Papers by Author: Mahmood Aliofkhazraei

Abstract: In this paper, plasma electrolytic carburizing has been applied on the commercially pure titanium substrates in an organic based electrolyte with presence of some hard tungsten carbide nanoparticulates in suspension state. Pulsed current with variable duty cycle has been used for fabrication of functionally gradient nanocomposite coating. As a result, a hard nanocomposite layer has been formed on the surface of the samples with complex titanium carbide as its matrix and tungsten carbide nanoparticulates as its reinforced phase. In addition of used SEM, TEM and AFM for evaluation of coating nature, the presence of tungsten in different depths of formed layer has been followed by means of EDS. The effects of rate of variable duty cycle of applied pulsed current or treatment time have been described. Hardness profiles showed that the higher rates for variable duty cycles will cause lower hardness and sharper profilesThis document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.

Abstract: In this paper, the effects of the average size of nanometric particles (ASNP) from submicron scale (less than 1 µm) to nanometric scale (less than 10 nm) have been studied on the properties of nanocomposite layers which usually have not been studied or rarely studied. These properties consist of corrosion current density after long time immersion, roughness of obtained layer and distribution of nanometric particles. All of the other effective factors for fabrication of nanocomposite coatings have been fixed for better studying the effect of the ASNP. It has been seen that decreasing the ASNP will lead to lower corrosion current densities however in some cases pitting phenomena has been observed. The roughness illustrated a minimum level while the distribution of nanometric particles will be more uniform by decreasing the ASNP.

Abstract: Up to the fourth moment distributions of carbide nanocrystallites, produced by duplex treatments of surface nanocrystallization and pulsed plasma electrolytic carburizing on AISI316 stainless steel, were investigated to high precision by means of figure analysis. A skewness and kurtosis study of the Gaussian distribution has been made, and the effect of an applied voltage has been determined. It is found that the use of higher applied voltages is more suitable for achieving lower sizes of carbide nanocrystallites. The surface roughness of treated samples was measured and it has been observed that there is an optimum level of applied voltage for surface roughness increase (difference between two measured data).