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First of all, before explaining this problem, we must first understand what is enamel. In our life, we can see the shadow of enamel in many places.
Enamel, pronounced (táng cí), also known as enamel, is a composite material in which inorganic vitreous materials are condensed on the base metal by melting and firmly combined with the metal. Enamel products are not only safe and non-toxic, but also easy to clean, and can be widely used as eating utensils and washing utensils in daily life.
Enamel mainly has two components: metal material (metal embryo) and enamel (inorganic vitreous material).
1. Enamel body (metal material)
Metal materials used for enamel mainly include steel, cast iron, aluminum, copper and stainless steel.
Steel for enamel generally refers to low carbon steel plate, that is, steel plate with low carbon content (generally ≤ 0.12%). Since its chemical composition, internal microstructure (metallographic structure), surface condition and mechanical properties play an important role in the quality of enamel, the larger manufacturers of enamel products in the market are using Baosteel, Wuhan Iron and Steel, Maanshan Iron and Steel, Anshan Iron and Steel, etc. The enamel special steel plates produced by large enterprises can ensure the enamel quality of the products.
Cast iron for enamel refers to iron-carbon alloys with carbon content greater than 2.11% (iron-carbon alloys with carbon content less than 2.11% are called steel). Mainly used in the production of sanitary ware (bathtub), cooking utensils, water supply and drainage pipes, etc.
The aluminum materials used for enamel are mainly pure aluminum and aluminum-magnesium alloys. The copper materials used for enamel mainly include red copper (ie pure copper), brass (copper-zinc alloy) and bronze (copper-tin alloy). Among them, red copper and brass are the most widely used and most representative copper enamel products. For example, cloisonne is a copper enamel product made of red copper.
2. Enamel (inorganic glass material)
Enamel raw materials used for enamel mainly include three categories: mineral raw materials, chemical raw materials and pigment raw materials.
Mineral raw materials are the main components of enamel. It mainly includes: quartz (the main component is silica-SiO2), feldspar (alkali metal or alkaline earth metal silicate, commonly used potassium feldspar-K2OAl2O36SiO2), clay (hydrous aluminum silicate minerals, mainly Al2O36SiO2 and crystal water).
Chemical raw materials are auxiliary components of enamel, mainly including: borax (Na2B4O710H2O), sodium nitrate (NaNO3), soda ash (Na2CO3), lithium carbonate (Li2CO3), calcium carbonate (CaCO3), magnesium oxide (MgO), zinc oxide (ZnO) ), titanium dioxide (TiO2), antimony oxide (Sb2O3), zirconium dioxide (ZrO2), cobalt oxide (CoO), nickel oxide (NiO), manganese dioxide (MnO2), iron oxide (Fe2O3), etc.
Pigment material refers to the material used to decorate the enamel color. There are the following types distinguished from color: black, blue, brown, gray, green, pink, white, yellow and red, etc.
The production of enamel is based on the above three raw materials mixed in a certain proportion, melted at a high temperature of about 1200 ° C, and then rapidly cooled into granular or flake borosilicate glass. According to the process performance, it is divided into bottom glaze, surface glaze and decorative glaze; according to the different matrix materials, it is divided into steel plate glaze, cast iron glaze, copper glaze, aluminum enamel glaze and stainless steel glaze.