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.