Porcelain crucible covers are laboratory accessories used to cover and protect porcelain crucibles during high-temperature heating and melting applications. They are typically made of porcelain, a type of ceramic material that is able to withstand high temperatures and chemical corrosion.

Crucible covers are designed to fit snugly on top of the crucible, helping to contain the substance and reduce the risk of spillage or evaporation. They also help to protect the contents of the crucible from contamination and can be used to regulate the flow of air into the crucible during heating.

Porcelain crucible covers are commonly used in chemistry, metallurgy, and other high-temperature applications where precise control over temperature and containment of substances is necessary. They are known for their durability, heat resistance, and ease of use, and provide a cost-effective solution for high-temperature applications in laboratory settings.