Question

Which material is often added to engobe for coloring?

• A. Silica
• B. Ball Clay
• C. Metal Oxide
• D. Alumina

Hint:

Metal oxides such as cobalt, iron, and copper are commonly used to color engobe and glazes.

Answer 1

The Correct Option is C

Step 1: Engobe and Coloring Fundamentals.
A liquid clay mixture applied to ceramics prior to firing is known as engobe. It can be colored using metal oxides, producing hues such as red, blue, green, or brown.
Step 2: Evaluation of Choices.
- (1) Silica: Incorrect. Silica contributes to the glassy phase in glaze, not to coloration.
- (2) Ball Clay: Incorrect. Ball clay's function is plasticity, not imparting color.
- (3) Metal Oxide: Correct. Metal oxides, for instance, iron oxide, copper oxide, or cobalt oxide, are frequently incorporated into engobe for coloration.
- (4) Alumina: Incorrect. Alumina enhances durability and hardness, not color.
Step 3: Determination.
Therefore, the correct selection is (3) Metal Oxide.