The purpose of this study was to investigate the DEPOSITION of the hydroxyapatite (HA) coating via the electrophoresis procedure. The HA DEPOSITION was performed in an ethanol, methanol, acetone and isopropanol suspension. Methanol was found to be the best DEPOSITION media. Among the different environmental conditions, including the encapsulation of the samples under two vacuum types of pressure (10-5-10-4 and 2x10-2 Torr) and also the purge of the argon gas in the tube-like furnace, the optimum environment was the one demonstrating the encapsulation under the vacuum pressure of 2x10-2 Torr (washing with argon gas of 99.9% purity). After the examination of 3 sintering temperatures (1020, 1050 and 1100oC), the sintering temperature at 1050oC illustrated the most desired results. The samples sintered under these conditions were apparently intact, most of the interfacial part of the coating was found to be attached to the substrate surface irregularities and no single cracks were observed.

In this study, hydroxyapatite powders as a bioceramic were coated on NiTi shape memory alloy by ELECTROPHORETIC method. Suspension solution used as a mixture of n -butanol and tri ethanol amine (TEA). DEPOSITION was carried out at different applied voltages of 20, 30 and 40 volts in different times from 1 to 5 minutes and constant voltage on the cathode. After DEPOSITION, the samples were dried at room temperature for 24 hours. Then weight and thickness of coating were measured. Ultimately the samples were sintered at 800oC in argon atmosphere for 2 hours. X-ray diffraction (XRD) and SEM were used for phase identification and morphological examining of coating consecutively. Composition of coating was analysied by Energy Dispersive X-ray (EDX). The results showed that a uniform, continuous and crack-free coating can be achieved at 30 volt and at shorter time after sintering. Moreover an increase in the DEPOSITION period, caused an increase in the weight and thickness of the DEPOSITION. The technique presented in this research can be a replacement technique for bioactive coatings in comparison with other techniques such as sol-gel and plasma spray coating.

in this paper, kinetics of DC ELECTROPHORETIC DEPOSITION (EPD) of carbon nanotubes (CNTs) are investigated. Suspension of carbon nanotubes in pure ethanol with addition of magnesium nitrate was used as DEPOSITION media. The effect of main EPD parameters such as DEPOSITION time, applied voltage and the CNTs concentration on deposit yield were investigated. The variation of current density vs. time and the effect of magnetic stirring were also examined. The results are in good agreement with Hamaker’s law and the deposit yield increases with increasing of applied voltage and CNTs concentration but there is a deviation from linear trend in longer DEPOSITION times. Stirring could compensate some of this deviation but increases the current density fluctuations.

Aluminum coating was prepared on AZ91D magnesium alloy substrate using the ELECTROPHORETIC DEPOSITION (EPD) method in absolute ethanol solvent. In order to determine the optimal concentration of AlCl3. 6H2O additive, the zeta potential and size of particles in the suspension were measured in the presence of different concentrations of AlCl3. 6H2O. The results showed that an appropriate coating is obtainable in the presence of 0. 6 mM AlCl3. 6H2O as an additive. The effects of applied voltage, DEPOSITION time, and additive concentration on DEPOSITION weight, DEPOSITION thickness, and coating morphology were also studied. A uniform coating with smaller pores and higher density was obtained at the additive concentration of 0. 6 mM, DEPOSITION time of 18 min, and applied voltage of 70 V. The thickness of this coating was measured at about 256. 91 μ m. According to the results of corrosion behavior studies, the corrosion current density was measured at 29. 16 and 12. 85 μ A/cm2 for uncoated and aluminum-coated AZ91D alloy, respectively.

In this work, the effect of coating parameters such as DEPOSITION time, voltage (field intensity), frequency and the liquid medium on deposit mass and DEPOSITION quality in alternating field electrophoresis (ACEPD) is investigated. For this purpose, suspensions of SnO2 nanoparticles in pure acetone were prepared. In order to investigate the coating quality (pattern), stereo optical microscopy was used and the coating process was performed on two parallel gold electrodes with a gap of 500 micron. Deposit mass measurements showed that the variation of deposit mass vs. DEPOSITION time and voltage follows theoretical relations. On the other hand, the deposit mass decreases at higher frequencies. The deposit pattern in each frequency is allocated to that frequency and does not change over longer DEPOSITION times. At last, the deposit mass in pure acetone was much more that the pure ethanol and distilled water due to the higher value for dielectric constant to viscosity ratio of pure acetone. So, it is possible to obtain wide variety of DEPOSITION quality by changing the ELECTROPHORETIC DEPOSITION parameters.