PPG培训阴极电泳漆涂装手册

Automotive Electrocoat
Reference Manual
阴极电泳漆涂装手册
PPG INDUSTRIES, INC.
3800 W. 143rd Street
Cleveland, OH 44111
216/671-0050
11-3-97 Ver1
Automotive Electrodeposition Reference Manual Table of Contents
目录
TO ELECTROCOAT (1)
1. INTRODUCTION
简介
1.1. History of Electrocoat (1)
电泳涂装的历史
1.2. Why Electrocoat (2)
为什么要采用电泳涂装
1.2.1. Advantages........................................................................1-5
优点
1.2.2. Limitations (5)
局限性
1.3. What is Electrocoat (5)
什么是电泳涂装
1.3.1. Anodic Versus Cathodic (5)
阳极电泳和阴极电泳的区别
1.4. Electrochemical Reactions...........................................................1-16
电化学反应
1.5. Components of Feed and Bath....................................................1-18
槽液及加料祖份
1.6. Deionized Water...........................................................................1-21
去离子水
1.7. Membranes...................................................................................1-21
隔膜
1.7.1. Ultrafilter Membranes.....................................................1-23 11-3-97 i Ver 1
Automotive Electrodeposition Reference Manual
超率膜
1.7.
2. Anolyte Membranes.........................................................1-23
阳极膜
1.8. Section Summary (24)
本节摘要
2. DESIGN
CONSIDERATIONS (1)
设计要素
2.1. Introduction (1)
简介
2.2. General Design (2)
总体设计
2.2.1. Basic Requirements (2)
基本要求
2.2.2. Sanitary Pans (2)
滴漏盘
2.2.
3. Carrier Design...................................................................2-4
吊具设计
2.3. Metal Preparation........................................................................2-4
金属预处理
2.3.1. Body Shop Washer...........................................................2-4
车身清洗
2.3.2. Phosphating.......................................................................2-6
磷化
2.4. Electrocoat Tank..........................................................................2-6
电泳槽
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2.4.1. Direction of Flow..............................................................2-6
流动方向
2.4.2. Adjustable Weir Plate.....................................................2-8
可调堰
2.4.
3. Freeboard and Overflow..................................................2-8
槽堰超出液面高度和溢流
2.4.4. Bottom Front End Filtration...........................................2-9
槽前端过滤
2.4.5. Dimensions: Clearance.....................................................2-12
尺寸：间隙
2.4.6. Effective Coating Time.....................................................2-13
电泳时间
2.4.7. Angle of Entry...................................................................2-13
入槽角度
2.5. Materials of Construction............................................................2-14
建槽材料
2.5.1. Dip Tanks..........................................................................2-14
浸槽
2.5.2. Tank Enclosure.................................................................2-14
槽的间壁
2.5.
3. Tank Lining.......................................................................2-15
槽衬里
2.6. Paint Circulation..........................................................................2-15
槽液循环
2.6.1. Surface Flow......................................................................2-16 11-3-97 iii Ver 1
Automotive Electrodeposition Reference Manual
表面液流
2.6.2. Pipe Velocity......................................................................2-17
管路内流速
2.6.
3. Pumps................................................................................2-17
泵
2.6.4 Piping.................................................................................2-18
管路
2.6.5. Valves.................................................................................2-19
阀
2.6.6. Pressure Gauges................................................................2-21
压力表
2.6.7. Gasket Materials...............................................................2-21
垫圈材料
2.6.8. Filtration............................................................................2-21
过滤
2.6.9. Paint Cooling.....................................................................2-22
槽液冷却
2.7. Electrical.......................................................................................2-23
电器
2.7.1. Anodes...............................................................................2-23
阳极
2.7.2. Roof Anodes......................................................................2-24
阳极顶盖
2.7.
3. Anolyte Cells.....................................................................2-26
阳极隔膜系统
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2.7.4. Power Supplies..................................................................2-28
电源
2.7.5. Ultrafilters.........................................................................2-30
超滤器
2.8. Rinses (35)
淋洗
2.8.1. General Rinses..................................................................2-31
概述
2.8.2. Over Tank Rinses.............................................................2-33
槽上冲洗
2.8.
3. Recirculated Rinses #1 AND #2.......................................2-34
第一道和第二道冲洗
2.8.4. Drainage Between Rinses.................................................2-37
各道冲洗之间的沥液
2.8.5. Dip Rinse...........................................................................2-37
浸洗
2.8.6. Recirculated D I Water Rinse..........................................2-39
循环去离子水
2.9. DI or RO Water............................................................................2-40
去离子水和渗透水
2.10. Temperature Protection..............................................................2-42
温度防护
2.11. Line Stops.....................................................................................2-42
停线
2.12. Baking...........................................................................................2-43 11-3-97 v Ver 1
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烘干
2.1
3. Paint Storage Tanks.....................................................................2-44
涂料储备槽
2.14. Tank Feed.....................................................................................2-44
槽液配制
2.14.1. Resin Component..............................................................2-45
树脂组份
2.14.2. Pigment Component.........................................................2-46
颜料组份
2.14.
3. Acid Injection....................................................................2-48
加酸
OPERATION (1)
3. SYSTEM
系统操作
3.1. Introduction (1)
简介
3.2. Metal Cleaning And Phosphating...............................................3-2
金属清洗及磷化
3.2.1. Precleaning........................................................................3-2
预清洗
3.2.2. Phosphating.......................................................................3-3
磷化
3.3. Tank Design and Construction...................................................3-4
槽的设计和结构
3.4. Paint Circulation..........................................................................3-6
槽液循环
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3.5. Tank Electrification.....................................................................3-8
电泳槽加电装置
3.5.1. Anodes...............................................................................3-8
阳极
3.5.2. Rectifiers............................................................................3-8
整流器
3.6. Ultrafiltration...............................................................................3-9
超滤
3.7. Rinse Systems...............................................................................3-11
清洗系统
3.8. Baking...........................................................................................3-12
烘干
TESTS (1)
4. ANALYTICAL
分析试验
4.1. Electrocoat Solids (Non-Volatile) (2)
电泳漆固体份（不挥发份）
4.2. Electrocoat pH..............................................................................4-5
电泳漆pH值
4.3. Electrocoat Conductivity.............................................................4-9
电泳漆的电导率
4.4. Panels and Panel Ratings.............................................................4-13
试板及试板评价
4.5. Measurement of Dry Film Thickness.........................................4-16
干膜厚度测量
4.6. Sandwich Compatibility Test......................................................4-18 11-3-97 vii Ver 1
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相容性试验
5. TERMINOLOGY (1)
专有名词
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Introduction to Electrocoat
电泳漆简介
1.1.History of Electrocoat
电泳涂装的历史
Research directed toward the development of a paint which could be deposited electrophoretically was begun in 1957 at the Ford Motor Company under the direction of Dr. George Brewer. This research was designed to develop a method for improving corrosion protection on hard-to-reach parts of car bodies.
在美国福特车厂George Brewer 博士的领导下，福特汽车公司从1957 年就着手研究电泳涂装。

这个计划是开发一种改善车身难涂部位防腐蚀性的方法。

Automobile manufacturers were well aware that rust occurred in interior recessed areas, also noting that flat exposed areas, such as roofs, were often rust free. Although dip coatings penetrated into the recessed areas, they were usually washed off by solvent vapors during baking. Thus, Dr. Brewer's group strove to create a paint in which the solvents could be removed from the film during the application process. Their work led to the development of electrocoat.
汽车制造厂商们早已注意到汽车内部隐蔽处的锈蚀，但暴露在外的平面部位，如车顶却不易锈蚀。

虽然浸涂法能使涂料进入汽车内部，但是在烘干过程中，油漆因溶剂蒸发而被洗掉。

于是Brewer博士领导小组努力去开发一种在施工过程中溶剂可以从涂膜中被排除掉的涂料，他们的工作开创了电泳涂装。

The first Ford production tank began operation on July 4, 1961 to coat wheels. The Wixom tank for auto bodies was installed in 1963. Both of these tanks used anodic electrodeposition.
福特公司的第一个用于车轮涂装的生产槽在1961年7月4日开始运行，用来涂装汽车车身的Wixom 槽建于1963年，这两个槽所用的均是阳极电泳漆。

Although market growth for electrodeposition steadily increased immediately after introduction, not until 1973, when cathodic products were introduced, did the market literally "boom". In 1965, only one car in 100 was primed with electropaint;
by 1970, ten of 100 were electropainted; now, almost 90% are primed with cathodic electrocoat.
开发电泳涂装后，虽然市场的需求稳定增长，但直到1973年阴极电泳漆问世时，市场需求才真正繁荣起来。

1965年只有1%轿车用电泳底漆，到1970年增加到10%，现在几乎90%用电泳底漆。

1.2.Why Electrocoat
为什么要电泳涂装
Because of the marked advantages of electrodeposition, the process has, during the last two decades, become the dominant method for priming automobiles. A listing of the advantages of electrodeposition clearly explains the reasons for its spectacular success.
由于电泳涂装具有明显的优点，此工艺在过去的20年中已成为汽车涂底漆的最主要方法。

以下的电泳涂装优点清楚地说明了它获得惊人成功的原因。

1.2.1.Advantages
优点
1Formation of protective films in highly recessed areas such as flanges and box sections provides critical corrosion protection.
2电泳漆在非常隐蔽的部位，如翻边以及箱式结构，仍能形成完整的保护膜，从而得到较高的防腐蚀性。

3Transfer efficiencies of better than 95% result in reduced paint waste, especially when compared with spray-applied coatings.
4尤其与喷涂法相比，涂料利用率能达到95%以上，减少了涂料的浪费。

5Use of water as practically the only carrier virtually eliminates fire hazard, materially reduces water and air pollution, and markedly reduces the cost of facilities for controlling these conditions.
6使用水做载体，免除了火灾危险。

大大降低了水和空气的污染，明显地减少了环保设备费用。

7The low paint bath viscosity (approximately equal to that of water) results in ease of pumping and allows drainage of the coated vehicle.
8槽液粘度低（大约等于水的粘度），泵送容易，也利于被涂车身的沥干。

9Freshly-deposited paint is insoluble in water, permitting complete rinsing and recovery of dragged-out material.
10刚沉积电泳上的漆不溶于水，允许彻底清洗，且可回收带出的槽液。

11Uncured paint is dry enough to allow some handling.
12未固化的漆膜不粘手，甚至可以作某些处理。

13Unlike spray coatings, electrodeposited paint will not sag during baking.
流。

14不象喷涂的涂膜，电泳沉积的涂膜在烘干时不掛
15Unlike dip coatings, electrodeposited paint is not washed off in enclosed areas by hot vapors during curing.
16与浸法涂装不同，电泳沉积在内腔部位的涂膜，在烘干过程中不会被热蒸汽洗掉。

17Since the process is automated, direct labor costs are markedly reduced.
18由于生产过程自动化，大大降低了直接劳动成本。

19The deposited film is reproducible from part to part and from day to day.
20电泳工艺稳定，可保证漆膜均一涂于工件上。

The electrochemical process of depositing paint appears, at first examination,
quite complicated; however, it is actually more trouble-free than other paint
application processes for several reasons:
电泳涂装法问世后，第一次考验是相当复杂的，但由于下列几个理由，实
际上掌握它并不比其它涂装方法难。

21The large tank volume tends to minimize variations in paint or process.
22槽的容量很大，使涂料或工艺参数的波动减少到最小。

23The operating parameters are well defined and are based on extensive experience. 24操作工艺参数已有明确的规定，且是以丰富的经验为基础。

25Samples from the tank, which are tested weekly at the PPG Electrocoat Laboratory, often predict problems before they appear on the line.
26PPG电泳漆实验室每周从槽中取的样品做实验，常常是在生产线上出现问题之前就能预报。

Since the PPG Electrocoat Laboratory constitutes a controlled environment, the
following controls permit close monitoring of the commercial-scale process:
由于PPG电泳漆实验室时监控实验室，可以实现以下对工业规模的工艺
过程的严密控制。

27 A variety of metal substrates can be coated to permit extensive examination of
differing conditions.
28可以涂装各种各样的金属底材，且可进行不同条件的严格考验。

29Several tanks can be easily cross-compared.
30可以容易的对几个槽进行相互比较。

31Close anode-cathode distances in the coating tubes that are used in the electrocoat laboratory can be employed to magnify problems experienced in the field.
32在电泳实验室使用的试验槽中，调近阳极-阴极间距可用来放大在这方面经常出现的问题。

1.2.2.Limitations
电泳涂装的局限性
Although the advantages of the electrodeposition process far outweigh
disadvantages, some limitations exist. Electrodeposition can take place only on
electrically-conductive substrates. When a unit is coated and baked, the
electrodeposition of a second coat is impossible with standard electrocoat
products. Thus, electrodeposition is used mainly for the application of prime
coats. Application of a variety of color coats requires separate dip tanks.
虽然电泳的优点比缺点多，但是还是有一些局限性。

电泳工艺只能用在导
电的底材上；当涂装的物体烘干后。

不可能进行第二次电泳涂装。

因
此，电泳涂装主要被用来涂底漆；涂不同的颜色涂膜要在不同的槽中进
行。

1.3.What is Electrocoat
什么是电泳涂装
1.3.1.Anodic Versus Cathodic
阳极沉积法和阴极沉积法的区别
Based upon the method of deposition, two types of electropaint have been
developed: anodic and cathodic. The anodic types were commercialized first for
two reasons:
基于沉积的电泳方式，已经开发了阳极电泳漆和阴极电泳漆两种类型的电
泳漆阳极电泳漆首先投入正式生产有两个原因：
33The earlier resin technology was based on resins which contained acid groups.
These could be neutralized to allow them to become soluble in water.
34早期的树脂制造技术都是以含酸基团的树脂为基础，中和后，他们可以溶于水。

35When the solubilized resin was deposited, it regained its acidic function. This acidity permits ready crosslinking (curing) when the coating is baked.
36当水溶性树脂沉积后，它可以恢复其酸性基团的功能。

当此涂层被烘干时，这种酸性基团可使漆膜其迅速交联（固化）。

The ability to produce a cathodic-type resin was available long before the resins
were introduced commercially in 1975. Two major problems had to be
overcome before commercialization became possible:
阴极电泳漆的树脂在1975年阳极型树脂商品化之前很长一段时间内就有
能力制造了，但其正式投产之前要克服以下两个主要的问题。

37 A method was needed to make alkaline polymers cure at temperatures low enough
to ensure body integrity.
38降低碱性聚合物固化的温度，同时还要确保漆膜的均一性。

39The corrosivity of the bath solution had to be reduced.
40必须降低槽液的腐蚀性。

The process of curing thermosetting resins is called "crosslinking". During this
process, which is driven by heat, the relatively small molecules deposited are
chemically intertwined to form a single uniform film..
热固型树脂的固化过程称为交联，这个过程是以热为动力，较小分子的
沉积膜经化学交联形成一个完整的表面。

.
The reactions involved in crosslinking deposited film depend upon the film's
chemical environment. The structures that are obtained by these curing
reactions are essential for the practical value of the coating. Reaction conditions
also determine bake time, temperature and, therefore, energy consumption.
电泳漆膜交联的反应取决于涂膜的化学反应环境，靠这些固化反应获得的
涂膜结构，对其防腐性能]具有真正的实际价值。

反应的条件也决定了烘干时间及温度，以及消耗能源。

Anodic electrocoats usually have a pH of approximately 9.0; however, the deposited film is, in contrast, highly acidic. Acid catalyzed crosslinking reactions can be used with little difficulty.
阳极电泳槽液一般pH约为9，可沉积涂层却是高酸性。

酸催化的交联反应比较容易进行。

The situation is somewhat different for cathodic materials. As with anodic resins, the crosslinking can be either internal or external. Because of the alkaline nature of the uncured cationic film, external linking reactions are sluggish.
对阴极电泳就有所不同了，阳离子树脂的交联反应可以在内部或外部进行，但因未固化阴离子涂膜具有碱性，所以外部交联反应较缓慢。

Internal crosslinking is carried out by urethane groups mixed with the cathodic resin. These crosslinkers are stable in water at normal bath temperature but become reactive at curing temperatures. Special procedures are used to ensure that these crosslinkers will not react at bath temperature to cause instability.
内部的交联是靠与阳离子树脂混合的氨基甲酸脂基团进行的。

这些交联剂于正常槽液温度下在水中很稳定，但在固化温度下就变得活泼起来。

通过采用一些特殊的处理工艺，确保这些交联剂不会在槽液温度起反应而引起槽液的不稳定性。

Although numerous types of resins may be suitable for electrodeposition, the most common ones are thermosetting. Thermosetting resins fuse or melt when baked into a hard, uniform, solvent-resistant film.
虽然多种树脂都可以适用于电泳涂装，但最常见的是热固型的
热固型的树脂在烘干时融合或融化成为一坚硬，均匀的耐溶剂涂膜。

Resin chemists must ensure that the resin has particular properties of hardness, flexibility, adhesion, water-and-chemical resistance, pigment wetting, and others. To be used as an electropaint, the resin must also have the following characteristics:
研发人员必须确保树脂具有硬度，柔韧性，附着力，耐水及化学品性，颜
料湿润性及其它特性。

用于制造电泳漆的树脂还必须具备如下特性：
41It must be soluble or dispersible to form a stable solution even when subjected to a wide variety of production conditions.
42树脂必须可溶解或分散成一种稳定的溶液，可以适应多种生产条件。

43It must deposit onto an electrode to form a smooth, dense, insulating, wet film which also contains pigment.
44树脂必须能沉积在一个电极上，形成一光滑，致密，绝缘，并含有颜料的湿涂膜。

45It must be able to coat a part which is complex in shape.
46必须能够泳涂外形复杂的工件。

47It must resist re-dissolution when rinsed.
48必须在冲洗时不再被溶解掉。

49It must become mechanically and chemically stable upon baking so that the resulting film can fulfill its protective and/or decorative requirements.
50经烘干后的涂膜具有机械及化学稳定性，以满足保护和（或）装饰的需要。

Although the principle of electrodeposition gained acceptance with the anodic
systems, it was not until the cathodic method was developed that
electrodeposition became the common method for priming automobiles. The
cathodic method has the following advantages:
虽然电泳涂装的原理是从阳极电泳系统获得的，但是直到开发出了阴极
电泳涂装法以后，电泳涂装才成为汽车涂底漆普遍采用的方法。

阴极电
泳漆有以下优点：
51It achieves corrosion resistance at low film thickness.
52较低的膜厚具有良好的防腐蚀性。

53It permits throwpower to interior surfaces without penalty of over-build on exterior surfaces.
54保证工件内表面泳透力的同时，外表面上涂膜也不会过厚。

55It achieves bimetallic joint corrosion resistance required by the increased use of galvanized metal.
56双金属复合层也能获得良好的防腐蚀性，可适应日益扩大的镀锌钢板用量的需求。

57It possesses saponification resistance and long-term adhesion retention over an entire galvanized body panel.
58它具有耐皂化性，在全镀锌的车身板上可长期保持其附着力。

59It requires substantially less electrical consumption for deposition and, as a result, less refrigeration for cooling.
60电泳本身耗电量少，从而用于冷却的冷量也少。

61It achieves gloss and hold-out with and without spray primers.
62本身具有足够的光泽度，可喷涂或不喷涂中涂，同时在没有中涂的情况下也不影响面漆的亮度。

The prime advantage for cathodic systems, however, is superior corrosion
protection. With anodic electrodeposition, metallic ions from the part being
coated often become included in the deposited film. This condition results from
anode reactions when current is applied. The presence of the iron ion in the film
provides a readily available site for rust to start. In addition, when deposited,
cationic resins are alkaline in nature and tend to be natural corrosion inhibitors.
其实，阴极电泳的最主要优点还是防腐蚀性非常优良。

材用阳极电泳
时，由于通电时的阳极反应从被涂工件上溶下的金属离子常常包含在漆膜
中，。

在漆膜中存在的铁离子就成了开始生锈的诱因。

另外，沉积时，阳
粒子树脂呈碱性，这样就成为天然的缓蚀剂。

1.4.Electrochemical Reactions
电化学反应
To this point, we have discussed anodic and cathodic paint and have used the terms anionic and cationic as well. Although the terms "cathodic" and "cationic" may be used as synonyms, they refer to two different aspects of the subject.
到此为止，我们已经讨论了阳极漆和阴极漆，并且已使用了阳离子，阴离子等术语，虽然阳极和阴离子可以作为同义词使用，其实他们是用于表示一个事物的两个不同方面的。

Positively charged electrodes are called anodes while negatively charged ones are called cathodes. A water solution contains charged particles which are called "ions". Ions are atoms or molecules with charges. Anions have negative charges, and cations have positive charges. If one remembers that opposites attract, the problem simplifies. The cathode is negative: thus, it repels negative charges and attracts positive charges.
带正电荷的电极称为阳极，带负电荷的电极成为阴极，水溶液中含有的带电粒子称为离子，离子是带电荷的原子和分子，阴离子带负电荷，阳离子带正电荷，如果大家都明白异性相吸的道理，问题就简单了，阴极带负电：所以它排斥负电荷而吸引正电荷。

The positively-charged ions in the solution are called cations, and the negatively-charged particles are called anions. Thus, by the principle of opposites attracting, the cations (positive charges) are attracted to the cathode (which is negative in charge). Since the cathode is relatively fixed in position, the cations move toward it. This movement is called migration.
溶液中带正电荷的离子称为阳离子，带负电荷的离子称为阴离子。

这样，根据异性相吸的原理，阳离子（带正电荷）与阴极（带负电荷）相互吸引，由于阴极位置相对固定，故此阳离子便移向阴极，这种运动称为迁移。

Negatively-charged ions keep the positively-charged resin molecules in a cathodic system in solution. The solubility of the resin depends on the critical balance of positively and negatively charged ions.
带负电荷的离子把带正电的树脂分子存在于阴极系统的溶液中。

树脂的溶解性取决于阴，阳离子的电平衡。

When paint is deposited at the cathode, the process is called cathodic, and paint with a positive charge is called cationic paint. Thus, the terms cathodic and cationic refer, respectively, to where the paint is deposited and the type of charge of the deposited paint. The two terms are often used interchangeably.
电泳漆沉积在阴极上时，此工艺称为阴极电泳，带正电荷的漆称为阳离子型电泳漆。

故此“阴极的”极“阳离子的”两个术语即分别表示漆的沉积对象及沉积漆的带电类型。

这两个术语常可互换使用。

The electrocoating process is known by several names:
电泳涂装工艺在英语中有以下几个名词：
• Elpo
• E-Coat
• Electropainting
• Electrodeposition
• Electrophoretic Painting
Electrocoating is similar in process to that of electroplating, such as the application of chrome on automobile bumpers. The two processes are alike in that both use the passage of electric current for deposition. They differ, however, because electroplating deposits metallic ions whereas electrocoating deposits organic resin molecules.
跟电镀工艺相似，比如汽车保险杠度铬，电泳，电镀这两种工艺都是通过利用电流产生沉积。

不同之处在于，电镀时沉积金属离子，电泳时沉积有机树脂分子。

Cathodic electrocoating is a paint-plating type operation in which the object to
be coated is dipped into a water-thinned paint. A direct current is then passed
through the paint. In the cathodic system, the article to be coated is made the
cathode ( is charged negatively). The paint solids are positively charged and are,
therefore, attracted to the cathode.
阴极电泳涂装是一种将被涂件浸入水稀释的涂料中，进行类似电镀上漆的
涂漆工艺，通过在涂料中通直流电，在阴极电泳涂装体系中，被涂件作
为阴极（带负电）。

油漆固体份带正电荷，因此被吸引到阴极。

Electrodeposition of paint films simultaneously involves electrophoresis,
electrolysis, electrodeposition, and electroendosmosis. Although a thorough
understanding of these principles is not necessary for one to understand the
operation of an electrocoat tank, they are presented here to explain the
processes taking place beneath the surface of the tank.
漆膜的电沉积过程同时包含有电泳，电解，电沉积，电渗等过程。

对于电
泳槽的操作人员来说，他们不一定要懂得这些原理，我们在此只是把在
电泳槽中所发生的化学反应以及工艺原理进行解释。

63Electrolysis is the decomposition of a conductive liquid by the passage of an electric current. The electrolysis of water into hydrogen and oxygen is perhaps the best known example of this process. Electrolysis is usually accompanied by gas evolution at one or both electrodes. Gassing is undesirable in the electrocoating process, limiting the throwing power, an important property which will be discussed later. Since gassing is proportional to current flow, sudden current surges should be avoided during deposition, and bath conductivity should be held within specified limits. These limits are set to control the conductivity of the paint only and do not consider the conductivity effects of ionizable contaminants which result from phosphate drag-in or poor quality deionized water. (The effects of these and other contaminants will be discussed later. )
64电解是靠通电使导电液体分解。

水电解生成氢气和氧气是大家最熟悉的电解例子。

电解通常同时在一个或两个电极上析出气体。

在电泳涂装过程中这
种气体的析出却是不利的。

它对后面将要讨论的重要特性“泳透力”有影
响。

由于气体析出与电流成正比，因此要避免在沉积过程中突然的电流波
动，并且要将槽液电导率限制在特定的范围之内。

这种电导的限制只是对
油漆电导率的控制，并不考虑由于磷化液的带入或去离子水质量差所导致
的杂离子污染杂质离子物所产生的电导率作用（诸如此类污染的作用将会
在下文讨论）
65Electrophoresis is the migration of electrically charged colloidal particles in a conductive medium under the influence of an electrical potential (voltage). Examples of electrophoresis are the movements (migration) of pigment particles and colloidal resin particles which take place in the electrocoating process. Under the influence of an electrical potential, these particles will move towards the cathode by the process of electrophoresis.
66电泳是在一电势电压作用下。

导电介质中胶体离子的移动过程。

例如，发生在电泳涂装过程中电泳的是颜料粒子及胶体树脂粒子的运动(移动)，在这
电势的作用下，这些粒子靠电泳过程移向阴极。

67Electrodeposition is the precipitation of paint particles at an electrode. Positively-charged particles will coagulate at the cathode, and negatively- charged particles will collect at the anode. Since these negatively-charged particles (called ions) help keep the positively-charged resin in solution, they are sometimes referred to as counterions.
68电沉积就是油漆粒子沉积在一个电极上。

带正电的粒子将聚积在阴极上，带负电的粒子会在阳极上聚集。

由于这些带负电的粒子（称离子）使带正电
的树脂保持在溶液中，它们有时被叫做平衡离子。

69The paint vehicle is usually cationic, and deposition takes place only at the cathode.
It is an irreversible process. No coating can take place at the anode.
70涂料的漆基一般为阳离子型，沉积只发生在阴极上，它是一个不可逆过程。

在阳极上不形成涂膜。

71The first step in electrodeposition is the electrochemical decomposition of water (electrolysis). If the paint bath has a neutral pH, the primary reaction at the cathode is the formation of hydrogen gas and hydroxyl ions. This reaction causes
a highly-alkaline boundary layer to form in the area of the cathode. Film
deposition occurs when the cations (resin and pigment) react with the hydroxyl ions to become insoluble. This condition does not occur until the alkaline layer reaches a critical pH of about 12.
72电沉积的第一步是水的电化学分解（电解）。

如果漆液PH值呈中性，在阴极上最初的反应是产生氢气和氢氧根离子（OH-）,这个反应导致在阴极面
上形成一高碱性边界层。

当阳离子树脂（树脂及颜料）与氢氧根离子反
应，变为不溶于水时，这就产生了沉积后的涂膜。

但如果碱性边界层达不
到大约12的临界PH值，将得不到不溶于水的涂膜。

73Electroendosmosis is the final process to be discussed. As paint solids are drawn to the cathode and precipitated, the film becomes semi-permeable. Water is driven from the vicinity of the cathode through the deposited film, causing the dehydration of the film. Such a film is relatively resistant to physical distortion.
74电渗是要讨论的最后一个过程，当涂料固体份在阴极上沉积之后，此涂膜为半渗透性。

水份从阴极附近通过沉积过程排斥出来，引起涂膜脱水，这种
涂膜已具有抗物理变形性。

The water insolubility of the deposited coating permits rinsing with water to
remove bath drag-out. Drag-out consists of non-deposited paint which loosely
adheres to the coated article as it is removed from the bath. To achieve good
appearance for the deposited film, the drag-out must be rinsed away.
由于沉积涂膜的不溶于水性，允许用水清洗电泳板洗掉电泳带出的漆液。

当被涂工件从电泳槽中出来时，在其表面上附着一层未沉积的槽液，为了
获得外观良好的电泳漆膜，必须将带出的槽液洗掉。

In summary, the application of an electrical potential to two electrodes in a bath
containing a conductive solution produces electrolysis of the solution and
electrophoresis of the charged particles. Coagulation or deposition, occurs at the
cathode. This process continues until a continuous and even film coats the
entire surface of the cathode.
总之，当加电压于装有导电溶液槽中的两个电极时，就产生溶液的电解
和带电粒子的电泳，在阴极上发生聚积或沉积。

这个过程一直持续到整
个阴极表面被连续，均匀的涂膜所覆盖。

Because the electrodeposited film has a relatively high electrical resistance at a
given voltage, the process stops itself when the film is nearly equal on all。