Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite
Electrodeposition of tertiary Alumina/Yitria/carbon nanotube (Al2O3/Y2O3/CNT) nanocomposite by using pulsed current has been studied. Coating process has been performed in nickel sulphate bath and nanostructure of the obtained compound layer was examined with high precision figure analysis of SEM na...
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Фізико-механічний інститут ім. Г.В. Карпенка НАН України
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irk-123456789-317452012-03-18T12:11:13Z Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite Mirzamohammadi, S. Aliov, M.Kh. Sabur, A.R. Hassanzadeh-Tabrizi, A. Electrodeposition of tertiary Alumina/Yitria/carbon nanotube (Al2O3/Y2O3/CNT) nanocomposite by using pulsed current has been studied. Coating process has been performed in nickel sulphate bath and nanostructure of the obtained compound layer was examined with high precision figure analysis of SEM nanographs. The effects of process variables, i.e. Y2O3 concentration, treatment time, current density and temperature of electrolyte have been experimentally studied. Statistical methods were used to achieve the minimum wear rate and average size of nanoparticles. Finally the contribution percentage of different effective factors was revealed and confirmation run showed the validity of the obtained results. Also it has been revealed that by changing the size of nanoparticles, wear properties of coatings will change significantly. Atomic force microscopy (AFM) and transmission electron microscope (TEM) analysis have confirmed smooth surface and average size of nanoparticles in the optimal coating. Вивчено електроосадження методом імпульсного струму потрійного композиту на основі вуглецевих нанотрубок, алюмінію та ітрію оксидів. Покриви наносили у нікелесульфатній ванні, а наноструктуру отриманого складного шару досліджували методом комп’ютерного аналізу знімків, одержаних на електронному мікроскопі. Вплив змінних параметрів процесу, зокрема, концентрації Y2O3, часу обробки, густини струму та температури електроліту вивчали експериментально. Для мінімізації впливу відхилень швидкості зношування та середнього розміру наночастинок на аналіз експериментальних даних використовували статистичні методи. Встановлено процентний вклад різних факторів і виконано підтверджувальний розрахунок, який показав достовірність одержаних результатів. Також виявлено, що зміна розміру наночастинок та зносотривкість покривів матиматимуть значною мірою однаковий тренд. Изучено электроосаждение методом импульсного тока тройного композита на основе углеродных нанотрубок, алюминия и иттрия оксидов. Покрытия наносили в никельсульфатной ванне, а наноструктуру полученного сложного слоя исследовали методом компьютерного анализа снимков, полученных на электронном микроскопе. Влияние изменяющихся параметров процесса, в частности, концентрации Y2O3, времени обработки, плотности тока и температуры электролита изучали экспериментально. Для минимизации влияния отклонений скорости изнашивания и среднего размера наночастиц на анализ экспериментальных данных использовали статистические методы. Установлен процентный вклад разных факторов и проведен подтверждающий расчет, который показал достоверность полученных результатов. Также установлено, что изменение размера наночастиц и износостойкость покрытий имеют в значительной степени одинаковый тренд. 2010 Article Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite / S. Mirzamohammadi, M.Kh. Aliov, A.R. Sabur, A. Hassanzadeh-TAbrizi // Фізико-хімічна механіка матеріалів. — 2010. — Т. 46, № 1. — С. 67-75. — Бібліогр.: 13 назв. — англ. 0430-6252 http://dspace.nbuv.gov.ua/handle/123456789/31745 en Фізико-хімічна механіка матеріалів Фізико-механічний інститут ім. Г.В. Карпенка НАН України |
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Electrodeposition of tertiary Alumina/Yitria/carbon nanotube (Al2O3/Y2O3/CNT) nanocomposite by using pulsed current has been studied. Coating process has been performed in nickel sulphate bath and nanostructure of the obtained compound layer was examined with high precision figure analysis of SEM nanographs. The effects of process variables, i.e. Y2O3 concentration, treatment time, current density and temperature of electrolyte have been experimentally studied. Statistical methods were used to achieve the minimum wear rate and average size of nanoparticles. Finally the contribution percentage of different effective factors was revealed and confirmation run showed the validity of the obtained results. Also it has been revealed that by changing the size of nanoparticles, wear properties of coatings will change significantly. Atomic force microscopy (AFM) and transmission electron microscope (TEM) analysis have confirmed smooth surface and average size of nanoparticles in the optimal coating. |
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| author |
Mirzamohammadi, S. Aliov, M.Kh. Sabur, A.R. Hassanzadeh-Tabrizi, A. |
| spellingShingle |
Mirzamohammadi, S. Aliov, M.Kh. Sabur, A.R. Hassanzadeh-Tabrizi, A. Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite Фізико-хімічна механіка матеріалів |
| author_facet |
Mirzamohammadi, S. Aliov, M.Kh. Sabur, A.R. Hassanzadeh-Tabrizi, A. |
| author_sort |
Mirzamohammadi, S. |
| title |
Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite |
| title_short |
Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite |
| title_full |
Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite |
| title_fullStr |
Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite |
| title_full_unstemmed |
Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite |
| title_sort |
study of wear resistance and nanostructure of tertiary al2o3/y2o3/cnt pulsed electrodeposited ni-based nanocomposite |
| publisher |
Фізико-механічний інститут ім. Г.В. Карпенка НАН України |
| publishDate |
2010 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/31745 |
| citation_txt |
Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite / S. Mirzamohammadi, M.Kh. Aliov, A.R. Sabur, A. Hassanzadeh-TAbrizi // Фізико-хімічна механіка матеріалів. — 2010. — Т. 46, № 1. — С. 67-75. — Бібліогр.: 13 назв. — англ. |
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Фізико-хімічна механіка матеріалів |
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67
Ô³çèêî-õ³ì³÷íà ìåõàí³êà ìàòåð³àë³â. – 2010. – ¹ 1. – Physicochemical Mechanics of Materials
STUDY OF WEAR RESISTANCE AND NANOSTRUCTURE
OF TERTIARY Al2O3/Y2O3/CNT PULSED ELECTRODEPOSITED
Ni-BASED NANOCOMPOSITE
S. MIRZAMOHAMMADI, M. KH. ALIOV, A. R. SABUR,
A. HASSANZADEH-TABRIZI
Tarbiat Modares University, Tehran, Iran
Electrodeposition of tertiary Alumina/Yitria/carbon nanotube (Al2O3/Y2O3/CNT) nano-
composite by using pulsed current has been studied. Coating process has been performed
in nickel sulphate bath and nanostructure of the obtained compound layer was examined
with high precision figure analysis of SEM nanographs. The effects of process variables,
i.e. Y2O3 concentration, treatment time, current density and temperature of electrolyte have
been experimentally studied. Statistical methods were used to achieve the minimum wear
rate and average size of nanoparticles. Finally the contribution percentage of different
effective factors was revealed and confirmation run showed the validity of the obtained
results. Also it has been revealed that by changing the size of nanoparticles, wear
properties of coatings will change significantly. Atomic force microscopy (AFM) and
transmission electron microscope (TEM) analysis have confirmed smooth surface and
average size of nanoparticles in the optimal coating.
Key words: yitria, electrodeposition, tertiary nanocomposite coatings, wear, carbon nanotube.
Nickel and nickel-based alloys are used widely for numerous applications,
which most of them require corrosion, wear and heat resistances, including diffe-
rent turbine plants, nuclear power systems, and chemical and oil industries.
Ceramic or metal matrix nanocomposite coatings usually have special proper-
ties such as dispersion hardening, self-lubricity, high temperature inertness, good
wear and corrosion resistance, chemical and biological compatibility [1–7]. This
accounts for the increased application of Ni-based nanocomposites in different in-
dustries. In order to meet the requirement for developing novel metal-based nano-
composites, many preparation techniques have been investigated. Considering a
technique conducted at a normal pressure and ambient temperature and with low
cost and high deposition rate, electrodeposition is considered to be one of the most
important techniques for producing nanocomposites and nanocrystals [8–11].
In this paper, tertiary nanocomposite coatings consisting of nanometric-sized
Al2O3/Y2O3/CNT particles embedded in a Ni-matrix by pulsed electrodeposition
method were studied. The nanostructure and wear resistance of obtained nanocom-
posites were investigated with respect to the different effective factors of coating
process. Ni matrix composite coatings containing nano-sized Al2O3/Y2O3/CNT fine
particles with different average sizes of nanoparticles were prepared in a nickel
sulphate bath. The wear performance of these coatings and its relation to the distri-
bution of nanopaticles has been analyzed in a systematical way.
The design of experiment (Taguchi method) [12–13] took into account the
influencing extent of individual process parameter. This consideration led to the se-
lection of four influential factors, i.e. Y2O3 concentration, time, current density and
Corresponding author : М. KH. ALIOV, e-mail: aliov.kh@gmail.com
68
temperature of electrolyte with three different levels (1–3). Figure analysis measu-
rements were conducted to determine the size of nanocrystals of the coated samples.
The results of the factor response analysis were used to derive the optimal levels
combinations. Confirmation experiments were performed to verify the analytical
results. The percentage contribution of each factor was determined by the variance
analysis.
Experimental procedure. Materials and treatments. Electrodeposition nickel
sulphate bath is composed of pure 150 g/L NiSO4-7H2O, 15 g/L NH4Cl, 15 g/L
H3BO3, 0.1 g/L C12H25NaSO4, with 0.01 g/L saccharin (C7H5NO3S), 0.01 g/L SDS
(C12H25NaO4S) and 0.1 g/L CNT nanoparticles, 50 g/L Al2O3(X%)Y2O3 (X = 2, 6,
10). Pure copper 50×50×1 mm sheets were used as cathodic electrodes. The prepa-
ring process for all specimens was the following: first they were mechanically poli-
shed with different grade emery papers up to #3000 and then degreased in sodium
hydroxide solution, after that inserted in 10% HCl solution to be activated and
finally rinsed with acetone. The operating conditions for plating were such: average
current density equal to 10 A/dm2, stirring rate 200 rpm and bath temperature 60°C
while the frequency and duty cycle of monopolar pulsed current were adjusted at
1000 Hz and 50%.
Evaluation of coatings. After coating process, samples were rinsed thoroughly
with distilled water and then dried in flowing air. The microstructure of surfaces
and cross-section of the samples were examined by a Philips XL-30 scanning elec-
tron microscopy (SEM). The wear rate of the coatings was evaluated using the
standard pin on the disc wear test. The sample weight was measured every 100 m
of sliding distance and wear rate was calculated from obtained data using Archard
equation. Sample weight after wear tests was measured by Sartorious CP324S digi-
tal scale. To measure an average size of nanoparticles (ASN), 5 SEM nanostructures
with the same magnification were analyzed trough commercial software for figure
analysis called a4iDocu for each treated sample. Different measurements were
interpolated to obtain average results. At least 40 measurments were done in each
nanostructure for minimizing systematical errors. Nanostructure of optimal layer
was studied with AFM and TEM. AFM part was a NanoScope II from Digital
Instruments, USA and non-scraping Si3N4-tips were used throughout. TEM
analysis was done on a JEM-2000EX with 200 KV of bias voltage.
Statistical analysis. Design of orthogonal array and signal-to-noise analysis.
Four Taguchi independent factors (Y2O3 concentration, time, current density and
temperature of electrolyte) with three levels were selected (Table 1). The factors
and levels were used to design an orthogonal array L9 (34) for experiments. The
nine Taguchi experiments were conducted twice to ensure the reliability of experi-
mental data for a signal-to-noise analysis. In process design, it is almost impossible
to eliminate all errors caused by the variation of characteristics. An increase in the
variance of wear rate and nanoparticles average size lowers the quality reliability of
coatings. To minimize the influence of wear rate and average size of nanoparticles
variation on the analysis of experimental data, the signal-to-noise (S/N) ratio was
employed, which converts the trial result data into a value for the response to eva-
luate coating quality in the optimum setting analysis. The S/N ratio consolidates
several repetitions into one value which reflects the amount of variation present.
This is because the S/N ratio can reflect both the average and the variation of the
quality characteristics. There are several S/N ratios available depending on the
types of characteristics [12]: lower is best (LB), nominal is best (NB), and higher is
69
best (HB). In the present study wear rates and average sizes of nanoparticles are
treated as characteristic values. Since the wear rate and average size of nanopartic-
les of coatings intended to be minimized, the S/N ratio for LB characteristics was
selected which can be calculated as follows:
2
LB
1
1/ 10log
n
i
i
S N X
n =
⎛ ⎞
= − ⎜ ⎟
⎝ ⎠
∑ , (1)
where n is the repetition number of each experiment under the same condition for
design parameters, and Xi is the wear rate or the average size of nanoparticles for
individual measurement at the ith test. After calculating and plotting the mean S/N
ratios at each level for various factors the optimal level, that is the lowest S/N ratio
among all levels of the factors, can be determined.
Table 1. Design factors and levels
Factor
Level
Y2O3, % t, min i, A/cm2 T, °C
1 2 10 0.02 40
2 6 20 0.06 50
3 10 30 0.1 60
Analysis of variance (ANOVA). The ANOVA analysis of the experimental
results was performed to evaluate the source of variation during the electrodeposi-
tion. Following the analysis it is relatively easy to identify the effect order of fac-
tors on coatings and the contribution of factors to the wear rate and average size of
nanoparticles in coatings. In this study variation due to both the four factors and the
possible error was taken into consideration. The ANOVA was established based on
the sum of the square (SS), the degree of freedom (D), the variance (V), and the
percentage of the contribution to the total variation (P). The five parameters
symbols typically used in ANOVA [13] are described below:
1. Sum of squares (SS). SSp denotes the sum of squares of factors A, B, C, and
D; SSe is the error sum of squares; SST is the total sum of squares. The total sum of
square SST from S/N ratio can be calculated as:
2
2
1
1
i
m m
T i
i i
SS
m =
⎡ ⎤
= η − η⎢ ⎥
⎣ ⎦
∑ ∑ , (2)
where m is the total number of the experiments, and ηi is the S/N ratio at the i-th
test. The sum of squares from the tested factors, SSP, can be calculated as:
2 2
1 1
( ) 1j
p m
P i
j i
S
SS
t m
η
= =
⎛ ⎞
= − η⎜ ⎟
⎝ ⎠
∑ ∑ , (3)
where p represents one of the tested factors; j is the level number of this specific
factor p; t is the repetition of each level of the factor p; and Sηj is the sum of the S/N
ratio involving this factor and level j.
2. Degree of freedom (D). D denotes the number of independent variables.
The degree of freedom for each factor (DP) is the number of its levels minus one.
The total degrees of freedom (DT) is the number of total number of the result data
points minus one, i.e. the total number of trials times number of repetition minus
70
one. The degree of freedom for the error (De) is the number of the total degrees of
freedom minus the total of degree of freedom for each factor.
3. Variance (V). Variance is defined as the sum of squares of each trial sum
result involved in the factor, divided by the factor degrees of freedom:
(%) 100P
P
P
SSV
D
= × . (4)
4. The corrected sum of squares (SS′P). SS′P is defined as the sum of squares of
factors minus the error variance times the degree of freedom of each factor:
P P P eSS SS D V′ = − . (5)
5. Percentage of the contribution to the total variation (P). PP denotes the
percentage of the total variance of each individual factor:
(%) 100P
P
T
SSP
SS
′
= × . (6)
Determination of relationship to nanostructure. After determining optimal
levels, the changes (increasing/decreasing) of results with average size of nanopar-
ticles have been determined and the regressed plots show these relations. Obtained
formula from interpolating different achieved data for effective factors with Rfitt ≥
≥ 0.98 which shows excellent fittings have been determined beside the trend of
changing in relative figures and plots.
Results and discussions. Effect of coating effective parameters. Based on
equation (1), two wear rates and average sizes of nanoparticles measurements for
each experiment were converted into one S/N ratio. In the following discussion the
S/N ratios are employed as a response index to compare the wear rates and average
sizes of nanoparticles for different coatings instead of directly using their values.
The response of each factor to its individual level was calculated by averaging the
S/N ratios of all experiments at each level for each factor. The determined factor
responses are summarized in Table 2. Fig. 1 shows the effect of the four effective
factors on the mean S/N ratios for wear rates as well as Fig. 2 – average sizes of
nanoparticles.
Table 2. The S/N ratios
current
density,
mm3/N⋅m⋅10–5
average d,
nm
Expe-
riment,
№
Y2O3,
%
t,
min
i,
A/cm2
T,
°C
Test 1 Test 2
S/N
Test 1 Test 2
S/N
1 1 1 1 1 25.5 24.8 28.01 159 155 43.92
2 1 2 2 2 13.7 14.4 22.96 86 90 38.89
3 1 3 3 3 10.8 11.4 20.91 67 71 36.78
4 2 1 2 3 5.5 6 15.20 34 38 31.14
5 2 2 3 1 3.5 3.1 10.39 22 19 26.26
6 2 3 1 2 14.3 13.9 22.99 90 87 38.94
7 3 1 3 2 4.9 5.5 14.33 30 34 30.12
8 3 2 1 3 7 6.5 16.59 44 40 32.47
9 3 3 2 1 3.8 3.3 11.03 24 20 26.88
71
The response of the S/N ratio to the Y2O3 concentration, treatment time, current
density and temperature of electrolyte need to be further investigated. By selecting
the lowest value of mean S/N ratio for each factor, the optimal level can be deter-
mined. On this basis, the optimum combination of levels in terms of minimizing
the wear rates and average sizes of nanoparticles for coated samples is A2B2C3D1;
i.e. 6% for Y2O3 concentration, 20 min for treatment time, 0.1 A/cm2 for current
density and 40°C for temperature of electrolyte. Also the optimum combination of
levels in terms of minimizing the wear rates and average sizes of nanoparticles for
coated samples is equal for both of wear rates and average sizes of nanoparticles
which clearly show that decreasing the average sizes of nanoparticles will lead to
lower wear rates of samples.
Fig. 1. Effect of Y2O3 concentration (a), treatment time
of electrolyte (b), current density (c) and temperature
of electrolyte (d) on mean S/N ratio for wear rate.
Factor contributions. The contribution of
each factor to the wear rates and average sizes of
the nanoparticles of coatings can be determined
by performing analysis of variance based on Eqs. (2)–(6). The results of ANOVA
are summarized in Table 3. The data given in Tables 4 and 5 show that the
contribution of the four factors for wear rate, i.e. Y2O3 concentration, treatment
time, current density and temperature of electrolyte is 57.2%, 3.46%, 32.16% and
7.17%, respectively. The contribution of Y2O3 concentration (57.2%) is more than
the sum (42.8%) of the contributions of all the other three factors. It is evident that
among the selected factors Y2O3 concentration has the major influence on the wear
rate of performed coatings. It can be seen that the current density is the second
important factor that affects the wear rate of the treated substrates. Furthermore, it
can be assumed that treatment time and temperature of electrolyte have almost the
same effect on wear rates of coatings because of the minor difference in the
contribution percentages between these two factors. It is evident from Tables 4, 5,
and 6 that ANOVA analysis not only specifies how important a factor is to the
coatings wear rate by numbers but also shows their relative effect. By ranking their
relative contributions the sequence of the four factors affecting the wear rate is
Y2O3 concentration, current density, treatment time and temperature of electrolyte.
Tables 5, 6 show the contribution of the four factors for average sizes of
nanoparticles, i.e. 57.15%, 3.38%, 32.32% and 7.14%, respectively for Y2O3
concentration, treatment time, current density and temperature of electrolyte. As
mentioned in the previous section, changes of wear rates and average sizes of
nanoparticles of coatings with respect to different effective factors demonstrate
72
similar trends which show strong relation between average sizes of nanoparticles and
wear rates of coatings. It is also worthwhile mentioning that in the ANOVA
analysis, if the percentage error (Pe) contribution to the total variance is lower than
15%, no important factor is missing in the experimental design. In contrast, if the
percent contribution of the error exceeds 50%, certain significant factors have been
overlooked and the experiments must be re-designed [12].
Fig. 2. Effect of Y2O3 concentration (a), treatment time
of electrolyte (b), current density (c) and temperature
of electrolyte (d) on mean S/N ratio for average size
of nanoparticles.
Table 3. The factor response
Factor
Level
Y2O3, % t, min i, A/cm2 T, °C
1WR 23.959 19.183 22.530 16.475
2WR 16.191 16.645 16.395 20.092
3WR 13.984 18.307 15.210 17.568
1ASN 39.864 35.059 38.445 32.354
2ASN 32.113 32.542 32.305 35.984
3ASN 29.826 34.202 31.053 33.465
As shown in Tables 4 and 5 the percentage error (Pe) is 0%. This indicates that
no significant factors are missing in the experimental design.
Table 4. Results of the ANOVA for wear rate
Symbol Factors D SS V SS ′ P, % Rank
A Y2O3, % 2 164.7139 82.3569 164.7139 57.20 1
B t, min 2 9.9695 4.9847 9.9695 3.46 4
C i, A/cm2 2 92.6168 46.3084 92.6168 32.16 2
D T, °C 2 20.6522 10.3261 20.6522 7.17 3
Error 9 0 0 0
Total 17 287.9524 100
73
Table 5. Results of the ANOVA for average size of nanoparticles
Symbol Factors D SS V SS ′ P, % Rank
A Y2O3, % 2 166.0571 83.0285 166.0571 57.15 1
B t, min 2 9.83 4.9150 9.83 3.38 4
C i, A/cm2 2 93.8957 46.9478 93.8957 32.32 2
D T, ºC 2 20.7591 10.3795 20.7591 7.14 3
Error 9 0 0 0
Total 17 1056.2004 100
Confirmation run. The confirmation experiment is the final step in verifying
the conclusions from the previous round of experimentation. If the results of the
confirmation runs are not consistent with the expected conclusions, a new Taguchi
method design is required. The confirmation experiment was performed by setting
the experimental condition of the four factors: 6% for Y2O3 concentration, 20 min for
treatment time, 0.1 A/cm2 for current density and 40°C for temperature of elec-
trolyte for the minimum wear rate and average size of nanoparticles. Table 6 gives
the detailed results from the confirmation run on the optimized coating. Fig. 3
shows the SEM nanostructure of the coated samples from the confirmation run.
The size of nanoparticles of the optimized coating is about 19 nm, which is the
lowest value among other coatings obtained in the present study. During this study
it has been revealed that by lowering the average size of nanoparticles, the wear
rate of a compound layer will improve significantly. Fig. 4 shows this modification
for different coatings. Figures 5 and 6 illustrate smooth surface of optimal coating
after confirmation run and confirm the average size of nanoparticles with minimum
roughness on the surface.
Table 6. Results of wear rate and average size of nanoparticles for confirmation run
(optimal coating)
Experiment Y2O3, % t, min i, A/cm2 T, °C v, mm3/N⋅m ⋅10–5 d, nm
Optimal coating 6 20 0.1 40 3 19
Fig. 3. Fig. 4.
Fig. 3. SEM nanostructure of optimal coating.
Fig. 4. Relation between average size of nanoparticles and wear rate.
74
Fig. 5. Fig. 6.
Fig. 5. TEM (BFI) nanostructure of optimal coating.
Fig. 6. AFM nanostructure of optimal coating.
CONCLUSIONS
The Taguchi method for the design of experiment has been used for optimi-
zing tertiary (Al2O3/Y2O3/CNT) nanocomposite electrodeposited coating process
parameters for wear protection of treated samples. The contribution of Y2O3
concentration is more than the sum of the contributions of all the other three fac-
tors. It is evident that among the selected factors Y2O3 concentration has the major
influence on the wear rate of performed coatings. It can be seen that the current
density is the second important factor that affects the wear rate of the treated
substrates. Furthermore it can be assumed that treatment time and temperature of
electrolyte have almost the same effect on wear rates of coatings because of the
minor difference in the contribution percentages between these two factors. By
ranking their relative contributions the sequence of the four factors affecting the
wear rate is Y2O3 concentration, current density, treatment time and temperature of
electrolyte. In the case of average size of nanoparticles, ranking of effective factors
by their relative contributions is the same as for wear rate which shows strong
relation between these two measured properties of coatings. AFM and TEM
analysis have confirmed smooth surface and average size of nanoparticles in the
optimal coating.
РЕЗЮМЕ. Вивчено електроосадження методом імпульсного струму потрійного ком-
позиту на основі вуглецевих нанотрубок, алюмінію та ітрію оксидів. Покриви наносили у
нікелесульфатній ванні, а наноструктуру отриманого складного шару досліджували мето-
дом комп’ютерного аналізу знімків, одержаних на електронному мікроскопі. Вплив змін-
них параметрів процесу, зокрема, концентрації Y2O3, часу обробки, густини струму та
температури електроліту вивчали експериментально. Для мінімізації впливу відхилень
швидкості зношування та середнього розміру наночастинок на аналіз експериментальних
даних використовували статистичні методи. Встановлено процентний вклад різних факто-
рів і виконано підтверджувальний розрахунок, який показав достовірність одержаних ре-
зультатів. Також виявлено, що зміна розміру наночастинок та зносотривкість покривів
матиматимуть значною мірою однаковий тренд.
РЕЗЮМЕ. Изучено электроосаждение методом импульсного тока тройного компо-
зита на основе углеродных нанотрубок, алюминия и иттрия оксидов. Покрытия наносили
в никельсульфатной ванне, а наноструктуру полученного сложного слоя исследовали ме-
тодом компьютерного анализа снимков, полученных на электронном микроскопе. Влия-
ние изменяющихся параметров процесса, в частности, концентрации Y2O3, времени об-
работки, плотности тока и температуры электролита изучали экспериментально. Для ми-
нимизации влияния отклонений скорости изнашивания и среднего размера наночастиц на
75
анализ экспериментальных данных использовали статистические методы. Установлен
процентный вклад разных факторов и проведен подтверджающий расчет, который пока-
зал достоверность полученных результатов. Также установлено, что изменение размера
наночастиц и износостойкость покрытий имеют в значительной степени одинаковый
тренд.
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