No abstract

Electrodeposition of tertiary Alumina/Yitria/carbon nanotube (Al 2 O 3 /Y 2 O 3 /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. Y 2 O 3 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 different turbine plants, nuclear power systems, and chemical and oil industries.Ceramic or metal matrix nanocomposite coatings usually have special properties such as dispersion hardening, self-lubricity, high temperature inertness, good wear and corrosion resistance, chemical and biological compatibility [1][2][3][4][5][6][7]. This accounts for the increased application of Ni-based nanocomposites in different industries. In order to meet the requirement for developing novel metal-based nanocomposites, 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][9][10][11].In this paper, tertiary nanocomposite coatings consisting of nanometric-sized Al 2 O 3 /Y 2 O 3 /CNT particles embedded in a Ni-matrix by pulsed electrodeposition method were studied. The nanostructure and wear resistance of obtained nanocomposites were investigated with respect to the different effective factors of coating process. Ni matrix composite coatings containing nano-sized Al 2 O 3 /Y 2 O 3 /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 distribution 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 selection of four influential factors, i.e. Y 2 O 3 concentration, time, current density and

In this paper, hard silica/epoxy nanocomposite coatings were prepared by a spinning method on the surface of AA6082 aluminum alloy with addition of CdTe quantum dots as the second phase in hard nanocomposite coating with different ratios with respect to main phase (silica nanoparticulates). Wear and electrical conductivity test have been done on the coatings for investigation of the possible enhanced or inverse effects of addition QDs on properties of hard nanocomposite. The effect of coating time, rotating speed and SiO 2/QD ratio have been investigated and it has been shown that by adding QD nanoparticulates, the electrical conductivity of layers is completely controllable without adverse effect on wear resistance. The effects of mentioned parameters on the trend of obtained curves have been discussed.

Wear resistance of electrodeposited tertiary alumina/carbon nanotube/nanodiamond nanocomposite using pulsed current has been studied in Ni–W binary alloy matrix. Electroplating process was performed in citrate based Ni–W bath, and the nanostructure of obtained compound layer was examined by AFM. The effects of process variables, i.e. tungsten concentration in electrolyte, treatment time, frequency and duty cycle, were experimentally studied. Statistical methods were used in order to provide the minimised wear rate. Finally, the contribution percentage of different effective factors was calculated and confirmation run revealed the validity of obtained results. Nanocomposite layers with higher density of nanoparticles will show better tribological properties.

UDC 621.762 Electrodeposition of tertiary alumina/yttria/carbon nanotube (Al 2 O 3 /Y 2 O 3 /CNT) nanocomposite by using pulsed current has been studied in this investigation. Coating process has been performed on nickel sulphate bath and nanostructure of obtained compound layer is examined with high precision figure analysis of SEM nanographs. The effects of process variables, i.e., Y 2 O 3 concentration, treatment time, frequency and duty cycle, have been experimentally studied. Statistical methods are used to achieve the minimum of corrosion rate and average size of nanoparticles. Finally the contribution percentage of different effective factors is revealed and confirmation run shows the validity of obtained results. Also it has been revealed that by changing the size of nanoparticles, corrosion properties of coatings will change significantly in the same trend. AFM and TEM analyses have confirmed smooth surface and average size of nanoparticles in the optimal coating.