Comparison between ordinary enamel and flexible metal enamel

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This post was last edited by Wang Wei2 on 2020-6-19 at 15:45. 1. Ordinary enamel: A commonly used enamel material, which is a metal-glass composite formed by combining a metal with an inorganic material through a special process. Enameled products not only possess the physical properties and functions of metal materials, but also have the various physicochemical properties of the ceramic layer, offering excellent chemical stability and mechanical strength. Enameling is a vitreous inorganic coating that is melted onto metal surfaces to form a thin layer, serving as a protective barrier against corrosion for the metal substrate. It possesses good corrosion resistance, wear resistance, high-temperature resistance, and so on. Ordinary enamel glazes are primarily composed of glassy phases; therefore, their structure is similar to that of glass. The enamel glaze can be regarded as a kind of isotropic amorphous material, featuring long-range disorder and short-range order in its structure. What constitutes the matrix of the ceramic glaze are mainly SiO2, B2O3, etc., which combine with each other in a polyhedral form to form a continuous network structure within the glaze. Metal cations introduced into the ceramic glaze, such as Na+, K+, Li+, Ca2+, etc., enter the interstitial pores of the glaze network according to certain coordination relationships. These metal cations have a strong influence on the properties of the glaze, making them an essential component of it. By observing the structure of a conventional enamel layer under a metallographic microscope and an electron microscope, it can be seen that the structure of the enamel layer is uneven. The enamel layer contains glaze particles, various oxides, inert refractory materials, and a large number of bubbles. The defects in enamel products are closely related to the bubble structure within the enamel layer: if the bubbles are relatively small in size but numerous in number, the enamel products are prone to the defect of flaking. If the bubble structure is too large, the enamel layer becomes too thin, weakening the bond between the porcelain layer and the metal, which reduces the strength of the entire enamel layer and makes other defects more likely to occur in the enamel products. 2. Flexible metal enamel: Based on conventional enamel, this material is produced by applying the principles of fluidized crushing dynamics and incorporating metal elements with corrosion-resistant properties. At the nanoscale, its surface activity increases, and it forms strong chemical adsorption and bonding relationships with flux compounds, resulting in the formation of polymers that effectively improve the weak points at the interface ； It significantly enhances various special properties of this metal enamel, such as strength, flexibility, wear resistance, corrosion resistance (against water, oil, acids, alkalis, and salts), heat resistance, and scale resistance; it is also known as \"flexible metal enamel\". 3. Properties of flexible metal enamel 3.1 Impermeability (1) At the nanoscale, chemical bonding and chemical adsorption occur between the metal polymer and the fluxing compounds, blocking the pathways for penetration ； (2) At the nanoscale, metal particles fill the voids; the ions of corrosive media cannot pass directly through these metal enamel particles, and must find alternative paths to penetrate. This lengthens the path of penetration, creating a labyrinthine effect that prevents the corrosive agents from penetrating ； (3) The anti-corrosion metal particles are coated with a polymer, giving them wetting resistance and enabling them to prevent polar media and ions from passing through the metal enamel layer. 3.2 Corrosion resistance (1) The three key factors contributing to corrosion are water, oxygen, and ions; the excellent impermeability of flexible metal enamel coatings provides a shielding effect, enabling them to effectively prevent corrosion ； (2) The flexible metal enamel layer is in a state of combination between free bonds and the metal, which renders the molecular chains flexible and easy to rotate; this allows internal stresses to be reduced. Its internal stress is very low, and there are no microcracks within it, granting it strong resistance to cracking and peeling ； Improved the ability to prevent physical damage ； (3) Addition of corrosion-resistant metal elements ； Chemical bonding and chemical adsorption create stable structures that prevent water, oxygen, and other corrosive agents from taking their place, thereby reducing the likelihood of corrosion reactions and enhancing the resistance to chemical corrosion damage. 3.3 Scale resistance: (1) On rough surfaces, the increased surface energy raises the resistance to fluid flow, reducing the flow velocity and increasing the thickness of the near-wall flow layer, which leads to the formation of more scale nuclei and facilitates the deposition and growth of dirt. The flexible metal enamel layer has a very high surface smoothness due to the filling of fine particles, and the thin near-wall flow layer makes scaling less likely ； (2) The flexible metal enamel layer possesses special properties that allow it to shape dirt particles so that they arrange themselves neatly, preventing the formation of hard deposits resulting from interlaced dirt molecules. (3) The special chemical structure of the flexible metal enamel layer creates a water-repelling surface that repels dirt particles, preventing them from adhering to this surface and thus achieving anti-scaling effects. 3.4 Thermal Conductivity (1) The flexible metal enamel layer has a high radiation heat absorption rate due to its black color ； (2) The three-dimensional network structure in the flexible metal enamel layer not only facilitates electrical conduction but also creates heat conduction pathways, resulting in a thermal conductivity close to that of metals. 3.5 Heat resistance: Flexible metal enamel coatings can generally be used at temperatures below 150°C, with a maximum of 200°C. For petrochemical heating furnaces, boilers, etc., the recovery of waste heat at the exhaust end can basically meet the requirements.