防錆塗料用顔料に就いて(第3報)

Abstract

The hydroyen ion concentration (pH) of the pigments, in aqueous suspension, were measured by the author, and it has become clear that they are closely related to the rust inhibitive properties of the pigments.All the acidic pigments, whose pH lying below 6, have shown to be rust stimulative, and none of them were rust inhibitive; vice ver'sa, all the basic pigments, whose pH being higher than 8, inhibited the rusting, and none stimulated the corrosion.The rust inhibitive properties of the pigments, whose pH lying between 6.2 and 7.8, have mostly shown to be indeterminate or somewhat inhibitive; while a few of them were strongly rust inhibitive or stimulative.