Ultralow Wear Behavior of Iron–Cobalt-Filled PTFE Composites
Ultralow Wear Behavior of Iron–Cobalt-Filled PTFE Composites
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DOI：
10.1007/s11249-022-01679-z
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发表时间：
2022-11
影响因子：
3.2
通讯作者：
Kylie E. Van Meter;T. Babuska;C. Junk;Kasey L. Campbell;M. Sidebottom;Tomas Grejtak;A. Kustas;B. Krick
中科院分区：
文献类型：
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作者：
Kylie E. Van Meter;T. Babuska;C. Junk;Kasey L. Campbell;M. Sidebottom;Tomas Grejtak;A. Kustas;B. Krick
首次证明了铁钴微粒填充聚四氟乙烯是一种超低磨损、磁性、多功能的摩擦学材料。添加5wt%等原子预合金化FeCo粉的聚四氟乙烯的稳态磨损率为2.8mm3× 10-7mm3/Nm，接近填充聚四氟乙烯的氧化铝的稳态磨损率。单独填充元素铁(Fe)和钴(Co)微粒的聚四氟乙烯没有观察到类似的磨损率。与未填充的聚四氟乙烯相比，添加Fe或Co微粒的聚四氟乙烯的稳态磨损性能仅有较大幅度的改善(改善1个数量级或更少)。粒度分析和形貌分析表明，Fe和Co微粒是由较小的一次粒子或特征组成的强熔块(5~20µm)，而FeCo微粒是大的(~ 40µm)、球形、致密的颗粒。红外光谱表明，PTFE-FeCo复合材料比元素Fe或Co填充的复合材料形成了更多的摩擦化学物种，导致了磨损率的提高。作为超低磨损聚四氟乙烯的填充材料，FeCo颗粒大得惊人。根据这些结果，我们得出结论，完全致密的、金属的、微尺度的和本质上脆性的FeCo颗粒可能是脆性的，并在滑动过程中分解，以增强和促进稳定的摩擦膜，类似于先前报道的超低磨损PTFE-Al_2O_3复合材料中的氧化铝颗粒。
For the first time, we demonstrate that PTFE filled with iron–cobalt (FeCo) microparticles is an ultralow wear, magnetic, multifunctional tribological material. PTFE filled with 5 wt% of equiatomic, pre-alloyed FeCo powder resulted in steady-state wear rates of 2.8 × 10–7mm3/Nm, approaching that of PTFE-filled alumina. Comparable wear rates were not observed for PTFE filled separately with elemental iron (Fe) or cobalt (Co) microparticles. PTFE filled with either Fe or Co microparticles exhibited only incremental improvements in steady-state wear behavior when compared to unfilled PTFE (1 order of magnitude or less improvement). Particle size analysis and morphology indicate that the Fe and Co microparticles are strongly fused agglomerates (5–20 µm) made of smaller primary particles or features, while the FeCo microparticles are large (~ 40 µm), spherical, dense particles. IR spectroscopy shows that PTFE-FeCo composites form more tribochemical species than elemental Fe- or Co-filled composites, leading to the observed improvements in wear rate. The FeCo particles are surprisingly large as a filler for ultralow wear PTFE. From these results, we conclude that the fully dense, metallic, microscale, and intrinsically brittle FeCo particles may be friable and break down during sliding to reinforce and promote stable tribofilms, akin to the previously reported alumina particles in ultralow wear PTFE-alumina composites.