Ceramic heating body principle design
In life, many household appliances need to rely on their heating components for heating, such as coffee machines, water dispensers, ovens, etc. In the past, the fabrication of these large-scale components has often involved metals as the basic structural raw material. During use, due to long-term heating, it is easy to cause oxidation of parts and affect its service life.
Alumina ceramics are a good choice to avoid these problems. A new generation of medium and low temperature heating elements—alumina ceramic heating elements——alumina ceramic heating elements can be synthesized by printing resistance paste on alumina ceramics, high-temperature co-firing, and processed by electrodes and leads.
The main raw and auxiliary materials are alumina ceramic heating elements.
At the melting point of 2050°C, the amphoteric oxide is hardly soluble in water and non-polar organic solvents, generally between 93 and 96%.
Water-soluble polymer insoluble in gasoline, kerosene, vegetable oil, etc.
1. Working principle.
The currently popular resistance heating principle is designed for the alumina ceramic heating body, that is, when the current passes through the heating wire, the heating wire will be heated, and the alumina ceramic heating body has a metal positive temperature characteristic, and the product resistance will increase with the increase of temperature , so as to reduce the actual power of the product without affecting the heating effect.
A ceramic heating element that generates heat when energized.
2. Classification and application.
At present, common alumina ceramic heating elements include: ceramic electric heating tube, ceramic heating plate, ceramic heating plate, ceramic electric heating coil, etc., and different shapes and styles can be selected according to different applications. Their common features are high electrical conversion efficiency, fast heating speed, high temperature resistance, corrosion resistance, and long service life.
In terms of application, ceramic heating element components are mainly used for: household electric heating appliances - small warm air heaters, hair dryers, clothes dryers, heaters, heating mobile phones, dryers, electric splints, electric irons, electric welding irons, hair straighteners Appliances, curling irons, electronic thermos bottles, insulation cabinets, electric cookers, toilet ceramic heaters, water heaters, etc.; industry-industrial drying equipment, electric thermal bonders, water, oil, acid heaters, etc.; electronics industry-small Constant temperature tank for special crystal devices; in medical treatment, such as infrared physiotherapy instrument, intravenous injection heater, etc.
Three, preparation points.
Take alumina ceramic heaters as an example – in many high-power applications, alumina heaters have high quality requirements, especially their thermal shock resistance. The thermal shock resistance of a material depends on the internal thermal stress of the material, the geometric shape and the influence of the environmental medium, so the thermal shock resistance of a ceramic material is a comprehensive performance corresponding to various heating conditions and external constraints.
Since the preparation of the alumina ceramic heating sheet is based on the design requirements of the heating circuit, the heating resistance paste is printed on the ceramic blank, and then stacked and burned in multiple layers. Therefore, in addition to the performance of the alumina ceramic itself, the heat resistance of the alumina ceramic heating element is also related to the bonding ability of the resistance sauce and the alumina ceramic, the heating uniformity of the heating line, the residual stress of the screen printing process, and the sintering process. Its distribution, installation and use stress and other conditions have a relationship that cannot be ignored. For example, the design of the printing line should make the temperature gradient during heating as small as possible, so that the thermal stress concentration effect is not easy to form, otherwise the heating sheet is easy to break.
Alumina ceramic burst heater.
Small alumina ceramic heating parts not only meet environmental protection requirements, do not contain harmful substances such as lead, cadmium, mercury, polybrominated biphenyls, and polybrominated diphenyl ethers, but also have corrosion resistance and high temperature resistance.