Leachable ceramic is used extensively in the precision foundry industry. Ceramic rods and tubes act as cores– incorporated into moulds and metal castings in the lost wax process, from which they are leached under acidic or alkaline conditions to provide cavities within the castings.
Using this technique, very fine tolerances on diameters can be obtained. All ceramic material is leached away by using sodium hydroxide solution once the cast metal has solidified. Leachable Ceramic cores are made with material which has sufficient zinc oxide, which helps provide essential continuity throughout the structure of the rods and tubes. Leachable ceramics typically have high porosity, do not include an organic binder, but also do not absorb water easily.