Composite metal electrothermal film sol and method for producing electroheating tube with the same

Abstract

The compound metal electrothermal film sol is prepared with nanometer level tin powder 8-20 weight portions, antimony trichloride 4-10 weight portions, stannous chloride 1-4 weight portions, gold chloride 0.01-0.1 weight portions, germanium tetrachloride 0.01-0.1 weight portions, silver chloride 0.8-2 weight portions, nickel chloride 0.1-1 weight portions, copper chloride or zinc chloride 2-7 weight portions, sodium chloride or potassium chloride 2-7 weight portions, deionized water 24-60 weight portions and ethanol 99.2-312 weight portions. The sol may be prepared into electrothermal film with high electricity-to-heat conversion efficiency, and other advantages. The present invention also discloses the method of making electrothermal pipe with the sol, and the making process is simple and practical and has less environmental pollution.

Description

technical field [0001] The invention relates to the technical field of electric heating films, in particular to a composite metal electric heating film sol; the invention also relates to a method for manufacturing electric heating pipes by using the sol. Background technique [0002] Electric heating film is a new type of electric heating device, because of its main features such as water and electricity isolation, fast power saving, etc., it has been widely used in the field of electric heating. A known electrothermal film made of tin dioxide, antimony pentoxide, indium trioxide and oxide resistance regulator with a particle size of 16-18nm has the above characteristics. However, the electric heating film made of it can only be used within 220V and the power is not greater than 10W / cm 2 It is used for about 500h in the normal state, and the service life is short, which limits the use range and effect of electric heating film technology and end products. The reason is that...

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Problems solved by technology

However, the electric heating film made of it can only be used within 220V and the power is not greater than 10W / cm 2 It is used for about 500h under normal conditions, and the service life is short, which limits the range and effect of electric heating film technology and end products.

The reason is that when the electrothermal film sol or gel prepared from the above-mentioned raw materials is thermally sprayed in an environment rich in oxygen in natural air, while oxygen reacts with metal ions to form metal oxide semiconductor crystals, the thermal reaction process must be in the crystal. Excess oxygen ions are generated in the "lattice" of the crystal lattice. When the temperature drops or precipitates or is heated by electricity, the oxygen ions in the lattice gradually "escape", and excessive negative ion vacancies gradually appear. If there is not enough active Metal ions give vacancies to fill. Due to the ion vacancies, under a certain external stress or under the action of crystal internal stress, the accumulation of "lattice" will gradually occur, which will gradually cause changes and inconsistencies in the electrical characteristics of the crystal on the homogeneous surface. When Crystal stress release or accumulation changes will occur after 220Vac is powered, which is manifested as when the surface temperature of the film reaches 200°C or above or after several hours of continuous electrification (some are set to 30min), local spark breakdown occurs and the electrothermal film is scrapped

Moreover, the metal tin used in the electrothermal film needs to be indirectly produced by tin tetrachloride, the production efficiency is low, and the environment is polluted due to the generation of hydrogen chloride gas during the reaction process.

[0003] Secondly, in the configuration process of the above-mentioned sol or gel, there are defects in the reaction temperature, time, agitation adequacy, and operation links, mainly manifested in the influence of low reaction temperature, insufficient time, insufficient agitation, and impurities other than metals. The structural density, uniformity and homogeneity of the membrane are affected, which in turn affects the life of the membrane. About 50% of the membranes have a life span of less than 500h

[0004] In addition, each operation in the above method will produce a large amount of waste liquid, such as: the Cl-containing waste liquid that is poured out after centrifugation - Mixed solution of water, ammonia water, ethanol, etc., washing to remove Cl - Wastewater, etc., directly discharged into the sewer will cause a certain degree of environmental pollution