The investigation of morphological and electrochemical behavior of 34CrNiMo6 steel coated by PACVD method

By applying the appropriate parameters in the PACVD process, It is possible to influence and improve the performance of lowalloy steels against surface factors. In this study, low-alloy steel substrate, 34CrNiMo6 is used in order to create microstructural changes and improve its surface properties, the coating process by method PACVD Contains vapors of TiCl4, CH4 and N2 in order to apply Ti, C, N along with adding Fe to the composition of the coatings by this process. Investigations of microstructure and chemical composition by X-ray diffraction, Field emission scanning electron microscopy and energy dispersive spectroscopy (EDS) have been characterized.to check the electrochemical properties of the samples, a 3.5% wt NaCl solution was used, and potential dynamic polarization and impedance spectroscopy (EIS) tests were performed on the samples. The results of the research show that by applying more CH4 gas, the sputter rate of Fe increased and its amount was increased at the surface of the coatings, and the surface of the coatings has been improved. Also, it can be seen that the formation of C3N4 phase and the amount of nitrogen on the surface of the coatings are considered to be the determining factors of the corrosion resistance of the coatings.