表面双重改性304钢干摩擦特性研究

为了改善304钢的干滑动摩擦学性能,采用激光打标机在304钢基体表面刻蚀出直径及间距为300μm的点坑状织构,之后对织构前后试样表面进行盐浴渗氮处理。分别采用D/MAX-Ultima+型X射线衍射仪、3D形貌仪、开尔文探针及Fisherscope型显微硬度测试仪对复合改性表面的化学成分、表面形貌、表面电子功函数及表面显微硬度进行了检测。采用CSEM旋转摩擦磨损试验机测试3种试样的摩擦学性能,试验条件为干摩擦。试验结果表明:盐浴渗氮处理后表面的显微硬度大大高于304钢基体表面,渗氮表面功函数明显高于304钢基体表面。渗氮光滑表面的抗磨性能显著优于304钢基体表面,而复合改性表面又明显优于渗氮光滑表面,说明复合改性表面具有极为优异的抗磨特性。     

H13钢双保温固体渗硼高温磨损机理

研究了H13钢高能喷丸辅助双保温固体渗硼试样和未渗硼试样的高温摩擦磨损性能,并探讨了磨损机理。结果表明,高能喷丸辅助双保温固体渗硼后的试样得到Fe2B单相渗硼层,高能喷丸能显著提高固体渗硼效率;渗硼试样的高温磨损率比未渗硼试样降低了30%,表明渗硼提高了H13钢的高温耐磨损性能。渗硼和未渗硼试样高温摩擦磨损后磨损表面均形成了氧化层,氧化物为Fe2O3。渗硼层在高温下具有较高的硬度及良好的抗氧化性,因此渗硼试样的高温磨损机理主要是渗硼层的疲劳剥落和氧化磨损,而未渗硼试样的高温磨损机理主要为氧化磨损和磨粒磨损协同机制。     

弹簧用51CrV4钢渗氮层微观组织与摩擦性能分析北大核心CSCD

为提高弹簧用51CrV4钢表面的耐磨性能,对其进行不同时间和温度下的渗氮处理,实验测试其微观组织,硬度以及摩擦性能。研究结果表明:渗氮层形成了未被腐蚀的明亮化合物层,扩散层由于受到浸蚀作用而转变为黑色。基底只有一种α-Fe组织。渗氮处理后形成了γ-Fe4N相、CrN相等多个物相组织。随着渗氮时间的增加和渗氮温度的增加,渗氮层厚度表现出单调增加的变化规律。渗氮后试样硬度达到950 HV以上,相对于原始试样硬度发生了明显上升。经过450℃与20 h处理后获得最小磨损率和摩擦系数,此时试样形成了较为光滑的磨痕形貌,磨损程度很小,当硬度提高后可以获得更高的耐磨能力。当温度继续上升以及时间延长后,渗氮物发生了粗化的现象,引起表面硬度减小,最终降低了耐磨性。     

弹簧用51CrV4钢渗氮层微观组织与摩擦性能分析

为提高弹簧用51CrV4钢表面的耐磨性能,对其进行不同时间和温度下的渗氮处理,实验测试其微观组织,硬度以及摩擦性能。研究结果表明:渗氮层形成了未被腐蚀的明亮化合物层,扩散层由于受到浸蚀作用而转变为黑色。基底只有一种α-Fe组织。渗氮处理后形成了γ-Fe4N相、CrN相等多个物相组织。随着渗氮时间的增加和渗氮温度的增加,渗氮层厚度表现出单调增加的变化规律。渗氮后试样硬度达到950 HV以上,相对于原始试样硬度发生了明显上升。经过450℃与20 h处理后获得最小磨损率和摩擦系数,此时试样形成了较为光滑的磨痕形貌,磨损程度很小,当硬度提高后可以获得更高的耐磨能力。当温度继续上升以及时间延长后,渗氮物发生了粗化的现象,引起表面硬度减小,最终降低了耐磨性。     

表面织构参数对渗氮304钢在纳米微粒添加剂润滑油作用下摩擦特性的影响

采用激光打标机在304钢基体表面刻蚀出孔径与间距数值相等的均布微坑;将激光织构的试样放入渗氮炉中进行表面渗氮处理;采用表面修饰剂对质量比为1∶1的SiO_2和TiO_2混合纳米微粒进行表面修饰后,将其(3%,质量分数)加入到基础油中,使用摩擦磨损试验机对其进行摩擦磨损实验。系统地对试样复合改性表面硬度、表面化学成分、表面形貌及摩擦磨损形貌进行研究。实验结果表明:表面织构参数影响304钢的摩擦学性能,其摩擦因数随孔径及间距的增大而减小,在摩擦过程中,织构微坑能够起到收集磨屑、存储润滑剂、降低磨损的作用;表面经盐浴渗氮处理后,其显微硬度由222.53HV0.1提高到573.63HV0.1,硬度显著提升;纳米微粒作为润滑油添加剂不仅能够产生微轴承作用将部分滑动摩擦转变为滚动摩擦,同时还能生成一层润滑保护膜。复合润滑结构与含有纳米添加剂的润滑油配合能够显著地降低磨损,使材料具有优异的摩擦学性能。     

表面机械研磨对H13钢表面性能的影响

使用表面机械研磨（SMA）方法处理H13钢表面使其表面获得一层变形层。采用SEM,TEM及硬度试验等检测方法对变形层的厚度、晶粒大小、截面硬度梯度和热稳定性等进行了分析;同时对H13钢在SMA处理前后的渗氮行为进行了比较。结果表明,经SMA处理后,H13钢表面形成了约10μm厚的变形层,变形层内的晶粒明显细化,并且这些晶粒具有较好的热稳定性;此外,可以大大提高H13钢渗氮的效率。     

H13钢离子渗氮(PN)与类金刚石(DLC)复合处理的摩擦磨损性能研究

采用阳极层流离子源与非平衡磁控溅射结合的沉积方法在H13钢基体表面沉积出类金刚石膜(DLC),并对H13钢经不同表面预处理对后沉积的DLC膜的摩擦学性能进行了对比研究.结果表明:DLC膜结构致密,且DLC膜与梯度过渡层及基体三者之间结合牢固;H13钢经离子氮化后,梯度过渡层与氮化层间结合紧密,提高了膜与基体的承载能力;在保持相同摩擦速率的条件下,摩擦系数随着载荷的增加先增大后减小;H13钢离子渗氮处理后沉积的DLC膜其摩擦系数远小于未采用离子渗氮处理沉积的DLC薄膜.     

激光冲击波增强38CrMoAl钢渗氮耐磨性能研究

为提高38CrMoAl钢渗氮层的质量和耐磨性能,提出并采用激光冲击增强渗氮的方法,进行了不同处理状态试样的磨损性能试验,采用XRD、SEM对试样微观组织进行分析,并探讨激光冲击增强渗氮的机理.试验结果表明:与渗氮相比,激光冲击波处理后渗氮试样的比磨损率为9.47×10-15m3/Nm,降低了50%,其表面显微硬度提高了12%;激光冲击波作用使表层材料产生高密度位错,甚至细化晶粒,从而在渗氮过程中增加了扩散通道,使更多的N原子间隙固溶到α-Fe中,对渗层起到了固溶强化的作用;形成的渗氮层微观组织致密,无缺陷,大量氮化物沿晶界高度弥散均匀分布,起到弥散强化的作用,从而提高了材料耐磨性能.     

表面纳米化预处理对316L不锈钢渗氮层摩擦学性能的影响

为改善奥氏体不锈钢的表面硬度和耐磨性,采用超声滚压与离子渗氮复合工艺对316L不锈钢表面进行了表面强化处理。利用扫描电镜(SEM)、硬度计、X射线衍射仪(XRD)和能谱仪以及摩擦磨损试验机等测定了渗氮层的硬度、深度、含氮量和物相组成,研究了表面晶层组织结构对离子渗氮行为和渗氮层在润滑油条件下摩擦学性能的影响。结果表明:直接渗氮和超声滚压/渗氮试样表层组织均由S、γ'、ε和Cr N相组成,渗氮层厚度均为20μm,直接渗氮层以S相为主,超声滚压后渗氮层以ε和γ'相为主,组织结构较为致密;超声滚压/渗氮层的平均渗氮含量是直接渗氮层的2.88倍,摩擦系数降低了0.04,显微硬度和耐磨性是直接渗氮层的1.15倍和2.76倍;超声滚压处理诱使316L不锈钢表面形成的纳米晶层组织结构增强了渗氮试样表面的催渗效能和对渗氮层的支撑强度,超声滚压后渗氮试样的表面耐磨性能最好。     

不同温度下等离子渗氮后TC4钛合金的摩擦磨损性能EI北大核心CSCD

采用等离子渗氮技术提升TC4钛合金的耐磨性并探究最优渗氮温度。利用LDM 1-100型等离子渗氮设备,在650,700,750,800,850℃和900℃温度下对TC4钛合金进行渗氮处理,保温时间均为10 h。利用光学显微镜、扫描电子显微镜、白光三维形貌仪、X射线衍射仪和显微硬度计分别对不同温度渗氮试样的微观组织结构、表面形貌、表面粗糙度、相结构和硬度进行表征。利用CETR UMT-3型多功能摩擦磨损试验机测试等离子渗氮后TC4钛合金的摩擦学性能。结果表明:TC4钛合金表面显微硬度和粗糙度随温度升高而增大,在900℃渗氮后TC4钛合金表面显微硬度达到了1318HV 0.05,约为基体(360HV 0.05)的4倍。硬度的升高是由于渗氮后试样表面形成了硬质氮化物相(TiN和Ti2N相),且随着渗氮温度升高氮化物的含量增加。相较于低温渗氮(低于750℃)的试样,850℃和900℃渗氮试样的承载能力显著提升。与原始TC4试样相比,渗氮处理后试样的磨损体积显著降低。当渗氮温度为850℃时,试样磨损体积为未处理试样磨损体积的1.2%(1 N),3.0%(3 N)和62.2%(5 N),试样的耐磨性提升更为显著。     

不同基体热浸镀铝镀层组织和高温磨损行为

选取45钢和H13钢进行热浸镀铝和高温扩散处理,采用X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等微观分析手段表征镀层物相、形貌和成分。采用销盘式高温磨损试验机对比研究不同基体下镀层的干滑动高温磨损行为,并探讨其磨损机制。结果表明:扩散层均以FeAl和Fe_3Al韧性相为主,两相之间界面周围存在平行于表面的Kikendall孔洞;镀层与45钢基体过渡平缓,结合良好,而与H13钢界面之间存在颗粒聚集,导致镀层与H13钢基体结合较差;45钢镀层在400℃/50~200N具有较好耐磨性,随环境温度升高,出现轻微-严重的磨损转变;H13钢镀层在400℃磨损率较低,在600℃也仅略高于400℃;Fe-Al镀层的磨损机制以氧化轻微磨损为主,45钢镀层在600℃出现塑性挤出磨损。     

电流密度对Ni-W合金镀层摩擦磨损性能的影响

现有的Ni-W合金镀层摩擦磨损性能研究较少涉及镀层制备条件的影响。在不同电流密度下采用脉冲电沉积法在45钢表面制备了Ni-W合金镀层,测试了Ni-W合金镀层在干摩擦及油润滑摩擦条件下的摩擦磨损性能,并观察磨损形貌,分析其磨损机理。结果表明:在干摩擦状态下,随着电流密度增加,Ni-W合金镀层的磨损量逐渐降低,但摩擦系数逐渐升高,45钢的磨损主要是黏着磨损中的擦伤磨损,Ni-W合金镀层主要为磨粒磨损,个别存在少量疲劳磨损;在油润滑摩擦状态下,随着电流密度增加摩擦系数保持稳定,磨损量逐渐降低,Ni-W镀层与45钢的磨损形式均为磨粒磨损,45钢存在少量疲劳磨损。     

Tungsten/tungsten nitride performance at elevated temperature

Abstract

Multilayer physical vapour deposition (PVD) coating of W/W₂N (tungsten/tungsten nitride) on Orvar Supreme steel was tested under the different conditions to investigate their friction and wear behaviour with their mechanical properties. Coatings were sputtered by reactive magnetron sputtering in a N₂/Ar atmosphere. Pin on disc test was performed on Orvar Supreme steel at room temperature to elevated temperature (800°C). Steel ball (100Cr6) and alumina ball are used to evaluate the frictional and wear properties. Scanning electron microscopy (SEM) and energy dispersive X-ray analyses were performed to obtain the microstructure and chemical composition of the material. Mechanical properties of coating were evaluated using nanoindentation and scratch test.     

C+和Ti+注入铝型材热挤压模表面改性研究

应用MEVVA源离子注入技术,在氮化处理基础上对H13钢模具进行了C和Ti双重离子注入表面改性研究.结果表明,C和Ti双重离子注入可以显著提高H13钢的表面硬度和耐磨性,降低摩擦系数,从而大幅度提高模具的使用寿命和产品质量,使模具挤压产量由离子注入前的3.51t提高到9.86t,提高了近200%.     

汽车用钛合金表面双辉等离子Mo合金化层的制备及其摩擦磨损性能

为了改善钛合金的表面摩擦磨损性能,采用双辉等离子合金化法在汽车用近β型钛合金(Ti-5Zn-3Sn)表面制备了Mo合金层,通过微观组织观察及硬度、摩擦系数、磨损率测试等考察了合金化层的形貌以及摩擦磨损性能.结果表明:钛合金表面等离子合金化后,呈现出银白色,表面形貌很不平整,粗糙度和致密性得到提高.钛合金Mo合金化层与基体之间结合很好,没有出现不可控的断层以及裂纹.随着合金化层的逐渐深入,Mo元素占比慢慢降低.在Mo元素固溶强化作用的影响之下,钛合金表面硬度得到明显提高,有效地改善了钛合金表面摩擦学性能.随着Mo合金化温度增加,合金化层的硬度明显增加.合金化后钛合金表面硬度高,受压屈服极限大,黏着效应小,摩擦系数小,磨损率明显降低.     

Tribologische Untersuchung bionischer und mikrostrukturierter Funktionsflächen

An established concept adjusting tribological properties and for increasing the wear resistance is presented by coatings. In addition to the material adaption of surfaces, there are efforts of applying structures on tool active parts in order to allow a further adjustment on the property profile. For this reason, the presented article investigates the influence of bionic and technologically textured surfaces on the friction and wear behavior with and without near‐net shaped wear‐resistant PVD coatings. Based on the example of nature, a honeycombed surface structure discovered on the head of scarab beetles as well as a dimple structure optimized for the manufacturing time were transferred on HSS steel by means of micro‐milling. The analyses focus on the influence of the surface structures, the effects of PVD coatings and their interactions on the friction and wear behavior. The investigations show that the tribological properties depend on each surface structure and the material pairing. Both the technological and the bionic structures show a reduction of the friction coefficient in combination with the material pairing 100Cr6 and WCCo compared to polished samples. Furthermore, it is shown that the CrAlN coating has no influence on the friction behavior, but rather leads to the desired increase in the wear resistance.     

Tribological property and drilling application of Ti-C:H and Cr-C:H coatings on high-speed steel substrates

This study investigates the tribological properties and cutting performance of Ti-DLC and Cr-DLC doped metal coatings. The tribological properties of the coatings are evaluated by testing coated disks against an AISI 1045 steel counterbody under dry conditions using an oscillating friction wear tester, and then measuring the subsequent wear depth on the coated disk, the wear width on the steel counterbody, and the friction coefficient. The cutting performance of the coatings is evaluated by using coated high-speed drills to machine stainless steel workpieces, and then measuring the resulting flank wear and hole surface roughness. The results of the wear tests show that the Ti-C:H and Ti-C:H/TiC/TiCN/TiN coatings possess excellent tribological properties, including low coefficients of friction, low wear depths, and low wear widths. Regarding the machining tests, the Ti-C:H/TiC/TiCN/TiN coating has the lowest flank wear and yields the highest hole surface quality under both dry and cutting fluid drilling conditions. The single Ti-C:H coating has excellent tribological properties, but demonstrates a relatively poorer performance in the drilling of stainless steel. Finally, the Cr-DLC coatings all exhibit a poor cutting performance under dry cutting conditions.     

Cr3C2-NiCr涂层对水力机械材料耐磨蚀性能影响研究

以水力机械材料中的A3钢为基体材料,选取UDS-200全自动爆炸喷涂系统为喷涂设备,通过不同喷涂功率在A3钢表面喷涂了5种不同孔隙率的Cr₃C₂-NiCr涂层样品。采用FE-SEM和显微硬度计,研究了Cr₃C₂-NiCr涂层样品的表面形貌和显微硬度;通过摩擦磨损试验和中性盐雾腐蚀试验,研究了Cr₃C₂-NiCr涂层样品对水力机械材料的耐磨性能和耐腐蚀性能的影响。结果表明,实施摩擦磨损后,Cr₃C₂-NiCr涂层样品表面的磨痕部位比其余部位更为光滑,磨痕呈现清晰的条纹状;Cr₃C₂-NiCr涂层样品的摩擦系数呈现先升高后降低的趋势,升高和降低的波动幅度较小,摩擦系数基本稳定在0.6左右;Cr₃C₂-NiCr涂层属于脆性材料,其质量磨损率与摩擦角度和摩擦速度成正比,而与摩擦温度成反比,孔隙率越高耐磨性能越差;Cr₃C₂-NiCr涂层样品的孔隙率越高,耐腐蚀性能就越差;随着孔隙率的逐渐提升,Cr₃C₂-NiCr涂层样品的失重量和失重速率均不断提升;喷涂层数越多,则Cr₃C₂-NiCr涂层的腐蚀速率越低,耐腐蚀性能越好,能够更好地保护水力机械材料不被介质腐蚀。     

Differences in dry sliding wear behavior between HVAF-sprayed amorphous steel and crystalline stainless steel coatings

Dry sliding wear behavior of amorphous steel coating(ASC) and crystalline stainless steel coating(SSC)manufactured by high-velocity-air-fuel-spraying was investigated. With increasing normal load, coefficient of friction(COF) of ASC decreases slightly from 0.78 to 0.69. COF of SSC presents a minor difference under various normal loads but increases with sliding time accompanied by relatively large fluctuation.Such a difference in friction behavior between such two coatings can be understood based upon the roles of shear stress and flash temperature. Wear rate of SSC is much higher than that of ASC, suggesting better wear resistance of ASC. The enhanced wear resistance is correlated with high hardness(H), reduced Young's modulus(E_r), and ratios of H/Erand H~3/E_r~2. Detailed analyses on worn surfaces and sub-surfaces indicate that the wear mechanisms for ASC include delamination, abrasive and oxidation wear, whereas those for SSC are delamination and oxidation.