Traditional Culture Encyclopedia - Weather inquiry - A layer of frost appeared on the security door in rainy weather.

A layer of frost appeared on the security door in rainy weather.

It is calcium oxide formed by carbide in the air and surface substance of security door.

This shows that the door is wet and needs repainting. This paint is waterproof to some extent. As long as it is not soaked in water or not done well, wet weather has little effect. Erosion at a height of 30cm from the ground means that the ground returns to the wall, so the wall should be waterproof to a height of 40cm.

Calcium oxide is an inorganic compound with chemical formula of CaO, commonly known as quicklime. Physical properties: the surface is white powder, grayish white when it is impure, pale yellow or gray when it contains impurities, and it is hygroscopic. Calcium oxide is an alkaline oxide, which is very sensitive to moisture. Easy to absorb carbon dioxide and moisture in the air. It reacts with water to generate calcium hydroxide (Ca(OH)2) and generates a lot of heat, which is corrosive.