Influence of the nanostructure of surface ceramic coatings on their tribological properties
This study is an attempt of applying new electrolytes to obtain new generation oxide coatings. An oxide coating was deposited on aluminium Al(Al 99.5). The influence of an organic additive and anodizing parameters on the nanomorphology and nanostructure of the obtained coatings is described. The nan...
Gespeichert in:
| Datum: | 2014 |
|---|---|
| 1. Verfasser: | |
| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
Фізико-механічний інститут ім. Г.В. Карпенка НАН України
2014
|
| Schriftenreihe: | Фізико-хімічна механіка матеріалів |
| Online Zugang: | http://dspace.nbuv.gov.ua/handle/123456789/136121 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Influence of the nanostructure of surface ceramic coatings on their tribological properties / W. Skoneczny // Фізико-хімічна механіка матеріалів. — 2014. — Т. 50, № 3. — С. 111-116. — Бібліогр.: 10 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-136121 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1361212018-06-16T03:07:02Z Influence of the nanostructure of surface ceramic coatings on their tribological properties Skoneczny, W. This study is an attempt of applying new electrolytes to obtain new generation oxide coatings. An oxide coating was deposited on aluminium Al(Al 99.5). The influence of an organic additive and anodizing parameters on the nanomorphology and nanostructure of the obtained coatings is described. The nanostructure and nanomorphology of oxide coatings were determined using a scanning electron microscope (SEM). An attempt was made to apply a new oxide coating for a sliding interaction with TGK 20/5 material. Tests were carried out under dry friction conditions. The friction coefficient was evaluated for the investigated sliding couple, as well as the intensity of wear of the specimens made of this material. The influence of the oxide coating nanostructure on the tribological properties of the tested couple was also determined. Розроблено електроліти для формування нової генерації оксидних покривів на алюмінії. Методом сканівної електронної мікроскопії досліджено вплив органічних додатків до цих електролітів та параметрів анодування алюмінію на наноморфологію та наноструктуру покриву. Застосовано новий покрив у парі ковзання з матеріалом TGK 20/5. Випробувано за умов сухого тертя. Встановлено коефіцієнт тертя пари ковзання, а також інтенсивність зношування зразків з цього матеріалу. Визначено вплив наноструктури оксидного покриву на трибологічні властивості досліджуваної пари. Разработаны электролиты для формирования новой генерации оксидных покрытий на алюминии. Методом сканирующей электронной микроскопии исследовано влияние органических добавок к этим электролитам и параметров анодирования алюминия на наноморфологию и наноструктуру покрытия. Применено новое покрытие в паре скольжения с материалом TGK 20/5. Испытано в условиях сухого трения. Установлен коэффициент трения пары скольжения, а также интенсивность изнашивания образцов из этого материала. Определено влияние наноструктуры оксидного покрытия на трибологические свойства исследуемой пары. 2014 Article Influence of the nanostructure of surface ceramic coatings on their tribological properties / W. Skoneczny // Фізико-хімічна механіка матеріалів. — 2014. — Т. 50, № 3. — С. 111-116. — Бібліогр.: 10 назв. — англ. 0430-6252 http://dspace.nbuv.gov.ua/handle/123456789/136121 en Фізико-хімічна механіка матеріалів Фізико-механічний інститут ім. Г.В. Карпенка НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
This study is an attempt of applying new electrolytes to obtain new generation oxide coatings. An oxide coating was deposited on aluminium Al(Al 99.5). The influence of an organic additive and anodizing parameters on the nanomorphology and nanostructure of the obtained coatings is described. The nanostructure and nanomorphology of oxide coatings were determined using a scanning electron microscope (SEM). An attempt was made to apply a new oxide coating for a sliding interaction with TGK 20/5 material. Tests were carried out under dry friction conditions. The friction coefficient was evaluated for the investigated sliding couple, as well as the intensity of wear of the specimens made of this material. The influence of the oxide coating nanostructure on the tribological properties of the tested couple was also determined. |
| format |
Article |
| author |
Skoneczny, W. |
| spellingShingle |
Skoneczny, W. Influence of the nanostructure of surface ceramic coatings on their tribological properties Фізико-хімічна механіка матеріалів |
| author_facet |
Skoneczny, W. |
| author_sort |
Skoneczny, W. |
| title |
Influence of the nanostructure of surface ceramic coatings on their tribological properties |
| title_short |
Influence of the nanostructure of surface ceramic coatings on their tribological properties |
| title_full |
Influence of the nanostructure of surface ceramic coatings on their tribological properties |
| title_fullStr |
Influence of the nanostructure of surface ceramic coatings on their tribological properties |
| title_full_unstemmed |
Influence of the nanostructure of surface ceramic coatings on their tribological properties |
| title_sort |
influence of the nanostructure of surface ceramic coatings on their tribological properties |
| publisher |
Фізико-механічний інститут ім. Г.В. Карпенка НАН України |
| publishDate |
2014 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/136121 |
| citation_txt |
Influence of the nanostructure of surface ceramic coatings on their tribological properties / W. Skoneczny // Фізико-хімічна механіка матеріалів. — 2014. — Т. 50, № 3. — С. 111-116. — Бібліогр.: 10 назв. — англ. |
| series |
Фізико-хімічна механіка матеріалів |
| work_keys_str_mv |
AT skonecznyw influenceofthenanostructureofsurfaceceramiccoatingsontheirtribologicalproperties |
| first_indexed |
2025-07-10T00:40:41Z |
| last_indexed |
2025-07-10T00:40:41Z |
| _version_ |
1837218442819665920 |
| fulltext |
111
Ô³çèêî-õ³ì³÷íà ìåõàí³êà ìàòåð³àë³â. – 2014. – ¹ 3. – Physicochemical Mechanics of Materials
INFLUENCE OF THE NANOSTRUCTURE OF SURFACE
CERAMIC COATINGS ON THEIR TRIBOLOGICAL PROPERTIES
W. SKONECZNY
University of Silesia, Sosnowiec, Poland
This study is an attempt of applying new electrolytes to obtain new generation oxide
coatings. An oxide coating was deposited on aluminium Al(Al 99.5). The influence of an
organic additive and anodizing parameters on the nanomorphology and nanostructure of
the obtained coatings is described. The nanostructure and nanomorphology of oxide
coatings were determined using a scanning electron microscope (SEM). An attempt was
made to apply a new oxide coating for a sliding interaction with TGK 20/5 material. Tests
were carried out under dry friction conditions. The friction coefficient was evaluated for
the investigated sliding couple, as well as the intensity of wear of the specimens made of
this material. The influence of the oxide coating nanostructure on the tribological proper-
ties of the tested couple was also determined.
Keywords: nanostructure, oxide layers, hard anodising method, plastic, tribology.
One of the basic problems in the continuously developing fields of engineering
and technology is the manufacturing of high quality products with the production costs
which are as low as possible. Therefore, an important factor which determines the
method of forming parts of machines and devices is the manufacturing cost. The
above-mentioned minimization does not, however, consist in the technological or
organizational concentration of operations, but instead, in the design of a part which
can be manufactured with the lowest possible number of operations or treatments,
while simultaneously creating a surface coating with the required properties. Contem-
porary engineering and technology must satisfy at least the following requirements:
manufacturing cost minimization, while maintaining the appropriate quality of the pro-
duct; development of new engineering materials with consciously shaped properties;
development of new engineering materials able to operate at high temperatures [1].
The meeting of these expectations requires intensive development of the methods
of forming surface coatings. There are significant facts which support the usefulness of
directing further research towards improvement of the existing properties of oxide
coatings, thereby revealing the possibilities of applying them in the machine-building
industry. The list of engineering materials presented in paper [2], shows that these will
be ceramic materials and composites [2, 4] that shall predominate in the automotive
industry in the future.
A characteristic feature of ceramic materials is their insignificant wear and low
friction coefficient when co-working with other materials in the presence of a lubricant.
The most recent world trends in the machine-building sector, in particular with refe-
rence to piston machines, are heading towards reducing their lubrication and cooling.
Hence, the question arises of what the upper layer of a ceramic material should be like
in order to maintain low wear and frictional resistance.
The possibility of covering aluminium and its alloys with oxide coatings has re-
sulted in an enhanced application of these materials, especially as: anticorrosion protec-
Corresponding author: W. SKONECZNY, e-mail: wladyslaw.skoneczny@us.edu.pl
112
tion, protective and decorative coatings, undercoatings; components of couplings,
transmissions, guides and slideways; components in automatics and hydraulic con-
trollers; rolling bearing races in steel–Al2O3 couple; engine pistons and compressor
cylinders’ sliding surfaces.
In order to strengthen the surface layer of aluminium alloys for cooperation sli-
ding at high pressures (for example in lubricant free compressors) we use hard anoding.
The objective of the presented study is to determine the principal physico-mecha-
nical and tribological characteristics of newly developed oxide coatings in interaction
with the TGK 20/5 material, and to determine the usefulness of this couple for further
operational tests which precede their potential implementation in lubricant-free com-
pressors and pneumatic servo-motors.
Experimental details. Adding the organic substances with surface-active proper-
ties to the electrolyte has a significant influence on the mechanism of forming oxide
coatings on aluminium. The mechanism of the influence of organic substances depends
on the additive properties, as well as on the composition and properties of the electro-
lyte. A supposition can be made that under proper conditions the surface-active organic
substances fully or partly cover the surface of the anode (on active places), as a result
of which the oxidation of aluminium is considerably impaired. On the other hand, the
adsorption of organic substances at the anode/electrolyte interface leads to holding up
the secondary dissolution of the coating by the electrolyte. The role of this mechanism
is performed by the addition of the above-mentioned organic acids.
The method developed does not require cooling, and the process heat is used for
controlling the properties of the obtained oxide coatings. The control of the anodizing
parameters allows, within some limits, programming the selected functional properties
of the future surface coatings [5–10]. The above-mentioned method consists in oxi-
dizing aluminium and its alloys in three-component electrolytes. An organic acid is
added to the electrolyte mixture, composed of sulphuric and oxalic acids.
The first stage of the tests carried out as part of the study consisted in preparing
the appropriate electrolytes and samples. The electrolytes, in which anodic oxidation
was conducted at elevated temperatures, were based on sulphuric and oxalic acids. The
following organic acids were marked out for the mixture of the above-mentioned
components:
– electrolyte 1 – benzoic acid;
– electrolyte 2 – sebacic acid;
– electrolyte 3 – succinic acid;
– electrolyte 4 – glutaric acid;
– electrolyte 5 – cuberic acid.
Primary aluminium, A1(Al 99.5), was used for the tests. Specimens were cut out
of a 1 mm thick sheet metal.
In order to obtain the oxide coating of appropriate quality, and to avoid any irre-
gularities in its structure, the surfaces of the specimens had to be correctly prepared
before the oxidation process. For this purpose they were subjected to mechanical sur-
face treatment which allowed the elimination of different scratches and irregularities,
and standardizing the surface of the prepared specimens. The test chart is presented in
the Table.
The specimens with the highest and the lowest porosity were selected for the tri-
bological tests.The sliding interaction between the produced oxide coating and counter-
specimens proceeded in the conditions of technically dry friction; the unit pressure
amounted to 0.1MPa, the average sliding speed was 1 m/s, and the area of the speci-
men contact with the counterspecimen was 1 cm2.
113
The counterspecimens in the tribological tests were cylinders made of TGK 20/5
material (PTFE containing 20% graphite and 5% coke) with a cross-section area equal
to 1 cm2.
Parameters of forming oxide coatings
Type of
electrolyte
Symbol
Samales
Current
density, A/dm2 Temeprature, K Time, min
A 2 293 40
B 3 303 60 1
C 4 313 80
D 2 293 40
E 3 303 60 2
F 4 313 80
G 2 293 40
H 3 303 60 3
I 4 313 80
J 2 293 40
K 3 303 60 4
L 4 313 80
Ł 2 293 40
M 3 303 60 5
N 4 313 80
Investigation of the tribological properties of the oxide coatings produced was
conducted on the SDN measuring stand, constructed at the Department of Materials
Science, University of Silesia (Fig. 1).
Fig. 1. Schematic of the SDN-set-up:
1 – specimen; 2 – counter-specimen;
3 – slide bar; 4 – frames; 5 – beam;
6 – strain gauges; 7 – hydraulic cylinder;
8 – joint; 9 – wires; 10 – regulator;
11 –manometer; 12 – pump;
13 – electric motor; 14 – manometer.
The value of wear was determined by weighing the counterspecimens before and
after the sliding interaction. The counterspecimens were weighed after each stage of
the interaction (every 96 km), using an analytical balance, WA 35, type TA 14, with a
range of 100 g and accuracy of 0.01 mg. The friction coefficient value was calculated
from the Amontons’ formula.
Results and discussion. Results of examination of the nanomorphology and
nanostructure of the obtained oxide coatings are presented in Fig. 2. The examination
was conducted using a Philips X130 scanning electron microscope.
A model of the structure of the oxide coating produced by hard anodizing in three-
component electrolytes is presented in Fig. 3 [5].
114
Fig. 2. SEM images of morphology (a, b) and cross-section (c, d) of Al2O3 oxide layers.
Fig. 3. Model of real structure
of oxide layers of Al2O3 obtained via
hard anodic treatment [5]:
1 – metal; 2 – admixture;
3 – microporous; 4 – nanoporous;
5 – oxide cover; 6 – porous layer;
7 – barrier layer.
Fig. 4. Fig. 5.
Fig. 4. Thickness of the oxide coatings depending on current density in particular electrolytes:
1 – electrolyte 1; 2 – electrolyte 2; 3 – electrolyte 3; 4 – electrolyte 4; 5 – electrolyte 5.
Fig. 5. Volumetric porosity of the oxide coatings depending on the current density in particular
electrolytes: 1 – the lowest process parameters; 2 – the medium process parameters;
3 – the highest process parameters.
115
Based on the tests carried out, characteristics were prepared for the oxide coatings
in each of the electrolytes, describing their thickness, porosity and microhardness. Fig. 4
shows the correlations between the thickness of the obtained oxide coatings and current
density in the particular electrolytes. Results of porosity measurements of the oxide
coatings formed in the particular electrolytes are presented in Fig. 5. A comparative
juxtaposition of microhardness measurements of the oxide coatings is shown in Fig. 6.
Changes in the friction coefficient value for the oxide coatings in cooperation with
the material applied are presented in Fig. 7.
Fig. 6. Fig. 7.
Fig. 6. Microhardness of the oxide coatings: 1 – the lowest process parameters;
2 – the medium process parameters; 3 – the highest process parameters.
Fig. 7. Changes in the friction coefficient as a function of friction distance:
1 – specimen with the highest porosity; 2 – specimen with the lowest porosity.
Fig. 8 shows the value of wear intensity of the TGK 20/5 specimens material in
their wearing-in period (friction distance: 96 km) and during normal operation.
There are two stages to be distinguished in the period of friction and wear tests of
a friction couple: wearing-in; regular operation.
Based on the results obtained, it can be concluded that the friction coefficient of
the oxide coating working in a couple with the TGK 20/5 material is significantly
affected by the parameters of the oxidation process (current density, electrolyte tempe-
rature and oxidation time).
Fig. 8. Intensity of wear of the specimens
made from the material in interaction
with an oxide coating:
1 – wearing-in;
2 – operation stage.
Measurements of the wear intensity of specimens made from the above-mentioned
material under sliding interaction with an oxide coating have shown an 8-fold increase
in wear during the wearing-in period and a 7-fold increase at the operation stage in the
case of oxide coatings with the highest porosity.
CONCLUSION
From the results of the investigations presented it is possible to obtain oxide
coatings with predefined properties by appropriately controlling their production para-
116
meters. The microhardness and volumetric porosity of the oxide coatings obtained in
three-component electrolytes make these coatings preferred for sliding couples. The
addition of organic acid to the electrolyte enables the elimination of the cooling pro-
cess, which significantly reduces the production cost of the oxide coatings.
Based on the tribological tests it can be affirmed that, compared to other sliding
couples which work in the conditions of technically dry friction, the investigated
coatings, in particular those obtained with appropriate oxidation parameters, show
good tribological properties. Taking into account the wear of the TGK 20/5 material,
the tested couple can be applied in lubricant-free compressors or pneumatic servo-
motors. The cylinder bearing surfaces (in servo-motors) would be strengthened with an
oxide coating formed in a three-component electrolyte, and piston rings could be made
from TGK 20/5.
РЕЗЮМЕ. Розроблено електроліти для формування нової генерації оксидних покри-
вів на алюмінії. Методом сканівної електронної мікроскопії досліджено вплив органічних
додатків до цих електролітів та параметрів анодування алюмінію на наноморфологію та
наноструктуру покриву. Застосовано новий покрив у парі ковзання з матеріалом TGK 20/5.
Випробувано за умов сухого тертя. Встановлено коефіцієнт тертя пари ковзання, а також
інтенсивність зношування зразків з цього матеріалу. Визначено вплив наноструктури ок-
сидного покриву на трибологічні властивості досліджуваної пари.
РЕЗЮМЕ. Разработаны электролиты для формирования новой генерации оксидных
покрытий на алюминии. Методом сканирующей электронной микроскопии исследовано
влияние органических добавок к этим электролитам и параметров анодирования алюми-
ния на наноморфологию и наноструктуру покрытия. Применено новое покрытие в паре
скольжения с материалом TGK 20/5. Испытано в условиях сухого трения. Установлен
коэффициент трения пары скольжения, а также интенсивность изнашивания образцов из
этого материала. Определено влияние наноструктуры оксидного покрытия на трибологи-
ческие свойства исследуемой пары.
1. Skoneczny W. Shaping the properties of aluminium and aluminium alloys’ upper layers by
the hard anodizing method. – Bielsko-Biała: Łódź University of Technology, 2001. – 116 p.
2. Pytko S. The directions of tribology development in the world // Conf. on New Tendencies in
Tribology and Tribotechnology. – Częstochowa, 1997. – P. 5–14 .
3. Ciszewski B., Przetakiewicz W. Modern materials in technology. – Warsaw: Bellona
Publishing House, 1993. – 242 p.
4. Student M. M., Dovhunyk V. М., and Klapkiv М. D. Tribological properties of combined
metal-oxide–ceramic layers on light alloys // Material Science. – 2012. – 48, № 2. – P. 180–191.
5. Skoneczny W. Model of structure of Al2O3 layer obtained via hard anodizing method
// Surface Engng. – 2001. – 17. – P. 389–392.
6. Skoneczny W. Analysis of morphology and microstructure Al2O3 layers // Materials Science.
– 2010. – 46, № 2. – P. 276–282.
7. Skoneczny W., Jurusik J., and Burian A. Investigations of the surface morphology of Al2O3
layers by atomic force microscopy // Materials Science. – Poland. – 2004, 3. – P. 265–278.
8. Kmita T., Szade J., and Skoneczny W. Gradient oxide layers with an increased carbon content
on en AW-5251 alloy // Chemical and Process Engng. – 2008. – 29. – P. 375–387.
9. Bara M., Skoneczny W., and Hajduga M. Ceramic-graphite surface layers obtained by the
duplex method on an aluminum alloy substrate // Ibid. – 2009. – 30. – P. 431–442.
10. Kmita T. and Skoneczny W. Gradient layers on aluminium alloys created electrolytically
method // Ibid. – 2005. – 26. – P. 735–744.
Received 22.07.2013
|