China fast development of electrolytic capacitors, according to statistics, in 1997 the annual output of about 15 billion, may have been recently estimated that more than 20 billion. From the development of China's electronics industry to see, in recent years, production of aluminum electrolytic capacitors will have a greater increase. Aluminum electrolytic capacitor is currently part of our homemade foil, with substantial dependence on imports. To change this situation, the domestic manufacturers, in the localization of a lot of work done. Not long ago, Southwest Aluminum electrolytic capacitors with high-pressure research project successfully developed, product quality has reached international advanced level, has been completely replaced by imports. It should be said, after 10 years of development, especially in the last five to six years, the quality of China's electronic aluminum foil has been greatly improved.
Aluminum electrolytic capacitors are used in the context of electronic aluminum foil, which is a work in polar conditions, the corrosion of materials. Different polarity of electronic aluminum foil require different types of corrosion. High-voltage anode foil for a column-shaped hole corrosion, low-voltage anode foil for the sponge-like corrosion, medium-pressure section of the anode foil for the insect-like corrosion.
20 Before the 1980s, large electrolytic capacitors are in use hand-chemical corrosion, 80 years after the use of linkage electrochemical corrosion. Corrosion of aluminum foil with a purity of hand low (99.3% to 99.7%), the aluminum foil processing quality requirements are not high. Linkage electrochemical corrosion demands increasingly high purity aluminum foil, aluminum foil processing on the quality requirements are fine. From the purity of aluminum, the aluminum-1980s 99.99% so far has reached 99.993% purity aluminum. This is a foil but also of the aluminum industry's technological progress.
Aluminum foil to improve the purity, of course, improve the quality of the foil positive impact, but the other is the cost increase. At the same time, corrosive media is also changing, and some media concentration was increased, and some media type changes, which are detrimental to the environmental protection work, the heavy task of leading manufacturers of environmental protection, which may require the purity of aluminum decreased. The latest from Japan aluminum foil component analysis, we found a trend in this area have been.
Improve the quality of corrosion foil and aluminum foil light quality and progress are inseparable from the Japanese point of view of patents, patent foil anode peak in the 1980s, the peak anode foil has two patents: one peak about 1977 to 1978, another peak in 1983 or so. The patent describes the peak of the rapid advances in technology.
From a global perspective, the development trend of electronic aluminum foil as follows:
High-voltage anode foil
High-voltage anode foil can be divided into two categories, one is high-quality high-pressure foil; one is an ordinary high-pressure foil.
Anode foil is characterized by high quality, "two high and one thin," that high-purity, high cube texture and thin surface oxide film. Quality of these products, but the cost is high. Aluminum purity> 99.99%, 96% cube texture. Vacuum heat treatment at 10-3pa ~ 10-5Pa conditions.
Ordinary high voltage anode foil is an economical and practical high-voltage anode foil, aluminum purity> 99.98%, cube texture> 92%, vacuum heat treatment at 10-1pa ~ 10-2pa conditions.
Low-voltage anode foil
Low-voltage anode foil process more complicated, we believe that a method can not be used to meet the requirements of paragraphs voltage, can be roughly divided as follows.
Less than 35Vf low-voltage foil, should develop a hard-state purity aluminum foil corrosion, and there is a hard state can provide a small quantity of corrosion and corrosion of the core channel, as the DC and AC corrosion corrosion better need to study what kind of power. The industry believes that the specific volume of the law than the law can improve the soft state 5μF/cm2.
Low-voltage greater than 50Vf foil, soft-state high-purity aluminum foil to provide a number of bit planes to poor condition, you can get a larger corrosion pits foil.
Anode foil has a soft state and hard state of the points. Japan-based soft-state electrochemical corrosion, chemical attack Western Europe, mainly in hard state. Both have their advantages and disadvantages, soft state with high purity aluminum (> 99.85%), no copper, superior quality and high cost; hard state using a low-purity copper foil, low cost, easy to raise more than . To develop the electrostatic capacity is moderate, low-cost or low-copper-free copper anode foil, you can use AL-Fe, AL-Mg alloy. Low-purity copper foil which, in high purity aluminum as the base add small amount of copper as corrosion of the core, specific volume with high purity soft-state electrochemical etching of aluminum foil comparable, because of its low cost, should win the market.