Preparation Technology and Performances of Zn-Cr Coating on Sintered NdFeB Permanent Magnet

Zn-Cr coating was prepared on the surface of sintered NdFeB permanent magnet samples and preparation parameters were established. The anticorrosive property of Zn-Cr coating on NdFeB was studied by whole-immersion test in NaCl solution and compared with that of zinc plating and nickel plating on NdFeB. Open-circuit potential and self-corrosion current of NdFeB samples with and without Zn-Cr coating were measured. The micro-morphology and composition of Zn-Cr coming were analyzed through SEM, XPS, EDS and XRD. The effect of Zn-Cr coating on magnetic property of NdFeB magnet was also investigated. It is exposed that Zn-Cr coating is anodic type coating for NdFeB magnet, and provided substrate electrochemical protection, barrier protection and passivation protection. The anticorrosion property of NdFeB magnet is obviously enhanced by Zn-Cr coating while the magnet property of NdFeB magnet changed little.

Measurements of Formaldehyde and TVOC Emission from Paints and Coating Materials using Small Chamber Method for Building Composites

An optimal test method for paint is proposed; additionally, the Field and Laboratory Emission Cell （FLEC） method used in Europe is applied as a substitute for the 20 L small chamber method. The emission factors of total volatile organic compounds （TVOC） and formaldehyde from oil-based paint, emulsion paint, and water-dispersion paint with a coating weight of 300 g/m2, cured for 24/48 hours, were measured using the 20 L small chamber method. The emission rate of TVOC and formaldehyde from all paints began to stabilize after approximately 7 days after 24/48 hours of curing even though Korean standards stipulate that paint should be measured and analyzed after the third day of application. The emission factor of TVOC and formaldehyde from oil-based, emulsion, and water-dispersion paints were also measured using the FLEC method. There was good correlation between the 20 L small chamber method and the FLEC method for oil-based, emulsion, and water-dispersion paint emissions. With the FLEC method, using paints prepared under identical conditions, the emission rate was stable 24 hours after installation of samples because the air flow rate of FLEC is much higher than that of a 20 L small chamber, and the relative cell volume of FLEC is much smaller than that of a 20 L small chamber.

THE CURING THEORY OF SILlCONE PAINT AND THE STRUCTURE OF COATING FILM

This paper puts forward the two methods of weightlessness and alkoxyl group content determination to calculate the amount of cross-linking agent after elaborating the curing essence of silicone paint under the action of catalysis , and provides the theoretical basis of fixing the amoount of cross-linking agent accurately and quantitatively. At the same time, the structure of coating film is studied by the use of photoelectronic spectromenter and some other modern technology, and verified in theory. At last, this paper analyses the layer structure and the relationship between it and the coating properties.

Influence of Painting and Dyeing on Temperature Fluctuation of Northern Tibetan Salt Brines

Introduction The amount of the total dissolved salts(TDS)in most of the salt brines on northern Tibet is relatively lower.So the effective brine concentration technique is needed for lithium,boron and potassium extraction from these brine

Removal of organic solvent from cathodic electrophoretic emulsion paint by vacuum steam stripping

The production of environmental friendly emulsion paint is of great significance. Vacuum steam stripping of methyl isobutyl ketone （MIBK） and methyl ethyl ketone （MEK） from cathodic electrophoretic emulsion was studied. The effects of mass ratio of vapor to feed （V/F）, vacuum degree and feed temperature on removal rate of MIBK and MEK, emulsion size and solid volume fraction of the emulsion were investigated, and the removal of MIBK and MEK from cathodic electrophoretic emulsion by vacuum desorption was also studied. The results show that removal rates of both MIBK and MEK increase with the increase of V/F, vacuum degree and feed temperature. Removal rates of MIBK and MEK are 98.3% and 93.6%, respectively, at the operating condition V/F of 0.7, feed temperature of 27℃ and vacuum degree of 90 kPa. The emulsion size of cathodic electrophoretic emulsion increases slightly with feed temperature when temperature is below 42 ℃, and increases rapidly with feed temperature when temperature is above 42℃. Solid volume fraction increases by 10% as vacuum degree increases from 0 to 90 kPa at V/F of 0.7 and feed temperature of 27 ℃. Compared with vacuum desorption, vacuum steam stripping can get a higher removal rate of MIBK and MEK under the same feed flow, vacuum degree and feed temperature.

Optimising the corrosion performance of pre-painted steels

Pre-painted steel is one of the most important structural material of the 20th century well known for its excellent corrosion resistance and wide ranging applications.A typical pre-painted steel usually consists of a layer of metal coating system,preferably zinc or zinc alloy coating and a combination of layers of inorganic - organic coatings usually referred to as paint system.The corrosion resistance of the metal coating as well as the paint system may vary considerably based on their composition and the environment.For optimal corrosion performance of pre-painted steel,a judicious selection of both metal and inorganic-organic coating systems are essential.This paper reviews different types of possible corrosion issues in pre-painted steels and methods to optimise their performance.

Improvement of anticorrosion and adhesion to magnesium alloy by phosphate coating formed at room temperature

A new surface protection process was developed to magnesium alloy against corrosion in aggressive environments.Firstly,a phosphate coating was formed on rinsed magnesium alloy.Then,powder painting was carried out on the phosphated magnesium alloy.Surface morphologies and phase compositions of the phosphate coating were investigated by X-ray diffraction(XRD) and scanning electron microscope(SEM) .The results show that the phosphate coatings formed in bath containing earth additives at room temperature have dense and fine microstructure.The phosphate coating provides excellent paint adhesion to the magnesium alloy. Salt spray tests indicate that the corrosion resistance of the phosphate coating plus paint could meet the demand of magnesium alloy automobile components in aggressive environments.

Structure, properties and application to water-soluble coatings of complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole

The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free-NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coil, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20 -80, 15 -60, 20 - 55, 40 - 250, and 400 - 1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.

Coating Protection for Production Facilities of Offshore Oil Fields

This paper describes coating protection of production facilities of offshore oil fields based on the practice of development of Bohai Offshore Oil Field, with focus laid on the selection of coating systems, surface preparation, coating application, as well as coating inspection for four types of major production facilities.

Oxidation behavior of oxidation protective coatings for C/C-SiC composites at 1500 ℃

Porous carbon/carbon preforms were infiltrated with melted silicon to form C/C-SiC composites. Three-layer Si-Mo coating prepared by slurry painting and SiC/Si-Mo multilayer coating prepared by chemical vapor deposition(CVD) alternated with slurry painting were applied on C/C-SiC composites, respectively. The oxidation of three samples at 1 500 ℃ was compared. The results show that the C/C-SiC substrate is distorted quickly. Three-layer Si-Mo coating is out of service soon due to the formation of many bubbles on surface. The mass loss of coated sample is 0.76% after 1 h oxidation. The sample with SiC/Si-Mo multilayer coating gains mass even after 105 h oxidation. SiC/Si-Mo multilayer coating can provide longtime protection for C/C-SiC composites and has excellent thermal shock resistance. This is attributed to the combination of dense SiC layer and porous Si-Mo layer. Dense SiC layer plays the dual role of physical and chemical barrier, and resists the oxidation of porous Si-Mo layer. Porous Si-Mo layer improves the thermal shock resistance of the coating.

带锈涂装有机硅涂料的制备及性能

[目的]为了满足内陆地区通信铁塔防腐的实际需求,开展了带锈涂装底面合一有机硅涂料的研制工作。[方法]以羟基有机硅树脂作为基础树脂,甲基三甲氧基硅烷作为交联剂,KH570作为偶联剂,二月桂酸二丁基锡作为催化剂,没食子酸和三聚磷酸铝作为锈转化剂和稳定剂,气相二氧化硅、氧化锌和金红石型二氧化钛作为颜填料,环己酮作为溶剂,制成涂料后在经盐雾腐蚀的Q235B钢板上直接涂装,从涂层的外观、附着力、铅笔硬度、光泽度、色差、电化学阻抗等方面进行评价,并通过中性盐雾试验和老化试验来考察涂层的耐蚀性与耐久性。[结果]中性盐雾试验300 h和老化试验20个循环后,涂层外观良好,附着力大于4.4 MPa,光泽度无变化,只因轻微发黄而出现色差,防腐蚀性能仍保持良好。[结论]该涂料具有较好的附着力和耐腐蚀、耐老化性能,能满足内陆地区通信铁塔带锈涂装的需求。

涂料制造与涂装过程中废气排放与治理技术研究

为了应对涂料制造与涂装过程中废气排放对环境和健康的威胁,对涂料制造与涂装过程中废气的排放特点及其成因进行了研究,对废气的成分和浓度变化进行了探讨,分析了不同涂料种类对废气成分的影响,介绍了多种废气治理技术,包括燃烧法、冷凝技术、喷涂废气预处理—除漆雾以及生物过滤技术。探讨了废气治理系统的设计与优化,分析了废气收集与净化系统的设计要点以及系统能效的优化与控制技术,提出了废气排放与治理效果的监测方法,还提出了评估治理效果的关键指标。研究显示,结合多种技术的系统化废气治理可实现VOCs去除效率超过90%,达标排放率达到98%,且能耗与运行成本控制在合理范围内。旨在为涂料制造与涂装过程中废气治理提供科学依据和技术支持。

漆雾残渣对海洋平台大气区涂层体系防腐性能影响实验室研究

漆雾残渣是海洋平台涂装过程中一种不可避免的缺陷,按照现行验收标准,需人工手动打磨去除涂装过程中涂层表面附着的漆雾残渣;这一环节不但投入大量额外人力且对项目工期挑战极大。该文研究了漆雾残渣对两种海洋平台大气区常用配套防腐体系防腐性能的影响,通过对防腐体系的附着力、耐盐雾、冷凝试验等测试,得出结论:在涂膜外观无缺陷的情况下,漆雾残渣对大气区配套防腐体系的性能不利影响较小,可在涂装过程中适当简化打磨环节。

湿热盐雾大气环境印制电路板防护棚下试验研究

目的 试验研究不同防护工艺的印制电路板在湿热盐雾大气环境下的适应性。方法 结合无防护试件,在严苛的濒海棚下环境开展4种印制电路板防护工艺的暴露试验,通过观察电路板外观,测量计算绝缘电阻、介质耐压、品质因数,以及扫描电镜、能谱分析等技术手段评价印制电路板防护工艺的性能。结果 濒海棚下环境中,无防护印制电路板腐蚀严重,电气性能显著下降。改性硅、有机硅三防漆防护的印制电路板在整个试验周期内腐蚀程度轻微,电气性能较好,表面涂层仅存在轻微起泡现象。丙烯酸三防漆防护印制电路板防护性能不稳定,印制电路板出现腐蚀现象,品质因数总体低于改性硅、有机硅三防漆防护。聚氨酯三防漆防护印制电路板在电气测试性能中表现良好,但涂层出现太多破损、起泡等缺陷,铜导线出现异常生锈现象。在介质耐压测试中,多周期呈现击穿状态。结论 在濒海区域棚下湿热盐雾环境中,涂覆有机硅、改性硅三防漆的印制电路板防护状态最好,可优先选择作为防护手段。

PSPC规范在深水半潜浮式生产平台涂装设计施工中的应用

深水半潜浮式生产平台(SEMI FPU)与传统船舶相比具有设计使用时间长、服役环境复杂、防腐要求高、施工及检验要求严苛等特点,同时又兼具油气钻采设施和船舶双重特点,压载舱、货油舱、空舱等舱室涂装及船级社入级需要遵从IMO PSPC规范要求。本研究从PSPC规范在半潜浮式生产平台防护涂层系统设计、涂层系统认可、涂装施工、检验及涂层技术文件等方面,结合实际工程案例进行解读总结,给出了相应的工程经验推荐作法,希望能为从事相关工作人员提供参考。

涂料工业废水处理技术研究与应用进展

[目的]涂料工业废水成分复杂、难生物降解、有机物浓度高,同时含有悬浮物、重金属等污染物。[方法]按照废水处理工艺流程,综合阐述了近年来涂料工业废水处理方法的研究进展,解析了预处理、生化处理及深度处理技术的作用机理及局限性,介绍了部分可行但尚未应用于涂料工业废水的前沿技术,以拓展未来可能的研究重点和应用方向。[结果]综合废水处理案例分析表明单一方法无法实现涂料废水的有效处理。[结论]多种技术组合能使大部分废水在处理后达到排放标准。

一种多孔介质的表面散斑图转印涂装方法研究

本研究的目的在于探索一种可行的方法,即利用水转印技术,在多孔的高分子发泡材料上实现散斑图的转印,以便于在涂装时候能够适用于多种场景。由于在一般的散斑图制备方法中,每一次制斑时所得到的散斑图是不同的,而通过转印相关方法,可以采用打印技术将散斑图稳定地转印在水转印纸上,使得每次得到的散斑图图形完全相同,从而有利于进行后续试验和测试。通过文献分析和试验验证,水转印技术被认为是可行的应用方法。通过拉伸试验验证了经转印的散斑图可以随试件的变形而变形,并且在变形过程中不会发生脱落现象,从而证明了本研究工艺及方法的可行性。

硅氧烷改性聚醚胺固化剂对环氧连接漆的性能影响研究

为了解决低表面能防污面漆与常规防腐底漆之间匹配应用性能较差的问题,利用低表面能防污面漆的物理特性及活性基团特征,制备硅氧烷改性聚醚胺固化剂;以常规环氧连接漆配方为基础,通过探讨硅氧烷改性聚醚胺固化剂对连接漆的微观形貌、邵氏A型硬度、静态水接触角、附着强度的影响,确定专用连接漆中硅氧烷改性聚醚胺固化剂的添加量;将专用连接漆与低表面能防污面漆结合后,测试了体系的FIIR谱,对体系进行了耐甲苯/氨溶液浸泡和浅海浸泡性能测试,探究了专用连接漆的界面反应机理及实海应用性能。结果表明:硅氧烷改性聚醚胺固化剂的胺氢当量为200~300,旋转黏度为180~250 mPa·s(25℃),硅氧烷改性聚醚胺固化剂可显著提高专用连接漆的自流平性能、降低邵氏A型硬度、增大静态水接触角、增强各漆膜间的相容性;当硅氧烷改性聚醚胺固化剂添加质量分数为6%时,可实现与防污面漆的最佳连接效果,附着强度达2.1 MPa左右,且相互间为稳定牢固的化学键合,浅海浸泡试验结果明显优于常规环氧连接漆。本研究结果可有效解决低表面能防污面漆与底漆之间的配套问题,延长防腐防污涂层整体的使用寿命。

阻镀漆智能涂绘生产线气动控制系统设计

汽车上有许多塑料材质的饰件,通过电镀工艺可增加装饰性、提高硬度和耐磨性。饰件在安装时利用自身卡扣或者进行超声焊接,由于工艺需要,卡扣及焊接处不能被电镀,需涂绘阻镀漆实现这些位置的防护。因汽车更新换代迅速,饰件需求量大,并且种类繁多、形状复杂,阻镀涂绘工作劳动强度较高。为解决这一现状,研制阻镀漆智能涂绘生产线,利用机械手实现阻镀漆自动化涂绘。生产线设计为多工位,机械手循环作业方式。鉴于饰件单批次数量少、种类多,设计为三种类型饰件同时涂绘,设计气动快速夹具系统实现三维复杂饰件的平面内定位;针对不同类型饰件涂绘出漆量、涂绘速度不同,设计出漆自动控制系统;针对阻镀漆易固化堵塞管线的特性,设计自动气、液冲洗系统。经实验验证,气压设定误差±0.5%范围内,不影响涂绘效果;气动夹具系统配合机械手视觉实现涂绘位置的精确控制,重复定位精度可达0.1 mm;通过自动气、液冲洗系统清洗管线回路后,系统长时间停机可保证不发生堵塞。

无气离心喷涂涂料液滴流场和分布特性的数值模拟

目的探究无气体输送的无气离心喷涂法过程中涂料液滴与管道内壁面之间的相互碰撞接触作用,以在高分子涂料离心喷涂法中获得致密高强度涂料内衬层。方法将涂料液滴视为离散相,利用离散元方法和涂料液滴附着力JKR接触模型,模拟无气离心喷涂涂料液滴运动特性。通过堆积角虚拟试验确定涂料液滴与壁面表面能。基于离心场作用下涂料液滴运动方程,导出旋转喷枪射流小孔出流速度计算模型。数值模拟无气离心喷涂过程涂料液滴流体动力特性,揭示涂料液滴碰撞作用下动态喷涂成膜规律。结果统计得到涂料液滴在水平壁面展平的表面能为32.7 J/m^(2)。对于一定的喷嘴射流小孔,涂料液滴小孔出流系数接近于常数。随着计算时间的推进,壁面黏附涂料液滴数不断增加。在无气旋转喷枪II旋转速度2500 r/min下,统计单元涂料液滴数最大,并且有较大的液滴数方差和相对误差。随着喷枪旋转速度的提高,涂料液滴数的方差和相对误差降低。结论为实现沿管道壁面涂料液滴均匀分布,旋转喷枪II旋转速度建议不应低于5000 r/min。