Influence of Hydrofluoric Acid Concentration and pH on Corrosion of Porous Multi-Oxide Engineering Ceramics

The object of the research was to compare the corrosion resistance of three types of multioxide technical ceramics in hydrofluoric acid containing aqueous media according to a full factorial experimental plan with pH and fluoride ion concentration as variables. The samples were a silicon carbide doped aluminum silicate material, and two membrane coated aluminum silicates with one containing a membrane on both sides of the ceramic plate. The substrates contained more additives on alumina, while the membrane coats were of higher grade aluminum oxide. The samples were shaken in containers for up to two weeks, and their remaining hardness and weight losses were measured. Daily samples drawn from the liquid phase were analyzed for dissolved components. With respect to all measured properties, fluoride concentration affected the materials more detrimentally than alterations in pH.