Oxidizing bubbles: blisters caused by incomplete oxidation are called oxidizing blisters. It has the size of millet and is covered with a glaze layer. It’s not easy to touch by hand, and most are produced at low temperatures. Mainly, the decomposition products in the porcelain and glaze are not completely oxidized, and the disappearance is not completely eliminated.
The reasons are:
1, the oxidation temperature is low, the oxidation atmosphere of the high temperature part of the oxidation zone is insufficient or fluctuating.
2. The temperature of the pre-tropical zone rises rapidly, the oxidation decomposition stage is short, the temperature in the kiln is too low at the end of oxidation, and the temperature difference between the upper and lower levels is too large.
Matters needing attention
1, appropriately increase the temperature in the oxidation process, and maintain a strong oxidation roasting in the oxidation stage;
2, in the oxidation stage, the temperature should be slowly increased or properly maintained to make the preheating of the green uniformly and fully oxidized; (3) When the billet enters the kiln, the water is evaporated. If the billet is not dry, it can burn for 30 minutes to 1 hour in the range of 0-300°C.
Second, reduction bubble: the bubble generated due to insufficient reduction is a reduction bubble, the diameter is greater than the diameter of the oxidation bubble, and the cross-section is yellow, and the ceramic is produced at high temperatures near high temperatures.
The reasons are:
1, mainly due to the insufficient reduction of sulfate and high price iron in the body, foaming at high temperatures.
2. The temperature of the kiln is too high, and the temperature in the kiln after oxidation is completed is high. Strong reducing atmosphere is insufficient;
3, cooling time is long, resulting in insufficient product reduction, burning temperature is too high.
Note:
1. Properly reduce the furnace temperature so that the temperature entering the strong reduction stage is appropriate;
2, appropriate control of reducing atmosphere and firing temperature.
Post time: Oct-03-2023