N+离子注入聚四氟乙烯表面改性研究

在剂量为1×1014—1×1017ions／cm2的范围内，在不同的温度条件下，用 能量为160keV氮离子对PTFE表面进行注入处理，处理后的样品用可见(514．5nm)和傅里叶红 外(1064nm)拉曼(Raman)光谱以及扫描电镜和x射线能谱仪进行检测.实验结果表明低剂量注 入可以增强PTFE晶体结构的取向和有序性；中等剂量时溅射损失效应明显，表面粗糙度加大 ：高剂量注入时微观结构强烈地变化并生成CC双键，导致表面碳化.另外温度对表面改性效 果有很大的影响.刻蚀率和表面的微观结构的变化随着温度的升高而增强.离子注入前，用喷 射技术使样品覆盖一层150nm的金膜，薄膜的黏结性和硬度用划痕和透明胶带测试配合扫描 电镜进行分析.分析结果表明，黏结性在注入剂量为1014ions／cm2时明显增强，这 个结果与表面亲水性测量结果是一致的.但表面硬度只在温度为180℃时才得到了增强. 关键词： 离子注入 聚四氟乙烯 表面改性     

离子束注入对聚四氟乙烯表面改性研究

在剂量为1×1014～1×1017 ions/cm2的范围内,用能量为160 keV氮离子对PTFE表面进行注入处理,处理后的样品用可见(514.5nm)和傅立叶红外(1064 nm)喇曼(Raman)光谱以及扫描电镜进行检测.结果表明低剂量注入可导致弱C-C键的断裂,中等剂量时溅射损失效应明显,高剂量注入时微观结构强烈地变化并生成C=C双键.     

用于材料表面改性的多功能等离子体浸没离子注入装置

详细叙述了新近研制的多功能等离子体浸没离子注入（ＰⅢ）装置，在装置设计中，考虑了等离子体产生手段、高压脉冲电源和真空抽气系统多项功能要求，把离子注入、涂敷和溅射沉积结合起来，该已实现了多种气体等离子体注入、气－固离子混合与注入、金属等离子体沉积与注入、离子束混合与离子束增强沉积等，以满足不同材料制成的不同零件对多种表面处理工艺的需要，初步应用结果证明，该装置对于改进４５号钢、Ｔｉ－６Ａｌ０－４Ｖ和     

LZ-50离子注入装置及其在材料表面改性中的应用

本文叙述了LZ-50离子注入装置及其在材料表面改性中的应用。该装置离子能量80keV,氮离子束流强～10mA,注入面积～200cm~2,性能稳定,重复性好,可长期稳态运行。利用该装置对硬质合金、工具钢、钛合金、陶瓷及其它有色金属材料进行了氮离子注入实验,并取得了一些有应用价值的工艺结果,如离子注入使Co-WC机械夹固刀片的耐磨性能提高2—4倍。     

聚四氟乙烯材料表面激光改性与刻蚀

利用波长为248 nm的准分子激光束在不同激光能量密度下照射聚四氟乙烯(PTFE)材料的表面,并用扫描电镜(SEM)、X射线光电子能谱(XPS)、拉曼(Raman)光谱等手段对激光处理前后样品的表面形貌、化学成分和结构进行测量和分析,进而对激光与聚四氟乙烯相互作用的机理进行了研究。实验结果表明,激光辐照使聚四氟乙烯表面产生去氟效应,导致表面碳化、分子链的交联以及含氧基团的产生,随着激光能量密度的增加,C=C双键逐渐形成。这些结构的变化可以导致表面硬度和粘结性增强。激光能量密度的大小对照射后样品表面的物理性质和化学结构有着重要的影响,它是聚合物表面激光改性和烧蚀的关键因素。     

氮离子注入纯铁中表面改性的穆斯堡尔谱研究

采用等离子体源离子注入方法,将氮离子注入纯铁粉中,对样品进行穆斯堡尔谱研究.对注氮前后样品的无反冲因子f、同质异能移位δ、电四极裂距ΔEQ进行了比较分析.解释了氮离子注入钢材表面其硬度和耐磨性提高的原因. 关键词：     

低能强流离子注入丁腈橡胶的表面改性(英文)北大核心CSCD

丁腈橡胶是一种广泛使用的合成橡胶,目前应用于各种非轮胎制品。离子注入被认为是一种提高丁腈橡胶表面特性的有效手段,比如降低摩擦系数、提高耐抗性等。最近,为了理解辐照效应对于硫化橡胶的功能特性如摩擦系数和硬度等的影响,利用北京大学离子源测试平台将N^+和H^+注入丁腈橡胶表面进行研究。离子注入完成以后,对丁腈橡胶表面的摩擦系数、硬度、耐热老化性能、摩擦特性以及耐磨损性能进行了分析。     

氮离子注入对聚四氟乙烯表面电荷积聚和消散特性的影响北大核心CSCD

为了抑制聚四氟乙烯材料表面电荷积聚,采用射频产生氮等离子体对其表面进行等离子体浸没离子注入以改善其表面性能。对注入前后的聚四氟乙烯材料样品进行了X射线光电子能谱分析(XPS)、傅里叶红外光谱测试(FTIR)、水接触角测量、表面电阻率测量以及表面电位衰减测量,并基于等温表面电位衰减理论对其表面陷阱能级和密度分布进行了计算,以分析聚四氟乙烯样品经离子注入处理后其表面成分和物理性能的变化,并研究了这些变化对聚四氟乙烯样品表面电荷积聚和消散特性的影响。结果表明:氮离子注入后,聚四氟乙烯材料表面化学成分的主要变化是自身分子结构的破坏和转化,部分CF2结构转变为CF和CF3结构,导致样品表面陷阱能级变浅;水接触角升至140°左右,比未处理样品上升了约27°,表面电阻率降至3×10^15Ω,比未处理样品下降了两个数量级;表面电晕放电1 min后,经氮离子注入处理的聚四氟乙烯材料表面积聚电荷量减少,消散速度加快,这是因为表面陷阱能级变浅有利于表面电荷脱陷,同时表面电阻率降低也促进了表面电荷沿面传导的消散过程,聚四氟乙烯样品表面陷阱能级分布曲线也证实了这一论点。     

Reflectivity modification of polymethylmethacrylate by silicon ion implantation

The effect of silicon ion implantation on the optical reflection of bulk polymethylmethacrylate (PMMA) was examined in the visible and near UV. A low-energy (30 and 50 keV) Si⁺ beam at fluences in the range from 10¹³ to 10¹⁷ cm⁻² was used for ion implantation of PMMA. The results show that a significant enhancement of the reflectivity from Si⁺-implanted PMMA occurs at appropriate implantation energy and fluence. The structural modifications of PMMA by the silicon ion implantation were characterized by means of photoluminescence and Raman spectroscopy. Formation of hydrogenated amorphous carbon (HAC) layer beneath the surface of the samples was established and the corresponding HAC domain size was estimated.     

Influence of N+ ion implantation at different temperatures on nanostructural modifications and characteristics of Al alloy surface

Thick (3.0 mm) Al samples (7049 an alloy with 15 elements) were implanted by N⁺ ions of 30 keV energy and fluence of 5 × 10 ¹⁷ N⁺ cm^?2 at different temperatures. The surface modification of the samples was studied using X-ray diffraction (XRD) and atomic force microscope (AFM) analysis. XRD spectra of the samples clearly showed the formation of different phases of AlN. Crystallite sizes (coherently diffracting domains) obtained from AlN diffraction lines showed that at a certain substrate temperature the crystallite size decreases considerably. AFM images showed the formation of grains on Al samples, and it was observed that both grain size and sample surface roughness first decrease and then increase with temperature (i.e. a minimum at a certain temperature is observed). In addition at this temperature, a minimum of intensity is also observed for the intensity of different phases of AlN and the intensity ratio of AlN (200)/AlN (311). This phenomenon is similar to those obtained for thin films and pure metal foils though the sample studied in this work is an Al alloy and the minimum for Al occurred at a value three times larger than that reported for the above cases. Alloy nature of this sample with 14 elements is responsible for the observed results because they may act as defects. Results may also be affected by the residual gases, substrate temperature, dissociation of water in the chamber and the ion energy. Results also showed that the processes of Al nitride and Al oxide formations are competing with each other; decrease of aluminium nitride phases are associated with increase of aluminium oxide phases.     

Conductivity modification of ZnO film by low energy Fe ion implantation

In this paper we report the structural, optical and electrical behaviours of ZnO films implanted with 300 keV Fe¹⁰⁺ ions. From UV-vis spectroscopy it is observed that the band gap of the films decreases after implantation. Photoluminescence yield seems to increase in the implanted samples. From Hall measurements it is observed that the unimplanted sample shows n-type conductivity for the entire temperature range (100-300 K), whereas after implantation the samples show p-type conductivity for ≤200 K. The DC resistivity of the implanted samples is found to be lower than that of the unimplanted sample. We have found that the magnetoresistance of our samples is positive in the temperature range 200-300 K, but it becomes negative below 200 K.     

Surface modification of hard alloy by Y ion implantation under different atmosphere

To enhance the properties of hard alloy, rare-earth metal yttrium (Y) was implanted into its surface by using Metal Vapor Vacuum Arc (MEVVA) source implantor. The experiments were finished under different vacuum conditions with/without aerating nitrogen in the chamber. The metallograph and phase formation of sample were characterized and analyzed with metallurgical microscope and X-ray diffraction. The results show that there exist new phases of C, YC₂, Y₂O₃, and WN in the sample surface. Moreover, it can be found that the performances of sample surface (such as microhardness, friction coefficient and corrosion resistance) are evidently improved, and that nitrogen atmosphere plays a very important role in farther promoting these performances. The surface modification of hard alloy is not only affected by the implantation itself, but also related to the microstructure transformation, which can be partly induced by the atmosphere.     

A comparative study of the structure and cytotoxicity of polytetrafluoroethylene after ion etching and ion implantation

The ion-plasma treatment has been widely used for modifying the surface structure of polymers in order to improve their properties, but it can lead to destruction of the surface and, as a consequence, to an increase in their toxicity. A comparative study of the structure and cytotoxicity of polytetrafluoroethylene (PTFE) after the ion etching (IE) and ion implantation (II) for 10 min with energy densities of 363 and 226 J/cm², respectively, has been performed. It has been shown that, unlike the ion implantation, the ion etching results in the destruction of the polymer and in the appearance of the cytotoxicity. The factors responsible for this effect, which are associated with the bulk and surface treatment, as well as with the influence of the temperature, have been discussed.     

Surface modification of poly(propylene carbonate) by oxygen ion implantation

Poly(propylene carbonate) (PPC) was implanted by oxygen ion with energy of 40 keV. The influence of experimental parameters was investigated by varying ion fluence from 1 × 10¹² to 1 × 10¹⁵ ions/cm². XPS, SEM, surface roughness, wettability, hardness, and modulus were employed to investigate structure and properties of the as-implanted PPC samples. Eight chemical groups, i.e., carbon, CH, COC, CO, OCO, CO, , and groups were observed on surfaces of the as-implanted samples. The species and relative intensities of the chemical groups changed with increasing ion fluence. SEM images displayed that irradiation damage was related strongly with ion fluence. Both surface-recovering and shrunken behavior were observed on surface of the PPC sample implanted with fluence of 1 × 10¹⁵ ions/cm². As increasing ion fluence, the surface roughness of the as-implanted PPC samples increased firstly, reached the maximum value of 159 nm, and finally decreased down the minimum value. The water droplet contact angle of the as-implanted PPC samples changed gradually with fluence, and reached the minimum value of 70° with fluence of 1 × 10¹⁵ ions/cm². The hardness and modulus of the as-implanted PPC samples increased with increasing ion fluence, and reached their corresponding maximum values with fluence of 1 × 10¹⁵ ions/cm². The experimental results revealed that oxygen ion fluence closely affected surface chemical group, morphology, surface roughness, wettability, and mechanical properties of the as-implanted PPC samples.     

Properties of TiN coating on 45# steel for inner surface modification by grid-enhanced plasma source ion implantation method

Using a new inner surface modification method named GEPSII (grid-enhanced plasma source ion implantation), which is designed for inner surface modification of tubular work pieces, we successfully produced polycrystalline TiN coating on 0.45% C steel (45^# steel) samples. Compared with the uncoated 45^# steel sample, the electrochemical corrosion test on the coated 45^# steel samples presents evident improvement in their corrosion resistance. Two implanted voltages, direct current (－2kV) and pulsed negative voltage (－10kV), are applied on the substrates. It is shown that the direct current implantation is more effective than the pulsed implantation in the surface corrosion resistance. AES depth profile shows that coating thickness is about tens of nanometres. The preferred orientations expressed by peaks at (111) and (200) can be seen clearly in XRD patterns.