Other practical conditions for electrolytic coloring treatment

Aluminum anode: Power supply waveform used for electrolytic coloring, obtained from dc and AC power sources (used alone or in combination). Combined waveforms come in a variety of forms and have been applied in industry. Ac coloring is a widely used method in electrolytic coloring treatment, which is basically applicable to all kinds of metal electrolytic coloring. At present, improved AC coloring power supply, including asymmetrical AC waveform power supply, rectangular (square wave) pulse, deformation pulse waveform power supply has also been used, can be regarded as a branch of AC coloring.

A widely used power supply is a short period of DC voltage for the aluminium anode, followed by a long period of AC voltage. Under DC voltage, the electrolytic staining solution is soaked in the micropores of aluminum anode, which is conducive to metal precipitation in the subsequent AC staining treatment. Sliding voltage regulator is widely used in AC power supply. For single-phase power supply, due to the restriction of phase imbalance, the use of current is limited to about 1300A. In the case of high current, induction type voltage regulator should be used. When a large current of alternating current is passed, an inductive electromagnetic field is generated. In order to reduce the loss of electromagnetic induction, the power supply cables should be arranged parallel to each other, can also be twisted cable. In the use of busbar, should be close to each other as far as possible, practical choice of stranded cable.

In Japan, the coloring ratio of nickel salt and tin salt is 7:3. Nickel salts are used more often. But in Europe, Southeast Asia and other countries, simple tin salts are often used. In most cases, there is no difference between various metal salts in the performance of electrolytically coloured anodized aluminium films. There seems to be a trend towards expanding the use of metal salt varieties. As far as anions are concerned, sulfates still seem to dominate. The higher conductivity of the chloride tank solution improves distribution, but nitrous solution is not often used due to various problems.

In addition to nickel salt, drilling salt is also commonly used as coloring salt. Drill ions have higher mobility and better distribution, but metal drills are actually much more expensive than nickel. The cheapest metal is iron salts, which are rarely used at present because they are more difficult to manage, but may be used more in the future. Gold salts are electrolytically colored to pink, silver salts to golden, and copper salts to red. Zinc salts are not electrolytically deposited when used alone, but are often used in combination with other metals. Selenium salts are another salt that gets a golden appearance, but are toxic and should be used with special care.

Although perceptions change over time, the current choice of metal salts is based primarily on productivity considerations and environmental considerations for effluent discharge