Volume 03 Issue 12-2023
49
International Journal of Advance Scientific Research
(ISSN
–
2750-1396)
VOLUME
03
ISSUE
12
Pages:
49-54
SJIF
I
MPACT
FACTOR
(2021:
5.478
)
(2022:
5.636
)
(2023:
6.741
)
OCLC
–
1368736135
A
BSTRACT
Currently, there are new, important tasks in the field of galvanotechnics. In addition to coatings with good
corrosion resistance and mechanical properties, it is required to create coatings with high gloss and special
magnetic properties, high conductivity, heat resistance, and the ability to retain the hardening property
even after long storage in the air. At the same time, automatic control and acceleration of the process,
control of electrolytic processes, and the introduction of automation of management are also important.
K
EYWORDS
Aluminum, tin, zinc, vibrogrinding and vibropolishing, copper (II) sulfate, oxalic acid, sulfuric acid,
hydrogen peroxide, thiourea, chromic anhydride, chloride and sulfuric acids, inhibitor, carpentry glue,
corrosion, etc.
I
NTRODUCTION
The purpose of preparing the surface of the object
to be coated with a metal coating is to remove
rust, oil, oxide film and other defects using
mechanical, chemical and electrochemical
methods.
Journal
Website:
http://sciencebring.co
m/index.php/ijasr
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Research Article
PROCESSES FOR SPECIAL SURFACE PREPARATION OF NON-
FRONTOUS METALS BEFORE COATING
Submission Date:
December 01, 2023,
Accepted Date:
December 06, 2023,
Published Date:
December 11, 2023
Crossref doi:
https://doi.org/10.37547/ijasr-03-12-09
Xolmominova Dilrabo Axmatqulovna
Jizzakh Polytechnic Institute, Uzbekistan
Saidmirzayeva Dilnoza Baqdurdiyevna
Jizzakh Polytechnic Institute, Uzbekistan
Volume 03 Issue 12-2023
50
International Journal of Advance Scientific Research
(ISSN
–
2750-1396)
VOLUME
03
ISSUE
12
Pages:
49-54
SJIF
I
MPACT
FACTOR
(2021:
5.478
)
(2022:
5.636
)
(2023:
6.741
)
OCLC
–
1368736135
Often, a 0.2-0.7% solution of household soap is
used as a working medium. To speed up the
process, especially when processing ferrous
metals, the soapy solution is heated to 40-50 °C.
The duration of use of the solution is up to 24
hours, after which it is necessary to replace it. To
improve the quality of processing, surfactant
additives are added to the soapy solution. "Petrov
contact", NP-2 and NP-3 preparations and
detergents such as "Progress" are effective in
processing ferrous metals. In addition to soap
solutions, other solutions are used for polishing
and polishing processes.
Aqueous solutions in product processing
Item material
Composition of the solution, %
Polishing
Glittering
Carbon steel
0,8Na
3
PO
4
+ 0,2NaNO
3
;
(1-2)Na
2
SO
3
+ 0,5kanifol;
(2-3)NaOH
0,3Na
3
PO
4
+ 0,8NaSiO
3
;
0,2Na
2
SO
3
+ 0,2CaSO
3
;
0,2NaNO
2
Corrosion resistant
steel
0,2Na
2
SO
3
+ 0,25NaNO
3
+ +
0,2Ca(OH)
2
;
0,8Na
3
PO
4
+ 0,2NaNO
3
;
1,0Na
2
SO
3
+ 0,25NaNO
3
+ +
0,2CaO;
Aluminum, tin, zinc and
their alloys
0,8Na
3
PO
4
1,0CrO
3
+ 0,5H
2
SO
4
;
Copper and its alloys
(0,5-1,0)Na
2
SO
3
;
0,8Na
3
PO
4
1,0CrO
3
+ 0,5NaCl
Vibration treatment is one of the most modern
methods of preparing the surface of the object to
be coated. Vibration processing (vibrogrinding
and vibropolishing) is a process of mechanical or
chemical-mechanical
leveling
of
micro-
uniformities and removal of small particles of
metal and its oxide with particles of the working
medium.
Vibrochemical processing is a somewhat effective
method. Chemically active liquids are used as a
working solution in processing using this method.
The difference between this method and the
method of vibration processing is that the use of
chemical solutions leads to the formation of a
porous film with passivating properties. For
vibrochemical processing, solutions of metal salts
are used, which have a higher electropositivity
compared to the electrode potential of the metal
being processed. When choosing a working
environment, it is necessary to take into account
its oxidizing effect, formation of galvanic pairs,
Volume 03 Issue 12-2023
51
International Journal of Advance Scientific Research
(ISSN
–
2750-1396)
VOLUME
03
ISSUE
12
Pages:
49-54
SJIF
I
MPACT
FACTOR
(2021:
5.478
)
(2022:
5.636
)
(2023:
6.741
)
OCLC
–
1368736135
mechanical solubility, easy cleaning of details
from reaction products.
In the vibrochemical treatment of ferrous metals,
it is considered appropriate to use one of the
solutions with the following composition (g/l):
-copper(II) sulfate (10-50) + oxalic acid (60) +
sulfuric acid (9) + hydrogen peroxide (13) +
thiourea (3);
-chromic anhydride (10) + "Progress" detergent
(10-15);
- hydrochloric and sulfuric acids (5 %) + PB-8
inhibitor carpentry glue (0.5-1.0).
For vibrochemical treatment of brass, solutions
with the following composition (g/l): copper(II)
sulfate (80-120) + 25% solution of ammonia
(100-140) are used.
Aluminum and its alloys are treated with
solutions of sodium alkali with a concentration of
10-30 g/l.
- Degreasing in alkaline solutions. Alkaline
degreasing can be carried out in pure alkaline
solutions, in solutions with special surfactants
added, and by adding surfactants to alkaline
solutions. The alkaline method of degreasing is
based on the properties of solutions and solutions
of alkali metal salts to wash away fats and oils, as
a result of which they are easily removed from the
surface of the treated surface. Surface degreasing
in solutions containing surfactants is based on:
- the treated surface is washed in an aqueous
solution of surfactants;
- the contaminated product formed due to
emulsification,
dispersion,
suspension,
solubilization is removed from the surface of the
processed material;
- the contaminated product is retained in the
washing solution and is removed from the
degreasing bath in suspended, emulsified and
solubilized form.
Alkaline environment has a positive effect on the
surface-active substances contained in the
washing solution, increases its dispersing
properties and increases the stability of the
suspension resulting from the cleaning of the
suspension.
The inclusion of silicates in the composition of
the washing solution ensures the inhibitory
properties of the solution against the treated
metal.
Phosphates reduce the hardness of water,
dissolve carbonates of multivalent metals,
convert iron salts into complex compounds and
neutralize them. In addition, phosphates have the
property of suspending and peptizing solid
particles, so the contaminated product is retained
in the solution in a finely dispersed form and, as a
result, does not settle on the surface being
degreased.
Detergents use anionic and foaming agents as
surfactants. For degreasing, parts are immersed
in a bath or washed in special machines in a
stream of degreasing solution.
Volume 03 Issue 12-2023
52
International Journal of Advance Scientific Research
(ISSN
–
2750-1396)
VOLUME
03
ISSUE
12
Pages:
49-54
SJIF
I
MPACT
FACTOR
(2021:
5.478
)
(2022:
5.636
)
(2023:
6.741
)
OCLC
–
1368736135
Before covering plastic parts with metals, they are
degreased for 5-10 minutes in solutions with the
following
composition:
15-20%
sodium
carbonate; 15-20% solutions of sodium
phosphate or 5-10% solutions of "Progress"
detergent.
Electrochemical Degreasing Electrochemical
degreasing of a metal coating before applying it to
the surface is one of the most effective methods of
surface cleaning. In this method, under the
influence of current, emulsification is observed at
the expense of hydrogen bubbles in the cathode
or oxygen bubbles in the anode.
Electrochemical degreasing also uses solutions
with a lower concentration than chemical
degreasing.
Electrochemical degreasing solutions are
required to easily wash away oils, easily emulsify
contaminated products, have high electrical
conductivity, and it is mainly determined by the
concentration of alkali, sodium carbonate.
Surfactants are not added to these solutions or
are added in minimal amounts. At the same time,
they tend to form foam, which makes it difficult
for the separation of gases in the electrodes and
causes the formation of explosive gas mixtures.
Non-ferrous solutions are degreased only at the
cathode, and most ferrous metals are degreased
first at the cathode and then at the anode
(tk:ta=5:4). As the temperature and current
density increase, the degreasing process
accelerates, but the consumption of electricity
decreases. In industry, it is possible to stop the
complete diffusion of hydrogen into the metal by
using an alternating current with a frequency
current density of 8-10 A/dm2 and a voltage of
10-15 V.
The composition of degreasing solutions is given
in the table below. In all cases, the electrolysis
process is carried out at 3-8 A/dm2, the
temperature of the solution with added
surfactants is 50-
60°С.
Electrolyte
Concentrations of solution components, g/l
1
2
3
4
5
6
NaOH
10
30-40
100
30-60
-
-
Na
3
PO
4
20-30
50-60
-
-
30-40
50-60
Na
2
CO
3
20-30
20-30
50
20-35
5-10
40-50
Suyuq shisha
3-5
8-10
3-5
5-10
3-5
3-5
Sintanol DS-10
-
1-2
-
-
-
1-2
Electrolyte
Concentrations of solution components, g/l
7
8
9
10
11
NaOH
-
10-12
10-20
10-20
-
Volume 03 Issue 12-2023
53
International Journal of Advance Scientific Research
(ISSN
–
2750-1396)
VOLUME
03
ISSUE
12
Pages:
49-54
SJIF
I
MPACT
FACTOR
(2021:
5.478
)
(2022:
5.636
)
(2023:
6.741
)
OCLC
–
1368736135
Na
3
PO
4
40-50
10-12
-
30-50
25-30
Na
2
CO
3
-
10-12
15-30
20-30
25-30
Liquid bottle
-
20-25
-
3-5
-
Sintanol DS-10
-
-
-
-
1-2
Note: Solution 10 contains 1-5 g/l Progress detergent.
Solutions 1 and 2 are designed for degreasing
steel products. Solution 2 is used for degreasing
copper and its alloys, and solution 3 is a universal
liquid for degreasing steel products and metal
details coated in special devices. Solutions 7 and
8 are used to cover zinc and its alloys, and
solution 9 is used to cover nickel and nickel-
plated details. Solution 10 is used for degreasing
steel, titanium, kovar, invar products and for
degreasing steel products before coating with
cadmium. Solution 11 is used for degreasing
under the influence of constant current.
The electrochemical pickling method ensures that
the metal does not completely displace hydrogen
during the pickling process, reduces the
consumption of chemicals, and shortens the
duration of the process. Electrochemical etching
of metal occurs mostly at a constant current
anode.
After degreasing and washing, a passive film is
formed on the surface of the metal, which must be
removed before immersing the details in the
coating bath. Activation (removal of the passive
film on the surface) is especially important for
corrosion-resistant and heat-resistant steels.
It is impossible to obtain a high-quality coating
without activating such films formed at the
expense of alloying components.
Carbon steels, copper, nickel and their alloys are
activated in 5-10% sulfuric or hydrochloric acid
solutions or their mixtures.
When chroming corrosion-resistant steels, their
electrochemical activation can be carried out
directly in the chroming bath itself at J=30-50
A/dm2, t=50±5 °C, t=15-30 seconds. Then the
items are transferred to the cathode, and chrome
plating is carried out in the usual mode.
R
EFERENCES
1.
Скопинцев
В.Д.
«Оксидирование
алюминия и его сплавов». –
М.: РХТУ
им.Д.И.Менделеева, 2015. –
120 с.
2.
Ротинян А.Л., Тихонов К.И., Шошина И.А.,
Тимонов
А.М.
«Теоретическая
электрохимия». –
М.: Студент, 2013. –
494 с.
3.
Истомина Н.В., Сосновская Н.Г., Ковалюк
Е.Н. «Оборудование электрохимических
производств». Учебное пособие. –
2-
е изд.,
перераб. –
Ангарск: АГТА, 2010. –
100 с.
4.
Федосова Н.Л. и др. «Антикоррозионная
защита металлов». –
Иваново, 2009. –
187 с.
Volume 03 Issue 12-2023
54
International Journal of Advance Scientific Research
(ISSN
–
2750-1396)
VOLUME
03
ISSUE
12
Pages:
49-54
SJIF
I
MPACT
FACTOR
(2021:
5.478
)
(2022:
5.636
)
(2023:
6.741
)
OCLC
–
1368736135
5.
Окулов В.В. «Цинкование. Техника и
технология». –
М.: Глобус, 2008. –
252 с.
6.
Григорян Н.С., Акимова Е.Ф., Ваграмян Т.А.
«Фосфатирование». –
М.: Глобус, 2008. –
144 с.
