1 Introduction Metal-type electrothermal materials are the most widely used heating elements for domestic and industrial heaters. When arranging metal electric heating elements, in order to insulate between electric heating bodies and prevent short circuits, the method of use is generally mechanical, that is, in the electric heating body. The insulating part is made of high temperature resistant insulating medium, such as refractory brick magnesia, alumina, etc., so that the electric heating body is isolated. If the heating wire is wound into a spiral shape, each ring must be pulled apart to form a certain width between each ring. Therefore, if the gap i can generate a high temperature resistant insulating layer in situ on the surface of the electric heating body, the electric heating wire can be directly used in the winding state, and can maintain the insulation performance of the voltage not exceeding 150V at the working temperature. It will be a breakthrough to improve the structure of all current electrothermal alloy heating elements, so that the electric heating device does not need or consider additional insulation parts, reduce cost, beautify the structure, and play a role in manufacturing more new heating elements. The great push action 甩Fe-Cr-Al alloy itself has a high aluminum content. When used in an oxygen-containing atmosphere, the surface will spontaneously form an Al23 film, and Al23 is good. Insulator. According to this principle, a fund project was prepared in advance on the surface of Fe-:i-Al electrothermal alloy by gas phase reaction method: Guangdong Provincial Natural Science Fund Project (116-B63980) 1973-), female, Wuhu, Anhui, PhD student , mainly engaged in the in-situ formation of insulating film dynamics of vacuum gas phase reaction on the surface of electrothermal alloy; Meng Jilong (1938-), male, Guangxi, professor.
Layer Al23 film, which can exert good insulation during the installation and use of electric heating elements. The microstructure and phase composition of the film were studied, and the factors affecting the breakdown voltage of the film were analyzed. The lining of the Al23 insulating film is significantly less than 6. 7kPa when the insulating film has been used in some electrical components, and has achieved good results. The grain size is because the grain density of the oxide is large as the oxygen pressure is increased. The larger the grain density, the more grain boundaries between the grains. The breakdown performance of the insulating material is diminished with the amorphous-single crystal P polycrystal. In the case of the same thickness, the more grain boundaries, the worse the breakdown performance. When the thickness of the insulating film reaches a certain level (for example, when the oxygen pressure is 40 kPa), the through passage of the electron becomes complicated, and the influence of the grain boundary is weakened, so that the breakdown voltage is increased in terms of the influence of the alloying elements, and the two types of 0Cr27A17Mo2 are compared. The breakdown performance of the Al23 insulating film on the surface of the electrothermal alloy. From the chemical composition of the two alloys, the main difference is that the latter contains 2% of Mo. Table 1 is the breakdown voltage comparison of the two alloys. It can be seen that no matter what Under the partial pressure of oxygen, the breakdown voltage of Al23 insulating film on the surface of 0Cr27A17Mo2 alloy is lower than that of 0Cr25Al5 alloy.
The breakdown voltage of two alloy insulating films is compared with V oxygen pressure / kPa alloy reaction time / h The purpose of adding Mo element in Fe-Cr-Al electrothermal alloy is to improve the high temperature mechanical properties of the alloy. The CrCl content of 0Cr27Al7Mo alloy is higher. It can be applied to higher temperatures, but the breakdown voltage of the Al23 film formed by the alloy here is lower, and it is estimated that Mo is easy to form volatile oxides at high temperature, such as Mo2 (melting point 795*C) and Mo2. -Mo3 eutectic (melting point 778*C). Under the condition of 1000*C, Mo may be internally oxidized under the surface layer. The inner oxide layer is liquid phase, and the liquid oxide can pass through the grain boundary of Afc3 film. The outer surface penetrates, and once it reaches the surface, the liquid oxide volatilizes, leaving a hole locally in the surface of the Al23 insulating film. The grain boundary of the polycrystalline insulating film itself is the weak point of breakdown, and the void left by the volatilization of the liquid oxide at the grain boundary inevitably leads to a decrease in the breakdown voltage.
4 Conclusion It is feasible to form an insulating film in situ on the surface of Fe-Cr-Al electrothermal alloy by gas phase reaction; the insulating film is mainly composed of TAl23 phase, and its growth conforms to the parabolic law; the breakdown performance of the insulating film and the surface oxygen pressure reaction time Related to alloying elements.
Our Beauty Salon Nail Display is suitable to use for beauty salons advertising display and beauty products trade paper showing for beauty Salon Furniture. The display stand is easy to transport and carry.
At the same time, it is easy to assemble, saving shipping cost , labor and power. We have several kinds of display units, welcome to contact us to know more details.
Makeup Display Unit,Cosmetic Display Unit,Salon Display Cabinet,Cosmetic Display Shelf
TOM SPA BEAUTY SALON EQUIPMENT CO.,LTD , https://www.tomspabeauty.com