In this module we will look at crystalline ceramics and how they are produced and used. We will look at clay products, refractories and advanced ceramics.
One of the most common ceramic raw materials is clay. It is used widely because it is found in great quantities naturally and it is easily formed. Clay is used in structural clay products (bricks, pipes, tiles) and whitewares (pottery, tableware, china, sanitaryware).
Clay is made up of alumina and silica with some water. Most clay products also contain an inexpensive filler, often quartz, and a flux that forms a glass to bind ceramic particles during heat treatment.
After forming, the ceramic piece is still porous, contains some liquid and has very low strength. To remove the liquid, the product is dried. As the moisture evaporates in the process, the piece shrinks. This can create stresses if the exterior dries faster than the interior. The temperature, humidity and airflow are controlled to limit the rate of evaporation.
Click on the graphic to view process.