Electrodeposition of titanium diboride from oxide based melts

An alternative electrochemical co-deposition method was introduced for the growth of TiB2 from the formulated, environmentally friendly, oxide-type electrolyte containing both titanium and boron ions. The depositions of TiB2 were carried out on nickel substrates at various current densities (50-150 mA/cm2), temperatures (800-1000 °C), and durations (30-360 min). The stoichiometric TiB2 formations at all applied process conditions were confirmed by thin film X-ray diffraction (XRD) method. Scanning electron microscopy (SEM) studies revealed that the thickness and morphology were highly dependent on the electrolysis parameters. The most compact, continuous and adherent TiB2 layers were achieved to form at the optimized settings, i.e. 70 mA/cm2 and 850 °C at which the thickness increased from 3 μm to 40 μm with increasing electrolysis time. Vickers micro-indentation tests conducted on the cross section of 120 min electrodeposited samples showed that the grown TiB2 layer was as hard as 3000 ± 200 HV. The co-deposition mechanism for the formation of TiB2 was also suggested with possible reactions.