Frequently, it is desired to preserve the original tones of copper, brass and bronze
surfaces which are used in decorative areas. This can be achieved by applying clear
protective coatings, acting as weather barriers and surface protections against
mechanical aggressions. The performance of two clear coatings and a hard coating is
evaluated, using a linear scratch test and abrasion tests. The hybrid sol-gel coating
greatly improves the wear resistance of brass. The corrosion-resistant varnish tested has
very poor wear resistance. Too thin and porous hard-coating layers have poor corrosion
and abrasion resistance. The hybrid sol-gel coating gives the best compromise in terms
of aspect, properties and cost.