KOH溶液中等离子体电解氧化涂层的制备及放电特性

在KOH溶液中采用等离子体电解氧化技术在AZ31镁合金表面制备了陶瓷涂层。对等离子体电解氧化过程放电特性、陶瓷涂层表面形貌、晶相组成及耐腐蚀性能进行了研究,采用光发射光谱对等离子体电解氧化放电阶段等离子体活性物种进行了监测。结果表明,陶瓷涂层主要由Mg O和Mg(OH)2组成,表面具有层次感,耐腐蚀电流密度相对于基体材料提高了4个数量级。在75 V时,等离子体活性物种主要由O2+383.1 nm,Na 589.0 nm,Mg 519.4 nm,K 769.9 nm组成。这些活性物种对等离子体场能量的稳定起到了关键的作用。     

铝合金等离子体氧化放电特性及陶瓷膜层耐腐蚀性能研究

采用等离子体电解氧化技术在AA6063铝合金表面制备陶瓷膜层,拟提高铝合金耐腐蚀性能。对等离子体氧化过程电流电压特性及击穿放电特性进行了分析和探讨,采用光发射光谱仪对等离子体氧化放电阶段等离子体活性组分进行分析,对陶瓷膜层的耐腐蚀性能进行了研究。结果表明,相比于基体而言,等离子体氧化陶瓷膜层腐蚀电位正移了0.86V。在470V时,等离子体活性物种主要由Al、Al+、Mg、O+、Hα、Hβ、OH、Na和K组成,且金属活性物种先被激发。这些活性物种中金属元素及工作电极表面产生的气体的原子和分子对等离子体场能量的稳定起到关键的作用。     

激光熔覆法制备ZrO2-Y2O3涂层的显微组织与性能研究

采用预制粉末式激光熔覆法在钛合金(Ti-6Al-4V)表面制备了纳米ZrO2-8％ Y2O3涂层,利用X射线衍射仪(XRD)、扫描电镜(SEM)和光学显微镜(OM)对涂层的相组成及组织结构进行分析,同时分析了涂层的显微硬度分布情况.结果表明:在一定功率范围内,涂层气孔随激光功率增大而逐渐减少,裂纹随激光功率增大而增多;ZrO2陶瓷涂层与基体间结合良好,熔覆层微观组织结构主要以细小的树枝晶形态存在.在不同区域表现出不同的组织特征,靠近表面处晶体尺寸相对较小,呈柱状整齐排列在熔覆层表层区域;熔覆层中部主要包含块状晶及少量树枝晶;熔覆层底部主要为树枝晶,其一次品轴方向沿垂直于涂层截面方向生长;熔覆层主要由四方相(t相)ZrO2和立方相(c相)ZrO2组成;熔覆层平均硬度达到1000～ 1300 HV0.2,约为基材硬度的3.5倍.     

镍基高温合金陶瓷涂层的制备及性能表征

以Cr2O3粉、玻璃料及黏土为原料制成料浆,通过喷涂将其涂覆在镍基高温合金GH44的表面,采用热化学反应法于1050°C保温10min,熔烧制备出高温陶瓷涂层。通过扫描电镜和X射线衍射分析了高温陶瓷涂层的表面和截面形貌以及相组成,对涂覆陶瓷涂层的镍基合金的抗热震性能、抗氧化性能以及高温疲劳性能进行了测试。结果表明,陶瓷涂层结构致密,与基体结合牢固,具有良好的抗热震性能。涂覆陶瓷涂层的镍基合金其高温抗氧化性相对于基体提高了6倍以上,其高温疲劳性能明显改善。     

N80钢表面陶瓷涂层的制备及耐酸蚀性研究

采用热化学反应方法在N80钢基体表面制备了陶瓷涂层。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、体视显微镜和划痕仪对涂层的物相结构、组织形貌和膜基界面结合力进行了研究,利用失重法在20%的质量分数盐酸溶液中测试了涂层的耐蚀性能。结果表明:在600℃固化温度下,以SiO2粉体和SiO2、Al2O3、MgO等两类不同骨料制得的陶瓷涂层中,前者无新相生成,涂层与基体界面结合力24 N;后者有新相MgAl2O4生成,且涂层比较致密,涂层与基体界面结合力约40 N。以水玻璃作粘结剂的复合氧化物陶瓷涂层的表面致密度、平整性均优于以磷酸氢铝作粘结剂的涂层。酸腐蚀测试表明,以水玻璃作粘结剂的复合氧化物陶瓷涂层的平均腐蚀速率约为基体的1/2左右。     

Fe/Al2O3陶瓷涂层在HNO3溶液中的腐蚀行为研究

采用喷涂和溶胶-凝胶相结合的方法制备了Fe／Al2O3陶瓷涂层。对其与45号钢在65％HNO3溶液中的腐蚀行为进行研究。应用金相显微镜和X射线衍射仪分析陶瓷涂层的界面和组成。结果表明，Fe／Al2O3陶瓷涂层材料结构致密，孔隙率少，涂层与基体结合良好，能够有效阻止腐蚀液向陶瓷涂层内部浸入，其耐腐蚀性能明显高于钢基体；涂层中α-／Al2O3，FeAlO3以及Fe3Al相的均匀分布，提高了陶瓷涂层材料的耐腐蚀性。     

镁合金微弧氧化工艺及陶瓷层耐蚀性能研究

通过单因素试验讨论了镁合金微弧氧化电解液各组分对成膜的作用,得到电解液最佳配方:10g/L(NaPO3)6,5g/LNH4F,6g/LKOH,6mL/LC3H8O3。用扫描电镜(SEM)、X射线衍射(XRD)和能谱(EDS)分析了陶瓷膜层的表面形貌、截面形貌、相组成及元素组成;采用点滴试验、交流阻抗和盐雾试验考察了陶瓷层的耐腐蚀性能。结果表明:膜层表面分布着大量均匀的放电微孔,孔径在1~3μm之间,膜层截面内层与基体过渡部分呈犬牙交错状态,结合良好;膜层由大量非晶态相及少量MgO组成,耐蚀性能优良。P与F元素的存在,证明了电解液组分较好地参与了微弧氧化反应。     

改进的等离子体电解工艺制备氧化锆陶瓷薄膜及其性能

为改善氟锆酸盐电解液的老化现象,以氟锆酸盐为主电解液,在其中加入少量NaH2PO4 H3P04,对AZ31镁合金进行等离子体电解氧化处 理,制得氧化锆陶瓷薄膜.用扫描电镜、X射线衍射及能谱分析检测了添加剂对陶瓷薄膜的形貌特征、元素及物相组成的影响.结果表明:添加剂改 变了电解液体系的放电特性,能有效抑制氟锆酸盐电解液的老化;添加剂的加入能够提高膜中氧化锆的含量,且降低了F在膜中的含量.制得的氧化 锆薄膜能有效提高AZ31镁合金的耐腐蚀性能.     

溶胶-凝胶工艺制备ZrO2涂层对工程陶瓷表面改性的研究

采用无机盐先驱体 ,溶胶 -凝胶工艺在氧化铝基工程陶瓷上成功制备了ZrO2 涂层。用差热分析(DTA)、扫描电子显微镜 (SEM)、X射线衍射 (XRD)等分析手段对ZrO2 涂层的物相组成、表面和断面形貌进行了表征。对精磨、热处理、ZrO2 涂层试样的抗弯强度和Weibull模数进行了比较。结果表明 :ZrO2 涂层可以明显改善陶瓷的表面质量 ;涂层与基体结合紧密 ,无明显的界面层 ;涂层试样的抗弯强度和Weibull模数均比未涂层试样有明显的提高。     

粉煤灰玻璃/陶瓷复合涂层制备工艺及性能研究

以粉煤灰为原料,采用热化学应法在Q235钢表面制备了玻璃/陶瓷复合涂层.采用X射线、扫描电镜(SEM)分别研究了涂层的物相组成及截面形貌,并测试了涂层的耐蚀、耐磨性能.结果表明:热固化后复合涂层有新相MgAl2O4 、Mg2Al4Si5O18、AlP04、Cr2O3等产生.复合涂层具有良好的热震性,相对基体的耐酸性、耐盐性分别提高21.3倍、2.5倍;耐磨粒磨损性提高6.6倍.     

底喷式等离子体发生器射流的输出特性

通过自行设计的可以综合评定等离子体射流速度、温度、压力分布等特性的实验装置,研究了底喷式等离子体射流特性。采用压电测量装置、光电测量装置和数字高速摄影研究了射流在一定距离上的压力分布特性、射流速度及射流形貌特征。结果表明,该发生器所产生等离子体射流随着距射流中心位置距离的增大迅速衰减,等离子体射流速度约500m/s,射流运动过程可分为两个阶段:第一阶段是电爆炸丝产生高温、高压等离子体射流;第二阶段是消融管消融所产生的射流。     

微波等离子体技术在纳米粉体中的应用

介绍了微波等离子体技术制备纳米粉体的原理和特点,综述了微波等离子体在纳米粉体中的应用情况。     

等离子体技术在废水处理中的应用

低温等离子体的特点在于通过放电产生的电子温度远远高于系统中其他重粒子的温度。根据这一特点．阐述了低温等离子体技术处理废水的基本原理,研究了低温等离子体对废水的处理技术,分析了低温等离子体与废水的作用过程及其机理,介绍了低温等离子体技术的国内外研究现状,最后探讨了该技术在废水处理中的应用前景及其存在的问题。     

热等离子体雾态气化制备薄膜技术

热等离子体雾态气化制备薄膜技术(mist plasma evaporation, MPE)以液态源物质溶液为先体,采用超声雾化将先体溶液雾化为细小液滴,用载气将雾化液滴输运到射频感应热等离子体中,利用热等离子体的超高温,将液滴中的源物质彻底气化和分解为其组分粒子,通过气相输运,最终在基片上沉积薄膜.MPE制备薄膜技术采用单一先体溶液,源物质来源广泛,沉积速率快,不需后续热处理.本文介绍了MPE制备薄膜技术原理及工艺,综述了近年来在制备薄膜方面的研究进展.     

Surface analysis of cotton fabrics fluorinated in radio‐frequency plasma

Cotton fabrics were treated by radio‐frequency plasma with tetrafluoromethane (CF₄) and hexafluoropropene (C₃F₆) gases under different exposure times, pressures, and power levels. The hydrophobicity and water repellency were analyzed with measurements of the cosine of the contact angle (cos θ) and wet‐out time. The hydrophobicity was enhanced with treatments of both gases. X‐ray photoelectron spectroscopy (XPS) revealed increases in the surface fluorine content of 1–2% for CF₄ plasma and of 2.3–7.8% for C₃F₆ plasma. The relative chemical composition of the C_1s spectra after CF₄ and C₃F₆ plasma treatments showed increases in the relative amounts of ? C? O? C? and fluorocarbon groups (? CF, ? CF₂, and ? CF₃), whereas peak areas for ? COH and ? COOH decreased. The hydrophobicity was enhanced by the increase in the fluorine content and fluorocarbon groups. C₃F₆ plasma treatment resulted in higher hydrophobicity than CF₄ plasma treatment according to not only cos θ and wet‐out measurements but also XPS analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2038–2047, 2003     

非常规等离子喷涂技术及其特点分析

本文简要介绍了反应等离子喷涂、微束等离子喷涂、层流等离子喷涂和电磁脉冲辅助-等离子喷涂等几种非常规等离子喷涂技术的原理、特点和研究现状.通过这几种非常规等离子喷涂技术特点分析,以期从中获取对未来等离子喷涂工艺发展的一些启示.     

Processing map to control the erosion of Y2O3 in fluorine based etching plasmas

Due to the increasing number of applications for ceramic components in reactive etching processes, the interest in the specific erosion behavior of highly etch-resistant materials like yttrium oxide (Y₂O₃) has increased in the past years. Despite the large number of investigations already existing in this field, a more general understanding of the erosion mechanisms still lacks due to the limited comparability of these investigations. The huge difference in the kind of etching setups, processing parameters (bias voltage and plasma gas composition), and sample microstructures prevented consistent conclusions so far. To achieve a more general understanding, this study investigates the erosion behavior Y₂O₃ under a broad spectrum of plasma etching parameters. Therefore, the bias voltage is increased from 50 to 300 V and the plasma gas composition is gradually changed from Ar-rich to CF₄-rich compositions. This systematic approach allows to directly correlate the morphology changes caused by plasma erosion with the related plasma etching parameters and enables to better understand their influence on the depth of physical and chemical interactions, surface damage, and etching rate. We discovered three distinct erosion regimes, which exhibit specific erosion characteristics. Using these observations, a schematic processing map for Y₂O₃ was developed, which could help to estimate the severity of the erosion attack dependent on the processing parameters.     

Plasma‐induced,solid‐state polymerization of N‐isopropylacrylamide

The radio‐frequency plasma‐initiated polymerization of N‐isopropylacrylamide (NIPAM) in the solid state was performed. The isolated linear polymer was characterized by ¹³C‐NMR, ¹H‐NMR, and Fourier transform infrared spectroscopy, and the effects of selected operational plasma parameters (discharge power and time) on the conversion rates were studied. Reversible transitions at the volume‐phase‐transition temperatures of the swelled poly(N‐isopropylacrylamide) hydrogels were investigated by differential scanning calorimetry. The surface morphologies before and after plasma treatment were followed by scanning electron microscopy. With the obtained X‐ray diffraction results, we propose a solid‐state plasma polymerization mechanism for the NIPAM. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Surface modification of graphite encapsulated iron nanoparticles by plasma processing

The graphite encapsulated iron nanoparticles were fabricated by using arc discharge method. The synthesized nanoparticles were pre-treated by an inductively-coupled RF Ar plasma and then post-treated by NH₃ plasma under various gas pressures and treatment times. Analyses of XPS spectra have been carried out to study the effect of the plasma treatment on the surface modification of nitrogen-containing groups. The morphological changes of the particles surface by plasma treatment have also been analyzed by using HR-TEM. Present results show that the highest values of N/C atomic ratio of 5.4 % is obtained by applying 10 min of Ar plasma pre-treatment and 2 min of NH₃ plasma post-treatment conducted in RF power of 80 W and gas pressure of 50 Pa.     

非平衡等离子体在水处理技术中的应用及研究

非平衡等离子体水处理方法是一项高效、无二次污染的绿色环保技术。它具备高温热解、光化学氧化、高能电子、超临界水氧化等多种方法的综合效应,有广泛的适用性。本文系统介绍了非平衡等离子体技术在废水处理中的应用,通过总结和分析目前研究中存在的不足,提出该技术今后发展的方向。