It can be considered to use plasma electrolyte polishing process to deal with, the effect is good and very environmental protection. The details are as follows;

Yb-66 environmental friendly aluminum and aluminum alloy electropolishing additive

New process of yb-66 environmental friendly aluminum and aluminum alloy electropolishing additive

1、 Features

1. Polishing liquid does not contain chromic acid, which meets the requirements of environmental protection today, and saves investment in environmental protection equipment and waste water treatment costs.

2. The current density of polishing is smaller than that of traditional technology, so it is not only low power consumption, long service life of polishing liquid, but also suitable for surface polishing of large aluminum and aluminum alloy parts.

3. It is suitable for all kinds of aluminum alloys with pure aluminum and desilication content greater than 2%.

2、 Composition and operating conditions of polishing fluid

Concentrated phosphoric acid (specific gravity 1.74) 70% (weight)

Yb-66 additive 30% (weight

Temperature 55-65 ℃ 60 ℃ best

Anode current density, Da 2 – 8 a/dm2 (no agitation)

12 – 20 a/dm2 (STIR)

Voltage 10 – 15 volts

Polishing time 3-5 minutes

Cathode material lead or stainless steel

Cathode area: anode area 2-3:1

3、 Slotting procedure

1. The specific gravity of the polishing fluid before use is within 1.50-1.52. According to the volume of polishing liquid, the proportion of polishing liquid and the proportion of phosphoric acid in polishing liquid, the amount of phosphoric acid to be added is calculated and added.

2. The weight of yb-66 additive is calculated and added.

3. Heat to operating temperature.

4、 Operation instruction

1. Whether to use stirring (cathode moving and air stirring) in polishing mainly depends on the shape of polishing parts: if the shape of polishing parts is simple and the width of transverse is narrow, stirring is not used; On the contrary, if the shape of polishing parts is irregular or the width of the polishing part is large, especially when some parts of the polishing part prevent the gas from escaping and form "air bag" and affect the surface polishing, the mixing method must be adopted. In the case of mixing, the current density of anode must be improved correspondingly, otherwise, the polishing surface is difficult to achieve high brightness.

2. Most impurities are deposited on the cathode surface during polishing, but some solid sludge generated by polishing remains in polishing liquid, so it is necessary to filter polishing liquid regularly to remove impurities.

3. In the polishing process, due to the production of phosphate, the electrolysis and volatilization of water and the loss of entrainment of polishing liquid, phosphoric acid and yb-66 additives should be added continuously.

4. The proportion of phosphoric acid and yb-66 additive is still 70% and 30%, but the specific gravity of polishing solution should be measured after each addition, and then adjusted according to the test results.

5. The original specific gravity of the polishing fluid before preparation without use is within the range of 1.50-1.52, and the specific gravity of the polishing fluid shall be controlled within 1.50-1.65 during the operation of the polishing groove. The high proportion of polishing liquid indicates that the water content of polishing liquid is insufficient; On the contrary, the specific gravity of polishing liquid is too low, indicating that the polishing liquid water content is too high and phosphoric acid content is low. It is an effective method to control the concentration and quality of polishing liquid components by hydrometer.

6. The polishing process with high anode current density may cause the aluminum content in polishing liquid to be too high (the semi melting substance on the top of polishing liquid is the mark of excessive aluminum content). At this time, it must be replaced with a new polishing liquid to reduce the aluminum content in polishing liquid,

5、 Pre plating and post plating treatment

1. Pre plating treatment

Aluminum or aluminum alloy parts must be degreased before polishing. According to the degree of oil sludge contamination on the surface of polishing parts, one of the following two oil removal processes can be selected for treatment.

The first process: the sludge on the surface of aluminum parts is slightly polluted and distributed evenly. Generally, the weak etched alkaline oil removal liquid is used. Its composition and operation conditions are as follows:

Anhydrous sodium carbonate 25 g/l

Trisodium phosphate 25 g/l

Temperature 60 – 70 ° C

Immersion time 1-3 minutes

The second process is that the sludge on the surface of aluminum parts is heavily contaminated, and the alkaline oil removal liquid without corrosion is commonly used. Its composition and operation conditions are as follows:

Anhydrous sodium carbonate 40 – 60 g/l

Trisodium phosphate 40 – 60 g/l

Sodium silicate 20 – 30 g/l

Temperature 50 – 70 ° C

Immersion time 15 – 30 minutes

Sodium silicate is a corrosion inhibitor, which can inhibit the corrosion of aluminum. However, when using this inhibitor, aluminum parts will produce a layer of aluminum silicate film. Therefore, after oil removal and cleaning, sludge removal (usually called light) must be carried out in the solution containing fluorine ion. The composition and operation conditions of sludge removal treatment solution for aluminum and aluminum alloy are as follows:

Nitric acid (65%) 500 – 700 ml/l

Ammonium fluoride 50 – 120 g/l

Temperature 20 – 25 ° C

Immersion time 30 seconds

2. Post treatment

Most aluminum and aluminum alloys can be coated with various coating after electropolishing and cleaning, such as anodizing, electrophoretic coating and various metal coatings. However, some aluminum alloys, such as high copper content, need to be sludge removed after electropolishing and cleaning to improve the surface brightness.