喷涂频率对车用316L钢表面等离子Mo-Al膜摩擦性能的影响

以车用316L不锈钢作为基材,对其实施等离子喷涂处理使其表面生成Mo-Al膜,分析表面温度变化、电弧特征以及形成的磨痕特点,对比了不同喷涂频率下得到的膜载流摩擦磨损特性。研究结果表明:当频率20 Hz时,在磨痕的表面区域形成了一层具有均匀尺寸的磨粒。元素分布表明Al元素发生了少量转移,跟膜层组织成分较为接近。在频率20 Hz下形成了具有完整结构的摩擦膜,此时在表面区域形成了尺寸均匀的磨粒。提高喷涂频率后,会引起摩擦副的大幅冲击并发生明显震动,温度迅速上升,更易发生氧化。当提高喷涂频率后,摩擦系数以及磨损率都发生了先减小再升高的变化规律,转折点在喷涂频率20 Hz,此时取值分别为0.326和68.5。

Influenceof Spraying Frequency on Tribological Property of 316L Steel Surface-Modified with Plasma Sprayed Mo-Al Coatings

The surfaces of 316 L stainless steel,an advanced automotive gear material,were modified with Mo-Al coatings,deposited by plasma spraying.The influence of the spraying frequency on the microstructures and tribological behavior was investigated with scanning electron microscopy(SEM) and multifunctional tribological tester.The results show that the spraying frequency had a major impact.To be specific,as the frequency increased from 5 Hz to 30 Hz,the compactness,uniformity and microstructures of Mo-Al coatings changed in an improvement-deterioration manner; the friction coefficient and wear rate varied in a decrease-increase mode.Plasma sprayed at an optimized frequency of 20 Hz,the lowest friction coefficient and wear rate were found to be 0.326 and 68.5,respectively; and quite a few uniform clusters,with contents resembling to those of Mo-Al coatings,were observed around the wear tracks on the fairly compact Mo-Al coatings.