用ECRCVD方法制备优质氮化硅钝化膜

利用电子回旋共振等离子体化学气相沉积(ECR—CVD)技术，以SiH4和N2为反应气体进行了氮化硅钝化薄膜的低温沉积技术的研究。采用原子力显微镜、傅立叶变换红外光谱和椭圆偏振光检测等技术对薄膜的表面形貌、结构、厚度和折射率等性质进行了测量。结果表明，采用ECR—CVD技术能够在较低的衬底温度条件下以较高的沉积速率制备厚度均匀的氮化硅薄膜，薄膜中H含量很低。薄膜沉积速率随微波功率和混合气体中硅烷比例的增加而增大。折射率随微波功率的增大而减小，随混合气体中硅炕比例的增大而增大。在相同气体混合比和微波功率条件下，较高衬底温度条件下制备的薄膜折射率较大。     

热丝CVD大面积金刚石薄膜的生长动力学研究

在传统工业型热丝化学气相沉积（HFCVD）反应腔内，相关工艺参数取模拟计算优化值的条件下，采用XRD，SEM及Raman光谱等分析手段研究了单晶Si（100）上较大面积金刚石薄膜的动力学生长行为，讨论了晶格取向的变化规律。结果表明：优化工艺参数条件下，在模拟计算的衬底温度和气体温度分布均匀的区域内，沉积的金刚石薄膜虽存在一定的内应力，但整体薄膜连续、均匀，几何晶形良好，质量较高，生长速率达1．8μm／h。薄膜生长过程中晶形显露面受衬底温度和活性生长基团浓度的影响较大。     

HfO2薄膜的制备与光学性能

采用射频磁控反应溅射法，以高纯热压HfO2陶瓷为靶材，在Si衬底上成功制备出HfO2薄膜。系统研究了工艺参数对薄膜沉积速率的影响规律，并对薄膜的光学性能进行了研究。结果表明，射频功率对薄膜沉积速率的影响最为明显，O2／Ar流量比和衬底温度对沉积速率的作用不明显，所制备薄膜的折射率较高在近红外波段趋于1．95，在500-1650nm波段范围内薄膜几乎无吸收，透过率较高。     

热丝化学气相沉积纳米金刚石修复损伤PCD刀具的研究北大核心CSCD

利用热丝化学气相沉积装置,以聚晶金刚石片为衬底,在氢气/丙酮/氩气反应体系中研究了衬底温度对纳米金刚石生长的影响。采用扫描电子显微镜对生长结果进行了表征,结果表明在衬底温度950℃的情况下,金刚石薄膜表面结构呈"菜花"状,致密性较差,生长速率为4.44μm/h。随着温度当衬底温度的降低,"菜花"状结构逐渐消失,致密性提高,生长速率降低。当衬底温度下降到750℃时,"菜花"状结构完全消失,生长速率为3.43μm/h。根据实验结果对损伤长度从几微米到几十微米的聚晶金刚石铣刀刃口进行了修复,并采用扫描电子显微镜进行了表征,结果显示修复后表面光洁度有明显改善。对钛合金片表现为良好的加工效果。     

柔性ITO衬底上铜酞菁薄膜有序生长的X射线衍射研究

采用石英晶体微天平实时监测薄膜生长速率,通过控制衬底温度与薄膜生长速率,在柔性ITO导电衬底上真空蒸发沉积了铜酞菁薄膜.X射线衍射分析表明,适当提高衬底温度与薄膜生长速率,可促进薄膜的有序生长.当衬底温度为90℃,生长速率为10nm/min时,薄膜的有序度最高,薄膜晶型呈(相和(200)晶面.     

提高CVD金刚石薄膜附着力的方法及其研究进展

概述了金刚石薄膜与衬底附着力研究的最新进展,详细讨论了衬底材料的性质、衬底预处理方法、过渡层、负偏压以及CVD沉积条件对金刚石薄膜附着力的影响,总结出提高附着力的主要方法,并分析了金刚石薄膜的应用状况,指出了扩大金刚石薄膜应用的新方向及存在的主要问题.     

衬底温度对低温制备纳米晶硅薄膜的影响

采用传统的射频等离子体增强化学气相沉积技术,在较高的工作气压130Pa和较高的射频功率70W下,在＞100℃的低温下,以0.14nm/s速率制备出优质的纳米晶硅薄膜.研究结果表明,薄膜晶化率和沉积速率与衬底温度有密切关系.当衬底温度＞100℃,薄膜由非晶相向晶相转化,随着衬底温度的进一步升高,薄膜晶化率增大,当温度为300℃时,薄膜的晶化率达82%,暗电导率为10-4·cm-1数量级,激活能为0.31eV.当薄膜晶化后,沉积速率随衬底温度升高而略有增加.     

Se离子束辅助沉积CIS过程的数值分析

通过研究连续Se离子束辅助磁控溅射技术,在柔性聚酰亚胺基底上沉积形成CIS薄膜的过程,建立了相应的薄膜沉积模型。在此基础上,以离子注入深度效应作为研究对象,从扩散均匀性角度进行模拟计算,并与传统气相原子沉积方法进行比较。通过比较分析,计算出Se扩散均匀性为90%时,采用离子束辅助沉积所需的衬底温度明显低于气相原子沉积所需的衬底温度。     

HWCVD在玻璃衬底上沉积硅薄膜的研究

采用热丝化学气相沉积法在玻璃衬底上沉积硅薄膜,采用扫描电子显微镜、拉曼光谱分析表征样品的形貌和结晶性,较为系统地研究了硅烷浓度、衬底到热丝的距离对硅薄膜生长过程及各种性质的影响,结果表明,较高的衬底温度及较低的硅烷浓度有利于薄膜的结晶.     

工艺参数对直流反应磁控溅射ZnO:Al薄膜沉积速率的影响

实验以合金靶材在玻璃衬底上运用直流反应磁控溅射法制备了ZAO(ZnO:Al)透明导电薄膜样品.研究了O2气流量,衬底温度,以及反应气压和溅射功率等工艺参数对ZAO薄膜沉积速率的影响规律.结果表明:沉积速率随O2气流量的增加显著降低,靶面溅射模式由金属模式转变为氧化物模式,而且这种转变趋势在改变其他参数时依然明显;沉积速率随溅射功率的增大几乎成线性增加,但随衬底温度的变化并不大;在反应气压增大的情况下,沉积速率不断上升,达到最大值后,又随气压的增大不断下降.     

低压冷喷涂铝涂层微观结构与沉积特性研究

低压冷喷涂技术是一种不同于高压冷喷涂技术的新型喷涂工艺。本文以体积比为3:7的氧化铝粉末和铝粉的混合粉末为原料,以压缩空气为工作气体,利用低压冷喷涂设备在Q235钢基体上制备Al涂层,研究了温度、喷距、送粉速率和喷嘴横向移动速度等工艺参数对涂层沉积效率的影响。采用光学显微镜、扫描电镜,研究了涂层的微观结构和沉积特性。实验结果表明:在工作气体压力保持0.6 MPa不变的情况下,温度400℃、喷距25 mm、送粉速率为30—40 g/min、喷嘴横向移动速度4.0 m/min时,铝涂层沉积效率最佳;同时Al2O3陶瓷相的加入有利于涂层的沉积。     

CVD nanocrystalline diamond coatings on Ti alloy: A synchrotron-assisted interfacial investigation

Diamond coating on Ti-6Al-4V alloy was carried out using microwave plasma enhanced CVD with a super high CH₄ concentration, and at a moderate deposition temperature close to 500 °C. The nucleation, growth, adhesion behaviors of the diamond coating and the interfacial structures were investigated using Raman, XRD, SEM/TEM, synchrotron radiation and indentation test. Nanocrystalline diamond coatings have been produced and the nucleation density, nucleation rate and adhesion strength of diamond coatings on Ti alloy substrate are significantly enhanced. An intermediate layer of TiC is formed between the diamond coating and the alloy substrate, while diamond coating debonding occurs both at the diamond-TiC interface and TiC-substrate interface. The simultaneous hydrogenation and carburization also cause complex micro-structural and microhardness changes on the alloy substrates. The low deposition temperature and extremely high methane concentration demonstrate beneficial to enhance coating adhesion strength and reduce substrate damage.     

Uniform coating of CVD diamond on metallic wire substrates

Diamond was coated onto wire substrates of various transition metals (Mo, W or Ti) of 0.5 mm diameter by the microwave plasma CVD method from a gas mixture of the CO–H₂ system. The CVD conditions for a uniform diamond coating were microwave power, 750–1100 W; total pressure, 2000 Pa; total flow rate, 200 ml min-1; CO concentration, 5 vol%; treatment time, 5 h. The wire substrates were mounted vertically or horizontally on a pyrophyllite susceptor, which was placed parallel to the irradiation direction of microwave power. Homogeneous and fine-grained diamond film was prepared on the whole surface of horizontal W wire substrate with a wire height of 2 mm from the susceptor. To obtain a dense diamond coating, the height has to be as low as possible in the plasma region, where the plasma density is higher at lower substrate temperature. Low pressure and high microwave power were suited for fine-grained coating. Diamond deposition rate was found to be more dependent on pressure than substrate temperature. As the pressure increased, a glassy carbon film was formed instead of diamond. This revised version was published online in November 2006 with corrections to the Cover Date.     

Amorphous carbon coating mixed with nano-diamonds

A low temperature plasma process for alternately depositing a diamond layer and an amorphous-carbon layer, i.e. DLC (diamond like carbon), on a same substrate was developed. In order to make both DLC and diamond coexist on a same substrate, we developed a method to form diamond at lower temperature than 500 K, since at a higher temperature DLC is easily crystallized and changed to graphite. We constructed an apparatus that had two types of plasma generators for radio frequency and microwave. The substrate temperature can be kept at 473 K during depositions for both DLC and diamond. Laser-Raman spectrometry and transmission electron microscope observation showed existence of both DLC and diamond in the coated layers. The coating has excellent mechanical properties, such as higher hardness than DLC and very low friction comparable to DLC.     

Study of the interfacial phenomena during friction surfacing of mild steel with tool steel and inconel

Friction surfacing was carried out with tool steel (AISI 01) and inconel 600 consumables on mild steel 1020 substrate in an argon atmosphere. Inconel bonded strongly with the substrate and there was evidence of interfacial compound formation between the substrate and coating. For tool steel coatings, a sharp boundary between the substrate and coating was observed by scanning electron microscopy. X-ray fluoroscopic imaging also revealed this boundary. Mechanical interlocking between the coating and the substrate appears to be insignificant so adhesion between the coatings and the substrate may be caused by solid-phase bonding. For friction surfacing of both tool steel and inconel, a nominal contact pressure as high as 21.8 MPa was required to obtain an adherent coating of uniform quality. © 1998 Chapman & Hall     

电弧喷涂工艺参数对1Cr13涂层与45钢结合强度的影响

电弧喷涂技术常用于机械零件如柱塞、曲轴等的修复.喷涂层与基体的结合强度直接影响其寿命,并与喷涂工艺有密切的关系.用正交设计试验方案,在45钢基体上采用电弧喷涂方法制备了1Cr13涂层,并通过涂层结合强度试验考察了喷涂工艺参数与涂层结合强度的关系.结果表明:电弧喷涂1Cr13钢丝的优化工艺参数为:电压32 V,电流240 A,喷涂压力0.7 MPa,喷涂距离150 mm;影响涂层结合强度的工艺参数从主到次依次为电弧电流、喷涂压力、喷涂距离和喷涂电压.     

A study on the microstructure and property development of d.c. magnetron cosputtered ternary titanium aluminium nitride coatings Part III effect of substrate bias voltage and temperature

Advanced ternary (Ti,Al)N coatings were produced by reactive magnetron co-sputtering technique with separate titanium and aluminium targets at a 30° magnetron configuration under various substrate bias voltages and temperatures. The effect of substrate bias and temperature on the microstructure and property development of the coatings was investigated. It was found that an increase in substrate bias and/or substrate temperature imposed no major effect on the composition and phase formation of the (Ti,Al)N coatings, but had significant influence on the development of their microstructure and surface morphology. As the substrate bias and/or temperature increased, the coating structure was densified with development of fine grain size and reduced surface roughness, resulting in a substantial increase of the coating hardness. However as the substrate bias increased over 200 volts, excessive residual stress was built up, causing a fracture of the coatings. It is believed that the microstructure and property enhancement is attributed to an increased translational kinetic energy of the depositing atoms and a greater thermal energy provided to the substrate and the coating material with increasing substrate bias and/or temperature. The adatom mobility and the surface diffusion of atoms are enhanced to reduce the detrimental effects induced by the statistical roughening and self-shadowing of asputter deposition process. A densified zone T structure with low porosity and improved properties is produced.     

Biocompatible and mechanical properties of low temperature deposited quaternary (Ti, Al, V) N coatings on Ti6Al4V titanium alloy substrates

A series of quaternary (Ti, Al, V) N coating layers were obtained by low temperature reactive plasma sputtering in differing deposition conditions to improve the wear resistance and the biocompatibility of a titanium surgical alloy, specifically Ti-6Al-4V. Characterization of the mechanical properties, structure and the chemical composition of the coating layer was explored by microhardness test, ball against flat wear test, scanning electron microscopy and X-ray diffraction. The biocompatibility of the optimum coating layer (as determined by mechanical performance) was examined by a modified MTT toxicity test and by monitoring cell growth assessed by quantitative stereological analysis. The experimental results are encouraging, indicating that this low temperature deposited, dense, quaternary (Ti, Al, V) N coating layer exhibits improved mechanical properties such as high hardness and excellent adhesion to a Ti alloy substrate and is highly biocompatible.     

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.     

TVibological Behavior of TiN and TiAIN Deposited on Substrates Plasma Nitrided at Low Pressure

Binary and ternary compounds of TiN and (Ti,Al)N were deposited by magnetron sputtering over low pressure plasma nitrided layer. Tribological behavior under dry-sliding conditions was evaluated with pin-on-ring test machine. The significant process parameters, friction coefficient and contact temperature, were checked with a modern measurement line that includes computer for acquisition and processing of data and monitoring the wear process. The wear zone morphology and characteristics of surface layer structure as well as important properties were investigated by scanning electron microscopy (SEM). Energy-dispersive x-ray analysis (EDAX) of the wear-scars on pins provided essential information on the wear characteristics. Based on all results the correlation between the surface structure and tribological wear characteristics were explained. It was concluded that formation of the plasma nitrided layer at low pressure, beneath a TiN and (Ti,Al)N over coating, is important in determining the use of hard coating for reducing the wear. An excellent coating to substrate adhesion and low friction coefficient was found to be significant factor influencing the use of plasma nitriding at low pressure.