The monitoring of coating health by in situ luminescent layers

Abstract

The monitoring of coating health is crucial for the assessment of wear life in service. Electrodeposition is one of most common methods used for producing coatings including composite layers by electrophoretic deposition of particles into a growing metal electrodeposit. A new luminescent Ni coating containing an embedded, blue-emitting rare-earth mixed metal oxide (BaMgAl₁₁O₁₇:Eu²⁺) phosphor has been electrodeposited successfully from an aqueous electrolyte. Two types of surfactants were utilised to study the effective co-deposition of these particles into the nickel matrix. The surfactants of non-ionic PEG (polyethylene glycol) and cationic CTAB (cetyl trimethylammonium bromide) were observed to increase the particle content in the deposit from zero to 4.6% and 11.5%, respectively. A mixture of these two surfactants produced the highest particle embedded coverage (15.6%). The feasibility of luminescent layers in monitoring the wear of coatings has also been verified in the final part of the manuscript.