Improvement of TiN nanoparticles EPD inducing steric stabilization in non-aqueous suspensions

In this work, the process parameters involved in the electrophoretic deposition (EPD) to obtain thin TiN films was studied and optimised. The stability of commercial TiN nanopowder in isopropyl alcohol adding a cationic polymer (polyethylenimine) as dispersant, with different molecular weights, was investigated to determine the kinetics of the deposition and to reach the most efficient EPD process. Cathodic EPD was performed over electro-polished stainless steel substrates. It was found that the provided dispersion when the PEI with the highest molecular weight was added to the suspension, leads to the best deposition behaviour for short times. New flocculation phenomena were described which affect to the sticking factor, and thus to the evolution of the EPD kinetics. As a result of the designed stabilization system, a reliable and versatile EPD method to produce well consolidated nano-TiN coatings at 1200 °C in vacuum atmosphere was described.