高功率脉冲磁控溅射管内壁沉积Cr薄膜结构及性能

由于管腔空间限制,物理气相沉积领域中管内壁沉积薄膜的均匀性和质量有待研究和改善。采用高功率脉冲磁控溅射技术(HiPIMS)在直径 40 mm、长度 120 mm 的 20 #碳钢管内表面进行 Cr 薄膜沉积,并探究管内不同位置沉积 Cr 薄膜的结构和力学性能。采用 SEM 分析薄膜的截面形貌和厚度变化,采用 AFM 分析薄膜的表面形貌和表面粗糙度变化,采用 XRD 分析薄膜的晶相结构和晶粒尺寸,采用球-盘式旋转摩擦磨损试验机对薄膜的耐摩擦磨损性能进行测试。结果表明,随着管内深度的增加,距管口距离为 15 mm(位置 1)、45 mm(位置 2)、75 mm(位置 3)和 105 mm(位置 4)位置的膜层厚度分别为 1 690 nm、827 nm、210 nm 和 0 nm。从位置 1 到位置 3,所沉积的 Cr 薄膜表面粗糙度由 12.6 nm 下降到 4.8 nm,晶粒尺寸由 15 nm 增加到 38 nm,摩擦因数由 0.68 上升到 0.89。     

PEO protective coatings on inner surface of tubes

Plasma electrolytic oxidation (PEO), also called micro-arc oxidation (MAO) or anode spark deposition (ASD), is a novel technique to produce hard ceramic coatings on metals, such as aluminum, titanium, magnesium (called valve metals) and their alloys. Up to now, many researchers focused on the PEO process for workpieces of regular shapes such as cube, cake or stick samples, etc. But no one paid attention to the irregular samples such as tubular materials. This research emphasized the PEO process of long tubes, especially the way to obtain uniform thickness of ceramic coatings on inner surface of tubes. Furthermore, the PEO kinetic behaviors of aluminum tubes were also investigated. The potential difference between the electrodes indicated a linear relationship with the coating thickness. A central accessory electrode was axially used to eliminate the shielding effect of electric field and was effective to obtain axially uniform coating on the inner surface of the tubes. The combination of hot-dipping aluminum and PEO process to obtain ceramic coating on 45# steel tubes was also performed in this work.     

Coating the inner walls of metal tubes with carbon films by physical vapor deposition at low temperature

Tubes are often required to exhibit better performance in corrosion and wear behavior than the material the tube is made of can offer. The situation can be improved when the tube is coated with a protective film. This can be achieved by sputter coating with an ion beam. A sputter target is located inside the tube. Energetic ions are accelerated into the tube and impinge onto the target. Thus, material is sputtered from the target onto the inner walls of the tube. Two apparatus for coating tubes of different lengths and diameters are described. Aluminum and stainless steel tubes were coated with amorphous carbon films. Results on adhesion, corrosion performance in aqueous media and thickness uniformity are shown.     

Synchronous plasma enhancement in RF-driven plasma source for ion implantation

We report an original method to increase periodically the plasma density in RF-driven plasma source for surface treatment of materials by ion implantation. The method consists of supplementary injection of ions, electrons and metastable atoms into the processing RF plasma using very short high voltage pulsed discharges applied on a separate electrode at the same repetition rate as the negative accelerating pulses applied on the target. Thus plasma density is periodically increased by an order of magnitude so that the synchronized negative pulses applied on the target for ion implantation find a background plasma about 10 times denser. The advantages of this new method were revealed by nitrogen implanted tests on copper and brass samples.     

Shunting arc-produced hybrid plasma and its magnetic drive for PBII&D

Hybrid plasmas produced by shunting arc discharge are described in this article. The shunting arc was generated in various ambient atmospheres. When a carbon-shunting arc was generated in a nitrogen atmosphere, the carbon ion species were produced at the arc stage, the electrons of which accelerated toward the wall, colliding with the gas species in the chamber to produce nitrogen ions. When the arc was generated in a methane atmosphere, the hydrogen content in the deposited carbon film changed with the gas pressure. When the arc was generated in gaseous RF plasma, an enhancement in the plasma density was confirmed with ion current measurement. Another method of the shunting arc application is the usage of the Lorentz force, which accelerates the entire plasma body toward the target. This results in a fast deposition of the plasma species such as carbon.     

电场增强的阴极弧放电TiCN薄膜结构及性能研究

采用一种新型的电场增强阴极弧沉积技术在304不锈钢表面制备了TiCN涂层。研究了附加电极电流对阴极弧放电特性、涂层相结构、截面形貌、耐磨性以及结合力的影响。结果表明:附加电极的引入显著增加真空室内等离子体密度,工件偏流提高近100%;只有超过一定阈值,附加电极电流才能有效减小晶粒尺寸、提高膜层致密性,同时也提高膜基结合力。附加电极电流为30 A时,膜基结合力达到HF1,相对于无附加电极情况样品表面摩擦系数降低了33%,磨痕宽度最小,耐磨性最好。可见电场增强阴极弧放电是一种非常有效的TiCN制备方法。     

不同靶基距下凹槽表面HIPIMS法制备钒膜的微观结构及膜厚均匀性

目的研究不同靶基距对高功率脉冲磁控溅射(HIPIMS)在凹槽表面制备钒膜微观结构和膜厚均匀性的影响,实现凹槽表面高膜层致密性和均匀性的钒膜制备。方法采用HIPIMS方法制备钒膜,在其他工艺参数不变的前提下,探讨不同靶基距对凹槽表面钒膜相结构、表面形貌及表面粗糙度、膜层厚度均匀性的影响。采用XRD、AFM及SEM等观测钒膜的表面形貌及生长特征。结果随着靶基距的增加,V(111)晶面衍射峰强度逐渐降低。当靶基距为12 cm时,钒膜膜层表面粗糙度最小,为0.434nm。相比直流磁控溅射(DCMS),采用HIPIMS制备的钒膜呈现出致密的膜层结构且柱状晶晶界不清晰。采用HIPIMS和DCMS方法制备钒膜时的沉积速率均随靶基距的增加而减少。当靶基距为8 cm时,采用HIPIMS方法在凹槽表面制备的钒膜均匀性最佳。结论采用HIPIMS方法凹槽表面钒膜生长的择优取向、表面形貌、沉积速率及膜厚均匀性均有影响。在相同的靶基距下,采用HIPIMS获得的钒膜膜厚均匀性优于DCMS方法。     

Study of adhesion of TiN grown on a polymer substrate

TiN films were deposited on polycarbonate substrates by cathodic vacuum arc using the plasma immersion ion implantation and deposition (PIII&D) method. The biaxial intrinsic stress in the film deposited using PIII&D with 3 kV applied bias was 0.3 GPa — much lower than that found in films deposited without the application of high-voltage pulsed bias. It was found that the dominant mechanism for generating stress in the TiN film was thermal stress arising from the large difference between the thermal expansion coefficient of TiN and that of the polymer. Tensile testing was used to ascertain film adhesion and a model was used to estimate the adhesion between the film and the substrate. It was found that PIII&D strongly reduced the stress in the TiN film and increased the adhesion to the polycarbonate. The ultimate shear strength of adhesion is of the same order of magnitude as that of TiN on stainless steel.     

Fast chemical vapor deposition of microcrystalline silicon by applying magnetic field to hollow electrode enhanced radio frequency glow plasma

Fast chemical vapor deposition of microcrystalline silicon by applying magnetic field to hollow electrode enhanced radio frequency (rf) glow plasma has been investigated. We have already developed a plasma generation technique called hollow electrode enhanced rf glow plasma transportation (HEEPT). In this study, we equipped a HEEPT system with a hollow cylinder shaped permanent magnet around an orifice prepared at the center of the counter electrode. The plasma was characterized by plasma emission spectroscopy. Silicon thin films were deposited on a glass substrate. It was found that increasing the magnetic flux density resulted in increasing plasma emission intensity, film deposition rate, and crystallinity. The maximum deposition rate of 6.9 nm/s was achieved with high crystallinity and photo-sensitivity at a plasma excitation frequency of 13.56 MHz, a substrate temperature of 300 °C and a magnetic flux density of 75 mT. Our results indicate that the magnetic field is effective in promoting fast chemical vapor deposition of microcrystalline silicon thin films with photo-sensitivity using the HEEPT technique. We consider that the effectiveness is due to a decrease of electron temperature caused by drift motion of electrons in the magnetic field inside the orifice.     

阴极弧径向不同位置膜层性能分布规律

利用阴极弧沉积的方法在201不锈钢基体上制备了TiN薄膜,研究了阴极弧径向不同位置大颗粒、膜厚以及膜层性能的分布规律.分别采用X射线衍射(XRD)和扫描电子显微镜(SEM)分析了膜层的相结构、膜层的表面形貌和截面形貌.研究了镀膜试样和基体在3.5%(质量分数)NaCl溶液中的腐蚀行为,并利用电化学方法分析其抗腐蚀性能,并采用球-盘式摩擦磨损、划痕测试以及微小压痕等方法测试了径向不同位置沉积的TiN薄膜摩擦磨损性能、膜基结合力以及硬度.结果表明,靠近靶材中心的位置,膜层的硬度、厚度最大,电化学腐蚀电位最高,在径向夹角20°处的膜层厚度、硬度最小.在靠近出气位置侧沉积的TiN薄膜大颗粒数目较多,造成表面缺陷增加,TiN薄膜的抗腐蚀性能下降.靠近弧源中心位置沉积的膜层摩擦磨损系数较大,两侧处的膜层摩擦系数较小,膜基结合力与表面形貌和膜层厚度有很大关系.     

Lubrication of tube in cold pilgering

A new method of evaluating the lubrication state of a tube in cold pilgering has been studied. A method of calculating the oil film thickness in a bite area on both the outer and inner sides of a tube using the Reynolds equation was proposed. The calculation results revealed that the effects of the tool design, rolling speed, and feed rate on the oil film thickness were significant. Cold pilgering tests were performed on zirconium alloy tubes, including measurement of the oil film thickness using laser equipment and observation of the surface characteristics of tubes. The test results proved the validity of the proposed method. The method is expected to assist the selection of appropriate operation conditions in cold pilgering.     

X-ray reflectivity studies on DLC films deposited by microwave ECR CVD: Effect of substrate bias

Diamond like carbon (DLC) films were deposited at room temperature on Si (111) substrates by microwave electron cyclotron resonance (ECR) plasma chemical vapor deposition (CVD) process using plasma of methane diluted with argon gas. During deposition, dc self bias (− 25 V to − 200 V) on substrate was varied by application of RF power to the substrate. The influence of substrate bias on density of the deposited films was studied by X-ray reflectivity (XRR). The results from these measurements are further correlated with the results from UV and visible Raman spectroscopy. DLC film is modeled as a structure having three different layers such as low density surface, bulk and interface with the substrate. This three-layer model is used to fit the measured XRR data to evaluate the surface, interface and interlayer roughness, thickness and density of these films. The surface roughness obtained from XRR is correlated with the results from Atomic Force Microscopy (AFM) measurements. The observed results are explained based on the subplantation model for DLC film growth.     

Effect of negative pulsed high-voltage-bias on diamond-like carbon thin film preparation using capacitively coupled radio-frequency plasma chemical vapor deposition

Mechanical properties of diamond-like carbon films by an effective addition of negative pulsed high-voltage-bias have been investigated in capacitively coupled CH₄/Ar radio-frequency plasma. The results revealed that hardness and elastic modulus of the deposited film, estimated from nano-indentation load-displacement curve for about 1 μm-thick films, increase with the increase of the absolute value of high-voltage V_NPHV for V_NPHV < 5 kV and then saturate. Elastic recovery R got the highest value (> 90%) at V_NPHV = 5 kV.     

一种提高MPCVD法制备金刚石膜均匀性的方法

采用自制的1 kW石英钟罩式微波等离子体化学气相沉积装置,以氢气和甲烷作为气源在镜面抛光的(100)面单晶硅片上沉积了金刚石薄膜。实验共制得两个样品,其中一个样品在制备的过程中加装了难熔的金属钽环,利用等离子体易吸附于金属钽环表面的特性,缩小了硅片中间与边缘等离子体密度差异,另外一个样品没有加装难熔的金属钽环。利用激光拉曼光谱仪和扫描电子显微镜(SEM)对制备的样品进行了表征,发现没有加装金属钽环的样品中间位置沉积的金刚石膜质量明显高于边缘位置沉积的金刚石膜,中间位置、离中间5 mm位置、边缘位置沉积膜层的厚度差别很大;加装了金属钽环的样品中间位置与边缘位置沉积的金刚石膜质量差不多,中间位置、离中间5 mm位置、边缘位置沉积膜层的厚度差别不大,上述结果证明金属钽环的加入是一种提高MPCVD法制备金刚石膜均匀性的方法。     

Study?on?Vanadium?Films?Deposited?on?Concave?Object?by?Conventional?Direct?Current?and?High?Power?Pulsed?Magnetron?Sputtering

高功率脉冲磁控溅射是一种制备高质量薄膜的新兴方法。在相同的平均功率下分别采用HPPMS技术和传统DCMS技术在凹槽工件表面制备了钒薄膜。对比研究了两种方法下的等离子体组成、薄膜的晶体结构、表面形貌及膜层厚度的异同。结果表明：HPPMS产生的等离子体包括Ar(1+),V(0)和相当数量的V(1+);而DCMS放电时的等离子体包括Ar(1+),V(0)和极少量的V(1+)。两种方法制备的凹槽不同位置处钒薄膜相结构的变化规律大致相似。HPPMS制备的钒薄膜表面致密、平整;而DCMS制备的膜层表面出现非常锐利的尖峰且高度很高,凹槽不同位置表面状态表现出较大差异。DCMS制备的钒薄膜截面表现为疏松的柱状晶结构;而HPPMS制备的膜层也具有轻微的柱状晶结构,但结构更为致密。HPPMS时的膜层厚度小于DCMS时的膜层厚度。与凹槽工件的上表面相比,DCMS时侧壁膜层的厚度为上表面的32%,底部膜层的厚度为上表面的55%。而HPPMS时侧壁的厚度为上表面的35%,底部膜层的厚度为上表面的69%。采用HPPMS方法在凹槽工件表面获得的膜层厚度整体上表现出更好的均匀性     

Evolution of the Corrosion Product Film and Its Effect on the Erosion–Corrosion Behavior of Two Commercial 90Cu–10Ni Tubes in Seawater

The composition and structural evolution of the corrosion product film of two commercial 90Cu–10Ni tubes, namely Tube A and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and its effect on the erosion–corrosion behavior of the tubes was determined through a rotating cylinder electrode system using various electrochemical techniques. For the freshly polished samples used as contrast samples, the flow velocity mainly enhanced the cathodic reaction at low flow velocities while both the anodic and the cathodic reactions were remarkably accelerated at higher flow velocities. The corrosion product films formed on the two commercial 90Cu–10Ni tubes after being immersed in seawater for up to 6 months are of a complex three-layer or multilayer structure. The structural evolution of the films is out of sync for the two tubes. A continuous residual substrate layer depleted of Ni was observed in the inner layer of the films on Tube B after 30, 90, and 180 days' immersion, while it was observed in the film on Tube A only after 180 days' immersion. The nature of the inner layer plays a crucial role in the erosion–corrosion resistance of the 90Cu–10Ni tubes at higher flow velocity. The film with a compact and continuous inner layer of Cu_2O doped with Ni~(2+)and Ni~(3+)which bonds firmly with the substrate could survive and even get repaired with the increased flow velocity. The film on Tube B possessing a hollow and discontinuous inner layer composed of the residual substrate was degraded rapidly with increasing rotation speed in spite of its quite good resistance at the stagnant or lower speed conditions.     

内压对薄壁管充液压弯时的影响

失稳起皱和截面畸变是薄壁管弯曲成形过程中的主要缺陷,通过数值模拟和实验的方法,研究了液压支承下管材的弯曲变形行为,进行了从无内压到内压为18MPa的管材充液弯曲成形,分析了充液弯曲成形过程中的内压值对成形的影响,给出了成形后的不圆度和典型点壁厚减薄率的变化规律,结果显示,随着充液压力的增加,管材的截面不圆度逐渐减小,管材内侧壁厚增厚趋势减小,外侧壁厚减薄趋势增大。并根据模拟结果给出了成形后的典型点的应力状态。     

Influence of bias on properties of carbon films deposited by MCECR plasma sputtering method

The mirror-confinement-type electron cyclotron resonance(MCECR) plasma source has high plasma density and high electron temperature. It is quite useful in many plasma processing, and has been used for etching and thin-film deposition. The carbon films with 40 nm thickness were deposited by MCECR plasma sputtering method on Si, and the influence of substrate bias on the properties of carbon films was studied. The bonding structure of the film was analyzed by the X-ray photoelectron spectroscopy(XPS), the tribological properties were measured by the pin-on-disk(POD) tribometer, the nanohardness of the films was measured by the nanoindenter, and the deposition speed and the refractive index were measured by the ellipse meter. The better substrate bias was obtained, and the better properties of carbon films were obtained.     

Plasma immersion ion implantation into cylindrical bore using internal inductively-coupled radio-frequency discharge

Plasma immersion ion implantation (PIII) is a potentially excellent interior surface treatment technique due to no line-of-sight restriction. However, some problems have been encountered due to the low ion energy and ion fluence non-uniformity especially for treatment of the interior wall of a thin tube. In this paper, a new method for inner surface PIII using internal inductively-coupled radio-frequency (RF) discharge is described. A cylindrical inductive coil inserted inside the tube serves as both the plasma source and grounded electrode to avoid overlapping of the plasma sheath fronts propagating from opposite sides. The effects of the gas species, gas pressure, RF power, and number of coil turns are investigated. Our results demonstrate the feasibility of this novel inner surface treatment method and the number of turns in the coil has a critical influence on the discharge behavior. If the number of turns is little, the plasma density is low and non-uniform inside the tube due to the relatively intense capacitively-coupled RF discharge at the two ends. In contrast, the plasma density and uniformity are evidently improved by using more turns in the coil.