CLAM钢表面硬质薄膜的制备与性能研究

采用射频反应磁控溅射法在中国低活化马氏体(CLAM)不锈钢表面制备了单层Al2O3、SiC、W薄膜以及SiC/Al2O3、W/Al2O3双层膜.对所制备的薄膜进行了XRD结构分析、AFM表面形貌测试和显微硬度测试.结果表明:单层SiC薄膜表面出现了部分脱落,而SiC/AlO3双层膜表面完整光滑.W/Al2O3双层薄膜表面平整光滑,均方根粗糙度为4.28 Ha.W单层薄膜和W/Al2O3双层薄膜经氩气中800℃退火2 h后硬度最高,分别达到了34.4 GPa和31.3 GPa.     

去皮山药的护色保鲜包装研究

为了解决去皮山药易褐变的问题,利用糖或碱溶液对去皮山药进行浸泡处理,根据山药的褐变度分别得出最佳的浸泡液组成;根据单因素试验结果制成糖碱复合浸泡液对去皮山药进行预处理,再分别选用生物气调保鲜膜、百合保鲜膜、普通PE保鲜膜对其进行包装,通过对山药的色差、硬度、失重率及菌落总数的测定,研究不同保鲜膜对山药的保鲜效果。研究表明：质量分数为9%的糖溶液、pH值为9的碱溶液对山药的护色效果较好;生物气调保鲜膜对山药的保鲜效果较好。     

The mechanical behaviour of polyimide-copper laminates

The peel energies of flexible laminates consisting of polyimide films bonded to copper foil with a polymeric adhesive have been measured and the peel mechanisms investigated by conducting peel tests inside a scanning electron microscope. These laminates were prepared from polyimide films that had been subjected to either a “high-thermal history” or “low-thermal history” treatment during the production of the film. The laminates prepared from the “high-thermal history” polyimide films had higher recorded peel energies and the locus of failure during the peel test was mainly by cohesive fracture through the adhesive layer. The laminates prepared from the “low-thermal history” polyimide films tended to fail in a weak boundary layer of the polyimide film. The peel energies were lower and displayed a greater scatter. Thein situ peel tests have also identified various failure mechanisms which account for the different features observed on the peeled surfaces and the various types of peel energy traces which were recorded.     

Influence of bias voltages on the structure and wear properties of TiSiN coating synthesized by cathodic arc plasma evaporation

Nanocomposite TiSiN films have been deposited on M2 tool steel substrates using TiSi alloy as target by a dual cathodic arc plasma deposition (CAPD) system. The influences of bias voltages on the microstructure, mechanical and tribological properties of the films were investigated. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction techniques were employed to analyse the microstructure, grain size and residual stress. Nano-indentation and tribometer testers were used to measure the mechanical and tribological properties of nanocomposite TiSiN thin films. The results showed that the hardness of the films ranged from 25 to 37 GPa, which were higher than that of TiN (21 GPa). The coefficient of friction of the TiSiN thin films was more stable but was higher than that of TiN when wear against both Cr steel and WC-Co ball, respectively. When encountered with both Cr steel and WC-Co ball of the counter ball, the tribological mechanisms of TiSiN thin films are adhesive and abrasion wears, respectively. It has been found that the microstructure, mechanical and wear properties of the films were correlated to bias voltage, grain size, and amorphous Si₃N₄ nanocomposite formed in film structure, resulting in a superhard TiSiN coating.     

镍基合金基体上离子镀TiN薄膜的制备及性能

在镍基合金Inconel 740H基底上通过多弧离子镀制备Ti N薄膜.控制温度、气体流量、过渡层成分等重要参数,研究其对Ti N薄膜的表面形貌、力学性能以及耐腐蚀性的影响.多弧离子镀沉积过程中,沉积温度分别为200、250、300℃;过渡层成分分别为Al、Cr、Ti;气体流量分别为Ar 5 Sccm∶N240 Sccm,Ar 6 Sccm∶N248 Sccm,Ar 8 Sccm∶N264 Sccm.实验结果表明:在本实验的温度范围内,Ti N薄膜的致密度、结合力以及表面硬度均随着沉积温度的提高而提高;Cr作为过渡层的效果优于Al和Ti,薄膜成分均匀、表面致密,硬度更高,且耐腐蚀性能优异;在Ar、N2流量比一定的情况下,气体流量对Ti N薄膜的表面形貌和力学性能影响不大.本实验的最佳参数是:沉积温度300℃,过渡层成分为Cr,气体流量为Ar 6 Sccm、N248 Sccm.     

基片与膜厚对硬质薄膜力学性能的影响

采用毫牛力学探针技术的两步压入试验法研究了高速钢和不锈钢基片上不同厚度TiN薄膜的硬度和弹性模量。结果表明 :采用同样工艺制备的TiN薄膜 ,其力学性能随基片类型和膜厚的不同有明显变化。薄膜的硬度和弹性模量随膜厚的增加而提高 ;基体硬度的提高也使薄膜呈现较高的硬度和模量。分析认为薄膜内应力状态的改变是产生这些现象的主要原因。     

Extracting thin film hardness of extremely compliant films on stiff substrates

A previously reported method for extracting the thin film hardness from nanoindentation into a film on an elastically mismatched substrate was applied to four different cases of extreme mismatch in elastic properties: Parmax, Ultem, Polysulfone and Perfluorocyclobutyl polymer thin films on Si substrates. All of these cases represent extremely compliant films on a stiff substrate, where the ratio of film shear modulus to substrate shear modulus ranged from 0.008 to 0.036. Analyzing the nanoindentation data into these film/substrate systems poses a significant limitation when using the Oliver and Pharr method as the hardness increases rapidly with indentation depth. Therefore, a method involving the measured contact stiffnesses to more accurately determine the correct contact areas was used to extract the true hardness of the polymer thin films. The results indicate that our method is able to remove the substrate effects as well as the complications arising from pile-up and surface roughness to yield a wide plateau in hardness despite the extreme elastic mismatch conditions.     

Microstructural characteristics and mechanical properties of magnetron sputtered nanocrystalline TiN films on glass substrate

Nanocrystalline TiN thin films were deposited on glass substrate by d.c. magnetron sputtering. The microstructural characteristics of the thin films were characterized by XRD, FE-SEM and AFM. XRD analysis of the thin films, with increasing thickness, showed the (200) preferred orientation up to 1·26 μm thickness and then it transformed into (220) and (200) peaks with further increase in thickness up to 2·83 μm. The variation in preferred orientation was due to the competition between surface energy and strain energy during film growth. The deposited films were found to be very dense nanocrystalline film with less porosity as evident from their FE-SEM and AFM images. The surface roughness of the TiN films has increased slightly with the film thickness as observed from its AFM images. The mechanical properties of TiN films such as hardness and modulus of elasticity (E) were investigated by nanoindentation technique. The hardness of TiN thin film was found to be thickness dependent. The highest hardness value (24 GPa) was observed for the TiN thin films with less positive micro strain.     

Interface stress induced hardness enhancement and superelasticity in polytetrafluoroethylene/metal multilayer thin films

Polytetrafluoroethylene (PTFE)/Al, PTFE/Cu, and PTFE/Ti multilayer thin films have been deposited in order to investigate effects of interface energy on mechanical properties. PTFE, which has a low surface energy of 19.2 mJ/m², was used to introduce a large interface energy into multilayer thin films. PTFE thin film was deposited by rf magnetron sputtering using a PTFE sheet target. Al, Cu, and Ti were deposited by dc magnetron sputtering. The multilayer thin films were fabricated sequentially without breaking vacuum. Substrate used was aluminosilicate glass. The modulation period was changed from 6.7 to 200 nm. The total thickness was about 200 nm for all samples. The internal stress of metal layers changed from tensile to compressive and increased with decreasing modulation period for all of PTFE/Al, PTFE/Cu, and PTFE/Ti. Both hardness enhancement and superelasticity were observed in the results of nanoindentation measurements. The energy dissipated during nanoindentation process (one load and unload cycle) decreased with decreasing modulation period. The minimum value of the ratio of dissipated/loaded energy was < 40%, which is smaller than the values obtained for monolithic PTFE or metal films (about 73% for PTFE and 87% for Al, 72% for Cu, and 71% for Ti, respectively). This meant that the PTFE/metal nano-multilayer thin films became more elastic with decreasing modulation period. The tendency of change in the mechanical properties strongly correlated to internal stress. Mechanisms involved in anomalous behaviors in film hardness and elasticity were discussed based on the relationship to interface energy, interface stress, and internal stress, induced by multilayering of the films. It is concluded that a large compressive stress introduced in the thin films increased the energy needed to deform elastically or plastically the thin film during indentation, resulting in the increase in hardness and elasticity. The nanoindentation analysis of the multilayer thin films emphasized that in PTFE/metal multilayer thin films mechanical properties of the films depend on interface stress induced by the accumulated interface energy, being independent of bulk materials properties composing thin films, resulting in increase in hardness and elasticity.     

金属间化合物Ni3Al薄膜的制备及性能研究

采用直流磁控共溅射法,在衬底温度为450℃的SiO2基体上制备了厚度为500nm的Ni3Al薄膜,X射线衍射(XRD)和透射电子显微镜(TEM)等测试表明,薄膜为(111)取向的L12型晶体结构金属间化合物。采用纳米压痕方法测试了薄膜的力学性能,其硬度为8.00GPa,弹性模量为200GPa。为克服亚微米级薄膜氧化增重难以测量的困难,采用四探针测试金属薄膜电阻的方法,间接给出了薄膜的腐蚀性能和高温氧化程度。结果表明Ni3Al金属间化合物薄膜的氧化速率为2.28×10-13g2/(cm4.s),薄膜具有良好的高温抗氧化性能。     

TiNi shape memory alloy coated with tungsten: a novel approach for biomedical applications

This study explores the use of DC magnetron sputtering tungsten thin films for surface modification of TiNi shape memory alloy (SMA) targeting for biomedical applications. SEM, AFM and automatic contact angle meter instrument were used to determine the surface characteristics of the tungsten thin films. The hardness of the TiNi SMA with and without tungsten thin films was measured by nanoindentation tests. It is demonstrated that the tungsten thin films deposited at different magnetron sputtering conditions are characterized by a columnar microstructure and exhibit different surface morphology and roughness. The hardness of the TiNi SMA was improved significantly by tungsten thin films. The ion release, hemolysis rate, cell adhesion and cell proliferation have been investigated by inductively coupled plasma atomic emission spectrometry, CCK-8 assay and alkaline phosphatase activity test. The experimental findings indicate that TiNi SMA coated with tungsten thin film shows a substantial reduction in the release of nickel. Therefore, it has a better in vitro biocompatibility, in particular, reduced hemolysis rate, enhanced cell adhesion and differentiation due to the hydrophilic properties of the tungsten films.     

Tribological properties of Cr-Si-N nanocomposite film adherent silicon under various environments

Chromium nitride thin films have good corrosion resistance and mechanical properties. However, their hardness is slightly lower than that of other hard coatings. The concept of nanocomposite thin films is employed by adding silicon to form Cr-Si-N thin films with enhanced hardness and wear resistance. In this study, Cr-Si-N films with various Si contents were coated on silicon wafer to enhance the tribological properties and anticorrosion by a bipolar symmetry pulsed DC reactive magnetron sputtering process. The tribological properties were studied by a pin-on-disk tester. The tests were conducted with the same operating condition under three different environments. They were performed in the ambient atmosphere (in 55% humid air), DI water, and 0.01 M NaCl aqueous solution, respectively. The wear tests revealed that, as the silicon content was increased, even though the Cr-Si-N films had a better anticorrosion property they had an inferior performance on wear resistance. The results were concluded to be mainly due to Cr-Si-N films’ microstructures and adhesion to the Si substrate rather than their hardness and toughness.     

射频功率对氧化铬薄膜的力学性能和耐磨损性能的影响

利用射频反应磁控溅射法在45钢基体上制备了氧化铬薄膜.采用XRD测试了薄膜的晶体结构,用Tribo-Indentor纳米力学测试系统得到了薄膜的硬度及微观形貌,在UMT显微力学测试仪上测试了薄膜的耐磨损性能,在此基础上讨论了铬靶溅射功率对薄膜的力学性能和耐磨损性能的影响.结果表明:在射频功率较低的情况下薄膜为Cr2O3结构.随着射频功率的提高,薄膜表面的大颗粒物质增多,硬度下降.射频功率增大时,磨损体积增加,薄膜的耐磨损性能下降.     

Si3N4和52100钢对磨副材料对CrN薄膜干摩擦学行为的影响

利用阴极电弧离子镀技术在316L不锈钢基体上制备了CrN薄膜。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、纳米压痕仪对CrN薄膜的形貌、成分和力学性能进行了表征。为了研究Si_3N_4和52100钢对磨副材料对CrN薄膜和316L不锈钢干摩擦行为的影响,在2N、5N、8N三种载荷下,将CrN薄膜和316L不锈钢基体与Si_3N_4陶瓷球和52100钢球分别进行了往复式滑动干摩擦实验。采用扫描电子显微镜观察了磨痕的微观形貌,并对CrN薄膜和316L不锈钢基体的磨损机制进行了分析。结果表明:CrN薄膜表面平整,缺陷较少;CrN薄膜的纳米硬度约为28GPa,弹性模量约为350GPa;与Si_3N_4陶瓷球相比,CrN薄膜与52100钢球摩擦时摩擦因数相对较小(保持在0.7左右)且更加稳定;316L不锈钢的摩擦因数远大于CrN薄膜且波动较大;对磨球为Si_3N_4陶瓷球时,CrN薄膜的主要磨损机制为磨粒磨损,伴有少量的氧化和黏着磨损,316L不锈钢的磨损机制主要为磨粒磨损和塑性变形,伴有少量的氧化和黏着磨损;对磨球为52100钢球时,CrN薄膜的主要磨损机制为黏着磨损,伴有少量的氧化,316L不锈钢的磨损机制主要为黏着磨损,伴有少量的氧化和磨粒磨损。CrN薄膜与两种对磨球的磨损量均小于316L不锈钢基体的磨损量,说明CrN薄膜有效提高了基体的耐磨性。     

Thin film metallic glasses: Unique properties and potential applications

A new group of thin film metallic glasses (TFMGs) have been reported to exhibit properties different from conventional crystalline metal films, though their bulk forms are already well-known for high strength and toughness, large elastic limits, and excellent corrosion and wear resistance because of their amorphous structure. In recent decades, bulk metallic glasses have gained a great deal of interest due to substantial improvements in specimen sizes. In contrast, much less attention has been devoted to TFMGs, despite the fact that they have many properties and characteristics, which are not readily achievable with other types of metallic or oxide films. Nevertheless, TFMGs have been progressively used for engineering applications and, thus, deserve to be recognized in the field of thin film coatings. This article will thus discuss both properties and applications of TFMGs including a review of solid-state amorphization upon annealing, the glass-forming ability improvement due to thin film deposition, and mechanical properties, including residual stress, hardness and microcompression, adhesion, and wear resistance. Potential applications and simulations will also be discussed.     

Mechanical properties and scratch resistance of filtered-arc-deposited titanium oxide thin films on glass

The mechanical properties and the scratch resistance of titanium oxide (TiO₂) thin films on a glass substrate have been investigated. Three films, with crystalline (rutile and anatase) and amorphous structures, were deposited by the filtered cathodic vacuum arc deposition technique on glass, and characterized by means of nanoindentation and scratch tests. The different damage modes (arc-like, longitudinal and channel cracks in the crystalline films; Hertzian cracks in the amorphous film) were assessed by means of optical and focused ion beam microscopy. In all cases, the deposition of the TiO₂ film improved the contact-mechanical properties of uncoated glass. Crystalline films were found to possess a better combination of mechanical properties (i.e. elastic modulus up to 221 GPa, hardness up to 21 GPa, and fracture strength up to 3.6 GPa) than the amorphous film. However, under cyclic sliding contact above the critical fracture load, the amorphous film was found to withstand a higher number of cycles. The results are expected to provide useful insight for the design of optical coatings with improved contact-damage resistance.     

AZ31镁合金基材非平衡磁控溅射镀膜工艺研究

采用中频孪生靶非平衡磁控溅射技术在AZ31镁合金基底上制备出氮化硅薄膜。利用傅里叶变换红外光谱仪、电子探针、X射线衍射仪等研究了氮气流量比率对氮化硅薄膜的成分、微观结构的影响。通过对薄膜力学性能和抗腐蚀性能的检测分析了氮化硅薄膜对AZ31镁合金基底表面改性的作用。结果表明:中频孪生非平衡磁控溅射技术制备的薄膜为非晶态富N氮化硅。随着氮气流量比率的增加,薄膜的沉积速率降低,Si含量减少。在AZ31镁合金基底上制备氮化硅薄膜有效提高了基底的力学性能和抗腐蚀性能,显微硬度得到显著提高,腐蚀电流密度降低了3个数量级,并且薄膜与基底之间的结合力良好。     

奥氏体不锈钢表面硬质薄膜的制备与性能研究

用磁控溅射法在奥氏体不锈钢基片上分别制备了TiN薄膜和Al2O3薄膜,并用XRD、SEM和显微硬度等测试手段对沉积态和退火态薄膜进行表征,分析了不同工艺参数对薄膜的沉积速率、结构和性能的影响,从而得到最佳工艺参数。TiN薄膜在沉积气压为1．5Pa,氩氮比为16：16时薄膜的硬度值最大为16．0GPa。Al2O3薄膜在沉积气压为0．5Pa,氩氧比为10：1时薄膜的硬度值可达25．2GPa。     

Analysis on microstructure and characteristics of TiAlN/CrN nano-multilayer films deposited by cathodic arc deposition

In this study, TiAlN/CrN multilayer thin films were deposited on SUS 403 stainless steel by cathodic arc deposition. The effects of substrate orientation (substrate surface parallel/perpendicular to target surface) and rotation speed were investigated in detail. Microstructure of the coatings was analyzed by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. Meanwhile, tribological and corrosion tests were performed. The experimental results showed that the as-deposited films exhibit a nano-scale multilayer structure consisting of TiAlN and CrN phases. The TiAlN/CrN multilayer films prepared by a parallel orientation and a rotation speed of 4 rpm not only possesses the best coating hardness and hardness/elastic modulus ratio, but also reveals superior abrasion resistance and corrosion resistance.     

C-Ti nanocomposite thin films: Structure, mechanical and electrical properties

Carbon-titanium nanocomposite thin films were deposited by DC magnetron sputtering on oxidized silicon substrates in argon. The films were prepared at different deposition temperatures between 25 and 800 °C. Transmission electron microscopy was used to determine the structure of the films. All the C-Ti nanocomposites consisted of columnar TiC structure with average column width ∼10 and 20 nm and a thin carbon matrix. The thickness of the carbon matrix between adjacent TiC columns was ∼2-5 nm.Mechanical properties (hardness, reduced modulus) of C-Ti films showed a distinct variation depending on the deposition temperature. Films deposited at 200 °C had the highest hardness ∼18 GPa and the highest reduced modulus ∼205 GPa.Temperature dependence of the film resistance was measured between 80 and 330 K. C-Ti nanocomposites have a non-metallic conduction mechanism characterized by a negative temperature coefficient of resistivity (TCR). The most negative TCR was observed for films showing high hardness and reduced modulus of elasticity.