Oxidation or oxidizing atmosphere
Oxidation in ceramics refers to a type of atmosphere during firing in which there is an abundant supply of oxygen. This environment is crucial for certain ceramics and glazes that depend on the presence of oxygen to develop bright, consistent colors and specific glaze properties. In an oxidizing atmosphere, the free oxygen in the kiln reacts with the glaze and clay components, preventing them from reducing (losing oxygen) and ensuring that the metal oxides maintain their original oxidation states.
In an oxidation kiln, precise control of the amount of oxygen is essential to achieve the desired results. For example, iron oxide in an oxidizing atmosphere tends to produce red, orange and brown colors, while in a reducing atmosphere it can produce dark green or black tones. This control is achieved by regulating air flow and combustion within the kiln, allowing the visual and physical properties of the parts to be manipulated.
In addition to influencing color, the oxidizing atmosphere affects the texture and finish of the glaze. Glazes applied in this environment tend to develop more uniform surfaces that are less prone to defects such as pullout or staining. This is particularly important in the production of utilitarian and decorative ceramics where aesthetics and functionality are paramount.Interesting Fact
Oxidizing atmosphere is especially prevalent in modern electric kilns, as they allow precise and constant control of oxygen input. Unlike gas or wood-fired kilns, which require more manual and careful management to maintain an oxidizing atmosphere, electric kilns can automatically adjust oxygen levels, facilitating the production of ceramics with consistent, high-quality finishes.Helpful Tip
When working with glazes or bright colors that rely on an oxidizing atmosphere, be sure to properly calibrate your kiln to maintain a constant oxygen flow. This will minimize variations in the final color and prevent glaze defects. Test small pieces before proceeding to full production to adjust oxidation parameters and ensure optimal results.
