Adhesion Between Enamel and Metal (2) - Chemical Adhesion

Release time:

2026-04-03 15:25

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Glass and Enamel

(Continued from previous article)

2.2 Chemical Adhesion Theory

This theory posits that the bonding between porcelain enamel and metal is due to the formation of various bonds through complex chemical reactions such as diffusion and melting. The main insights are as follows:

Nedel Jkovic conducted detailed research, exploring the contribution of NiO to adhesion, which can be summarized as follows:

(1) Promotes interfacial wetting;

(2) Promotes the dissolution and diffusion of iron and iron oxide;

(3) Controls the oxidation conditions at the interface;

(4) Facilitates the formation of a more uniform bubble structure in the porcelain layer. During the enamel firing process, nickel forms and deposits at the interface, forming a suitable alloy phase with iron. This face-centered cubic structure is highly beneficial for the adhesion of nickel-containing ground coat enamel to the metal.

Healy and Andrews research shows that cobalt and iron dissolved in the enamel can form a tight contact with the enamel. Sweat, Lynch et al. believe that CoO and NiO can control the interfacial wetting and oxidation conditions of the metal interface, causing iron to form high-valence iron oxide. Dietz et al. believe that cobalt, nickel and iron can generate a current loop, producing a continuous electronic structure and chemical bonds in the interface, causing corrosion of the metal surface. The molten enamel enters the cavity formed by corrosion and forms a good adhesion with the metal. Some scholars also believe that during the enamel firing process, Fe-Ni and Fe-Co alloys are formed at the interface between the enamel and the metal. These components can maintain chemical and thermodynamic equilibrium with the enamel under appropriate conditions.

Chemical adhesion mainly involves the following chemical reactions:

2Fe + O₂ → 2FeO;

Fe + CoO- → FeO + Co;

FeO + silicate → iron silicate;

Fe + NiO- → FeO + Ni;

4NiO + 3Fe- → Fe₃O₄, + 4Ni

NiO + 3FeO- → Fe₃O₄ + Ni