High-temperature evaluation of solid lubricant coatings in a foil thrust bearing
High-temperature evaluation of solid lubricant coatings in a foil thrust bearing
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DOI：
10.1016/j.wear.2008.02.009
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发表时间：
2008-09
期刊：
影响因子：
5
通讯作者：
Christopher E. Fanning;T. Blanchet
中科院分区：
文献类型：
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作者：
Christopher E. Fanning;T. Blanchet
PS304和Korolon™ 1350 A箔片轴承涂层在顺应性推力瓦对推力转轮盘的启动/关闭测试中进行了评估。测试在540°C下进行，其中垫在恒定的3.44kPa压力下加载，同时盘速度在0和19 m/s之间循环。与未涂覆的Inconel X750垫相对于未涂覆的Inconel 718盘的情况相反，PS304盘涂层允许更容易地获得流体动力学条件，如由垫离地和触地发生时的降低的速度和全速下存在的较低的摩擦系数所指示的。在发生直接滑动的循环低速部分，PS304磁盘涂层还降低了摩擦。PS304磁盘涂层的高速氧燃料（HVOF）沉积获得这些改进的摩擦学性能后，所需的运行周期比那些等离子喷涂，由于较低的可达到的水平作为成品粗糙度。HVOF沉积需要减小尺寸的进料粉末，利用该粉末，除了氢燃料HVOF系统之外，还可以使用传统的丙烯燃料沉积PS304盘涂层。HVOF沉积的PS304另外具有比等离子体喷涂的PS304更高的沉积强度。如果推力瓦涂上K1350 A，则可以获得更好的流体动力学性能，并大大降低起飞和着陆速度以及全速时的摩擦系数。当与PS304涂层的磁盘结合使用时，K1350 A垫涂层立即提供了更好的流体动力学性能，在达到之前需要很少的磨合周期。然而，K1350 A衬垫涂层的一个缺点似乎是在低速滑动条件下与盘发生直接滑动接触时摩擦水平增加。
PS304 and Korolon™ 1350A foil bearing coatings were evaluated in startup/shutdown testing of compliant thrust pads against thrust runner disks. Tests were conducted at 540°C, with pads loaded at a constant 3.44kPa pressure while disk speed cycled between 0 and 19m/s. As opposed to the case of uncoated Inconel X750 pads against uncoated Inconel 718 disks, PS304 disk coatings allowed hydrodynamic conditions to be more readily attained, as indicated by reduced speeds at which pad liftoff and touchdown occurred and lower coefficients of friction that existed at full speed. During low-speed portions of the cycle where direct sliding occurred, the PS304 disk coatings also lowered friction. PS304 disk coatings that were high-velocity oxyfuel (HVOF)-deposited attained these improved tribological performances following fewer required run-in cycles than those that were plasma-sprayed, as a result of lower attainable levels of as-finished roughness. HVOF deposition required reduced-size feed powder, with which PS304 disk coatings could be deposited using conventional propylene-fueled in addition to hydrogen-fueled HVOF systems. HVOF-deposited PS304 additionally possessed higher as-deposited strength than plasma-sprayed PS304. If instead the thrust pad was coated, with K1350A, even better hydrodynamic performance was attained with substantial further reductions in liftoff and touchdown speeds and coefficients of friction at full speed. When coupled with a PS304-coated disk the K1350A pad coating immediately provided this better hydrodynamic performance, with very few run-in cycles required before attainment. However, one drawback of K1350A pad coatings appeared to be an increased level of friction during low-speed sliding conditions where direct sliding contact with the disk occurred.