等离子喷涂NiCrAlY-Cu涂层中Cu在宽温域环境下的扩散及摩擦耗散机制  

Diffusion and Friction Dissipation Mechanisms in Wide-temperaturerange of Cu in NiCrAlY-Cu Coating by Plasma Sprayed

作　　者：方子文 何乃如 贾均红 杨杰 刘宁[2] FANG Ziwen;HE Nairu;JIA Junhong;YANG Jie;LIU Ning(School of Mechanical and Electrical Engineering,Shaanxi University of Science and Technology,Xi’an 710021,China;Xi’an Aerospace Composite Materials Research Institute,Xi’an 710021,China)

机构地区：[1]陕西科技大学机电工程学院,西安710021 [2]西安航天复合材料研究所,西安710021

出　　处：《中国表面工程》2023年第2期65-78,共14页China Surface Engineering

基　　金：国家自然科学基金资助项目(51905325)。

摘　　要：含软金属自适应涂层在摩擦过程因软金属独特的性能而具备良好的摩擦学性能,然而在不断摩擦过程中软金属会发生一定的耗散导致涂层失效。为了研究软金属润滑剂在宽温域摩擦过程中的耗散机制,利用等离子喷涂技术制备NiCrAlY-Cu涂层;通过分析热处理及宽温域摩擦前后涂层的组分与形貌演变,揭示NiCrAlY-Cu涂层中Cu的高温扩散及宽温域摩擦耗散机制。结果表明:Cu以片层状分布在NiCrAlY基础相中,软金属Cu在温度单因素影响下垂直向涂层表面扩散,随着温度的升高扩散加剧。在1000℃环境下Cu在涂层内部发生平行扩散,并最终呈现弥散态分布。在中低温环境下随着温度的升高Cu的剪切强度降低进而使得涂层摩擦因数逐渐下降,但是由于Cu呈片层状分布,随着温度的升高涂层发生疲劳剥落导致磨损率升高。随着温度的进一步升高,Cu扩散加剧,片层状Cu减少,同时发生氧化,使得摩擦因数升高,磨损率降低。在宽温域摩擦过程中由于温度和载荷的共同影响,Cu在涂层中的摩擦耗散机制为Cu垂直向涂层表面扩散,由磨痕区域内向磨痕外平行扩散。同时,磨痕内聚集的Cu以磨屑形式逐渐损耗。提出在不同温域摩擦过程中受力-热耦合影响的软金属耗散机制,可为解决含软金属自适应涂层的失效问题提供理论依据。Soft metal-containing composite coatings exhibit favorable tribological properties owing to extremely low shear strength.However,the soft metal dissipates during the friction process at elevated temperatures,resulting in the failure of such coatings.Recent studies have identified dissipation mechanisms of soft metals based on the effect of temperature.However,research on the dissipation mechanisms of soft metals by the synergetic effect of the load and temperature during the friction process at elevated temperatures has not yet been explored.NiCrAlY-Cu coatings were prepared using air plasma spraying technology to study the diffusion and dissipation mechanisms of soft metal lubrication in the composite coating by the synergetic effect of load and temperature.Heat treatment and tribological tests of the NiCrAlY-Cu coatings were carried out over a wide temperature range.The wear mechanisms of the NiCrAlY-Cu coatings are also discussed.The compositions and morphologies of the NiCrAlY-Cu coatings and worn tracks were determined using X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy-dispersive X-ray spectroscopy(EDS).The Cu content of the NiCrAlY-Cu coating was calculated and compared after heat treatment and tribological tests over a wide temperature range.The diffusion mechanisms of Cu at elevated temperatures and the dissipation mechanisms of Cu during the friction process were studied using compositional and morphological analyses.The results showed that Cu was uniformly distributed with a lamellar structure in the NiCrAlY-Cu coatings.According to the Gibbs-Thomson effect and Ostwald ripening theory,soft metal would diffuse vertically under the influence of temperature,which is consistent with Cu vertical diffusion to the coating surface.Meanwhile,the diffusion intensified as the temperature increased.Furthermore,Cu diffused in parallel and was dispersedly distributed in the NiCrAlY-Cu coating at 1 000 ℃.At low and moderate temperatures,the shear strength of Cu decreased with increasing temper

关 键 词：等离子喷涂 NiCrAlY-Cu涂层 宽温域摩擦学性能 扩散机制 摩擦耗散机制 

分 类 号：TG174[金属学及工艺—金属表面处理] TH117[金属学及工艺—金属学]