晶须CaCO_3和PTFE填充聚醚醚酮复合材料的摩擦学性能

Tribological behavior of CaCO3 whisker and polytetrafluoroethylene filled polyetheretherketone composites

用MM200磨损试验机和45钢环配副,研究不同含量碳酸钙(CaCO3)晶须和10%的聚四氟乙烯(PTFE)共同填充聚醚醚酮(PEEK)复合材料的摩擦磨损性能,用扫描电镜观察磨损表面形貌并分析磨损机理。结果表明,随着复合材料中晶须含量增加,摩擦系数持续降低,最低可降到纯PEEK的1/2;复合材料的磨损率随晶须含量的增加先大幅度减小后又缓慢回升,当晶须含量为15%-20%时,磨损率降至3.3×10-7mm3/Nm,仅为纯PEEK的3.6%,20%CaCO3/10%PTFE/PEEK综合摩擦学性价比较好。CaCO3晶须增强PEEK减少了复合材料在摩擦过程中摩擦副表面粘着和剥层,阻止基体树脂的热塑性变形,同时PTFE的优先粘着转移使得复合材料在对偶件表面形成连续、均匀的转移膜,两者协同有效降低摩擦系数和磨损率,提高材料的摩擦学性能。

The tribological behaviour of CaCO3/10% PTFE/PEEK composites with different content of CaCO3 whisker were investigated by MM200 block-on-ring apparatus in comparison with neat PEEK and CaCO3/PEEK. The morphology of wear traces and transfer film were observed by scanning electron microscopy (SEM). It is found that CaCO3/10% PTFE/PEEK exhibits considerably lower friction coefficient and wear rate in comparison with neat PEEK and CaCO3/PEEK. With increase of CaCO3 whisker content, coefficient of friction of PEEK composites continuously decreases but the trends in wear performance differs. The specific wear rate of (15%-20%)CaCO3/10% PTFE/PEEK shows a minimum value of 3.3 × 10-7 mm3/Nm, which is only 3.6% of that of neat PEEK, followed by a slow increase for further CaCO3 whisker addition.The 20% CaCO3/10% PTFE/PEEK composite shows excellent combination of friction coefficient, wear rate and cost. SEM observation indicates that CaCO3 whisker contributes to abate the scuffing, adhesion and plastic deformation of the filled composite, while a thin, uniform and tenacious transfer film closely related to tribological behavior is formed on the surface of the steel ring due to inclusion of PTFE, and the both contribute to the better wear resistance of the filled PEEK composite.