Chapter 37

Processes Used to Finish Ceramic Materials

Objectives

• Polishing and lapping to remove minor imperfections.

• Grinding to remove larger defects.• Glazing ceramics.• Decorating ceramics.

Grinding & Polishing

• Setters are solid masses of clay of the same composition as the part, placed under certain areas of the work piece for support.

• These setters cause imperfections that may require grinding.• Precision grinding: Silicon carbide grains provide extreme

hardness and are an ideal candidate for use in grinding, polishing, lapping, and pressure blasting applications on glass and ceramics.

• Flame polishing melts the thin surface layer of the product to reduce the size and quantity of surface defects.

Glazing• A glaze is a specially formulated glass that melts on the surface of the ceramic

work piece and adheres to the body after cooling.• Glazes are often applied to provide an impermeable surface on a porous product.• Glazes are also applied to improve the appearance of a product by giving it a

glossy surface.• A glaze is applied by curtain coating in recent years because it reduces the amount

of airborne contaminants produced.• Glaze additives: Colors can be applied before glazing or after glazing. • Gilding: The application of a gold gilt after glazing on products such as china, is

normally done by hand.• Banding: Banding is normally done with silver, or with a color complementing the

graphic design on the product.• Heat blocking ceramic finishes: A coating of ceramic paint can act like six inches of

fiberglass insulation when applied to any surface such as walls and roofs.

Summary• Precision grinding: Silicon carbide grains provide extreme hardness and

are an ideal candidate for use in grinding, polishing, lapping, and pressure blasting applications on glass and ceramics.

• Flame polishing melts the thin surface layer of the product to reduce the size and quantity of surface defects.

• A glaze is a specially formulated glass that melts on the surface of the ceramic work piece and adheres to the body after cooling.

• Gilding: The application of a gold gilt after glazing on products such as china, is normally done by hand.

• Banding: Banding is normally done with silver, or with a color complementing the graphic design on the product.

• Heat blocking ceramic finishes: A coating of ceramic paint can act like six inches of fiberglass insulation when applied to any surface such as walls and roofs.

Home Work

• 1. What material is used for precision grinding of ceramic products?

• 2. Give two reasons for applying glazes on ceramic products?