Enamel Basic Profile:
Enamel (táng cí), it is actually the inorganic vitreous material by melting the base metal in the condensate and strongly bonded together with a metal composite material .
Historical development: enamel glass decorative metal originated . First appeared in ancient Egypt , followed by Greece. 6 century Europe wired enamel, enamel flower tick , relief enamel, translucent enamel, painted enamel after another. 8th century China began to develop enamel, to the late 14th century enamel artistry matures, the mid- 15th century Ming Dynasty Jingtai products is particularly known, so there cloisonne said. Early 19th century , Europe developed enamel cast iron , enamel laid the foundation for the craft to daily necessities, but because the technology behind casting , cast iron enamel application is limited. The 19th century , the development of various industries , prompting the rise of steel enamel , creating a new era of modern enamel . The 19th century - 20th century , the advent of various performance enamel , steel and other metals to promote the use of materials, refractories, kilns, enamelling technology constantly updated, to accelerate the development of the ceramic industry.
Advantages : It is coated on the metal bottom blank burn inorganic glass enamel surface . Enamel coated metal surface to prevent rusting of metal lining , the metal when heated to form an oxide layer on the surface will not be able to resist corrosion and various liquids . Enamel products not only safe , non-toxic , easy to wash clean , can be widely used as eating utensils and washing utensils used in everyday life , but under certain conditions , high enamel enamelled metal body on exhibit hardness , high temperature , wear-resistant and insulating effect and excellent performance , making ceramic products have a more extensive use. Enamel layer can also be given to products with a beautiful appearance , decorate people's lives. Visible metal enamel products both strength and looks gorgeous enamel erosion and chemical resistance properties.
Variety Category: metal substrate can be divided into black and non-ferrous metal enamel enamel into two categories ; divided by product use , there are daily and non- daily enamel into two categories ;
Preparation process points, there are two or more times, once enamel and enamel ; terms of enamel features named , have acid enamel , low melt enamel and ceramics enamel .
General sense of enamel products can be roughly divided into the following categories
1 , class enamel utensils , including pots classes , cups , plates class , barrels , bowls , cans , pots classes , classes and other utensils spittoon class ceramic products such as medical needle pots, vases, candy boxes, tea boxes soot cylinder and so on.
2 , enamel kitchenware categories , including kitchen cabinets and kitchen facilities , range hoods, enamel gas stove , oven, stove , sterilizer , enamel beer cans and water tanks and so on.
3 , enamel sanitary ware category , including steel enamel bathtub , cast iron bathtub , shower trays and so on. Cast iron enamel .
4 , medical class enamel , including electromagnetic radiation therapy, dental enamel and so on.
5 , architectural decorative enamel , including wall panels , artistic wall heaters, hand dryers enamel cast iron , cast iron enamel funnel , ordinary enamel signs , luminous enamel signs , enamel whiteboard teaching .
6 , e- enamel type products, including electronic ceramic substrate , electric film enamel .
7 , glass-lined products category , compared with ordinary glass-lined steel enamel thin silicon content increased significantly, its performance closer to the chemistry of glass, in addition to hydrofluoric acid , fluoride ions in the medium , and the temperature is higher than the concentration of alkali outside of phosphoric acid, the ability of various concentrations of inorganic acids , organic acids, weak bases and organic solvents corrosion , which is other materials can not match .
Process: There enamel glaze production prepared blank prepared for enamelling and drying , firing, and inspection processes. For Art enamel, enamel household , sanitary ceramic, enamel and other buildings , and the need for the use of exterior decoration , decoration and assembly needs through color . Industrial Enamel equipment has been tested and then you need to be assembled . In the pre- stamped or cast metal blank forming the first end of the glaze coating , the coated surface and then firing the glaze ( one or several ) , which is the traditional method many enamelling . End of the glaze is combined with the metal billet mutual transition layer , with strong adhesion, surface enamel glaze coating on the bottom , from products to cover the background and gives a smooth surface and a series of beautiful and excellent physical and chemical properties. Opaque glazed surface enamel surface there (white and colored ) and colorless transparent glazes of the points of light . The latter is the outermost layer of paint burned in progress to enhance or improve performance with a gloss of additional surface glaze. Now has a new enamelling process, that formulate a glaze, both for the end of the glaze , but also for surface glaze, a coating, a firing that get products.
Preparation of enamel : enamel on the metal body is coated glassy silicate or borosilicate coatings. Enamel material , including seven kinds of components , each with a different role ( see table ) . The main base agent , wherein the majority of silicate , boron oxide , aluminum oxide and alkali metal oxides. Body materials and products according to the kind of performance requirements to determine the chemical composition of the glaze . Requirements accurately weighed , thoroughly mixed ( dry mix , but also add 5 to 15 % water, and made into small balls ) , in furnaces ( China Multi muffle furnaces ) , crucible melting furnace or a rotary kiln up to a certain uniformity by water quenching , into thin air or hot (0.6 ~ 1.5mm), then grinding ( ball mill grinding machine or airflow ) into a dry powder or water into the glaze glaze .
Enamelling : the glaze powder or glaze evenly coated on a metal mold and , after firing and then coated surface glaze. Enamelling methods are dipping, pouring , spraying, sprinkling the powder method. Sprinkle the powder method is scorching the bottom surface of the glaze glaze sprinkled with dry flour, sugar -coated and roasted together as one operation , but also the large cast iron ( tub, Fanyingguo , etc. ) will be used in the method . In addition, electrostatic powder coating and electrophoretic enamelling and other laws .
Products firing : enamel coated billet pieces placed in a box furnace , rotary furnace or tunnel furnace firing . Borosilicate end of the glaze containing adhesion agent , the firing temperature is about 880 ~ 930 ℃, to enable them to form iron oxide layer on the surface of the green body , help with body porcelain layer ( steel ) good adhesion , it shall take oxidizing atmosphere. Surface enamel firing temperature is slightly lower , with antimony and antimony milky colored enamel surface is 850 ~ 900 ℃, the titanium surface enamel of 820 ~ 860 ℃. To make the glaze has a good emulsion surface and bright colors , and closely integrated with the end of the glaze , firing time and must be strictly controlled atmosphere furnace , cast iron body if using antimony and titanium enamel glazes are particularly sensitive to the atmosphere .
Main components: There are two main components of enamel : enamel and enamel with a metal material (inorganic vitreous material ) .
Metal Material: enameled metal materials are mainly steel, cast iron , aluminum, copper and stainless steel. Enameled steel ( mainly steel ) generally refers to low- carbon steel plate , namely carbon content than the bottom plate ( usually ≤ 0.08%), which is the main material used for storage water heater liner . Because of its chemical composition , internal microstructure ( metallurgical structure ) , surface conditions and mechanical properties of the enamel quality plays an important role , therefore , is currently on the market a large water heater manufacturers have adopted or Baosteel Wuhan Iron and Steel Production enamelled steel, to ensure the quality of enamel liner .
Enameled cast iron is the carbon content of more than 2.11% of iron-carbon alloy ( less than 2.11% of iron- carbon alloy called steel ) , which is mainly used in the production of sanitary ware ( bath ) , chemical equipment, cooking utensils, water pipes and so on.
Aluminum is used mainly aluminum and enamel aluminum-magnesium alloy . Copper is used mainly enamel copper ( ie copper ) , brass ( copper - zinc alloy ) and bronze ( copper - tin alloy ) , of which the most widely used copper and brass , are more representative of the copper enamel products - Cloisonne with copper as the substrate is made ​​of copper enamel products . Stainless steel, general can be enamelling , but because the stainless steel strong antioxidant capacity , so it is necessary to use special enamel enamel, while due to higher processing costs, less use of such programs now .
Enamel : enamel enamel of the main raw materials used include three categories: mineral raw materials, chemical raw materials and pigments . Mineral raw materials , is the main component of enamel , a large proportion of the content ( due to different manufacturers at home and abroad are different ) . It includes : quartz (the main component is silica -SiO2), feldspar ( alkali metal or alkaline earth metal silicates , common feldspar -K2OAl2O36SiO2), clay ( hydrous aluminum silicon mineral salts , mainly Al2O36SiO2 and crystal water ) .
Auxiliary chemicals are an integral part of the enamel , which mainly include: 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) and the like.
Pigment material refers to a material for decorative enamel color. Consists of : black, blue , brown , gray, green , pink, white, yellow , etc. 8 .
The enamel is produced according to the above-mentioned three raw materials a certain proportion ( with different manufacturers and different) , after about 1200 ℃ melting temperature , and after the rapid cooling of a granular or flaky vitreous borosilicate . It is based on process performance into the bottom glaze, glazed surface , glaze and decorated with glaze side ; according to different substrate materials into steel enamel , enamel cast iron , copper, enamel , aluminum, enamel , stainless steel enamel .
Enamel trends
From centuries-old enamel industrial development , we can see the development of enamel industrial technology mainly due to fierce market competition , restricting other industries to promote technological progress and ecological environment and to continue moving forward . Enamel industry is relying on its own technological progress, with a strong industrial plastics , aluminum and stainless steel industrial products industry compared to exist , compete and develop . Into the nineties , due to the continuous progress of science and technology, increasing consumer demand and growing competition in the market , the gradual development of ceramic industry has two main characteristics: First, the electronic technology, materials technology and other high-tech with enamel the combination of products , ceramic products given to computerization , program and other new functions ; second is a combination of plastic products, aluminum products and stainless steel products and other industrial products with enamel products , making ceramic products become fully functional, wide application of composite materials . In summary, based enamel as the main organic compound in a variety of materials based on high technology . The formation of the two features is basically represents the development trend of China's modern industrial enamel , making ceramic products have a high technological content, high -grade quality , high added value and wide applications and other new features, and contributed to the historical development of enamel two changes , one change in the use of performance of ceramic products by the container type into functional ; Second, change the composition of the monomer , ceramic products into a combination of products from simple products, a variety of materials . Implement two changes , given the enamel products more living space and more powerful competitiveness , the development marks the enamel industry has entered a new historical stage.dangwei Xie July 1, 2010