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Файл:Metal corrosion. Electroplating (Защита металлов от коррозии. Гальванотехника). Учебно-методическое пособие
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8. Низкое качество покрытия нередко связано с повышенной
пористостью.
9. Во многих случаях увеличение толщины покрытия приводит
к ослаблению адгезии защитного слоя с металлом.
10. Для снижения смачиваемости водой лакокрасочные
покрытия иногда, в свою очередь, защищают восковыми составами
или кремнийорганическими соединениями.
13. Translate the following word combinations.
Cathodic protection – легирование металлов – unplated surface –
лакокрасочный слой – manufacturing issues – ослабление адгезии –
mechanical flexibility – снижение смачиваемости – corrosion – resistant
material – резкое повышение устойчивости к коррозии – electrical
current – атмосферное воздействие – sacrificial anode cathodic
protection
14. Give the definitions of the words and word combinations.
1. Plating is … .
2. Coating is … .
3. Inhibitor is … .
4. Electrical current is … .
5. Rust is … .
15. Give the example(s) of the metal alloying.
16. Answer the following questions using texts from Unit 8.
1. Name and describe several methods of corrosion control.
2. What does cathodic protection include?
3. What coatings possess gas- and vapour permeability and
waterproof properties?
17. Summarize the general ideas developed in all the texts of the
Unit 8.
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Unit 9
А
В
ELECTROPLATING
1. Read the international words, guess their meanings and give
the Russian equivalents.
Nickel, cadmium, chromium, bulletin, information, focus,
technology, optimum, plastics, conductor, decorative, product, automobile,
electronics, ion, electron, platinum, positively, negatively.
2. Read and translate the following verbs.
To deposit, to focus, to use, to treat, to improve, to achieve,
to enhance, to pass through, to need, to carry, to remove, to replace, to
complete, to charge, to plate, to reach, to attract, to constitute.
3. Match the English phrases from column A with the Russian
phrases in column B.
1) surface treatment
2) electroplating products
3) pretreatment and
posttreatment
4) electrodeposition process
5) surface properties
6) decorative effect
7) electrolytic cell
8) dissolvable anode
9) negatively charged
workpiece
10) electric circuit
11) positive charge
a) свойства поверхности
b) изделия с гальваническим
покрытием
c) декоративный эффект
d) растворимый анод
e) обработка поверхности
f) отрицательно заряженная
деталь
g) положительный заряд
h) подготовка и последующая
обработка
i) электрическая цепь
j) электропокрытие
k) гальванический элемент
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4. Read and translate the text. Summarize it in Russian.
Electroplating is a chemical or electrochemical process of surface
treatment. A metallic layer is deposited on the base material. Common
plating metals include: cadmium, chromium, copper, gold, nickel, silver
and their alloys. This information bulletin focuses on chrome plating.
Electroplating is used for components and equipment in all fields of
technology to:
- protect the material against corrosion
- improve the surface properties
- achieve optimum decorative effects
Electroplating is an electrodeposition process for producing a
dense, uniform, and adherent coating, usually of metal or alloys, upon a
surface by the act of electric current. The coating produced is usually for
decorative and/or protective purposes, or enhancing specific properties of
the surface. The surface can be conductors, such as metal, or
nonconductors, such as plastics. Electroplating products are widely used for
many industries, such as automobile, ship, air space, machinery, electronics,
jewelry, defense, and toy industries. The core part of the electroplating
process is the electrolytic cell (electroplating unit). In the electrolytic cell
(electroplating unit) a current is passed through a bath containing
electrolyte, the anode, and the cathode. In industrial production,
pretreatment and posttreatment steps are usually needed as well.
(From Electroplating: A Focus on Chrome Plating //
www.ohcow.memberlodge.com)
5. Read the text again. Decide whether the following
statements are true or false.
1. A metallic layer is deposited on the raw material.
2. Electroplating is a galvanic process of surface treatment.
3. The surface can be semi-conductors, such as metal and plastics.
4. The initial part of the electroplating is the electrolytic cell.
6. Read the text. What is its main idea?
Гальваностегия – электролитическое осаждение тонкого слоя
металла на поверхности какого-либо металлического предмета для
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защиты его от коррозии, повышения износоустойчивости,
предохранения от цементации, в декоративных целях и т. д.
Получаемые покрытия – осадки – должны быть плотными, а по
структуре – мелкозернистыми. Чтобы достигнуть мелкозернистого
строения осадков, необходимо выбрать соответствующие состав
электролита, температурный режим и плотность тока. Выбор способа
покрытия зависит от назначения и условий работы изделия. На
сегодняшний день изделия из металла, а также барельефы на стенах,
широко используются как в быту, так и в производстве, и в других
сферах промышленности. Надежность, прочность, многофункциональность, привлекательный внешний вид - вот что отличает металл
от других материалов. Литьевые пресс–формы значительно облегчают
производство товаров крупными партиями, художественные кованые
изделия позволяют превратить мебель и элементы интерьера в
предметы роскоши, ювелирные изделия были и остаются самым
лучшим украшением, а барельефы, расположенные на стенах,
существенно преображают интерьер.
(From ru.wikipedia.org/wiki/Гальванотехника)
7. Work in pairs. Translate the following text from English
into Russian.
The workpiece to be plated is the cathode (negative terminal). The
anode, however, can be one of the two types: sacrificial anode (dissolvable
anode) and permanent anode (inert anode). The sacrificial anodes are made
of the metal that is to be deposited. The permanent anodes can only
complete the electrical circuit, but cannot provide a source of fresh metal to
replace what has been removed from the solution by deposition at the
cathode. Platinum and carbon are usually used as inert anodes. Electrolyte
is the electrical conductor in which current is carried by ions rather than by
free electrons (as in a metal). Electrolyte completes an electric circuit
between two electrodes. Upon application of electric current, the positive
ions in the electrolyte will move toward the cathode and the negatively
charged ions toward the anode. This migration of ions through the
electrolyte constitutes the electric current in that part of the circuit. The
migration of electrons into the anode through the wiring and an electric
generator and then back to the cathode constitutes the current in the external
circuit. The metallic ions of the salt in the electrolyte carry a positive charge
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and are thus attracted to the cathode. When they reach the negatively
charged workpiece, it provides electrons to reduce those positively charged
ions to metallic form, and then the metal atoms will be deposited onto the
surface of the negatively charged workpiece.
8. Work in pairs. Interpret the following passage sentence by
sentence.
It is commonly accepted and often quoted by electroplaters that one
can make a poor coating perform with excellent pretreatment, but one
cannot make an excellent coating perform with poor pretreatment. Surface
pretreatment by chemical and/or mechanical means is important not only in
the case of preparations for electroplating but is also required in preparation
for painting. In either of these, methods are designed to ensure good
adhesion of the coating or paint to the surface. Most (metal) surface
treatment and plating operations have three basic steps:
- surface cleaning or preparation. Usually this includes employing
of solvents, alkaline cleaners, acid cleaners, abrasive materials and/or water.
- surface modification. That includes change in surface attributes,
such as application of (metal) layer(s) and/or hardening.
- rinsing or other work-piece finishing operations to produce/obtain
the final product.
9. Give English equivalents to the following word combinations
and learn them by heart:
кованые изделия
плотность тока
состав электролита
литьевые пресс-формы
мелкозернистая структура
температурный режим
строение осадков
гальванопластическое производство
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10. Give Russian equivalents to the following word
combinations and learn them by heart:
sacrificial anode
negative terminal
protective purpose
electroplating unit
alkaline cleaners
abrasive materials
dense coating
adherent coating
11. Translate the following sentences into Russian.
1. Electroplating has, over recent decades, evolved from an art to an
exact science.
2. Some of the technological areas in which means and methods of
electroplating constitute an essential component are all aspects of
electronics: macro and micro, optics, opto-electronics, and sensors of most
types.
3. The anode and cathode in the electroplating cell are both
connected to an external supply of direct current — a battery or, more
commonly, a rectifier.
4. The anode is connected to the positive terminal of the supply,
and the cathode (article to be plated) is connected to the negative terminal.
5. When the external power supply is switched on, the metal at the
anode is oxidized from the zero valence state to form cations with a positive
charge.
6. The plating is most commonly a single metallic element, not an
alloy.
7. If it is desirable to plate one type of deposit onto a metal to
improve corrosion resistance but this metal has inherently poor adhesion to
the substrate, a strike can be first deposited that is compatible with both.
8. The brush, typically a stainless steel body wrapped with a cloth
material that both holds the plating solution and prevents direct contact with
the item being plated, is connected to the positive side of a low voltage
direct-current power source, and the item to be plated connected to the
negative.
66
9. Brush electroplating has several advantages over tank plating,
including portability, ability to plate items that for some reason cannot be
tank plated, low or no masking requirements, and comparatively low
plating solution volume requirements.
10. Electroplating changes the chemical, physical, and mechanical
properties of the workpiece.
12. Translate the following sentences into English.
1. Гальванопластика – получение сравнительно толстого слоя
металлических осадков на поверхности какого-либо предмета.
2. Целью гальванопластики является получение точной
металлической копии предмета.
3. При гальванопластике осадки получаются массивными,
прочными, легко отделяющимися от покрываемой поверхности.
4. Основное применение в гальванопластике имеет медь; более
ограниченное использование железа, никеля, серебра, золота, а также
олова, хрома и других металлов и их сочетаний.
5. Копируемое изделие покрывают тонким слоем
электропроводящего материала и затем наносят гальваническое
покрытие.
6. Слой обычно делают легко отделяющимся от поверхности
изделия. Например, натирают порошок графита либо токопроводящий
лак.
7. В гальванопластическом производстве труб и других полых
предметов электролитическое осаждение в ряде случаев ведётся на
сердечники из легкоплавких сплавов, которые потом удаляются путём
нагрева выше температуры их плавления.
8. Ведущими отраслями промышленности, в которых
гальваностегия имеет широкое применение, являются
автомобилестроение, авиационная, радиотехническая и электронная
промышленность и др.
9. Технологический прогресс в гальваностегии развивается
по пути непосредственного получения блестящих покрытий, не
требующих дополнительной полировки.
10. Прогресс в области оборудования заключается в
разработке и внедрении механизированных и автоматизированных
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агрегатов для механической подготовки поверхности и нанесения
покрытий.
13. Translate the following word combinations.
Механизированные агрегаты – external supply of direct current –
легкоплавкий сплав – low voltage – дополнительная полировка – directcurrent power source – радиотехническая промышленность – zero
valence – гальваническое покрытие – form cations – прочные и
массивные осадки – poor adhesion.
14. Give the definitions of the words and word combinations.
1. Anode is … .
2. Electrolyte is … .
3. Galvanization is … .
4. Abrasion is … .
5. Melting point is … .
15. Describe the process of electroplating.
16. Answer the following questions using texts from Unit 9.
1. What is electroplating?
2. Where can electroplating be used?
3. What materials are taken for electroplating?
17. Summarize the general ideas developed in all the texts of the
Unit 9.
68
Unit 10
А
В
ZINC COATING
1. Read the international words, guess their meanings and give
the Russian equivalents.
Zinc, characteristics, unique, economics, adhesion, spraying,
specialist, noncyanide, color, adsorption, vanadyl, zirconium, titanium,
molybdenum, respect, composite.
2. Read and translate the following verbs.
To expose, to create, to afford, to spray, to galvanize, to assess, to
select, to range, to indicate, to restrict, to extend, to damage, to blacken, to
coat, to contain, to invent, to resist.
3. Match the English phrases from column A with the Russian
phrases in column B.
1) zinc surface
2) cyanide bath
3) base metal
4) post-plating treatments
5) zinc plating
6) mechanical plating
7) zinc spraying
8) zinc painting
9) matte finish
10) mild exposure
11) switch plate
12) translucent colors
a) слабое воздействие
b) прозрачные цвета
c) металлизация цинком
d) матовая поверхность
e) цинковая пластина
f) простой металл
g) щиток переключателя
h) цианистый электролит
i) механическое нанесение
покрытия
j) гальваническая оцинковка
k) цинковая краска
l) обработка деталей после
нанесения гальванического
покрытия
69
4. Read and translate the text. Summarize it in Russian.
Zinc has a number of characteristics that make it a well-suited
corrosion protective coating for iron and steel products in most
environments. The excellent field performance of zinc coatings results from
its ability to form dense, adherent corrosion product film sand a rate of
corrosion considerably below that of ferrous materials (some 10 to 100
times slower depending upon the environment). While a fresh zinc surface
is quite reactive when exposed to the atmosphere, a thin film of corrosion
products develops rapidly, greatly reducing the rate of further corrosion. In
addition to creating a barrier between steel and the environment, zinc also
has the ability to cathodically protect the base metal. Zinc, which is anodic
to iron and steel, will preferentially corrode and protect the iron or steel
against rusting when the coating is damaged. Many different types of zinc
coatings are commercially available, and each has unique characteristics.
These characteristics not only affect applicability but also the relative
economics and expected service life. The method of processing, adhesion to
the base metal, protection afforded at corners, edges, and threads, hardness,
coating density, and thickness can vary greatly among the different
coatings. This practical aid discusses each of the major types of zinc
coatings, applied by batch hot-dip galvanizing, continuous sheet
galvanizing, electrogalvanizing, zinc plating, mechanical plating, zinc
spraying, and zinc painting, to help specialists assess and select zinc
coatings for corrosion protection. (From Zinc Coatings / American
Galvanizers Association // www.galvanizeit.org)
5. Read the text again. Decide whether the following
statements are true or false.
1. Zinc has the ability to anodically and cathodically protect the
base metal.
2. Zinc will corrode and protect the iron or steel against
deterioration when the coating is damaged.
3. Zinc has several characteristics to protect iron and steel products
from corrosion only in humid environments.
4. Various types of zinc coatings are commercially available in
different countries.
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