基于电射流沉积的TiO2薄膜制备及其摩擦特性研究

采用电射流沉积技术在316L不锈钢基体上沉积二氧化钛(TiO_2)薄膜,并对薄膜进行高温烧结处理;在无润滑条件下,对薄膜进行往复式摩擦磨损试验,研究了温度对薄膜晶相及形貌变化的影响及TiO_2薄膜的摩擦学性能。结果表明:在电射流沉积条件为电源电压3.8～4.1kV、高度4mm、流量4μl/min时,可以制得均匀的TiO_2薄膜;随着温度升高,TiO_2晶体结构逐渐由锐钛相转变为金红石相;TiO_2薄膜能有效提高316L不锈钢表面的减摩性能。     

硬质合金表面化学镀Ni-P-金刚石粉沉积金刚石膜的研究

利用直流等离子射流装置在以化学镀Ni-P-金刚石粉为过渡层的硬质合金上沉积金刚石薄膜。采用SEM、EDS和X射线衍射仪(XRD)初步探讨了金刚石薄膜的表面形貌和物相组成。结果表明硬质合金刀片表面化学镀Ni-P后沉积金刚石薄膜,金刚石成核密度小、晶形差,难以得到结晶质量良好的金刚石膜。而在硬质合金刀片表面化学镀Ni-P-金刚石粉后沉积金刚石薄膜,成核密度比较高,晶形多为(100),但结合力较差。     

沉积温度对磁控溅射Ti/TiN多层膜光学和电学性能的影响

采用直流反应磁控溅射法于不同温度下在Si(111)基底上制备了Ti/TiN多层膜,采用X射线衍射仪和原子力显微镜对膜的物相和表面形貌进行了分析,研究了沉积温度对膜结构及其光学、电学性能的影响。结果表明:不同沉积温度下制备的Ti/TiN多层膜均由钛和TiN相组成,多层膜与单层TiN膜一样,其表面粗糙度随沉积温度的升高而减小,电阻率随沉积温度的升高显著降低;其表面形貌则比单层膜更加致密和均匀;多层膜红外反射率与其电阻率有关,当电阻率减小时,红外反射率增大。     

氧气闭环控制系统辅助反应磁控溅射沉积γ-Al_2O_3薄膜

采用双极脉冲反应磁控溅射方法在衬底温度300℃的条件下制备了结晶态γ相Al2O3薄膜。借用speedflo闭环控制系统,整个沉积过程持续稳定进行且沉积速率高达16 nm/min。XRD结果揭示,不同工作点下制备的薄膜均为单一相的γ-Al2O3。薄膜的硬度值受靶表面沉积状态影响很大,在反应模式状态下沉积的薄膜具有良好的硬度,而在靶表面中毒状态下沉积的薄膜硬度值很低。本文对硬度的变化原因做了详细的探讨。     

钛铝系金属间化合物薄膜的制备和摩擦性能

应用射频磁控溅射方法沉积钛铝系金属间化合物薄膜;用X射线衍射仪(XRD)、配有能谱仪(EDS)的扫描电子显微镜(SEM)和UMT-2型摩擦试验机对薄膜的相组成、形貌和摩擦性能进行了分析.结果表明:该薄膜是由TiAl、TiAl3、Al2O3和TiO2相组成;薄膜表面晶粒均匀细小;对于不同钛、铝含量的薄膜,当铝含量(原子分数)为45%时具有最低的摩擦因数;摩擦因数随着载荷、转速和摩擦时间的增加而减小.     

氮化硅陶瓷表面DLC膜的制备及摩擦性能研究

利用等离子体基离子注入与沉积技术,在氮化硅陶瓷片表面制备200～400nm的类金刚石碳膜。测试薄膜的厚度、表面形貌、结构、膜基结合力,利用球盘试验机考察DLC膜的摩擦性能。结果表明:沉积薄膜均匀光滑;薄膜的硬度和弹性模量与基体差异较小,膜基结合力强;DLC膜具有较低的摩擦因数,抗磨性能优异。     

基体偏压对磁控溅射制备CrAlN纳米多层薄膜微观结构和力学性能的影响

采用磁控溅射技术在不同基体偏压(-60,-70,-80,-90 V)下制备了CrAlN纳米多层薄膜,研究了基体偏压对薄膜微观结构和力学性能的影响。结果表明:随着基体偏压绝对值增大,CrAlN纳米多层薄膜中的氮含量增加,物相组成不变,择优取向由CrN(111)晶面转变为CrN(200)晶面,薄膜表面孔隙减少,组织致密性得到改善;基体偏压为-60~-80 V时,偏压对薄膜沉积速率的影响较小,偏压绝对值大于80 V时,沉积速率明显下降;随着基体偏压绝对值增大,薄膜的硬度和弹性模量提高,膜基结合力先增大后减小,在偏压为-80 V时达到最大。     

磁控溅射MoS2薄膜的生长特性研究

利用非平衡磁控溅射技术制备出二硫化钼薄膜,并通过扫描电子显微镜和X射线衍射仪研究了工作气压和沉积时间对薄膜表面形貌和结构的影响及其演化规律。实验结果表明,在小于0.40 Pa的气压下,沉积MoS2薄膜的（002）面平行于基体表面,而在高于0.60Pa的高气压下,膜层的（002）面垂直于基体表面.在沉积初期,无论工作气压的高低,薄膜均按（002）基面的方式生长;在沉积后期,低气压下形成的薄膜仍按（002）基面方式生长,而在高气压下薄膜将转向以（002）基面与（100）或（110）棱面联合的方式生长。薄膜的表面形貌、微观结构,与薄膜的生长速率和沉积粒子的能量有关。     

CVD-Si3N4薄膜工艺及性能研究

以三氯硅烷和氨气作为硅源和氮源，利用低压化学气相沉积工艺（LPCVD）在烧结氮化硅表面制备氮化硅薄膜。考察了工艺参数对沉积速率的影响，并对薄膜的组成、结构及硬度等性能进行了分析。结果表明，当载气为N2或N2＋H2、沉积温度为800℃、NH3／HSiCl3流量比为4时是较佳的工艺条件，此时薄膜沉积速率可达23．4nm／min，其膜层主要由Si-N组成，并含有部分Si-O，硬度为HV2865。     

在WC-TiC-Co硬质合金基体上制备金刚石薄膜的试验研究

通过采用Cu/Ti复合过渡层在WC TiC Co硬质合金基体上制备金刚石薄膜的试验 ,研究了沉积工艺对金刚石薄膜的质量、表面粗糙度及附着力的影响。研究结果表明 ,采用Cu/Ti复合过渡层有利于提高金刚石薄膜的附着力 ;适当降低沉积温度虽然会导致金刚石薄膜中非金刚石碳含量增加 ,但有利于增强膜层附着力。     

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。     

氩气与氮气流量比对磁控溅射法制备TiN薄膜的影响

用直流反应磁控溅射法在Si(100)基底上制备了TiN薄膜,采用X射线衍射仪和原子力显微镜对其结构和形貌进行了表征,利用四探针测试仪测量了TiN薄膜的方块电阻,使用紫外可见分光光度计测定了薄膜反射率;研究了溅射沉积过程中氩气与氮气流量比对TiN薄膜结构及性能的影响.结果表明:在不同氩气与氮气流量比下,所制备薄膜的主要组成相是(200)择优取向的立方相TiN;随着氩气与氮气流量比的增加,薄膜厚度逐渐增大,而表面粗糙度与电阻率先减小后增大;当氩气与氮气流量比为15:1时,薄膜表面粗糙度和电阻率均达到最小值;TiN薄膜的反射率与氩气与氮气流量比的关系不大.     

基体负偏压对CrAlN涂层组织和性能的影响

采用真空多弧离子镀技术,使用Cr30Al70(原子分数)复合靶,在不同的基体负偏压下,在不锈钢基体上制备了一系列CrAlN涂层;采用能谱仪、X射线衍射仪、扫描电子显微镜、粗糙度仪、显微硬度仪、摩擦磨损试验机和划痕仪等系统分析了涂层的成分、表面形貌、相结构、粗糙度、显微硬度、摩擦磨损性能和界面结合性能。结果表明:随着负偏压的增大,涂层中x(Cr)/x(Cr+Al)的比值先增大后减小,当负偏压为150V时,该值达到最大,并与靶材成分接近;基体负偏压为200V时,涂层的表面粗糙度最大,涂层结晶度、硬度最佳,晶体相为固溶铬的面心立方AlN;涂层的摩擦磨损性能不仅与涂层的表面粗糙度相关,还与涂层非晶相中铝元素的含量以及涂层的内应力大小密切相关;界面过渡层制备工艺相同时,基体偏压对涂层和基体之间的界面结合性能影响较小。     

Physical and tribological diagnostic of Ti-(Carbon Nitrides) and Ti-Nb-(Carbon Nitrides) coatings

Electrochemical, mechanical and tribological properties of Ti-C-N and Ti-Nb-C-N coatings deposited onto Si (100) and AISI 4140 steel substrates were determined in this work. Introduction of Nb in the ternary Ti C-N film was evaluated via quantitative elemental concentration depth profile by glow discharge optical emission spectroscopy (GDOES) and the morphology via scanning electron microscopy (SEM) were observed for the layers before the tests. The morphological surface was analyzed via AFM. Mechanical and tribological properties for both coatings were obtained by mean of nanoindentation measurements throughload versus displacement method, and scratch test using the critical load criterion, respectively. The failure modes from scratch test were observed via optical microscopy. Nanoindentation results reaching the elastic-plastic behavior of the TiCN and Ti-Nb-C-N coatings with inclusion of Nb (TiNbCN), indicated not only the hardness and elastic modulus but also the critical load for the adhesive failure increase when increasing r.f negative bias voltage. An improvement of hardness and critical load around 60% and 28% for TiCN as well as 26% and 31% for TiNbCN, respectively, was associated to an increasing in the r.f negative bias voltage from 0 V to -100 V.     

高能离子源清洗对AlCrN刀具涂层结构及性能的影响

采用自主研发的离子源增强多弧离子镀设备,研究涂层沉积前不同清洗工艺对基材表面粗糙度以及所制备的AlCrN涂层的表面形貌、硬度、膜基结合力、摩擦磨损和切削性能的影响。研究结果表明,高能Ar⁺清洗可以更有效清洁基材表面。与传统弧源清洗技术相比,经高能离子源清洗后的基体表面粗糙度降低,沉积态涂层的表面粗糙度更低。相比于传统弧源清洗工艺,高能Ar⁺清洗可以显著提高膜基结合强度,达到48.7 N,摩擦因数和磨损率均降低,涂层刀具寿命提高了3倍。     

Tribological behavior of plasma-enhanced CVD a-C:H films. Part I: effect of processing parameters

A systematic study was conducted on the effect of plasma-enhanced CVD processing parameters, namely bias voltage, pressure and CH₄/Ar flow ratio, on the characteristics and tribological response of amorphous hydrogenated carbon (a-C:H) films. Film hardness, intrinsic stress, structure, composition and tribological response were characterized. Variation of processing parameters was found to produce a-C:H films with a range of characteristics with the CH₄/Ar ratio exercising a dominant effect. A low ratio produced harder films with more sp³ bonding, low hydrogen content and low wear rate; whereas a high ratio produced softer films, with more sp² bonding, higher hydrogen content and low friction. Film characteristics were found to affect the wear mechanism with softer films showing a layer-by-layer removal and harder films involving formation of fine debris. These two diverse types of films offer the opportunity to synthesize multilayered films combining desirable properties from each component.     

A DOE nano-tribological study of thin amorphous carbon-based films

A design of experiment (DOE) matrix of 150 nm non-hydrogenated amorphous C and Cr doped amorphous C films was produced to investigate the effect of four key coating process parameters (use of an adhesion layer, Cr magnetron current, cathodic substrate bias voltage and Ar flow to the chamber) using a new rapid method of nano-scale wear test under conditions relevant to MEMS and similar devices. The condition of nano-wear was produced by controlled oscillation of the sample mounting within a nanoindentation system under ultra-low normal load. Specific wear rates were low, typically in the range 6-24×10⁻¹⁷ m³ N⁻¹ m⁻¹. The results were processed using an analysis of variance (ANOVA) procedure which showed that: hardness was reduced in the Cr containing films whilst specific wear rate and data scatter increased, increasing the cathodic substrate bias voltage reduced the specific wear rate due to increased coating hardness, the use of a Cr adhesion layer reduced the specific wear rate and scatter of results with Cr doped films but had no effect on pure a-C films, and Ar flow rate had no significant effect on specific wear rate but strongly interacted with the effect of the cathodic bias voltage.     

Effective removal of Ga residue from focused ion beam using a plasma cleaner

Samples prepared using the focused ion beam (FIB) inevitably contain the surface damage induced by energetic Ga+ ions. An effective method of removing the surface damage is demonstrated using a plasma cleaner, a device which is widely used to minimize the surface contamination in scanning transmission electron microscopy (STEM). Surface bombardment with low-energy Ar+ ions was induced by biasing the sample immersed in the plasma source, so as to etch off the surface materials. The etch rates of SiO2, measured with a bias voltage of 100-300 V, were found to vary linearly with both the time and bias and were able to be controlled from 1.4 to 9 nm/min. The removal of the Ga residue was confirmed using energy dispersive spectroscopy (EDS) after the plasma processing of the FIB-prepared sample. When the FIB-prepared sample was processed via plasma etching for 10 min with a bias of 150 V, the surface Ga damage was completely removed.     

TiAlN涂层及微观组织结构研究

通过改变工艺参数,采用非平衡磁控溅射法在硬质合金基体上制备Ti Al N涂层来研究涂层微观结构的变化规律。经表面和断口形貌的扫描电镜结果显示,增加主因素偏压,涂层表面趋向光滑平整,结构趋向致密,表面的大颗粒数量明显减少。EDS能谱分析表明,涂层元素的含量受偏压和N2流量影响较大。XRD分析发现,膜层中有Ti Al N系和Ti N系的物相结构,Ti N/Ti Al N多层涂层主要从(111)晶面择优取向生长。     

A contribution to the surface analysis and characterisation of HVOF coatings for petrochemical application

The appropriate selection of bulk materials and coatings of valve components is an important factor for the economic success of oil and gas production activities in the petrochemical field. Materials and coatings are important because particle erosion and surface wear are associated to corrosion by hydrogen sulphide during oil and gas flow. The wear of high pressure valves of gas system will lead to pollution, safety problems and cost increases. The most common solution of these problems is the deposition of hard materials as tungsten carbide or chromium carbide by thermal spray. These coatings are deposited by high velocity oxygen fuel (HVOF) thermal spray process to obtain a very high hardness with excellent cohesion and adhesion. Tungsten carbide cobalt–chromium based coating, chromium carbide nickel–chromium coating as well as Inconel 625 have been adopted in the specifications of petrochemical companies and their behaviour and wear, erosion and corrosion properties are reported in the literature.

This paper addresses the experimental study, surface analysis and functional characterisation of HVOF coatings innovative for the specific application such as NiAl and composite material WC/intermetallic compounds containing Ni, Cr, Co and Mo. These coatings have been systematically submitted to corrosion and functional tests based on the determination of the behaviour of the coatings in H₂S and CO₂ atmosphere and to wear and erosion according to standard ASTM G75-95 (slurry test); material loss and surface damage have been determined; the coatings have been completely characterised from the point of view of the structure (morphology, porosity, hardness, wear) and of the surface properties by means of a prototype 3-dimensional (3-D) stylus micro-geometrical surface analysis system; their corrosion and functional behaviour have been compared with the behaviour of the above mentioned coatings.

The slurry test allows a clear discrimination among the performances of analysed coatings. Namely, WC/Mo compound, because of its carbide content, shows fairly good behaviour in an erosive environment and higher erosion resistance than Inconel 625 and NiAl; all the tested coatings show similar behaviour in a corrosive environment.