聚苯硫醚复合涂层性能的研究

聚苯硫醚复合涂料是一种新型的特种涂料。本文研究了材料的表面处理方法、交联工艺及各种填料种类和用量对涂层性能的影响。试验结果表明：采用化学方法处理基材表面,不同的程度下多层涂覆烧结成膜可获得性能优异的涂层。     

铝合金化学镀镍

探讨了铝合金化学镀镍的镀前处理液、预镀液组成以及工艺条件对处理效果的影响。结果表明，所研究的溶液组成，在适当工艺条件下，可在铝合金表面获得质量良好的预镀镍层，化学镀镍后，镀层具有优异的结合力。本工艺操作简单，适用于多种铝合金。     

等离子体辉光溅射反应复合渗镀合成TiN的研究

本文介绍了一种新的制备TiN的工艺方法.利用辉光放电溅射现象、尖端放电和空心阴极效应,在钢铁材料表面直接复合形成TiN渗镀扩散层.用X射线衍射、辉光放电剥层成分分析仪、显微硬度仪等方法,对复合层进行分析.结果表明:本研究方法复合形成的TiN渗镀层,TiN呈溶质固溶于基体表面层中,呈梯度沿基体向内分布.该表面复合层与一般表面沉积的TiN层不同,是冶金结合扩散层,不会产生剥落现象.在1020 ℃复合形成渗镀层时,层深可达15 μm左右,并得到择优取向为(200)晶面的TiN相,渗镀TiN层的表面硬度随渗镀温度的提高而增加,渗镀TiN层随渗镀温度的升高而增厚.     

纯铜双层辉光离子渗镍研究

介绍了采用双层辉光离子渗金属技术在纯铜表面制备Cu-Ni合金层的新方法,讨论了Cu-Ni合金层的组织、成分和性能特点,分析了辉光放电条件、源极溅射率及表面金属势对Cu-Ni合金层形成过程的影响.试验结果表明渗层厚度及渗层质量与辉光放电条件有关,在保证渗金属温度的前提下,应尽可能提高源极电压,降低试件电压.此外,该工艺还具有渗速快、效率高、无污染等优点.     

低温等离子体技术在粉体表面处理中的应用

低温等离子体技术用于粉体表面处理具有工艺简单、无需溶剂、节能高效等特点.等离子体处理粉体表面利用的放电形式从真空放电到空气压力下的气体放电;范围从无机粉体的表面处理到纳米粉体、有机粉体的表面处理都有涉及.评述了国内外利用等离子体对无机粉体、有机粉体低温等离子体表面处理技术的进展.     

高功率脉冲磁控溅射技术的发展与研究

高功率脉冲磁控溅射技术(HPPMS)作为一种溅射粒子离化率高、可以沉积致密、高性能薄膜的新技术已经在国外广泛研究,但在国内尚未见研究报道.本文介绍了近十年来HPPMS技术在电源、脉冲形式、放电行为和薄膜沉积等方面的研究进展.在HPPMS过程中,粒子随脉冲开关通过电子冲击和电荷交换电离,并按照双极扩散理论向基体附近传输,离子能量分布随工作气压的不同而呈现不同的分布特征.这些放电特征有利于获得更宽的工艺范围和优异的膜层性能,最后介绍了我们实验室在HPPMS方面的研究工作.     

阳极层离子源的发展及应用

阳极层离子源结构简单,束流密度大,离子能量可控,在大面积表面改性处理方面具有独特的优势,还可应用于离子束辅助沉积、基片刻蚀和表面清洗等领域。本文回顾了阳极层离子源的起源和发展历程,介绍了阳极层离子源的工作原理和研究现状,讨论了阳极层离子源的电磁场的设计、电磁场模拟和气体放电模拟等关键设计方法,概述了阳极层离子源的应用现状,并对阳极层离子源的发展和应用前景进行了展望。     

增强硫化橡胶与金属粘接的表面处理技术

表面处理是提高橡胶与金属材料粘接性能的重要工艺之一。介绍了目前用于硫化橡胶和金属表面处理的技术,如橡胶表面采用的硫酸法、氯化法、等离子体法、电晕放电法、UV及臭氧法等,金属表面采用的机械法、化学法、阳极氧化法等,提出了硫化橡胶与金属粘接表面处理技术的发展方向。     

深冷处理对碳钢表面Mo-Cr合金层摩擦性能的影响

介绍了一种在Q235钢表面进行等离子合金化及热处理工艺,获得表面高性能强化层的技术方法.通过该技术方法的处理,使Q235钢表面含有Mo,Cr,C合金元素,成分达到或接近冶金高速钢.该工艺技术的基本原理是在真空容器中,利用辉光放电的溅射现象,首先在Q235钢表面渗入合金元素Mo,Cr,表面含量分别达到12%(质量分数,下同)和4%左右,随后进行超饱和渗碳,使表面含碳量达到2.0%以上,合金化层成分接近钼系高速钢.合金层中的碳化物细小、均匀、弥散,无粗大的共晶莱氏体组织.Q235钢表面合金化后分别采用淬火 低温回火,淬火 2h深冷处理 低温回火两种工艺.结果发现,经深冷处理的试样表面硬度达到1600HV,明显高于未经过深冷处理试样的表面硬度.摩擦磨损实验表明,经深冷处理试样的滑动摩擦系数较未经深冷处理试样的要小,经深冷处理试样的耐磨性是未经深冷处理的1.6倍.     

用氧化还原反应气体清洗不锈钢超高真空系统

对粒子加速器和储存环的超高真空系统，消除其表面污染的标准方法是化学清洗、真空炉焙烧、辉光放电清洗及原位烘烤真空系统，本文介绍一种可替代辉光放电的清洗方法；用一氧化氮反应气体进行清洗，它已被用于处理几种不锈钢制作的加速器真空室，用ＮＯ气体处理的效果与其它方法相比，优于普通化学清洗和真空炉焙烧，完全可以和辉光放电清洗相比较，却避免了溅射情况下可能引起的表面损伤。     

等离子体在陶瓷材料生产加工中的应用

本文就热等离子体涂覆、低温等离子体表面改性、等离子体用于超细粉的合成、等离子体烧结陶瓷材料及ICP MS分析陶瓷组成等五个方面详细介绍了等离子体在陶瓷材料发展中的应用背景、技术条件及发展方向。     

Plasma modification of viscose textile

A study on plasma treatment of a textile is presented. Samples of pure viscose textile were exposed to RF oxygen, nitrogen or hydrogen plasma for 5 s. The gas pressure was 75 Pa and the RF power was 250 W. In all cases plasma treatment induced chemical changes in the samples' surface, which were determined by using high-resolution XPS (X-ray photoelectron spectrometer). Treatments in oxygen and nitrogen plasma increased the concentration of existing as well as formation of oxygen functional groups, while hydrogen plasma caused a substantial decrease of these groups. SEM (Scanning electron microscopy) analysis of the surface of the textile fibres was performed as well. The results showed that the fibres' surface treated in nitrogen plasma was similar to the untreated surface, while after treatment in hydrogen or oxygen plasma, the surface became rougher.     

Contact angle analysis of low-temperature cyclonic atmospheric pressure plasma modified polyethylene terephthalate

Polyethylene terephthalate (PET) films are modified by cyclonic atmospheric pressure plasma. The experimentally measured gas phase temperature was around 30 °C to 90 °C, indicating that this cyclonic atmospheric pressure plasma can treat polymers without unfavorable thermal effects. The surface properties of cyclonic atmospheric pressure plasma-treated PET films were examined by the static contact angle measurements. The influences of plasma conditions such as treatment time, plasma power, nozzle distance, and gas flow rate on the PET surface properties were studied. It was found that such cyclonic atmospheric pressure plasma is very effective in PET surface modification, the reduced water contact angle was observed from 74° to less than 37° with only 10 s plasma treatment. The chemical composition of the PET films was analyzed by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was used to study the changes in PET surface feature of the polymer surfaces due to plasma treatment. The photoemission plasma species in the continuous cyclone atmospheric pressure plasma was identified by optical emission spectroscopy (OES). From OES analysis, the plasma modification efficiency can be attributed to the interaction of oxygen-based plasma species in the plasma with PET surface. In this study, it shows a novel way for large scale polymeric surface modification by continuous cyclone atmospheric pressure plasma processing.     

XPS分析微波等离子体处理的PTFE/陶瓷复合介质材料表面成分

采用不同气氛等离子体处理ＰＴＦＥ／陶瓷复合介质材料,利用ＸＰＳ分析了处理样品表面成分的变化,发现等离子体处理导致表面Ｆ的含量降低和Ｏ的含量增加。高分子表面出现了不同成分的含氧基因,且随着时间的增加,微波功率的增大,一ＣＦ２基团减少,含氧基团增加,这表明不同气氛等离子体与 ＰＴ－ＦＥＣ表面的作用是刻蚀、脱氟、交联和氧化同时并存,其中以氧等离子体刻蚀最为严重。     

Preparation of indium oxide powders by microwave plasma dehydration of indium hydroxide powders

Indium oxide was prepared from the dehydration of indium hydroxide using atmospheric-pressure microwave air plasma. Compared with the conventional thermal plasma processing that was performed with the vapor phase reaction, the solid-state reaction was attempted in this study because microwave plasma has an intermediate temperature that is comparable to the melting temperature of inorganic materials and between those of the electric furnace and the thermal plasma. The results were compared with those with the electric furnace and the thermal plasma. With both the microwave plasma and the electric furnace, the macro-morphologies of the raw material were maintained, which indicates successful dehydration. However, the micro-morphologies differed. The product of the microwave plasma had a smooth surface, whereas the product of the electric furnace had a cracked and rough surface. The cracks were regarded as the results of the poor diffusion of the dissociated water. In the microwave plasma, the high temperature and the fast heating rate enhanced the diffusion and controlled the formation of cracks. With the application of the thermal plasma, the nanoparticles were prepared due to the vaporization of the dehydrated material. Thus, the microwave plasma is considered applicable to the solid-state reaction accompanying degassing, without a change in the microstructure of the raw material.     

Effect of Plasma Power on the Deposition of Diamond Coatings on Pure Titanium

Diamond coatings appear to be a promising solution for the improvement of tribological behavior of titanium alloys. By means of microwave plasma assisted chemical vapor deposition (MW-PACVD), diamond coating was deposited on pure titanium using CH₄/H₂ gas mixtures under different plasma powers. Surface and interface characterization of the deposited coating under different plasma powers was carried out using SEM, grazing incidence x-ray diffraction (GIXD) and Raman spectroscopy. Adhesion of diamond coating with substrate was evaluated using an indentation tester. Results showed that adhesion of diamond coatings was not good under high plasma power, whereas the crystallinity of diamond coating was not good under low plasma power. The higher the plasma power, the larger the diamond crystal size, the less content of non-diamond carbon and the poorer the adhesion strength. During the diamond deposition, growth of TiC competed with diamond formation for the available carbon content. Relatively low plasma power inhibited TiC formation more than diamond formation. Under a high plasma power, the formation of a thick and porous TiC layer appeared to promote interfacial debonding and spallation of the diamond coating.     

Determination of the maximum temperature at the center of an optically thick laser-induced plasma using self-reversed spectral lines

A method of temperature measurement based on the model developed by Bartels of an optically thick inhomogeneous plasma was applied to a laser plasma induced on a target containing barium. The method involves the intensity ratio measurement of two self-reversed Ba(II) lines. The temperature thus determined corresponds to the maximum temperature in the plasma center. The plasma temperature was measured for delay times between 0.5 micros and 10 micros in two spectrometer operating modes: the scanning mode and the dual-wavelength mode, the latter resulting in better precision. A detailed analysis of experimental errors was performed. The error strongly depended on the wavelength separation of the lines used. The most accurate results were obtained for the largest line separation. Using one line in the UV and the other in the visible region, the relative error was 2-6% for temperatures between 8000 K and 20 000 K. The distribution of the plasma temperature along the plasma height was measured in the same delay time range. The temperature was found to be uniform along the plasma vertical axis, thus confirming the plasma cylindrical symmetry.     

Influence of rf-power on the plasma carbonitriding of titanium

The present work reports on the effect of input plasma processing power in the range of 350–650 W on the microstructure and mechanical properties of plasma nitrided Ti. The plasma processing time was 20 min and a gas mixture of 15% C₂H₂ and 85% N₂ was used. The characteristics of the carbonitrided layer have been investigated by microhardness measurements, surface roughness measurements, optical microscopy, and X-ray diffraction. The measured surface hardness values of the compound layer shows a maximum of 2050 HV0.1 for the sample treated at a plasma power of 550 W. The thickness of the carbonitrided layer continuously increases as the plasma power increases. Moreover, the highest carbonitriding rate of 3.52 μm²/s was observed when the input plasma power was adjusted at 600 W. This high carbonitriding rate of treated titanium samples is ascribed to the high concentration of active carbon and nitrogen species in the plasma atmosphere and the formed microcracks in the near surface of the sample during the plasma processing.     

The effects of competitive displacement on haloperidol's plasma distribution in normolipidemic and hyperlipidemic plasma

Purpose. To assess whether dyslipidemia affects haloperidol's overall plasma distribution when it is in the presence of another highly protein bound drug that competes for plasma protein binding sites. Methods. We performed in vitro studies in which warfarin sodium was pre-incubated in normolipidemic and hyperlipidemic plasma samples in varying concentrations. Following the pre-incubation with warfarin, [³H]-haloperidol mixed with unlabeled haloperidol was added to the plasma samples. The plasma was separated into its lipoprotein and lipoprotein deficient fractions by density gradient ultracentrifugation and haloperidol distribution was determined. Results. Our results indicate that when normolipidemic plasma was pre-incubated with various concentrations of warfarin no significant redistribution of haloperidol was noted among the various plasma lipoprotein fractions. However, in the case of the hyperlipidemic plasma, pre-incubating with warfarin did result in a significant redistribution of haloperidol from the lipoprotein-deficient fraction to the very-low-density and low-density fractions of lipoproteins. Conclusion. Understanding how plasma lipoproteins influence competitive displacement interactions would be valuable in helping to explain and perhaps predict pharmacokinetic parameters that may affect clinical outcome. The clinical significance of competitive displacement of drugs in patients with dyslipidemia requires further study.     

Effect of solute mixing in the liquid propellant of a pulsed plasma thruster

Sodium chloride or ammonia was dissolved in the water propellant of pulsed plasma thrusters to improve the performance. Pulsed plasma thrusters using liquid propellant utilize water as attractive alternative instead of Teflon. Water propellant enables in controlling propellant mass flow and leads to high specific impulse. However, liquid propellant pulsed plasma thrusters have larger plasma resistance and lower thrust power ratio than the common Teflon propellant thruster. Here, sodium chloride and ammonia solution of water were examined to decrease that plasma resistance. As a result, emission lines attributed from the solute were observed using sodium chloride aqueous solution propellant, and a 5% reduction of the plasma resistance was shown, and the thrust to power was increased. However, ammonia aqueous solution decreased the thruster performance.