Ultralow wear Perfluoroalkoxy (PFA) and alumina composites
Ultralow wear Perfluoroalkoxy (PFA) and alumina composites
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DOI：
10.1016/j.wear.2016.06.003
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发表时间：
2016-09-15
期刊：
影响因子：
5
通讯作者：
Krick, Brandon A.
中科院分区：
文献类型：
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作者：
Sidebottom, Mark A.;Pitenis, Angela A.;Krick, Brandon A.
氟聚合物具有独特的机械、化学和摩擦学性能(低摩擦系数)，但它们作为固体润滑剂的使用受到高磨损率(1-5X10(-4)mm(3)/Nm)的限制。添加某些类型的α-氧化铝可以使聚四氟乙烯的磨损率降低三个数量级以上，但由于其极高的相对分子质量，聚四氟乙烯不能进行螺杆注射成型。然而，四氟乙烯(TFE)和全氟烷基乙烯基醚(Pave)的全氟化共聚物PFA可以是。将不同质量分数的α-氧化铝(0%、5%、7.5%、10%)的聚四氟乙烯(Teflon(R)PFA340)样品注射成型，并对每个模具的样品进行与不锈钢的磨损试验(P=6.3 Mpa，Nu=50.8 mm/S)。实验表明，PFA 340-α氧化铝复合材料的摩擦性能与未填充的PFA 340和PTFE-α氧化铝复合材料的摩擦性能非常接近。未填充PFA 340的磨损率为1.4×10(-4)mm(3)/Nm，PFA-α氧化铝复合材料的磨损率降至4.0×10(-8)mm(3)/Nm。就像在PTFE-α氧化铝复合材料中一样，这些PFA复合材料在聚合物和金属表面都产生了棕色的摩擦膜，这表明摩擦化学变化。每个表面的ATR-IR和FTIR光谱表明有全氟羧酸盐和水合水的生成。PTFE和PFA 340样品的这种光谱相似性表明，PTFE-α氧化铝复合材料中发现的相同的摩擦学机理也是导致PFA-α氧化铝复合材料超低磨损的原因。(C)2016爱思唯尔B.V.保留所有权利。
Fluoropolymers have unique mechanical, chemical, and tribological properties (low friction coefficients) but their use as solid lubricants is inhibited by high wear rates (1-5X10(-4) mm(3)/Nm). The addition of certain types of alpha-alumina has been shown to reduce the wear rate of PTFE by over three orders of magnitude, but due to its extremely high molecular weight PTFE cannot be screw injection molded. However, PFA, a perfluorinated copolymer of tetrafluoroethylene (TFE) and a perfluorinated alkylvinyl ether (PAVE), can be. Teflon (R) PFA 340 samples with various weight fractions of alpha-alumina (0%, 5%, 7.5%, 10%) were injection molded, and samples from each mold were wear tested against stainless steel (P=6.3 MPa, nu=50.8 mm/s). Experiments showed that the friction behavior of the PFA 340-alpha alumina composite was very close to that of both unfilled PFA 340 and PTFE-alpha alumina composites. The wear rate of unfilled PFA 340 was 1.4X10(-4) mm(3)/Nm, and dropped to 4.0X10(-8) mm(3)/Nm for the PFA-alpha alumina composites. Just as in the case of PTFE-alpha alumina composites, these PFA composites generated brown-colored tribofilms on both the polymer and metal surfaces, which were indicative of tribochemical changes. ATR-IR and FTIR spectra of each surface showed evidence for the generation of perfluorinated carboxylate salts and waters of hydration. This spectral similarity between PTFE and PFA 340 samples shows that the same tribological mechanism found in PTFE-alpha alumina composites is responsible for ultralow wear in PFA-alpha alumina composites as well. (C) 2016 Elsevier B.V. All rights reserved.