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Файл:Metal corrosion. Electroplating (Защита металлов от коррозии. Гальванотехника). Учебно-методическое пособие
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6. Read the text. What is its main idea?
На сегодняшний день метод гальванического цинкования
является самым распространённым способом защиты метизов от
коррозии. Наибольшее распространение гальваническое цинкование
получило при производстве крепёжных изделий, гвоздей и стальной
сетки. В большей степени это обусловлено высокой
производительностью гальванических агрегатов, низкой
себестоимостью процесса и достаточной степенью защиты от
коррозии. Существует и ряд ограничений использования
гальванического цинкования как способа защиты метизов от коррозии.
Цинкование – основной способ защиты базового металла
метизов от коррозии. Как правило, защита этим способом
используется для различных марок углеродистых и легированных
сталей. Гальваническое цинкование в метизном производстве
применяется для защиты от коррозии изделий из проволоки и
различного крепежа. Цинковое покрытие значительно увеличивает
срок эксплуатации изделия и снижает затраты при его техническом
обслуживании и замене. Принцип защиты изделий на основе
цинкового покрытия определяется разностью электрохимических
потенциалов Zn и Fe. Цинковое покрытие во влажной среде выступает
в качестве анода, принимая на себя все пагубные процессы
окислительных реакций и защищая тем самым основной металл
изделия. (From Гальваническое цинкование / «Метизы», №1(22), 2010
// www.mtk-fortuna.ru/articles.aspx)
7. Work in pairs. Translate the following text from English
into Russian at sight.
Normal zinc-plated coatings are dull gray with a matte finish,
although whiter, more lustrous coatings can be produced, depending on the
process or agents added to the plating bath or through post-treatments. The
coating is thin, ranging up to 1 mil (25 μm), restricting zinc-plated parts to
very mild (indoor) exposures. The number indicates the coating thickness in
microns (μm). Zinc plating is typically used for screws and other light
fasteners, light switch plates, and various small parts. Materials for use in
moderate or severe environments must be chromate conversion coated for
additional corrosion protection.
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The coating is pure zinc, which has a hardness about one-third to
one-half that of most steels.
8. Work in pairs. Interpret the following passage sentence by
sentence.
Zinc plating is identical to electrogalvanizing in principle because
both are electrodeposition processes. Zinc plating is used for coatings
deposited on small parts such as fasteners, crank handles, springs and other
hardware items. The zinc is supplied as an expendable electrode in a
cyanide, alkaline noncyanide, or acid chloride salt solution. Cyanide baths
are the most operationally efficient but can potentially create pollution and
are hazardous. After alkaline or electrolytic cleaning, pickling to remove
surface oxides, and rinsing, the parts are loaded into a barrel, rack, or drum
and immersed in the plating solution. Various brightening agents may be
added to the solution to add luster, but careful control is needed to ensure a
quality product. Post-plating treatments may be used to passivate the zinc
surface as well as impart various translucent colors or to extend the life of
the coating.
9. Give English equivalents to the following word combinations
and learn them by heart:
защита от ржавчины
уникальные свойства
сетчатые секции
электролит для осаждения гальванических покрытий
металлоизделие
осветляющее средство
обеспечивать качественным продуктом
электролитическое травление
10. Give Russian equivalents to the following word
combinations and learn them by heart:
weakly acid solution
metal production
high coverability
72
cyanide zinc plating
alkaline zinc plating
zinc acid plating
fixing arrangements
high luster
11. Translate the following sentences into Russian.
1. Zinc coatings provide the most effective and economical way of
protecting steel against corrosion.
2. Zinc is an integral part of our environment and exists naturally in
rock, soil, air and water.
3. Zinc is also an essential element for all life, from humans and
animals to plants and micro-organisms.
4. All types of zinc-coated steel products are recyclable.
5. When left unprotected, steel will corrode in almost any
environment.
6. Zinc coatings protect steel by providing a physical barrier as well
as cathodic protection for the underlying steel.
7. It is important that the correct zinc coating is specified to provide
optimal performance under the exposure conditions to which the coating
will be subjected.
8. The term "duplex coating" is used for galvanized and painted
steel parts, whereas the term "coil coating" or “pre-painting” is used for
continuous galvanized and painted steel sheet.
9. Zinc is an excellent substrate for paint coatings because if the
paint film is broken, zinc’s high corrosion resistance prevents undercutting
of the paint film.
10. A pure zinc coating that is the standard continuous galvanized
product typically used in building panels, steel framing, agricultural and
automotive applications, as well as in numerous other functions.
12. Translate the following sentences into English.
1. Технология электролитического цинкования представляет
собой химический процесс – электролиз.
2. Цинк может использоваться в виде пластин, шаров,
загружаемых в специальные сетчатые секции, или в другом виде.
73
3. В процессе электролиза цинк (анод) растворяется, и его
ионы оседают на поверхности стальных изделий, формируя
гальваническое покрытие толщиной от 4 до 20 мкм.
4. Анодное растворение цинковых электродов происходит в
результате пропускания через электролит электрического тока с
катодной плотностью от 1 до 5 А/дм².
5. В настоящее время в метизном производстве для защиты
изделий от коррозии применяется три способа гальванического
цинкования: цианидное, щелочное и кислотное.
6. Наиболее популярной технологией гальванического
цинкования является технология цинкования в слабокислых
электролитах.
7. Технология цинкования обладает высокой степенью
укрываемости и улучшенным внешним видом цинкового покрытия.
8. В современном метизном производстве этот способ
нанесения защитного покрытия является самым распространенным
среди производителей крепёжных изделий.
9. Цинкование в слабокислых электролитах позволяет
получить наибольший декоративный эффект.
10. Изделия с защитным покрытием цинком, полученные по
технологии слабокислотного цинкования, обладают высоким блеском,
разнообразной цветовой гаммой и высокой коррозионной защитой.
13. Translate the following word combinations.
Protect the base metal – стальная сетка – plating bath –анодное
растворение – steel framing – электролитическое травление – corrosion
resistance – марка углеродистой стали – automotive application –
легированная сталь – expendable electrode – слабокислый электролит –
post-plating treatment – crank handles – разность потенциалов – ferrous
material.
14. Give the definitions of the words and word combinations.
1. Metalware is … .
2. Zinc coating is … .
3. Rectifier is … .
74
Unit 10.
4. Electro-chemical potential is … .
5. Oxidation is … .
15. Describe the process of electroetching.
16. Answer the following questions using texts from Unit 10.
1. What is zing coating?
2. Describe zinc coating technology. Give your examples.
3. What properties do zinc-coated products have?
17. Summarize the general ideas developed in all the texts of the
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Unit 11
А
В
NICKEL PLATING
1. Read the international words, guess their meanings and give
the Russian equivalents.
Engineering, parameter, nickel, million, process, polishing,
combination, period, diffusion, textile, photocopying, automotive,
electronics, communication, fabrication, telecommunication, barrier,
magnetic.
2. Read and translate the following verbs.
To vary, to operate, to consume, to deposit, to tarnish, to prevent, to
develop, to begin, to extend, to wear, to exist, to differ, electroplate, to
specify, to separate, to include, to entertain, to photocopy.
3. Match the English phrases from column A with the Russian
phrases in column B.
1) nickel plating
2) electroforming
3) electrodeposited nickel
4) annual consumption
5) organic additive
6) magnetic properties
7) tarnishing of nickel
8) multilayer nickel coating
9) discontinuous chromium
10) consumer electronics
11) surfaces for enameling
a) полимолекулярное
никелирование
b) магнитные свойства
c) бытовая электронная техника
d) электролитический никель
e) поверхности для покрытия
эмалью
f) годовой расход
g) никелирование
h) неоднородный хром
i) органический наполнитель
j) электролитическое
формование
k) окисление никеля
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4. Read and translate the text. Summarize it in Russian.
The nickel plating process is used extensively for decorative,
engineering and electroforming purposes because the appearance and other
properties of electrodeposited nickel can be varied over wide ranges by
controlling the composition and the operating parameters of the plating
solution. Decorative applications account for about 80% of the nickel
consumed in plating; 20% is consumed for engineering and electroforming
purposes. Autocatalytic (electroless) nickel plating processes are
commercially important, but are outside the scope of this article. The annual
worldwide consumption of nickel for electroplating, including nickel
consumed as plating salts, is approximately 180 million pounds (81,700
metric tons), and accounts for 11 to 12 percent of world nickel
consumption.
Decorative Plating
Modern decorative nickel plating solutions contain organic
additives that modify the electrocrystallization process so that mirror-bright,
highly-leveled nickel coatings are deposited directly from solution. Prior to
the introduction of the "organic" baths, decorative nickel coatings were
produced by polishing nickel-plated parts mechanically, a practice that
continued from 1870 to about 1945. Thin layers of chromium were
electrodeposited over polished nickel coatings for the first time in 1927 to
prevent the "yellowing" or tarnishing of nickel in outdoor atmospheres, and
that practice continues with the as-deposited bright nickel coatings now
available. An effort to develop improved decorative, electroplated nickel
coatings began in the late 1940's and led to the development of multilayer
nickel coatings (early 1950's) and microdiscontinuous chromium coatings
(mid-to-late 1960's). Modern multilayer nickel coatings in combination with
microdiscontinuous chromium are capable of protecting and enhancing the
appearance of most metals and alloys, plateable plastics and other materials
for extended periods of time. (From Nickel Plating by George Di Baki,
ASM Handbook, Vol.5, Surface Engineering, 1994, p.201 //
www.academicjournals.org)
77
5. Read the text again. Decide whether the following
statements are true or false.
1. The nickel plating process is used mostly for designing,
engineering and galvanizing purposes.
2. The annual consumption of nickel for electroplating is about 180
million pounds and accounts for 20 to 30 percent of European nickel
consumption.
3. Modern decorative nickel plating solutions contain inorganic
additives that modify the electrocrystallization process.
4. Mirror-bright, highly-leveled nickel coatings are deposited
indirectly from solution.
6. Read the text. What is its main idea?
Гальванические декоративно-защитные либо технологические
покрытия на металлических изделиях представляют собой тонкий
поверхностный слой другого металла, обладающего более лучшими
технологическими или антикоррозионными свойствами и хорошим
эстетическим видом (например, никель, хром, серебро, цинк).
При подготовке к выполнению гальванических работ мастерлюбитель должен иметь мощный заземленный источник питания
постоянным током с плавной регулировкой выходной мощности с
максимальным током 20 А. Это может быть выпрямитель заводского
производства либо простой, но мощный выпрямитель незаводского
изготовления.
Одним из самых важных условий получения качественного
гальванического покрытия является предварительная подготовка
пескоструйка, шлифовка, обезжиривание изделия.
Шлифовку осуществляют механическим способом с помощью
карцовочной щетки, шлифовочных паст и наждачных шкурок.
Обезжиривание подготавливаемых деталей производят в
органических растворителях: спирте, бензине, ацетоне, бензоле,
трихлорэтилене. Подготавливаемую деталь тщательно промывают в
растворителях, обращая внимание на труднодоступные места к
которым сложно подобраться. (From Гальваника в домашних условиях
// www.galvan.ru)
78
7. Work in pairs. Translate the following text from English into
Russian.
Engineering Plating
The engineering applications of nickel plating include those where
a fully-bright appearance is not required. Engineering nickel deposits are
usually sulfur-free, and matte in appearance. These deposits may be
specified to improve corrosion and wear resistance, to salvage or build up
worn or undersized parts, to modify magnetic properties, to prepare
surfaces for enameling or for organic coating, to function as diffusion
barriers in electronic applications and for other purposes. Engineering
applications exist in the chemical, nuclear, telecommunications, consumer
electronics and computer industries.
Electroforming
Nickel electroforming is electrodeposition applied to the
manufacture of nickel products of various kinds and differs from
electroplating in one major respect. In electroplating, the coating is
metallurgically bonded to the substrate and is an integral part of the surface.
In electroforming, nickel is deposited onto a mandrel or mold nonadherently so that the nickel can be separated from the mandrel when it is
removed from the plating solution. Electroforming applications include the
fabrication of molds and dies, mesh and other products that are
indispensable to operations in the textile, aerospace, communication,
electronics, automotive, photocopying and entertainment industries.
8. Work in pairs. Interpret the following passage sentence by
sentence.
Nickel plating is a process that deposits a thin layer of nickel onto
an underlying metal. Some of the benefits of nickel plating include
increased resistance to corrosion or rust, improved resistance to wear,
strength, and improved ductility. Nickel plating is often seen on hardware
for household use such as faucets, door hinges, and toasters. Military and
aerospace use nickel plating to protect parts from corrosion.
Two different methods may be used to add nickel plating:
electrolytic, also called "galvanic," and purely chemical, also called
"electroless." Electrolytic plating involves passing a small electric current
between the positive and negative electric poles, thereby depositing nickel
79
on the object being plated. The chemical method relies wholly upon a
chemical reaction to apply the layer of nickel.
Electrolytic nickel plating commonly uses the technique of first
depositing a thin copper film on the material being plated, the substrate, and
then plating nickel onto the copper. The reason for this approach is that
copper will adhere to other metals better than nickel. Copper first, then
nickel is a quicker process with a smoother and more consistent finish than
plating nickel directly onto the substrate. Either way, the surface of the
substrate must be chemically clean before the process begins. Rinsing or
other cleaning after is usual.
The most common plating, nickel-phosphorous, produces a hard
surface when small amounts of phosphorous are used. It also creates a
bright surface and a speedy process with moderate levels. This type of
plating provides very high corrosion resistance, and is suitable to use in
highly acidic conditions like oil drilling or coal mining, when high levels
are used.
9. Give English equivalents to the following word combinations
and learn them by heart:
улучшенная вязкость
тонкий слой никеля
использование в быту
химический метод
тонкая медная пленка
сильнокислая среда
переработка нефти
добыча угля
10. Give Russian equivalents to the following word
combinations and learn them by heart:
grounded source
anticorrosion properties
pick current
power output
electric pole
sanding apparatus
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