Volume 04 Issue 02-2022
19
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
I
SSUE
02
Pages:
19-22
SJIF
I
MPACT
FACTOR
(2020:
5.
32
)
(2021:
5.
705
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
ABSTRACT
One of the functions of the oil is to protect the surface of parts from corrosion. Corrosion becomes especially intense
when the engine is operated in hot, humid climates. In this case, oil plays a double role: on the one hand, it protects
the surfaces of parts from the aggressive influence of the external environment; on the other hand, the oil itself is
corrosive due to the presence of corrosive substances in it.
This article presents studies of the mechanism of action of assessing the protective, surface and electrochemical
properties of inhibited compounds used in the development of lubricants.
KEYWORDS
Corrosion, adsorption, films, oxidation, corrosion inhibitors, protective properties.
INTRODUCTION
One of the functions of the oil is to protect the surface
of the parts from corrosion. The protective effect is
based on the ability of oils to quickly displace active
compounds from the metal surface, retain it in the
Research Article
RESEARCH OF THE MECHANISM OF ACTION OF THE PROTECTIVE
PROPERTIES OF INHIBITED COMPOSITIONS
Submission Date:
February 11, 2022,
Accepted Date:
February 18, 2022,
Published Date:
February 28, 2022 |
Crossref doi:
https://doi.org/10.37547/tajet/Volume04Issue02-05
Alimova Zebo Xamidullayevna
Candidate of technical sciences, professor, Uzbekistan
Niyazova Gulhayo Parpiyevna
Senior lecturer, Tashkent State Transport University, Uzbekistan
Journal
Website:
https://theamericanjou
rnals.com/index.php/ta
jet
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 04 Issue 02-2022
20
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
I
SSUE
02
Pages:
19-22
SJIF
I
MPACT
FACTOR
(2020:
5.
32
)
(2021:
5.
705
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
volume of the lubricant and form strong adsorption
and chemo-sorption films on it, preventing the
development of electrochemical processes.
The corrosive aggressiveness of oils increases
significantly in the presence of water in them, which
can get into the crankcase from the atmosphere or
from the engine cooling system. Corrosion inhibitors
are designed to protect the surface of engine parts
from corrosion caused by organic and mineral acids.
The mechanism of their action is the formation of a
protective film on the surface of the parts and the
neutralization of acids. In this paper, we consider the
processes of the mechanism of protective action of
corrosion inhibitors used in the development of
lubricants.
RESEARCH ANALYSIS
The development of preservative lubricants is carried
out on the basis of studying the mechanism of
protective action and evaluating the properties of
materials using a set of laboratory test methods.
Modern ideas about the mechanism of the protective
action of the corrosion inhibitor are mainly reduced to
two factors:
Displacement of water and electrolyte present
from the metal surface;
Creation of chemo-sorption and adsorption films
on the metal surface
The ability of corrosion inhibitors to displace water
from the metal surface is provided by polar
components that are part of the combined protective
additives. At the same time, the surface properties of
inhibitors at the "oil-metal" and "oil-electrolyte-metal"
interface are more important.
The essential role of the corrosion factor in the general
wear of machines and mechanisms is determined not
only by the corrosion of metal products during their
transportation and storage, but also by the intensive
course of corrosion processes during the operation of
engines, transmissions and other components of
equipment at high temperatures.
To assess the combined effect of chemical and
electrochemical corrosion on the destruction of
metals, a method has been developed (GOST 9.044-
75), which allows determining the degree of oxidation
of oil with moist air, as well as a method that
comprehensively evaluates all corrosion processes
occurring in the engine, including the thermal oxidative
stability of oils. The installation makes it possible to
evaluate the corrosion and protective properties of the
oil and the kinetics of high-temperature corrosion in
the oil volume, the development of electrochemical
corrosion in the oil-electrolyte system, the protective
properties of the oil in a thin film, the thermal oxidative
stability of the oil by changing its physicochemical
properties after oxidation.
There is a relation between the adsorption value and
the surface tension at constant temperature and
pressure:
where:
Г-the surface concentration (the amount of substance
accumulated per unit of the interface surface);
a- the activity of the solute;
dy- the change in surface tension;
R -the universal gas constant; T - the absolute
temperature.
Volume 04 Issue 02-2022
21
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
I
SSUE
02
Pages:
19-22
SJIF
I
MPACT
FACTOR
(2020:
5.
32
)
(2021:
5.
705
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
If an increase in the concentration of the solute leads
to a decrease in the surface tension, then the solute
accumulates on the interface (positive adsorption). On
the contrary, if the surface tension increases as the
concentration of the solute increases, then the solute
is removed from the interface (negative adsorption).
At the same time, the activity of water molecules
adsorbed on the metal surface will be significantly
reduced. Finally, the components of protective
additives can be dissolved in water and the corrosion
of metals in electrolytes can be inhibited by an
electrochemical mechanism. In this case, the additive
components will act as water-soluble corrosion
inhibitors. At the same time, the greater the activity of
inhibitors, the more hydrocarbon atoms the radical
contains. The mechanism of their action is to create a
protective monomolecular layer on the metal,
preventing the effect of acidic and other active agents
on the metal.
Methods for assessing the surface properties of
corrosion inhibitors characterize their ability to
penetrate cracks and micro-gaps of metal structures
during their conservation. The essence of the method
of spreading corrosion inhibitors is to determine the
diameter of the spot formed when 0.2 ml of the
product is applied to a metal surface after 2 hours. The
penetrating ability of corrosion inhibitors is
determined by measuring the lifting height of the
product under study in a narrow gap formed by two
steel plates tightly adjacent to each other for a certain
time. The impregnating ability of iron oxide powder
consists in determining the depth of penetration of
iron oxide products by the test subject for a certain
time.
The water-displacing ability of corrosion inhibitors
consists in determining the diameter of the surface
area of a wetted steel disc freed from water by a drop
of the product under study. After 5 seconds after
applying a drop of the product, the diameter of the
initially displaced water is measured, a secondary
measurement is made after 5 minutes, then the disc is
thoroughly washed with a jet of distilled water and the
diameter of the area not wetted with water is
measured.
To assess the adhesive-cohesive forces, a method has
been developed by which this indicator is estimated by
the separation force (in N/cm2) of two steel cylinders
tightly pressed together with the product under study
at the contact point. The separation force is fixed using
a lever dynamometer. After water is displaced from the
metal surface to the released active centers of the
metal surface, the components of the chemo-sorption
action are adsorbed, providing high binding energy
with the metal. The chemo-sorption monomolecular
film is covered with poly-molecular layers of adsorption
inhibitors. Thus, a strong multi-layered structure is
created, providing a high protective effect. The basis of
this effect, according to modern concepts, is the
polarization resistance of the protective film, the
resistance to the transfer of electric charges
(electrolyte ions, metal, etc.), formed as a result of
polarization phenomena on metal under the influence
of the medium.
CONCLUSIONS
The presented set of methods allows for a
comprehensive assessment of the anticorrosive
properties of protective lubricants, as well as the
mechanism of action of corrosion inhibitors. Based on
the proposed studies, it is possible to further develop
corrosion inhibitors for specific lubricants and conduct
experimental studies.
Volume 04 Issue 02-2022
22
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
I
SSUE
02
Pages:
19-22
SJIF
I
MPACT
FACTOR
(2020:
5.
32
)
(2021:
5.
705
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
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