NiC/Ti中子多层膜的微结构和界面研究

NiC/Ti中子超镜是一种高性能的中子多层膜光学元件,是提升中子导管、聚焦装置等中子光学系统的中子利用率的关键之一。为了提升NiC/Ti中子超镜的性能,本文面向具有不同厚度NiC膜层的NiC/Ti多层膜,分别采用X射线掠入射反射和X射线衍射的方法表征了NiC/Ti多层膜的膜层厚度、界面粗糙度和膜层晶向结构。研究结果表明:随着NiC膜层厚度的增长,除了在较小尺度(≤2.5nm),NiC-on-Ti界面的粗糙度基本保持不变;而Ti-on-NiC界面的粗糙度却呈现出较大的变化。具有不同厚度的NiC膜层的NiC/Ti多层膜的界面粗糙度呈现不对称性的变化,主要原因在于NiC膜层的微结构随着膜层厚度的增长而产生了变化。     

反应溅射气体对Ni、Ti薄膜成膜特性的作用机制

反应溅射是降低薄膜表面和界面粗糙度的有效手段。为了研究反应溅射过程中氮气(N2)含量对所制备的Ni、Ti单层膜成膜特性的作用机制,利用掺氮气的反应直流磁控溅射方法制备了Ni和Ti的单层膜样品。首先,采用X射线光电子能谱(XPS)方法测量了Ni和Ti单层膜样品的组分。其次,基于样品的组分测量结果,结合X射线掠入射反射(XRR)方法对样品的厚度和表面粗糙度进行了测量与分析。实验结果表明,随着反应溅射中氮含量的增大,Ti膜的沉积速率呈现快速降低后迅速趋于缓慢变化的趋势,而Ni膜的沉积速率几乎没有变化,Ni膜和Ti膜的表面粗糙度都呈现先减小再增大的趋势,且在氮的含量为8%的条件下,表面粗糙度达到最小值。     

W/B4C、W/C、W/Si多层膜的研究

给出了W/B₄C、W/C、W/Si(钨/碳化硼、钨/碳、钨/硅)周期多层膜的制备和测量研究。用超高真空直流磁控溅射方法制备出周期在1.1~7.2 nm范围内的多层膜样品,采用X射线衍射仪(XRD)小角度测量方法检测多层膜的光学性能,并用透射电镜(TEM)对样品的微观结构进行了研究。结果表明:周期大于1.3 nm的多层膜样品的结构质量高,膜层结构清晰,界面粗糙度小;周期为1.15 nm的多层膜的膜层结构不是很明显;所有膜层均为非晶态,没有晶相生成。结果还表明:采用目前的溅射设备和工艺过程能够制备出满足同步辐射荧光光束线上单色器用多层膜。     

Al/TiN软硬交替多层膜的制备及摩擦磨损性能研究

软硬交替的多层膜体系具有超硬、强韧、耐磨、自润滑的优势,能大大提高金属切削刀具在现代加工过程中的耐用度和适应性。设计Al/TiN软硬交替纳米多层膜体系,并采用直流磁控溅射和阴极弧磁过滤等离子体沉积相结合的技术,室温下在单晶硅Si（100）衬底上制备一系列不同TiN层厚度纳米多层膜,研究其结构、形貌、力学及摩擦磨损性能。结果表明：该涂层具有良好的多层结构,多层膜中Al呈非晶态或纳米晶态,TiN结晶质量随其厚度增加得到提高;Al/TiN多层膜硬度均高于混合法则计算的硬度值,出现了硬度增强效应;该多层膜体系虽具有较高的摩擦因数,但表现出较好的韧性。     

Structural characterization of TiN/NbN multilayers: X-ray diffraction, energy-filtered TEM and Fresnel contrast techniques compared

Two TiN/NbN multilayers with wavelength 13.6 and 6.15 nm have been characterized by X-ray diffraction (XRD), Fresnel contrast analysis (FCA) and energy-filtered transmission electron microscopy (EFTEM). Good agreement between the composition profile obtained by FCA and EFTEM is obtained if the lower resolution of the EFTEM images is taken into account. The relative advantages and disadvantages of the techniques are discussed. Used together the two TEM techniques provide a quantitative characterization that is consistent with, and for some parameters provides more precise values than, that from XRD. The analysis shows that the multilayers have narrow interfaces (< 1 nm) and a composition amplitude close to 95% for the longer wavelength.     

Thermal stability and high-temperature wear of Ti–TiN and TiN–CrN nanomultilayer coatings under self-mated conditions

Ti–TiN and TiN–CrN nanomultilayers were thermally stable retaining uniform and sharp layer interfaces up to 24 h at 773 K, without any oxidation or phase transformation accompanying each individual layer. Decreasing the multilayer spacing resulted in an increase in the hardness in both cases. The coating hardness was found to be independent of the substrate type, when applied on HS718, Ti64 and HCHCr substrates. In scratch testing, the multilayers displayed a better resistance to the onset of failure, as compared to the monolayer TiN. The substrate plasticity played an important role in determining the coating failure mode. Self-mated wear tests revealed the CrN–TiN system to exhibit the best wear behaviour, both at room temperature and at 773 K. The Ti–TiN coatings are more accommodative with all three substrates, as compared to TiN–CrN and TiN.     

Substrate Effects on the Micro/Nanomechanical Properties of TiN Coatings

Nanoindentation and nanoscratch tests were performed for titanium nitride (TiN) coatings on different tool steel substrates to investigate the indentation/scratch induced deformation behavior of the coatings and the adhesion of the coating–substrate interfaces and their tribological property. In this work, TiN coatings with a thickness of about 500 nm were grown on GT35, 9Cr18 and 40CrNiMo steels using vacuum magnetic-filtering arc plasma deposition. In the nanoindentation tests, the hardness and modulus curves for TiN/GT35 reduced the slowest around the film thickness 500 nm with the increase of indentation depth, followed by TiN/9Cr18 and TiN/40CrNiMo. Improving adhesion properties of coating and substrate can decrease the differences of internal stress field. The scratch tests showed that the scratch response was controlled by plastic deformation in the substrate. The substrate plays an important role in determining the mechanical properties and wear resistance of such coatings. TiN/GT35 exhibited the best load-carrying capacity and scratch/wear resistance. As a consequence, GT35 is the best substrate for TiN coatings of the substrate materials tested.     

两步压入法--薄膜力学性能的可靠测量方法

提出了采用力学探针测量薄膜力学性能的两步压入法.该方法通过大载荷压入展示基体变形对薄膜硬度的影响,从而选择不影响基体变形的小载荷测出薄膜的硬度和弹性模量.对高速钢基片上的TiN硬质薄膜,单晶硅片上的金属Ni薄膜和(Ti,Al)N/VN纳米多层膜的测量表明,两步压入法能够测出各种性质薄膜的力学性能,并且具有准确可靠的特点.此外,两步法对(Ti,Al)N/VN纳米多层膜的力学性能的测量表明,该体系的纳米多层膜存在硬度和弹性模量异常升高的超硬、超模量效应.     

Ti/TiN复合膜工艺优化及性能研究

利用正交试验和极差分析方法，分析了多弧离子镀Ti／TiN复合膜中工艺参数（弧电流、氮气分压、基体负偏压、钛过渡层厚度）对Ti／TiN复合膜的纳米硬度和膜与基体的结合力的影响及主次关系，并通过正交试验对工艺参数进行了优化。研究表明，氮气分压和弧电流是影响Ti／TiN复合膜纳米硬度的2个最主要因素，膜层与基体的结合力随着弧电流的增加而下降；升高基体负偏压，虽然可以提高Ti／TiN复合膜纳米硬度和膜与基体的结合力，但是高负偏压将急剧升高基体温度，可能导致基体退火；沉积一定厚度的钛过渡层可以显著提高TiN膜层与基体的结合力。     

Tribotechnical and mechanical properties of Ti-Al-N nanocomposite coatings deposited by the ion-plasma method

The possibility of formation of nanocrystalline Ti-Al-N coatings using the method of ion-plasma deposition is demonstrated. The mechanical and tribotechnical characteristics of the coatings in comparison with TiN coating are studied. Ti-Al-N nanocomposite coatings possess high hardness (35 GPa) and higher wear resistance and lower wear capacity as compared to TiN coating. For a grain size of 12–15 nm the nanostructural Ti-Al-N coating has the following elemental composition: Ti ≈ 60 at %, N ≈ 30 at %, Al ≈ 10 at %. The phase composition of the coating represents the solid solution (Ti, Al)N. For this elemental and phase composition and nanograin size maximal hardness and elasticity modulus of the coating are found.     

Tribology and oxidation behavior of TiN/AlN nano-multilayer films

In this study, a series of TiN/AlN nano-multilayer films were prepared using a new sputtering setup, which features a medium frequency (MF) twin unbalanced magnetron sputtering system (UBMS) and a DC balanced magnetron sputtering system (BMS). The MF (6.78 MHz) twin UBMS, which is a modification of single RF power source system, is a special design of this deposition machine. The UBMS was employed to deposit the AlN film, and the BMS the TiN film. The aim of this study was to obtain, through controlling the deposition conditions, a group of TiN/AlN nano-multilayer films with various periods (λ). Then a series of experiments were conducted to understand their wear and oxidation properties.The results revealed that through controlling of the deposition parameters, the TiN/AlN nano-multilayer films with λ ranging from 2.4 to 67.6 nm were obtained. At λ3.6 nm, the nano-multilayers had extremely high hardness and excellent adhesion. The oxidation tests found that the multilayers had obviously better anti-oxidation property, as compared with the single-layer TiN film. The high hardness and good oxidation resistance contributed to very good wear performance of the TiN/AlN nano-multilayer films.     

TiN/Ti涂层在波箔轴承中的摩擦磨损性能

采用真空离子镀的方法在304不锈钢基体上喷涂厚度为3μm的TiN/Ti薄层,利用硬度计、三维形貌仪、划痕试验仪对涂层基本力学性能进行分析,通过球盘试验机分析涂层试样的摩擦磨损性能,根据波箔轴承性能测试实验台的测试结果:研究TiN/Ti涂层对基体表面耐磨减摩性能的影响。研究结果表明:TiN涂层硬度可达HV1500,是基材硬度的5.5倍;TiN/Ti涂层平均摩擦因数为0.23,相对不锈钢304基材的平均摩擦因数0.71,降低了68%,磨损量也仅为基材的18.75%;GCr15与PTFE对磨的最大摩擦力矩可达2.4 N·mm,而TiN/Ti与PTFE对磨的最大摩擦力矩仅为1 N·mm,仅为GCr15的41.7%。TiN/Ti涂层表现出了优异的承载能力和耐磨减摩性能。     

用磁控溅射法制备软X射线多层膜

本文介绍用直流-射频平面磁控溅射法制备软x射线多层膜的初步实验结果。在一定工艺条件下,采用计算机定时控制膜厚的方法,严格按照设计周期制备了多层膜样品,并给出了X射线衍射仪小角衍射的检测结果。     

Surface quality improvement of EDMed Ti–6Al–4V alloy using plasma etching and TiN coating

This paper seeks to improve the surface quality of electrical discharge machining (EDM) Ti–6Al–4V using plasma etching treatment and TiN coating. The EDM parameter setting is optimized firstly based on grey-Taguchi method. Four EDM parameters, including current (A), voltage (V), pulse duration (μs), and duty factor (%), are selected for multiple performance of lower electrode wear rate (EWR), higher material removal rate (MRR), and better surface roughness (SR). An orthogonal array, signal-to-noise (S/N) ratios, and analysis of variance (ANOVA) are used to analyze the effects of these EDM parameters. Normality tests show that all the distributions fit normality assumption with p?=?0.276, 0.688, and 0.663, respectively. The EDM process is stable over time monitored by Shewhart control charts. It is observed that there is an EDM damaged layer on the surface consisting of debris, microcracks, molten drops, and solidified metals by scanning electron microscopy. The plasma etching and TiN coating are employed to improve surface quality of the EDMed Ti–6Al–4V alloys. The results demonstrate that using the oxygen plasma etching treatment, the damaged phenomena are decreased, and the mean SR value is reduced from Ra?=?2.91 to Ra?=?2.50 μm. In addition, when the plasma-treated alloy is coated with Ti buffer/TiN coating by physical vapor deposition, the surface morphology exhibits less defects and a better surface finish. The mean SR values are further reduced from Ra?=?2.50 μm to Ra?=?1.48 μm (for 740 nm TiN film) and Ra?=?0.61 μm (for 1450 nm TiN film), respectively.     

柔性衬底直流磁控溅射ZnO基高性能透明导电薄膜的制备及性能研究

采用直流磁控溅射法,以柔性PET(聚对苯二甲酸乙二醇酯)为基底,通过参数优化以求在室温下制备高性能ZnO/Ag/ZnO多层薄膜。实验中,使用X射线衍射仪(XRD)、原子力显微镜(AFM)、紫外-可见分光光度计、四探针电阻测试仪等仪器分别对ZnO/Ag/ZnO多层薄膜的微观结构、表面形貌、透过率及方块电阻进行测试及表征。结果表明,随着Ag层厚度增加,薄膜方块电阻急剧下降,通过改变ZnO层厚度,可有效调节薄膜光学性能,随着ZnO层厚度增加,可见光区平均透过率先增大后减小。引入品质因子FTC作为评价指标可知,当依次沉积ZnO、Ag、ZnO厚度为50nm、8nm、50nm时,薄膜光电性能最佳,其在可见光平均透过率为82.3%、方块电阻为2.8Ω/、禁带宽度为3.332eV。     

Identification of intergranular phases in ceramic nanocomposites

Analytical FEG-TEM was used for nanostructural and nanochemical characterization of Al₂O₃–TiN (composite I) and Si₃N₄–TiN (composite II) ceramic composite systems. The presence of vitreous intergranular phases in pockets at multiple grain junctions and in thin films (≈ 0.8 nm thick) at grain boundaries was revealed by high resolution and Fresnel fringe imaging techniques. The existence of a Ti-rich thin intergranular film at alumina grain boundaries was revealed by EDS line-scanning across internal interfaces at the 1.5 nm lateral resolution level. Extracting interface specific information at subnanometre levels by means of quantitative spatial difference EELS allowed an identification of intergranular phases. Ti sub-oxide existed in thin films at Al₂O₃ and TiN grain boundaries, whereas a mixed Al–Ti–O–N glassy phase was observed in pockets at triple grain junctions in composite I. In composite II, residual siliceous oxide and oxynitride glass phases were identified in thin films at Si₃N₄ grain boundaries and multiple grain junctions, respectively. These observations indicated that the chemistry of the intergranular phase in thin grain boundary films is notably different from that in larger pockets at multiple grain junctions.     

Complementary techniques for the characterization of thin film Ti/Nb multilayers

An aberration corrector on the probe-forming lens of a scanning TEM (STEM) equipped with an electron energy-loss spectrometer (EELS) and X-ray energy-dispersive spectrometer (XEDS) has been employed to investigate the compositional variations as a function of length scale in nanoscale Ti/Nb metallic multilayers. The composition profiles of EELS and XEDS were compared with the profiles obtained from the complementary technique of 3D atom probe tomography. At large layer widths (h≥7 nm, where h is the layer width) of Ti and Nb, XEDS composition profiles of Ti/Nb metallic multilayers are in good agreement with the EELS results. However, at reduced layer widths (h≈2 nm), profiles of EELS and atom probe exhibited similar compositional variations, whereas XEDS results have shown a marked difference. This difference in the composition profiling of the layers has been addressed with reference to the effects of beam broadening and the origin of the signals collected in these techniques. The advantage of using EELS over XEDS for these nanoscaled multilayered materials is demonstrated.     

超细晶粒Ti(C,N)基金属陶瓷刀的磨损性能研究

研究了两种超细晶粒纳米改性Ti（C，N）基金属陶瓷刀具——44Ti（C，N）-5TiN（nm）-15WC-16M02C-20Ni（刀具A）和39Ti（C，N）-10TiN（nm）-15WC-16M02C-20Ni（刀具B）在加工正火态中碳钢时的切削性能和磨损机理。研究表明，两种刀具材料的显微组织都由金属相与陶瓷相组成，其中粗大的陶瓷相呈典型的芯／壳结构，陶瓷相晶粒尺寸为400～800nm。切削实验表明，刀具A的切削性能要优于刀具B，刀具A常以后刀面正常磨损的方式失效，刀具B则常以破损崩刃的方式失效。能谱（EDS）分析表明，高速切削时金属陶瓷刀具主要的磨损机制是扩散磨损和氧化磨损。     

eXTP望远镜用W/Si多层膜

针对增强型X射线时变与偏振探测卫星(eXTP)项目中嵌套式聚焦成像望远镜对柱面镜片上W/Si多层膜的要求,在掠入射角为0.5°,工作波段为1~30keV条件下,设计了非周期W/Si多层膜并优化了薄膜制备工艺。首先,利用分隔板和掩模板对溅射粒子进行准直,同时优化了本底真空度和溅射工作气压,提升了薄膜的成膜质量;然后,通过调整分隔板间距和公转速率提升了在柱面基底上薄膜的沉积均匀性;最后,利用幂指数算法设计了非周期多层膜,并在北京同步辐射光源上进行了多能点反射率测试,得到了与理论设计基本吻合的测试结果。基于优化的制备工艺制备了周期数为80,周期为3.8nm和W膜层厚度占比为0.47的W/Si周期多层膜,其界面粗糙度仅为0.29nm,柱面镜薄膜厚度误差可控制在3%以内,基本满足了eXTP项目中嵌套式掠入射望远镜镜片用多层膜对于成膜质量、沉积厚度均匀性和能谱响应宽度的需求。     

Formation of a Metallic Amorphous Layer During the Sliding Wear of Ti/TiN Nanolaminates

This paper describes experimental studies of metallic/ceramic nanolaminate performance under sliding contact and identifies the formation of an amorphous layer between the nanolaminate and counterface. Nanolaminates used for this study had either 20- or 100-nm-thick alternating layers of Ti and TiN, resulting in a total thickness of ~1-μm films. The structure of the Ti and TiN layers was confirmed using X-ray diffraction [(111)_TiN and (002)_Ti], and compositions were determined using electron energy loss spectroscopy (EELS)—Ti and TiN_0.7. Variation of the individual layer thicknesses within Ti/TiN nanolaminates was shown to influence both the deformation observed through the nanolaminate thickness and also the friction coefficient between the nanolaminate and 440C steel counterface during linear reciprocating wear. During sliding, the 100-nm-layered nanolaminate had a lower coefficient of friction (0.25 ± 0.01) than the 20-nm-layered nanolaminate (0.56 ± 0.06). An amorphous titanium layer developed during sliding at the interface between the 100-nm nanolaminate and steel counterface. EELS confirmed that this layer did not contain any nitrogen and recrystallization occurred near the in-contact surface. While phase changes under compressive loading have been reported for other systems, this is the first report to indicate this response within a titanium layer.