Point of zero charge of different carbides

Abstract Points of zero charge, pH pzc , of various samples of NbC, WC, SiC and TiC powders were investigated using a batch equilibration method. The examined powders were both laboratory prepared (NbC and WC via plasma-chemical method (PCM), while SiC was sol–gel derived) and commercial ones (WC, TiC, and laser derived SiC). The applied solid/liquid ratio ranged from 0.1 to 0.3 g/20 ml. The aqueous solution of KNO 3 (10 −3 to 10 −1  mol/l) was used as a background electrolyte. The points of zero charge for all investigated carbides were found to be between 3.2 and 5.0. They were not affected by the concentration of KNO 3 , indicating its nonspecific nature vis-a-vis studied carbides. The pH pzc values were correlated with the physicochemical properties of investigated powders.