the PTFE composite coating’s resistance to axial forces and reducing wear rate. When the mass fraction of silicon carbide whiskers is 17%, the composite coating exhibits optimal comprehensive performance, with an impact strength of 50 kg·cm, a wear rate of 1.456×10−4 mm3·N−1·m−1, a Vickers hardness of HV 54.82, and a coefficient of friction of 0.12. This whisker skeletal structure provides valuable insights for the design of high-performance resin-based composite coatings.

     

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