磷酸表面改性Kevlar纤维及其复合材料性能的研究

采用磷酸溶液对芳纶纤维(Kevlar)进行了表面改性,通过考察其表面化学结构、元素组成、表面形貌及表面粗糙度的变化研究了磷酸对Kevlar纤维表面改性的效果.结果发现,改性后的纤维表面引入了含氧基团,并产生了明显的刻蚀作用.利用溶液预浸渍工艺和高温模压成型技术制备了Kevlar增强双马来酰亚胺树脂(BMI)复合材料,通...     

二次喷涂改性无机涂层

首先提出一种相对简单的方法对无机涂层材料进行改性,即在处理的铝合金表面制备水性无机涂层,然后在无机涂层表面二次喷涂KH-550改性溶胶,对其进行改性,再经烘烤制备了有机改性无机涂层.对二次喷涂KH-550改性溶胶的一些因素对涂层表面性能影响的研究表明KH-550用量≥20%,能明显提高无机涂层的附着力、耐冲击性、耐水性等理化性能.对二次喷涂后涂层的微观形貌和接触角测试结果表明,在KH-550改性溶胶中引入无机纳米或超细粉体,获得了致密、平整的多功能涂层.最后通过对所提出方法的原理探讨及实验结果的分析,确定二次喷涂KH-550溶胶改性无机涂层材料,制备有机改性无机涂层的方法可行.     

机械力表面改性对镁合金含铝涂层耐腐蚀性能影响的研究

在AZ91D镁合金表面涂覆含有铝粉的缩丁醛有机涂层，并对涂层表面进行机械力表面改性通过中性盐雾试验和W=5％的NaCl溶液浸泡试验研究了机械力表面改性和不同铝粉粒径对该涂层耐腐蚀性能的影响时涂层经机械力表面改性前后的微观形貌和NaCI溶液中的交流阻抗分踟进行了探讨结果表明，涂液中铝粉的粒径对涂层的耐蚀性有较大影响；该机械力表面改性处理可以增强有机涂层与基体的结合强度，提高涂层表面的致密程度．从而提高了涂层的耐腐蚀性能。     

脉冲激光改性聚氨酯表面无钯化学镀铜的实验研究

提出了一种在改性聚氨酯(PUR)材料表面进行金属化的方法。以掺杂了铜基金属复合物粉末的PUR浆料为基体,采用SPI光纤激光器(波长1 064 nm)对PUR表面进行刻蚀改性,达到传统化学镀铜中粗化和活化的目的,最后进行化学镀铜。对铜镀层进行了结合力、导电性以及延展性测试。结果表明,制备的铜镀层光亮、致密、结合力强、导电性好、延展性优良。通过扫描电子显微镜、X射线能谱仪、X射线光电子能谱(XPS)分析和俄歇电子能谱(XAES)分析对经过激光刻蚀改性的基体表面形貌和成分进行表征。探讨了激光刻蚀改性材料表面后,基体表面上铜元素的价态,分析XPS图谱和XAES图谱发现,激光刻蚀改性后的基体表面上铜元素以Cu+形式存在。研究了不同激光功率对刻蚀表面粗糙度的影响规律,通过胶带拉力实验验证了基体表面形貌与镀层结合强度的关系,实验结果表明,当用功率为7 W的激光刻蚀基体表面时,材料表面粗糙度值最大,并且其镀层结合力也最强。     

TiAlN涂层的退除对高速钢基体界面性能的影响

本论文采用化学方法退除高速钢(HSS)基体上的硬质涂层.采用金相显微镜和光电子能谱(xPS)分析了HSS基体涂覆涂层前和退除涂层后表面形貌和成分变化.发现镀有TiAlN涂层的HSS在35℃,1.52 mol葡萄酸钠(GA)、30 mol 30％ H2O2、0.45 mol三聚磷酸钠(STPP)、13 mol NaOH组成的碱性退镀液中反应80 min后,TiAlN系涂层能被退除掉,且HSS基体表面光亮.通过对退镀后基体表面XPS定性分析发现,基体表面Ti、A1元素含量为零,涂层退除干净,溶液对基体腐蚀很小.     

PBO纤维增强有机硅压敏胶的制备及性能研究

采用60Coγ-射线辐照的方法,对硝酸酸化预处理后的PBO纤维进行表面原位改性.结果表明预处理后纤维表面被硝酸刻蚀,生成羧基,化学活性增强,且呈单根分散,尺寸减小,纤维在辐照溶液中的分散性大幅提高.辐照原位改性后纤维表面生成纳米含硅涂层,其与有机硅压敏胶的界面结合力得到了提高.采用辐照处理后的高耐温性PBO纤维改性有机...     

聚酰亚胺塑料表面激光诱导活化化学镀铜

以硫酸铜和次磷酸钠为主要成分配制活化液,并将其均匀涂在改性后的聚酰亚胺基体表面。通过激光诱导使基体活化,施镀后得到平整、致密的化学镀铜层。研究了不同改性工艺对激光诱导活化化学镀铜效果的影响。采用接触角测量仪分析了不同改性工艺条件下基体的亲水性,并通过扫描电镜观察改性前后和激光诱导活化前后基体的表面形貌。结果表明:飞秒激光刻蚀改性后的基体具有良好的亲水性,其表面形成的刻蚀孔洞为激光诱导活化后生成的铜微粒提供了吸附场所,施镀后得到结合力良好的化学镀铜层。     

双槽法KOH溶液电化学刻蚀金刚线切割多晶硅片的研究

为探讨金刚线切割多晶硅片的制绒方法和工艺,采用双槽法在KOH溶液中对金刚线切割的多晶硅片进行电化学刻蚀。实验研究了电化学刻蚀前的化学预处理、溶液浓度、外加电压及溶液温度对电化学刻蚀的试样形貌及其反射率的影响。结果表明,多晶硅片经过化学预处理可产生后续电化学刻蚀的激活点或诱发点,提高了电化学刻蚀的均匀性;KOH溶液浓度、刻蚀电压和溶液温度都对多晶硅片的电化学刻蚀的表面形貌和反射率有重要影响。通过分析讨论,得出了多晶硅片化学预处理和电化学刻蚀的优化工艺及其参数。     

PBO纤维表面改性的研究进展

聚对苯撑苯并双噁唑(PBO)由于其特殊的表层结构,与聚合物树脂基体复合时存在严重的界面不相容性。简要介绍了PBO纤维的结构与性能,综述了化学刻蚀、偶联剂处理、等离子体处理、电晕处理、辐射处理、酶处理、热处理、化学涂层和超临界液体处理等PBO纤维表面改性方法。     

不同电流下超音速等离子喷涂钼-钨复合涂层的性能

将Mo粉和W粉按质量比4:1混合后用超音速等离子喷涂系统在45CrNiMoVA钢表面制备了Mo-W复合涂层。通过扫描电镜、能谱仪、X射线衍射仪、显微硬度计和摩擦磨损试验机考察了不同喷涂电流下所制涂层的微观形貌、成分、物相、显微硬度及耐磨性。结果表明,喷涂电流对Mo-W复合涂层影响显著,喷涂电流为350 A时所制涂层的各项性能最好。电流过大或过小均会导致涂层疏松,孔隙增大。Mo-W复合涂层显著提高了基体的显微硬度及耐磨性。在摩擦磨损过程中涂层和基体表面均生成了一层薄薄的耐磨氧化膜。     

双组分丙烯酸聚氨酯自成型橘纹漆花型改进

采用以低羟值丙烯酸树脂配合快干聚氨酯固化剂,添加中等吸油量的惰性填料,使涂膜既能形成橘纹骨架,又不过度消光.并添加适宜的触变剂,提供假塑性,优选助橘剂,调节表面张力,协同造成橘纹.研制成花纹一次均匀成型、花型较大的双组分自成型橘纹漆.讨论了各种因素对涂料性能的影响.试验结果表明：配制的双组分丙烯酸聚氨酯自成型橘纹漆,一道喷涂可成均匀橘纹,且有柔光效果.     

电磁屏蔽导电涂料用镀银铜粉的制备

采用置换反应法制备镀银铜粉时,铜粉还原银氨溶液中的Ag+生成的Cu2+与NH3形成络合物[Cu(NH3)4]2+,它吸附于铜粉表面而阻碍还原反应的继续进行,使制备的镀银铜粉表层的银含量降低。用氨水提高银氨溶液的pH,可增加制备的镀银铜粉表层的银含量,提高其抗氧化性能。当用氨水调节银氨溶液的pH至11.50时,可制得表层银的质量分数高达47.91%且具有常温抗氧化性能的镀银铜粉。研究了pH、AgNO3用量、AgNO3浓度和反应温度对镀银铜粉的抗氧化性能的影响。     

电流密度对5,5-二甲基乙内酰脲体系电镀银的影响

采用5,5-二甲基乙内酰脲体系在黄铜及不锈钢基体上沉积厚度为6μm左右的银镀层,镀液组成和工艺条件为:硝酸银25 g/L,5,5-二甲基乙内酰脲80 g/L,烟酰胺60 g/L,碳酸钾40 g/L,复合光亮剂(包含2-巯基苯骈噻唑、1,4-丁炔二醇和十二烷基硫酸钠)2 mL/L,pH 10.5,温度60°C,电流密度0...     

Salt bath test for assessing the adhesion of silver to poly(ethylene terephthalate) web

A time-resolved salt bath technique was employed for assessing the adhesion of silver coatings on poly(ethylene terephthalate) (PET) web. Furthermore, a basis for quantitative comparisons of adhesion was developed. The salt bath test was applied to samples of silver on PET web, made with a variety of web surface treatments. The results of the salt bath test demonstrate that the technique is capable of distinguishing levels of adhesion and, therefore, levels of treatment. It is thus shown that the salt bath test can be used to study the effects of treatment and coating process parameters on the adhesion of silver coatings to PET substrates. Although the test is specifically applied to the case of silver on PET, the concepts of a time-resolved soak test are generally applicable to systems that are known to exhibit delamination when exposed to certian chemical agents or harsh environments.     

Corrosive wear behavior of HVOF-sprayed micro-nano-structured Cr3C2–NiCr cermet coatings under aqueous media

A novel micro-nano-structured Cr₃C₂–NiCr cermet coating was prepared on 316L stainless steel by high-velocity oxygen fuel spraying technology (HVOF). Cermet coatings with different contents of micro-and nano-sized Cr₃C₂ particles as the hard phase and a NiCr alloy matrix as the bonding phase were prepared and characterized in terms of porosity, microhardness, and corrosive wear resistance in a 3.5% NaCl solution and artificial seawater. Compared to nanostructured coatings, micro-nano-structured coatings avoid decarburization and reduce nanoparticle agglomeration during the spray process, and mechanical and electrochemical properties were improved in comparison with those of conventional coatings. The micro-nano-structured Cr₃C₂–NiCr coating rendered low porosity (≤0.34%) and high microhardness (≥1105.0HV_0.3). The coating comprising 50% nano-sized Cr₃C₂ grains exhibited the best corrosive wear resistance owing to its densest microstructure and highest microhardness. Furthermore, compared to static corrosion, the dynamic corrosion of the coatings led to more severe mechanical wear, because corrosion destroyed the coating surface and ions promoted corrosion to invade coatings through the pores during corrosion wear.     

弱浸蚀溶液对无氰电镀镉-钛合金镀层性能的影响

为了提高无氰电镀镉-钛合金镀层与基体的结合力,采用不同的弱浸蚀工艺对基体进行表面处理,利用场发射扫描电子显微镜及电化学工作站,观察和测试了两种不同弱浸蚀溶液对镉-钛合金镀层微观形貌、结合力及耐蚀性能的影响。结果表明,基体经过弱浸蚀后镀层完整、致密、结合力好,耐蚀性能增强。当H_2SO_4质量分数为5%,HCl质量浓度为40 mL/L时,对基体浸蚀效果较好,析氢不严重。     

Electrochemical impedance spectroscopy study on silver coated metallic implants

This work presents the preparation of nano-structured silver coatings on TiAl₆V₄ and CoCrMo alloys by a pulse current technique and the study of time dependent electrochemical behaviour of silver coated metallic implants. EIS data as a function of immersion time in 0.9 wt% NaCl solution have been obtained to clarify the electrochemical processes occurring in the system. During early stage immersion (1–2 days), the impedance response shows near capacitive behaviour. As the time passes, the electrolyte gradually penetrates the silver coating and the sandblasted metallic implants. The silver comes into contact with the electrolyte and the conditions for galvanic corrosion are fulfilled. Due to the potential difference between silver coating and the metallic alloy, discrete anodic and cathodic areas are formed, which result in the release of silver, since the silver acts as an anode in galvanic cells. The cathode process is the reduction of the dissolved oxygen at the surface of the substrate. For antimicrobial applications of nanosilver coated TiAl₆V₄ and CoCrMo alloys, it is very important to maintain the continuous release silver ions. Degradation of silver coatings have been traced and confirmed by different methods such as SEM micrographs, EDX analysis, EIS measurements and solution analysis by ICP-MS methods.     

Sol-enhanced electroplating of nanostructured Ni-TiO2 composite coatings—The effects of sol concentration on the mechanical and corrosion properties

Novel sol-enhanced Ni-TiO₂ nano-composite coatings were electroplated by adding a transparent TiO₂ sol into the traditional electroplating Ni solution. It was found that the structure, mechanical properties and corrosion resistance of the nano-composite coatings were largely determined by the sol concentration. The higher sol concentration in the plating electrolyte led to a higher content of TiO₂ nano-particles in the coating matrix. The coating prepared at the sol concentration of 12.5 mL/L had the best microhardness, wear resistance and corrosion resistance. Adding excessive sol to the electrolyte changed the surface microstructure, caused cracking on the coating surface and deteriorated the properties. It was demonstrated that the corrosion resistance of the composite coatings is determined by two factors: surface microstructure and incorporation of TiO₂ nano-particles.     

化学还原法制备不同形貌的纳米银粉

采用化学还原法,分别以还原糖溶液、聚乙二醇、三乙醇胺为还原剂制备纳米银粉,对还原机理进行了分析,探讨了还原剂种类、酸碱度pH值、溶液浓度、反应温度等对银粉形貌及粒度大小的影响。结果表明,分别以还原糖溶液、聚乙二醇、三乙醇胺为还原剂,制备了薄片状、棒状、类球形或线形纳米银粉,这主要与还原剂溶液的pH值有关。以三乙醇胺做还原剂40℃时,可以制得均匀的类球状纳米银粉。     

Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating) and one-step (chemical etching and coating in a single step) processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°). Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.