CrN和CrAlN涂层热稳定性、力学和摩擦学性能研究  

Thermal Stability,Mechanical and Tribological Properties of CrN and CrAlN Coatings

作　　者：金玉花[1] 李鑫栋 柴利强[2] 张学希 乔丽[2] 王鹏[2] JIN Yu-hua;LI Xin-dong;CHAI Li-qiang;ZHANG Xue-xi;QIAO Li;WANG Peng(State Key Laboratory of Advanced Processing and Reuse of Non-ferrous Metals Jointly Established by the Ministry and Province,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]中国科学院兰州化学物理研究所固体润滑国家重点实验室,兰州730000

出　　处：《表面技术》2023年第8期182-196,共15页Surface Technology

基　　金：国家自然科学基金(51865028);国家自然科学基金青年项目(52005483)。

摘　　要：目的针对现有刀具用硬质CrN及CrAlN涂层的热稳定性研究尚属空白,以及对其涂层摩擦学性能的影响尚不清楚等问题,开展CrN和CrAlN涂层的热稳定性、氧化行为、力学性能及摩擦磨损性能研究。方法采用中频反应磁控溅射技术制备CrN和CrAlN涂层,利用真空热脱附系统、场发射扫描电镜、原子力显微镜、能谱仪、X射线衍射、拉曼光谱仪、纳米压痕仪和摩擦磨损试验机等探究2种涂层的结构、热稳定性、力学性能和摩擦学性能。结果在真空温度为646℃左右时,CrN涂层开始发生N分解和释放,在885℃左右时N的释放速率达到峰值。CrAlN涂层在真空温度为722℃左右时才开始发生N分解和释放,而在1000℃下N的释放速率并未达到峰值。在大气温度600℃下,CrN涂层开始发生氧化,并生成Cr_(2)O_(3)相,且Cr_(2)O_(3)层的厚度随着温度的升高而增加,在900℃时涂层完全氧化。CrAlN涂层在900℃时才开始发生氧化,生成更为致密的Cr_(2)O_(3)和Al_(2)O_(3)混合氧化层,阻止涂层进一步氧化。在大气高温条件下,CrAlN涂层均具有比CrN涂层更高的硬度和弹性模量。随着温度的升高,2种涂层的表面粗糙度逐渐增加,摩擦因数逐渐降低,CrAlN涂层在600、800℃下的表面粗糙度和磨损率均低于CrN涂层。结论在真空下,CrAlN涂层中键能较高的Al-N共价键改善了涂层的热稳定性,提高了CrAlN涂层中N的分解温度。在大气中,CrAlN涂层具有比CrN涂层更高的抗氧化性、硬度和弹性模量,CrAlN涂层在高温氧化过程中生成了连续且致密的Cr_(2)O_(3)和Al_(2)O_(3)混合氧化层,能够减缓O原子向涂层内部的扩散。CrAlN涂层具有比CrN涂层更优异的耐磨性,更适合作为高温工况下服役的刀具和模具等易磨损材料的防护涂层。In view of the lack of research on the thermal stability of existing hard CrN and CrAlN coatings for cutting tools and their effects on the tribological properties of coatings,this paper carries out a study on the thermal stability,oxidation behavior,mechanical properties as well as friction and wear properties of CrN and CrAlN coatings.Both types of coatings were prepared by reactive magnetron sputtering.The thermal stability,mechanical properties and tribological properties of the two coatings were characterized by a vacuum thermal desorption system,a field emission scanning electron microscope,an atomic force microscope,an energy dispersive spectrometer,an X-ray diffractometer,a Raman spectrometer,a nano indentation instrument and a ball-on-disk wear tester.In vacuum,for CrN coating,the decomposition and the desorption of N began at about 646℃,and the release rates of N peaked at 885℃.In the case of CrAlN coating,the releasing of N began at about 722℃,and the release rates of N still continued to rise at 1000℃.The Al-N covalent bond with higher bond energy in the lattice of CrAlN could improve the thermal stability of the coating and inhibit the decomposition of N in the coating,increasing the decomposition temperature of N in CrAlN coating.In the atmosphere,CrN coating began to oxidize to form Cr_(2)O_(3)phase at 600℃.The thickness of oxide layer increased continuously with temperature,and the coating was completely oxidized at 900℃.CrAlN coating began to oxidize and form crystalline Cr_(2)O_(3)and Al_(2)O_(3)phases at 900℃.It was apparent that the oxidation resistance of CrN coating was improved due to the doping of Al elements.This was because the amorphous Al_(2)O_(3)phase formed in the surface layer at the early stage of oxidation could inhibit the oxidation of the coating.On the other hand,the oxide layer formed by the mixture of Cr_(2)O_(3)and Al_(2)O_(3)phases had a denser structure than the single Cr_(2)O_(3)layer,which could mitigate the diffusion of O atoms into the coating.The CrAlN c

关 键 词：CRN涂层 CrAlN涂层 热稳定性 氧化行为 力学性能 摩擦磨损性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]