结构调制高硬度TiCu/TiN-Cu纳米多层复合膜制备及其机械性能

为改善TiN硬质薄膜的硬度和耐摩擦磨损性能,采用多弧离子镀技术,在硬质合金基底上制备了单层TiN-Cu薄膜和调制周期Λ=5.9～62.1 nm的5组TiCu/TiN-Cu纳米多层复合膜。使用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、纳米压痕仪、划痕仪和摩擦磨损试验机等测试仪器,表征了薄膜的微观结构及机械性能,并研究了调制周期对纳米多层复合膜结构及机械性能的影响。实验结果表明:与单层TiN-Cu薄膜相比,TiCu/TiN-Cu纳米多层复合膜有效地抑制了晶粒生长,而且分层明显,薄膜均匀致密,薄膜中TiN晶粒以面心立方结构沿(111)方向生长。随着调制周期的减小,薄膜的结晶性有所下降,薄膜的硬度呈现先增大后减小的趋势。在调制周期为13.7 nm时,薄膜综合性能达到最佳,薄膜的硬度达到了42.6 GPa,H~3/E~2值也达到了0.689,摩擦系数为0.17,附着力为49.2 N,接近53.1 N的最高值,表明薄膜具有理想的硬度和耐摩擦磨损能力。在使用多弧离子镀工艺制备TiCu/TiN-Cu纳米多层复合多层膜的过程中,通过调整调制周期,有效地改善了膜层的机械性能,拓展了膜层的应用范围。     

CrAlN/VN多层膜调制周期对膜层性能的影响

针对磁控溅射制备CrAlN和VN的单层膜以及不同调制周期的CrAlN/VN纳米结构多层膜,采用X射线衍射仪、能谱仪、激光扫描共聚焦显微镜,维氏硬度计和纳米压痕仪对膜层性能进行表征。实验结果表明:CrAlN、VN以及CrAlN/VN多层膜均为面心立方结构,多层膜中VN层沿着CrAlN层共格生长。CrAlN/VN多层膜的硬度依赖于调制周期,在调制周期为10nm时,硬度达到最大值。多层膜的H~3/E~(*2)和韧性在调制周期较小时,更容易受到膜层中子层性能的影响。     

CrAlN/TiAlN 纳米多层膜的微结构及其性能研究

采用磁控反应溅射法制备了不同调制周期的CrAlN/TiAlN纳米多层膜,并通过X射线衍射仪 、显微硬度计、扫描电镜分析了调制周期对多层膜的微结构、力学性能和高温抗氧化性能的影响。结果表明：CrAlN/TiAlN纳米多层膜共格外延生长,呈现CrAlN（或TiAlN）面心立方结构,且呈（111）择优取向;CrAlN/TiAlN纳米多层膜在某些调制周期出现硬度异常升高的超硬度效应;CrAlN/TiAlN纳米多层膜比CrAlN, TiAlN单层膜具有更好的高温稳定性,高温时仍具有较高的硬度。     

CrAIN／TiAIN纳米多层膜的微结构及其性能研究

采用磁控反应溅射法制备了不同调制周期的CrAIN／TiAIN纳米多层膜,并通过x射线衍射仪、显微硬度计、扫描电镜分析了调制周期对多层膜的微结构、力学性能和高温抗氧化性能的影响。结果表明：CrAIN／TiAIN纳米多层膜共格外延生长,呈现CrAIN（或TiAIN）面心立方结构,且呈（111）择优取向;CrAIN／TiAIN纳米多层膜在某些调制周期出现硬度异常升高的超硬度效应;CrAIN／TiAIN纳米多层膜比CrAIN,TiAIN单层膜具有更好的高温稳定性,高温时仍具有较高的硬度。     

脉冲激光沉积制备TiN/AlN多层薄膜的研究

采用脉冲激光沉积(PLA)法,在单晶Si试样表面沉积制备了一系列TiN/AlN硬质多层膜,并采用基于免疫算法的免疫径向基函数(IRBF)神经网络对AlN厚度建立预测模型,设计出具有可控调制周期和调制比的TiN/AlN多层膜。X射线衍射(XRD)结果表明,小调制层周期下,过高或过低的工艺条件下薄膜通常为非晶态,适当的工艺条件下TiN、AlN形成具有强烈织构的超晶格柱状晶多层膜;与此相应,纳米多层膜产生了硬度和弹性模量异常增高;随着调制比增加,使纳米多层膜形成非晶AlN层和纳米晶TiN层的多层结构,多层膜的硬度和弹性模量逐渐下降。XPS结果表明,薄膜界面由Ti+4、Ti+3离子组成,N的负二价、三价亚谱结构预示着非当量TiN、AlN的形成。AFM研究显示,薄膜的调制周期均在10~200 nm范围内,且薄膜表面较均匀;当多层薄膜调制周期在50 nm以下时,薄膜的纳米硬度值明显高于TiN和AlN的混合硬度值,达30 Gpa。     

铜合金表面Ti/TiN多层膜的制备、结构及其性能

为了研究多层膜的腐蚀性能,促进多层膜在生产中的应用,采用电弧离子镀技术,通过调整环境N₂和Ar气的时间比例在铜衬底上成功制备了不同调制周期的Ti/TiN多层膜.利用x 射线衍射谱和交流阻抗谱研究了该多层膜的结构和腐蚀性能.表面形貌显示,沉积的Ti/TiN多层膜具有明显的周期性,环境中N2和Ar气的时间比例决定了多层膜的调制周期,N₂气时间越长,多层膜中TiN相层越厚.腐蚀性能测定表明,多层膜的调制周期影响其耐蚀性,当调制周期为550nm时,沉积膜的耐腐蚀性最好.     

1Cr11MoNiW1VNbN钢盐浴渗铬性能研究

为提高超(超)临界汽轮机气缸高温螺栓的抗咬死性能,对高温螺栓材料1Cr11MoNiW1VNbN钢进行盐浴渗铬处理,利用光学显微镜(OM)、扫描电镜(SEM)观察了渗层的组织,利用显微维氏硬度计和纳米硬度计分析了渗层的硬度、弹性模量和韧性,利用摩擦磨损试验机测试了渗层的耐磨性能,利用动电位极化曲线和高温氧化实验研究了渗层耐腐蚀性能.结果表明:1Cr11MoNiW1VNbN钢盐浴渗铬处理后的组织由Cr23C6和Fe-Cr铁素体(柱状晶)组成,渗层硬度和弹性模量较低,韧性较高,材料的耐磨性、耐电化学腐蚀和抗高温氧化性能得到了明显提高,这将是一种防止高温螺栓咬死的有效方法.     

Ti/TiB_2多层膜在模拟体液中生物摩擦学行为研究

采用磁控溅射的方法在医用钛合金Ti6Al4V表面制备了具有不同调制比的Ti/TiB2多层膜,并考察多层膜在Hank’s模拟体液中与超高分子量聚乙烯(UHMWPE)配副的摩擦磨损性能。研究结果表明:所制备的多层膜层状结构清晰,与基体结合良好,各子层保持一定的择优取向。多层膜在模拟体液中的摩擦磨损性能与调制比间存在着一定的依赖关系。当多层膜调制比为1:5时,其平均摩擦系数约为0.1,与Ti6Al4V相比降低了28.6%,UHMWPE磨损速率降低了近一个数量级,呈现出良好的减摩耐磨效应。多层膜的引入有效抑制了Ti6Al4V合金发生氧化磨损,而使其表现为不同程度的磨粒磨损和粘着磨损。在调制比为1:5时,多层膜/UHMWPE的生物摩擦学性能最佳,并有望在人工关节表面改性上获得应用。     

纳米级镍粉改善润滑油摩擦磨损性能的研究

在MHK－500型环块摩擦磨损试验机上,研究了纳米级金属镍粉（直径在10～50nm）加入到矿物油中的润滑性能,结果表明：在低中滑动速度下（滑动速度分别为1．285m／s和2．57m／s）,加有纳米级镍粉的润滑油表现出优良的抗磨性能．     

调制比对多层DLC薄膜性能的影响

针对DLC薄膜内应力大,膜基结合强度较差的问题。本文通过磁过滤真空阴极电弧设备,沉积不同偏压下的单层DLC薄膜,并以此为基础控制沉积多层DLC薄膜时各个阶段的偏压,镀制不同调制比下三层结构的DLC薄膜,最终使用纳米压痕划痕仪测试薄膜硬度、弹性模量和膜基结合强度,探讨了不同调制比对DLC薄膜机械性能的影响。实验结果表明:多层DLC薄膜硬度、弹性模量和膜基结合强度明显优于单层DLC薄膜。当多层DLC薄膜的调制比为1∶1∶8时薄膜硬度达到最大值70.14 GPa,薄膜弹性模量达到最大值794.8 GPa;当多层DLC薄膜的调制比为2∶2∶6时薄膜膜基结合强度较好,在最大划痕载荷25 mN的条件下,划痕的位移深度仅为57.3 nm,且薄膜硬度平均可达66.7 GPa,具有较好的综合性能。     

活塞环用钢6Cr13Mo异型截面轧制的显式动力学有限元分析

对活塞环用钢6Cr13Mo的成型过程建立了数学模型,并采用大型通用显式动力有限元分析软件AN SYS/LS_DYNA模拟了异型截面轧制的整个过程,所计算的变形情况与实际变形相符,证明显式动力有限元分析方法可有效地应用于活塞环用型钢的轧制分析.     

离子镀（Ti,Cr）N涂层的组织结构与耐蚀性能的研究

研究了离子镀（Ｔｉ,Ｃｒ）Ｎ涂层的组织结构和耐蚀性,经ＸＲＤ分析表明,（Ｔｉ,Ｃｒ）Ｎ涂层中的Ｃｒ原子部分置换ＴｉＮ晶格中的Ｔｉ原子,且部分与Ｎ反应生成ＣｒＮ,Ｃｒ２Ｎ或以单质态存在。经耐蚀性分析得知,由于Ｃｒ的加入,提高了（Ｔｉ,Ｃｒ）Ｎ涂层的致密度,同时加剧了阴极极化程度,延长了腐蚀原电池的开动过程,从而增强了涂层的耐蚀性。     

多层膜体系微硬度实验的有限元数值模拟

使用FEPG软件编程,对维氏压头的微硬度实验进行模拟,建立了一种针对膜基体系有限元计算的新模型,该模型考虑了边界摩擦和实时跟踪接触因素,在对TiN单层膜和TiN／Ti／TiN／Ti／TiN／Ti6层膜压痕的模拟分析后,得出“载荷-压痕对角线长度关系曲线”和“硬度-载荷关系曲线”以及塑性区分布图,并对微硬度实验中的压头的压入深度相对于单层膜膜层厚度和多层膜中组分膜膜层厚度的取值进行了讨论,与其他文献中的实验比较,结果吻合。说明模型是合理的,结果是可靠的,对实际应用具有指导意义,并为理论分析提供了研究方法。     

发动机活塞环—缸套间油膜特性的研究

本文从研究油膜厚度入手探讨了活塞环-缸套的润滑特性,在分析中考虑了表面粗糙度的影响,并用电容法对活塞环-缸套间油膜厚度进行了实测,理论值和实测值取得了一致。     

QPQ处理对Incone1718镍基合金结构的影响

采用QPQ工艺对Inconel718进行了渗氮处理,渗层的深度受扩散控制,渗层深度∝(√渗氮时间).XRD 测试结果表明温度对渗层深度的影响更明显,氮化处理后Inconel718表面硬度大约是基体的3倍;渗氮层中有CrN相,氮与Cr反应形成CrN.通过SEM观察到渗氮表面出现一些柱状物,渗层和基体之间有一个明显的分界线.     

Blow-by and tribological performance of piston ring pack during cold start and warm idle operations

To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numerical model considering the cylinder liner deformation and the piston ring conformability is developed to predict the blow-by, lubrication, friction and wear of the piston ring pack under different operating conditions. The gas flow rate, inter-ring gas pressures, minimum oil film thickness, frictional force and wear load during cold start are calculated and compared with those during warm idle operating conditions. The results show that cylinder liner deformation and piston ring conformability together obviously affect blow-by and other tribological performance. Meanwhile, it is found that friction loss is larger during cold start than during warm idle operating conditions. However, the wear process is more severe during warm idle operation than during cold start. From this research, the blow-by and tribological performance of the piston ring pack during cold start and warm idle operations are understood more deeply.     

码盘、圆光栅真空镀铬工艺的研究

通过对码盘、圆光栅真空镀铬原理及膜层形成机理的分析,给出膜层厚度和影响其均匀性和致密性的主要因素之间的关系式以及安全成膜时被镀件的临界转速,为真空条件下获得厚度均匀、致密性好的铬膜提供了理论依据.     

Tribological properties of CrN coating deposited on 20CrMo against tin bronze

A CrN coating was deposited on the piston pin material 20CrMo. The tribological properties of 20CrMo and CrN coating against tin bronze QSn7-0.2 were compared by pin-on-disk tests under dry friction and oil lubrication, respectively. The cross-sectional morphologies and structures of the coating were characterized through scanning electron microscopy and X-ray diffraction. The hardness, elastic modulus, and adhesion strength of the coating were tested through nano-hardness and scratch tests. The wear tracks were tested with an optical profilometer, and wear volume was calculated. Under dry friction conditions, the CrN coating exhibited a significantly stable friction coefficient and a relatively lower wear rate against QSn7-0.2 at various temperatures compared with 20CrMo. The wear rate decreased by 98.5% at 700°C. Under poly-alpha-olefine lubrication, the CrN coating reduced the load effect on the friction coefficient. Under engine oil 5 W40 lubrication, the CrN coating improved the tribological properties under high speed and heavy load conditions. Simultaneously, the CrN coating changed the friction and heat flow with increasing temperature.     

计量光栅盘真空镀铬机理与工艺研究

在计量光栅盘的制作过程中,真空镀铬是影响计量光栅盘精度和成品率的主要工序之一。为了提高计量光栅盘的精度及成品率,对计量光栅盘真空镀铬原理及膜层形成机理进行了分析,给出了影响铬层致密性及牢固度的主要因素与铬层均匀性和蒸发距离之间的关系式,并针对其原因对相关工艺进行了改进,实验证明改进后的工艺对改善铬膜的致密性和牢固度及均匀性起到了一定的作用,使计量光栅盘的成品率提高了10%,同时也为进一步改善后续工艺提供了理论依据。     

Removal of Cr（Ⅲ） and Cr（Ⅵ） from aqueous solution by adsorption on sugarcane pulp residue

Sugarcane pulp residue (SPR), a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium (Cr(III) and Cr(VI)) from wastewater. In this work, the kinetics, isotherms of Cr(III) and Cr(VI) adsorption and their removal by SPR were investigated. The results show that the removal percentages of Cr(VI) and Cr(III) increase with increasing SPR dosage and temperature and decrease with increasing SPR particle size and the initial concentration of chromium ions. However, the influence of pH value on the Cr(VI) removal differs from that of the Cr(III) removal. The Cr(VI) removal percentage decreases with increasing pH values, while the Cr(III) removal percentage increases with increasing pH value. The adsorption kinetics of Cr(VI) and Cr(III) well fits with pseudo-second-order model. Langmuir adsorption isotherm can well describe the adsorption phenomena of chromium ions with the maximum adsorption capacity of 0.567 mg/g for Cr(VI) and 3.446 mg/g for Cr(III). Moreover, SPR reveals higher adsorption capacity for Cr(III) than that for Cr(VI), which implies that SPR has more potential application for Cr(III)-containing wastewater treatment than that for Cr(VI)-containing wastewater treatment. Foundation item: Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of China; Project(2008SK2007) supported by the Key Program of Science and Technology of Hunan Province, China