本文關(guān)鍵詞：添加固體潤滑劑hBN的鈦合金激光熔覆高溫耐磨復(fù)合涂層研究　出處：《蘇州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 激光熔覆 Ti6Al4V 復(fù)合材料涂層 hBN 摩擦磨損

【摘要】：在鈦合金表面激光熔覆復(fù)合涂層是改善鈦合金摩擦學(xué)性能的一個有效途徑。目前,大多數(shù)的相關(guān)研究是通過提高表面硬度和強(qiáng)度來改善鈦合金基體摩擦學(xué)性能的,但仍呈現(xiàn)出較高的摩擦系數(shù),尤其在高溫、重載、不易潤滑的特殊工作環(huán)境下。較高的摩擦系數(shù)對鈦合金類零部件及其對磨件的耐用年限是有害的,克服這一問題的有效方法是設(shè)計一種具有高溫自潤滑性能的復(fù)合涂層。本文采用激光熔覆技術(shù)制備出了Ni60耐磨復(fù)合涂層、Ni60-5%h BN及Ni60-10%h BN高溫自潤滑耐磨復(fù)合涂層。采用X射線衍射儀(XRD)、掃描電子顯微鏡(SEM)、能譜儀(EDS)分析了涂層的物相及顯微組織。采用球-盤式高溫摩擦磨損試驗(yàn)機(jī)系統(tǒng)地研究了干滑動摩擦磨損試驗(yàn)條件下激光熔覆涂層在不同溫度(室溫、300℃、600℃)、室溫不同載荷、高溫不同載荷下的摩擦磨損性能并詳細(xì)地探討了復(fù)合涂層的磨損機(jī)理。試驗(yàn)結(jié)果表明:Ti6Al4V合金基體上預(yù)涂Ni60、Ni60-h BN合金粉末制備的復(fù)合涂層飽滿,無明顯的裂紋、氣孔等缺陷,涂層與基體形成了良好的冶金結(jié)合。激光熔覆層可以分為3個區(qū)域,由涂層表面到基體分別為熔覆區(qū)、結(jié)合區(qū)、熱影響區(qū)。激光熔覆Ni60涂層主要由γ-Ni、Ti B2、Ti C等物相組成,Ni60-h BN自潤滑耐磨復(fù)合涂層的主要物相除了γ-Ni、Ti B2、Ti C外,還出現(xiàn)了Cr B、Ni3B硬質(zhì)相及h BN潤滑相。隨著h BN含量的增加,硼化物的體積分?jǐn)?shù)有所增加,且在凝固過程中形成了外部為塊狀Ti B2,心部為Ti C樹枝晶的特殊復(fù)雜的相結(jié)構(gòu)。激光熔覆Ni60涂層平均顯微硬度約為946HV0.2,是Ti6Al4V基體(約為350 HV0.2)的3倍左右。添加h BN的復(fù)合涂層顯微硬度高于Ni60熔覆層的顯微硬度,Ni60-5%h BN涂層平均硬度約為1052 HV0.2,Ni60-10%h BN涂層的平均顯微硬度約為1109 HV0.2。Ni60涂層的磨損率與摩擦系數(shù)都隨著溫度的升高而升高,常溫時Ni60涂層的平均磨損率為11.23×10-6 mm3/Nm,比基體磨損率降低了近20倍,Ni60涂層呈現(xiàn)出良好的耐磨性。Ni60-h BN涂層在室溫、300℃、600℃下均表現(xiàn)出較好的耐磨性,且隨著溫度的升高,摩擦系數(shù)及磨損率逐漸下降,尤其溫度為600℃時,Ni60-10%h BN涂層的摩擦系數(shù)約為0.23,磨損率約為4.2×10-6 mm3/Nm是Ni60涂層的1/4,呈現(xiàn)出優(yōu)異的減摩耐磨性能。這是硼化物、碳化物等增強(qiáng)相及潤滑轉(zhuǎn)移膜綜合作用的結(jié)果。室溫時激光熔覆Ni60涂層的摩擦系數(shù)及磨損率隨著載荷增大而升高,2 N、5 N載荷時呈現(xiàn)出較好的耐磨性。600℃時Ni60-10%h BN涂層的摩擦系數(shù)及磨損率隨著載荷的增加先減小后增大,5 N載荷下顯示出優(yōu)異的自潤滑及耐磨性能。
[Abstract]:Laser cladding composite coating on titanium alloy surface is an effective way to improve the tribological properties of titanium alloy. Most of the related studies improve the tribological properties of titanium alloy matrix by increasing the surface hardness and strength, but still show high friction coefficient, especially at high temperature and heavy load. High friction coefficient is harmful to the durability of titanium alloy parts and grinding parts under the special working environment which is not easy to lubricate. The effective method to overcome this problem is to design a composite coating with high temperature self-lubricating properties. In this paper, the Ni60 wear-resistant composite coating was prepared by laser cladding technology. Ni60-5%h BN and Ni60-10%h BN high temperature self-lubricating and wear resistant composite coatings. X ray diffractometer and scanning electron microscope (SEM). The phase and microstructure of the coating were analyzed by energy dispersive spectrometer (EDS). The laser cladding coating at different temperature (room temperature) under dry sliding friction and wear test conditions was systematically studied by using a ball disk high temperature friction and wear tester. 300 鈩，

本文編號：1404647