The effect of Ti/Ru volume ratio in Titanium and Ruthenium Nano oxide mixed coating on Titanium by electrodeposition method

The aim of the current research is to create a double oxide coating of Titanium and Ruthenium oxides on a Titanium substrate by the method of electrical deposition. The coatings created by these oxides are used as anodes with stable dimensions in the chloralkali industry. The most important role of these groups is electro catalytic. Ruthenium is one of the six famous electro catalytic elements, therefore it plays an important role in these coatings. Ruthenium increases the efficiency and speed of the reaction by increasing the active surface of the anode. In this research, to observe the effect of the amount of Ruthenium in increasing the active surface of the anode, two volume ratios with different number of layers have been used. For this purpose, TiCl4 and RuCl3.nH2O salts with different volume ratios along with hydrogen peroxide, methanol alcohol and distilled water have been used as Electrolyte constituents were used in electrodeposition cell. The distance of 3cm2 was determined as the optimal distance between the anode and cathode electrodes. Then electrical deposition of the samples at a current density of 20mA/cm2 with a distance of 3cm between the anode (Platinum) and cathode (Titanium) electrodes in one, three and six steps and in two volume ratios Ti/Ru=3:1 and Ti/Ru=9:1 Was performed. The created coatings were heat treated at 500℃. 3 other samples were installed to determine the roughness level and the effect of increasing heat treatment temperature at 400℃, 550℃ and 750℃. To check the surface of the samples, scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray energy distribution (EDS) analyzes were performed. Polarization behavior and cyclic voltammetry of the samples were also investigated. The results of this research showed that by increasing the number of coating layers, significant changes are made in the morphology and active surface of the coating. The scanning electron microscope image of the six-layer sample with a volume ratio of Ti/Ru=3:1 heat treated at 500℃ shows a homogenous cracked morphology with modified grains. Also, in this sample, the size and number of micro cracks are also optimized, and this microstructure is due to Reducing the chlorine gas release voltage is desirable. By increasing the volume ratio of Ti/Ru=9:1, which reduces the amount of Ruthenium coating, the number of micro cracks and the active surface decreases, which reduces the active areas covered and increases the chlorine release voltage. The sample created under six coating steps with a ratio of Ti/Ru=3:1 has a high active surface and, as a result, high corrosion resistance, which increases the life of the coating. Also, by increasing the heat treatment temperature up to 750℃, the cracked morphology of the coating is lost and the coating is destroyed.