1. Chapter 37 Processes Used to Finish Ceramic Materials

2. Objectives Polishing and lapping to remove minor imperfections. Grinding to remove larger defects. Glazing ceramics. Decorating ceramics.

3. 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.

4. 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.

5. 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.

6. Home Work 1. What material is used for precision grinding of ceramic products? 2. Give two reasons for applying glazes on ceramic products?