Adhesion Between Enamel and Metal

Release time:

2026-04-02 16:43

Source:

Glass and Enamel

Abstract: With increasing emphasis on metal corrosion prevention, enamel coating can provide excellent corrosion protection. However, the adhesion between the metal and the enamel frit is crucial for the performance of enamel products. This paper provides a detailed summary of the adhesion mechanisms between enamel frit and metal, highlighting the significance of studying these mechanisms and introducing their practical applications.

Enamel, a traditional silicate product with over two thousand years of history, possesses advantages such as good adhesion, corrosion resistance, stability, high temperature and pressure resistance, and moderate price. In 1973, Hennickle and Sarlak studied the mechanical wear of enamel surfaces and found that the enamel layer was uneven. Treogel and Schultes demonstrated the presence of many oxides and inert corrosion-resistant materials at the enamel frit interface. Metal and enamel are two materials with different compositions and structures. Their strong bonding is an extremely complex physicochemical process.

1. Conditions for Adhesion

King Tripp and Duck Worth proposed the following basic requirements for adhesion between a metal surface and an enamel coating:

(1) The enamel must wet the metal;

(2) The enamel at the glass-metal interface must be saturated with metal oxides;

(3) The oxides must not be reduced by the metal when dissolved in the molten enamel.

For the steel plate used in enamel coating, the oxide is FeO. When the enamel-coated steel plate is placed in an air atmosphere at the firing temperature, FeO is formed.

2. Adhesion Theory

2.1 Physical Adhesion Theory

Physical adhesion, also known as mechanical adhesion, posits that the adhesion between the enamel and the metal is achieved by the molten enamel entering the cavities on the metal surface and mechanically interlocking with the metal (see Figure 1). The higher the interface roughness, the stronger the mechanical bonding force.

However, other studies have found that even with a fairly smooth interface between the enamel and the metal, the adhesion remains quite good. If steel plates are sandblasted like cast iron, the bonding at the interface after enameling and firing is actually worse. In other words, mechanical adhesion has certain limitations and cannot explain all adhesion phenomena.