In general borates are alkaline. This alkalinity plays a major role in their inhibitive properties [5.51]. Due to the utilization of borate-based anticorrosive pigments, there is the possibility to maintain a high pH value in the coating [5.56]. Borate pigments may also form soaps (mainly calcium or barium, depending on the pigment) with acidic products derived from the film [5.51]. It is also being discussed, that borates act as anodic passivators, forming a protective film on the metallic substrate [5.56]. Borates are said to be most effective in the initial phase of corrosion protection [5.56].
5.2.7.1