金属件涂装前纳米级转化膜处理工艺技术

根据涂装金属的腐蚀行为分析,涂层的防腐蚀性能主要取决于涂层与基体表面的附着力。本文结合传统的磷化处理技术特征,提出了节能环保型的涂装前纳米级转化膜处理技术,分别阐述了纳米陶瓷锆盐、硅烷处理金属时在其表面形成的纳米级转化膜的处理工艺技术,研究试验结果表明,纳米级转化膜均可显著提高涂层与金属基体的附着力,其相应的耐腐蚀性能亦接近或达到了磷化处理技术要求。金属件涂装前纳米级转化膜处理技术可广泛地应用于家电、汽车、五金等领域的油漆、粉末及电泳等涂装前处理生产中。     

改善汽车钢圈涂装前处理工艺的配套性

针对某轿车钢圈涂装存在窄夹缝磷化膜返锈和电泳涂层起泡的质量问题,提出了改进前处理工艺的措施,即优化前处理剂质量、调整前处理工艺条件和控制方法,从而改善了涂装前处理工艺的配套性,提高了钢圈涂装的质量。     

前处理方法对不锈钢涂装性能的影响

不锈钢涂装前处理工艺不当会造成表面涂层附着不良。目前,不锈钢涂装前处理工艺多集中在化学除油或喷砂两方面,不能兼顾涂层的附着性能与防腐蚀性能。通过进行化学除油-浸蚀-钝化配套工艺研究,结果表明,不锈钢基材表面粗糙度明显增大,自腐蚀电位提高,耐蚀能力得到增强。表面涂装后涂层的附着力级别达到1级,附着性能稳定,涂层抑制锈蚀蔓延的能力显著提高。     

硅烷在涂装前处理工艺中的神奇应用

在了解硅烷特性的基础上,推荐液相、气相和涂剂等3种涂装前硅烷表面处理工艺。介绍了硅烷处理技术在解决涂装前处理工艺的环保、节能减排、省资源和涂层难附着问题等方面的神奇功能及应用实例。     

聚乙烯塑料涂装工艺

聚乙烯塑料通常难以进行表面涂装。本文采用特殊前处理工艺改变塑料表面分子结构和表面粗糙度，提高涂层与塑料表面的结合力。提出了聚乙烯塑料前处理和涂装工艺，配方。     

磷化液中金属离子的分析

0 引言 磷化作为金属涂装前处理工艺,已经得到广泛的应用.磷化工艺以前主要以锌系、钙系、锰系或锌-钙、锌-锰系二元磷化体系为主.随着涂装对表面处理质量要求的提高,三元磷化开始在阴极电泳中广泛应用.它能显著提高涂层的附着力,改善磷化膜质量,增强涂层的耐蚀性能.     

钢铁件涂装前自沉积膜处理技术的探讨

基于钢铁件涂装前化学转化膜处理技术分析,目的是为了钢铁件涂装前工序间防锈与提高涂层附着力。应用电化学原电池反应原理,研究在钢铁表面自沉积制备一层基于环氧乳胶的转化膜层,并优化了其工艺条件。本研究还进行了自沉积膜的机械性能测试,转化膜及涂层电化学耐蚀、耐湿热等性能评估,并通过三维景深显微观测表面结构及采用DSC热分析法研究了该自沉积膜的玻璃化温度。结果表明,具有膜层致密性的自沉积膜的电化学耐蚀等性能优于其它传统化学转化膜。自沉积膜处理技术可以满足钢铁件涂装前处理的技术条件,但为实现钢铁件涂装工程化仍待进一步系统研究。     

镁合金件有机防护涂层的耐腐蚀性能研究

为提高镁合金的耐腐蚀性能,利用复合有机涂层技术在ZM5铸镁合金表面制得防腐涂层。研究了镁合金的前处理、有机防腐涂装以及装饰性涂装工艺条件及其涂膜性能。利用化学转化膜对镁合金进行表面处理,再用复合有机涂层提高镁合金的防腐性能。结果表明:该有机涂层体系对镁合金有较好的腐蚀防护作用,化学转化膜可以提高镁合金与有机涂层的结合力并提高其耐腐蚀性。     

钢材表面处理工艺对环氧涂层附着力的影响

海洋工程涂层保护性能的强弱与涂装作业前钢材表面处理质量的好坏有直接关系。基于此,寻找那些可以使钢材表面获得高附着力的表面处理工艺是相当有必要的。环氧涂层为本文的实验对象,通过试验数据分析钢材表面采用的不同喷砂工艺和粗糙度的关系,继而进一步分析粗糙度的变化对环氧涂层附着力变化的影响。     

HB系列前处理剂开辟金属涂装新途径

本文对传统的前处理工艺存在缺陷的因果关系作了分析，介绍了ＨＢ系列前处理剂的特性，通过新旧工艺的对比，就表面涂装中存在的问题进行剖析，并对涂层的附着力，磷化膜的耐蚀性，脱脂剂的除油性能，提出了自己新的观点。     

变形铝合金表面锆基化学转化膜的研究现状

化学转化膜是金属表面主要的处理方法之一,具备良好的附着力和耐蚀性,能为铝合金提供一定的临时防护。传统的六价铬酸盐化学转化膜在日渐严苛的环保压力下已经逐渐淘汰,取而代之的是近几年发展迅猛的三价铬及无铬锆基化学转化膜。铝合金可分为铸造铝合金和变形铝合金,按照所含主要合金元素和热处理状态可分为若干个系列和型号。本文选取几种典型的变形铝合金,综述了不同铝合金微观组织对转化膜成膜过程的影响,化学转化液添加剂、预处理和后处理工艺对转化膜性能的调控及作用机理,以及几种典型商业钝化剂在变形铝合金表面的应用。总结了目前变形铝合金表面锆基化学转化膜仍面临的问题和发展趋势,未来化学转化膜需在满足新型铝合金发展要求的基础上,通过不同有机、无机添加剂以及外场作用对转化膜的成膜均一性、完整性进行调控,以提高转化膜的综合性能。     

轮胎模具特氟龙涂料喷涂工艺及效果

介绍轮胎模具特氟龙涂料的喷涂工艺及应用效果。特氟龙涂层具有良好的不粘性,在轮胎模具表面喷涂特氟龙涂料,可以降低脱模剂用量,减小轮胎模具停机清洁频率,提高生产效率,降低成本,解决轮胎模具开模不易和脱模困难等问题,轮胎成品外观合格率大大提高。     

无机粉体材料的表面处理方法

无机粉体材料的表面包覆及改性是近年来冶金及材料界为寻求制备新型材料而涌现的一个新的研究领域。粉体材料经无机包覆后，表面可具有新的物理化学性质，制成的复合粉体可用于陶瓷、催化、防腐、颜料、粘结、电子等行业。本文对无机粉体材料的表面处理方法进行了详细综述。     

克劳斯工艺防腐蚀涂层数值模拟

燃料、烟气中的高浓度硫化氢以及液滴对克劳斯工艺中燃烧设备有严重的腐蚀和冲蚀作用,很容易引发大型生产安全事故。液滴的冲蚀在金属受热面壁面产生细微裂纹是化学腐蚀的起点。涂层能够防止化学腐蚀,本文通过建立数学模型准确描述了克劳斯硫黄回收工艺中液滴撞击防腐蚀涂层的过程,运用离散迭代方法对整个计算区域进行求解,得到了撞击过程中防腐蚀涂层内部、涂层与固体黏结面以及固体内部的应力分布,确认了涂层方案能够在克劳斯硫黄回收工艺中解决金属受热面液滴冲蚀的问题;同时研究了不同厚度的涂层对应力分布的影响,得出了量纲为1最大应力与撞击速度之间的经验公式,提出采用20μm厚的氮化硅涂层是经济高效的克劳斯工艺壁面保护措施。     

Investigation of coating failure on the surface of a water ballast tank of an oil tanker

The current crude oil tanker is constructed as a double-hull structure which consists of an oil tank and a water ballast tank whose surface is coated with epoxy paint to prevent corrosion. Since the cracks that developed in the epoxy coating have caused corrosion of the interface of the water ballast tank, the identification of the parameters for crack development is important. In addition, the moisture absorption by the epoxy coating can cause deterioration of bond strength, which results in delamination of the coating and accelerates the corrosion at the interface. In this study, after the mechanical and thermo-mechanical properties of epoxy paints were measured, the residual stresses induced by the temperature change and cure shrinkage were calculated by the finite element analysis, which were compared with the experimental results. Also, the pull-off tests were performed to investigate the deterioration of the bond strength of epoxy coatings due to moisture absorption. It was found that the thermo-mechanical properties such as the coefficient of thermal expansion and glass transition temperature of the coating materials had dominant effects on the crack resistance rather than the cure shrinkage; the moisture penetration to the bonding interface caused interfacial failure and a significant deterioration of bond strength.     

Influence of plasma nitriding treatment on the adhesion of DLC films deposited on AISI 4140 steel by PVD magnetron sputtering

Duplex surface treatments composed of diamond like carbon (DLC) coating followed by plasma nitriding have drawn attention for a while. In this study, AISI 4140 steel substrates were plasma nitrided at different treatment temperatures and times. Then, DLC films were deposited on both untreated and plasma nitrided samples using PVD magnetron sputtering. The effect of different plasma nitriding temperatures and times on the structural, mechanical and adhesion properties of DLC coatings was investigated by XRD, SEM, microhardness tester and scratch tester, respectively. It was found that surface hardness, intrinsic stresses, layer thickness values and phase distribution in modified layers and DLC coating were the main factors on adhesion properties of duplex coating system. The surface hardness and residual stress values of AISI 4140 steel substrates significantly increased with both DLC coating and duplex surface treatment (plasma nitriding + DLC coating). Increasing plasma nitriding temperature and time also increased the diffusion depth and the thickness of modified layers. Hard surface layers led to a significant improvement on load bearing capacity of the substrate material. However, it was also determined that the process parameters, which provided lower intrinsic stresses, improved the adhesion properties of the duplex coating system.     

CMAS corrosion resistance in high temperature and rainwater environment of double-layer thermal barrier coatings odified by rare earth

In order to explore the difference of CMAS corrosion resistance in high temperature and rainwater environment of single-layer and double-layer thermal barrier coatings (TBCs), and further reveal the mechanism of CMAS corrosion resistance in above environment of double-layer TBCs modified by rare earth, two TBCs were prepared by air plasma spraying, whose ceramic coating were single-layer ZrO₂–Y₂O₃ (YSZ) and double-layer La₂Zr₂O₇(LZ)/YSZ, respectively. Subsequently, CMAS corrosion resistance tests at 1200 °C and rainwater environment of two TBCs were carried out. Results demonstrate that after high temperature CMAS corrosion for the same time, due to phase transformation, the volume of YSZ ceramic coating in single-layer TBCs shrank and surface cracks formed, which would lead to coating failure. When LZ ceramic coating of double-layer TBCs reacted with CMAS, compact apatite phases and fluorite phases formed, the penetration of CMAS into ceramic coating was inhibited effectively. Raman analysis and calculation results show that both of the surface residual stress of ceramic coating in two TBCs were compressive stress, and the residual stress of ceramic coating in double-layer TBCs were smaller than that of single-layer TBCs. Atomic force microscopy of TBCs after CMAS corrosion show that surface of double-layer TBCs was more uniform and compact than that of single-layer TBCs. The electrochemical properties in simulated rainwater of two TBCs after high temperature CMAS corrosion showed that double-layer TBCs possessed higher free corrosion potential, lower corrosion current and higher polarization resistance than those of single-layer TBCs. Consequently, the presence of LZ ceramic coating effectively improved CMAS corrosion resistance in high temperature and rainwater environment of double-layer TBCs.     

金属表面硅烷处理技术

根据金属腐蚀及涂层防腐原理,研究了金属表面硅烷处理工艺技术及处理后的功能特性,分别进行了中性盐雾、铜加速醋酸盐雾、电偶腐蚀、大气暴露和海水浸泡试验。结果表明,金属表面硅烷处理工艺技术可以取代涂装前磷化及铬化处理。该技术具有常温处理、无毒性无污染的特点,可广泛应用于涂装前处理与防腐领域。     

化学镀制备高耐蚀耐磨Ni-P-SiC复合镀层

研究了Ni-P-SiC复合镀层的制备工艺和性能以及SiC含量对镀层性能的影响。采用Taber试验机对Ni-P-SiC复合镀层的磨损性能进行了测试,并用VHX-100型三维视频显微镜对磨损形貌进行了观察,分析了复合镀层的磨损机理。结果表明:SiC颗粒的加入能有效地降低摩擦副之间的犁沟效应及摩擦表面发生粘着的面积,从而减少镀层的磨损。采用电化学实验等手段研究了Ni-P-SiC复合镀层的耐蚀性能。当复合镀层均匀一致,能起到一个良好的屏蔽作用时,耐蚀性十分优异;而镀层缺陷的存在将导致耐蚀性能降低。     

电致发热多孔碳化硅陶瓷的绝缘涂层

以异丙醇铝{Al[OCH(CH3)2]3}为原料,用溶胶-凝胶法制备氧化铝(Al2O3)溶胶,然后再以碳化硅(SiC)多孔陶瓷为基体,用浸渍提拉法对陶瓷进行涂层,涂覆完成后进行热处理即可在陶瓷表面和孔隙内部形成致密的Al2O3涂层.当涂层后的陶瓷用作电加热元件时,就可以达到陶瓷和流体绝缘的目的.从扫描电镜照片可以看出:在陶瓷表面及其孔隙内部确实涂覆了Al2O3涂层.Al2O3具有高电阻系数、高介电常数,抗氧化、耐腐蚀性等优异性能,所以,涂层后陶瓷的电阻率明显增加,可以弥补电致发热过程可能引起危险性的缺陷.Al2O3的涂覆也很好地改善了陶瓷成分SiC的氧化问题.结果表明:涂层中Al2O3的质量分数(下同)为43.1%,二氧化硅(SiO2)为38.8%,硅(Si)为18.1%.Al2O3是涂层物质的主要成分,SiO2有两种来源,一是作为基体的多孔陶瓷在渗硅过程中的剩余硅在陶瓷冷却过程中氧化生成存留于陶瓷中;二是陶瓷中的剩余硅在涂层的热处理过程中再次氧化形成.所以SiO2的含量相对较高,其中的硅显然就是陶瓷中的残留硅.