沉积温度对CrN涂层干摩擦及大豆油润滑下摩擦学性能的影响

为探究沉积温度对CrN涂层摩擦学性能的影响,同时寻找适合CrN涂层润滑的绿色润滑剂,采用磁控溅射技术在不同温度下制备CrN涂层。利用X射线衍射仪、扫描电子显微镜、AFM原子力显微镜、划痕仪、纳米压痕仪和摩擦磨损试验机评价涂层的微观结构、力学性能,以及在干摩擦及大豆油润滑条件下的摩擦磨损性能。结果表明：在250 ℃下沉积的CrN涂层具有最致密的晶状结构,且力学性能最优。摩擦试验结果显示,在干摩擦和大豆油润滑下250 ℃下沉积的CrN涂层表现出最优的摩擦学特性。XPS分析表明,由于摩擦的存在,大豆油会在涂层表面发生摩擦化学反应并生成一层化学吸附膜,从而能有效减轻涂层的摩擦和磨损。250 ℃下沉积的CrN涂层具有最优的力学及摩擦学性能,且大豆油极为适合CrN涂层的润滑。     

不同基体CrN/CrCN多层涂层海水环境摩擦学性能研究*

为研究不同基体材料对CrN/CrCN多层涂层在海水环境下摩擦学性能的影响,采用多弧离子镀技术在H65铜合金、TC4钛合金和316L不锈钢基体上沉积CrN和CrN/CrCN多层复合涂层,通过XRD、SEM等技术对涂层的结构进行表征,通过结合力、硬度测试和摩擦磨损试验分析涂层在大气环境和海水环境下的力学性能和摩擦学性能。结果表明:CrN/CrCN多层涂层的内应力相对于CrN明显减小,且硬度相对CrN涂层较高;TC4钛合金为基体的涂层结合力较好且涂层硬度较高;在海水环境下涂层的摩擦因数相对于大气环境都有较大幅度下降,其中,以TC4钛合金和316L不锈钢为基体的涂层摩擦因数较小;以H65铜合金为基体的2种涂层在海水中的磨损率高于大气中,而以TC4合金、316L不锈钢为基体的CrN/CrCN多层涂层在海水环境下的磨损率低于大气环境;TC4钛合金为基体的CrN/CrCN多层涂层在海水环境下具有最低的磨损率,表明TC4钛合金更适合作为海水环境下CrN/CrCN多层涂层耐磨的基体材料。     

38CrMoAlA钢表面多弧离子镀CrN涂层的制备及其耐摩擦腐蚀性能研究

为提高酸性条件下38CrMoAlA钢的耐摩擦腐蚀性能,采用多弧离子镀技术在38CrMoAlA钢和渗氮38CrMoAlA钢基体上沉积CrN、Cr/CrN涂层,通过XRD、SEM等方法对涂层的微观结构进行表征,通过硬度和结合力测试、开路电位和极化性能测试、摩擦磨损试验,研究涂层的力学、电化学以及摩擦学性能。结果表明:CrN和Cr/CrN涂层开路电位较高,腐蚀电流密度小,涂层表面处于轻微钝化态,可提高酸性条件下38CrMoAlA钢的耐腐蚀性能;CrN和Cr/CrN涂层的摩擦因数和磨损率均小于38CrMoAlA钢基体,表明2种涂层均可提高38CrMoAlA钢基体的摩擦学性能;以渗氮38CrMoAlA钢为基体的Cr/CrN涂层的硬度虽略小于以38CrMoAlA钢为基体的CrN涂层,但其具有更高的膜基结合力和更优的耐摩擦腐蚀性能。     

氮气流量比对CrN涂层结构及摩擦磨损性能的影响

采用直流磁控溅射技术在不同氮气流量比下在YG6基体上制备CrN涂层,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)及能谱仪(EDS)分析涂层相组成、涂层形貌与涂层元素成分,利用数字式显微硬度仪、划痕仪测定涂层硬度与涂层结合力,在摩擦磨损试验机考察涂层摩擦学性能。结果表明:氮气流量比(氮气流量占气体总流量的比例)为20%、30%时,CrN/YG6涂层结构相对疏松,呈柱状生长;氮气流量比为40%、50%时,CrN/YG6涂层结构较致密,呈三角颗粒状生长;随氮气流量比增大,涂层硬度先增大后减小,当氮气流量比为40%时达到最大值HV1 752.5;CrN涂层的摩擦因数随氮气流量比的增大变化不大,但磨损率先增大后减小再增大,当氮气流量比为40%时达到最小值2.03×10~(-8)mm~3/(N·mm)。研究表明,当氮气流量比为40%时,所制备的CrN涂层具有良好的综合性能。     

电参数对CrN薄膜在去离子水环境下摩擦磨损性能的影响

采用多弧离子镀方法，在不同偏压和靶电流下在GH05合金试样表面制备系列CrN薄膜，利用扫描电子电镜、X射线衍射仪、显微硬度计、多功能材料表面试验仪对薄膜的微观组织结构和力学性能进行测试分析。利用盐雾磨损试验机的球-盘摩擦方式研究各CrN薄膜在去离子水环境下与Si3N4球对磨的摩擦学性能。结果表明：随着偏压增大，CrN薄膜表面微颗粒大小逐渐减小，硬度增大，结合力先增大后减小，随着靶电流增大，CrN薄膜表面凹坑逐渐减小，硬度减小，结合力先增大后减小；随着偏压增大，CrN薄膜的平均摩擦因数先增大后减小，磨损体积先减小后增大，随着靶电流增大，CrN薄膜的平均摩擦因数先减小后增大，磨损体积先减小后增大，当偏压为-80 V，靶电流为100 A时制备的CrN薄膜在去离子水环境下具有最佳的摩擦学性能；CrN薄膜在去离子水环境下的磨痕形貌主要呈现磨粒磨损的沟槽形貌，同时表现出抛光效果。     

基体偏压对CrN涂层结构和海水环境摩擦学性能的影响

采用多弧离子镀技术,在不同偏压(0~-100 V)下在316 L不锈钢基体上沉积CrN涂层,通过球-平面往复式摩擦磨损试验机研究基体偏压对涂层结构和海水环境下摩擦学性能的影响。结果表明:随着偏压的增大,涂层结构变为更加致密,涂层硬度先增加后基本稳定;随着偏压的增大,涂层与316L基体的结合力先增大后减小,偏压为-50~-75 V时涂层有最好的结合力;在海水环境下,涂层具有很低的摩擦因数(0.2~0.3),并随着偏压升高而降低;随着偏压的增大涂层的磨损率先减小后增大,偏压为-50~-75 V时涂层的磨损率较低。偏压为-50~-75 V时制备的涂层具有最好的综合机械性能。     

CrN、CrSiN薄膜在不同介质下的摩擦学性能对比研究

采用中频非平衡反应磁控溅射法在单晶硅〖BF〗P(111)〖BFQ〗和不锈钢（304SS）基材上制备CrN和CrSiN薄膜;利用球-盘式摩擦磨损试验机（CSM）考察2种薄膜在不同介质（空气、去离子水、质量分数35%NaCl 溶液）中和WC/Co球对摩的摩擦学性能。结果表明：大气环境下,CrN与CrSiN薄膜的磨损机制主要是磨粒磨损;水润滑下,CrN薄膜主要因机械抛光作用,CrSiN薄膜主要因摩擦化学反应,使得摩擦因数减小;在35%NaCl 溶液中CrN薄膜易被腐蚀,由于NaCl颗粒析出以及涂层接触区域的腐蚀和磨损产物,作为第三体的润滑作用,导致摩擦磨损发生明显变化,而CrSiN薄膜不易被腐蚀,主要因摩擦化学反应,使得摩擦磨损性能发生显著变化。     

CrN 活塞环涂层的磨擦学性能

以PVD方法在不锈钢渗氮活塞环基体上沉积了厚约30 μm的CrN涂层.采用2种GF-3等级的全配方发动机油作为润滑剂,在SRV试验机上,对比了具有/没有CrN涂层的不锈钢渗氮活塞环的摩擦学性能.试验结果表明,CrN涂层能使摩擦因数数较快的稳定且数值较低,同时活塞环及其对磨缸套的磨损量也大大降低,对磨缸套的磨损量减少了80%以上.SEM分析结果表明,由于CrN涂层具有较高的硬度和较低的表面粗糙度,可以降低磨粒磨损,且能使对磨的缸套试样较快地与之适配,从而促进了摩擦反应膜的形成和扩展,是摩擦因数和磨损量降低的主要原因.     

TiN、CrN的环境摩擦磨损对比研究

采用直流叠加脉冲偏压电弧离子镀技术在45钢表面沉积了TiN、CrN薄膜。用显微硬度计测试了薄膜的硬度,用划痕仪测量了薄膜的膜基结合力,用球-盘式摩擦磨损试验机评价了不同介质条件下（干摩擦、水润滑、油润滑）TiN、CrN薄膜的摩擦学特性,用表面轮廓仪测试了薄膜磨痕处的磨损轮廓,用扫描电镜（SEM）观察了薄膜磨痕形貌。结果表明,相对于干摩擦条件下,在水润滑和油润滑条件下TiN和CrN薄膜的摩擦因数和磨痕深度都有所降低。在相同的介质条件下,CrN薄膜的摩擦因数和磨痕深度始终小于TiN薄膜。     

CrN活塞环涂层的摩擦学性能

以PVD方法在不锈钢渗氮活塞环基体上沉积了厚约30μm的CrN涂层。采用2种GF-3等级的全配方发动机油作为润滑剂，在SRV试验机上，对比了具有／没有CrN涂层的不锈钢渗氮活塞环的摩擦学性能。试验结果表明，CrN涂层能使摩擦因数数较快的稳定且数值较低，同时活塞环及其对磨缸套的磨损量也大大降低，对磨缸套的磨损量减少了80％以上。SEM分析结果表明，由于CrN涂层具有较高的硬度和较低的表面粗糙度，可以降低磨粒磨损，且能使对磨的缸套试样较快地与之适配，从而促进了摩擦反应膜的形成和扩展，是摩擦因数和磨损量降低的主要原因。     

离子束增强沉积CrN镀层膜基结合强度的测定

采用球滚接触疲劳法评定不同界面共混工艺所制ＣｒＮ镀层膜基结合强度,并对试验结果进行分析对比。试验结果表明,在其它参数相同的条件下,随着氨离子轰击能量从１０ｋｅＶ、２０ｋｅＶ提高到４０ｋｅＶ,静反冲共混界面结合强度相应增大,而动反冲共混界面结合强度则有明显降低的趋势,较低能量（１０ｋｅＶ、２０ｋｅＶ）氨离子动态共混界面具有比其它共混界面更理想的膜基结合强度。     

金属复合CrN涂层的磨损性能及应用研究

为取代M2高速钢,降低空调压缩机叶片生产成本,在GCr15基体上分别沉积CrMoN和CrAlTiN涂层,采用XRD分析涂层的相组成,在MM-200试验机上对其进行摩擦磨损实验,用三维超景深显微镜测量其磨痕面积;并用SEM观察磨损后的磨痕形貌。结果表明:制备的CrAlTiN和CrMoN涂层都能在一定程度上提高基体GCr15的耐磨性能,其中CrMoN涂层是以单一的CrN面心立方结构存在,Mo起到置换固溶强化的作用,因此耐磨效果更明显;通过合理控制涂层厚度和提高膜基结合力,GCr15+CrMoN涂层很有希望能取代传统的空调压缩机叶片材料M2高速钢。     

Tribological and electrochemical performances of Cr/CrN and Cr/CrN/CrAlN multilayer coatings deposited by RF magnetron sputtering

CrN/CrAlN and Cr/CrN/CrAlN multilayers were grown with dual RF magnetron sputtering. The application of these multilayers will be wood machining of green wood. That is why ball-on-disc and electrochemical tests in NaCl aqueous solution were realized to elucidate the tribological and corrosion behavior of these coatings as they will be exposed to wear and corrosion during wood machining process. The samples/alumina and samples/WC coupling showed different wear mechanisms. The 300 nm thick Cr/CrN/CrAlN multilayer demonstrated the best tribological behavior and corrosion resistance. The influence of growth defects on corrosion resistance has been shown.     

Advances and problems with TEM characterization of Cr/CrN multilayer coatings

Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite substrates using pulsed laser deposition (PLD) technique. The microstructure observations were performed using Philips CM20?, TECNAI G² F20 – TWIN? and JEOL EX4000? transmission microscopes. The performed experiments indicated that lowering the argon flow from 60 to 30 cm³/s during chromium ablation changes buffer layers microstructure from nearly amorphous to nano‐crystalline. The nitride or carbo‐nitride layers turned out to be less sensitive to changes in nitrogen flow during deposition. The columnar microstructure of Cr layers is coarser than those in CrN ones under the same deposition condition. This observation proved also that relying on PLD technique as thin as 30 nm layers might be formed within multilayer Cr/CrN coatings.     

Architecture of Multilayer Cr/CrN Coatings for Wear Protection in Seawater: Cr/CrN Ratio and Total Thickness

Cr/CrN multilayer coatings with various Cr/CrN thickness ratios and total thicknesses were deposited on 316L stainless steel by multi-arc ion plating. The coatings were systematically characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and nanoindentation. Tribological behaviors were investigated using a ball-on-disk tribometer in artificial seawater. The results showed that the multilayer coating phases changed from Cr₂N + CrN to Cr + Cr₂N + CrN phases with an increase in Cr/CrN thickness ratio. The adhesion showed a slight difference for the coatings with different thickness ratios but significantly increased with total thickness. The hardness was also slightly improved by thickening the coatings. The friction coefficient and wear rate were lowest at a thickness ratio of about 0.3. However, there was no large difference in the friction coefficient between coatings with different thicknesses. The wear rate was lower for the thicker coatings under various loads. The load-bearing capacity was also improved by thickening the coatings.     

Dry Sliding Wear Model of Nanometer Scale Multilayered TiN/CrN PVD Hard Coatings

Dry sliding wear resistance of nanomultilayered TiN/CrN coatings has been evaluated using a ball-on-disk tribometer and compared with TiN and CrN monolayered references. The significant extend of lifetime of the nanostratified coatings is explained by a particular stress field generated in the whole thickness and a degradation model is proposed.     

The slurry erosive wear of physically vapour deposited TiN and CrN coatings under controlled corrosion

The erosion-corrosion of mild steel (BS6323), in the presence and absence of physically vapour deposited (PVD) TiN and CrN coatings, was studied, in comparison with that of AISI 304 stainless steel, in an aqueous alkaline slurry solution containing alumina particles. The influence of applied potential and particle velocity on the total erosion-corrosion loss was examined, and the respective corrosion and erosion damage (both contributing to the overall weight loss) then assessed by means of microscopical investigation of the morphology of the damaged surface, and subsequently evaluated quantitatively. The superior erosion-corrosion resistance of both the coatings compared to that of the uncoated mild and stainless steels was shown to be due to their resistance to both wear and corrosion. According to the detailed corrosion mechanisms revealed and different responses to wear, schematic diagrams were proposed to outline the main features of the corrosion-erosion process and the individual roles of erosion and corrosion. Discrete differences, in terms of the respective erosion and corrosion processes, between the TiN and CrN coatings, and between the mild and stainless steels, were also investigated and discussed. This revised version was published online in August 2006 with corrections to the Cover Date.