Final answer:
Hydrofluoric acid is traditionally used for etching glass ceramics, but ammonium bifluoride is a safer alternative. Ceramics can also be decorated through incising, glazing, or applying slip before firing in a kiln.
Step-by-step explanation:
The etchant used for ceramic materials varies depending on the specific application and the type of ceramic being etched. Traditional methods of etching glass, a type of ceramic, have employed dilute hydrofluoric acid which reacts with silica in the glass to gradually dissolve it.
However, due to the hazardous nature of hydrofluoric acid, safer alternatives like ammonium bifluoride are sometimes used. For decoration of ceramics, techniques such as incising lines or applying slip made from fine particles of clay may be used prior to firing in a kiln.