Anode degreasing and anode surface treatment
One of the functions of titanium anode surface active agent is emulsification. Surface active agent is a kind of substance rich in two types of opposite groups: hydrophilic group and hydrophobic group. Hydrophilic groups are associated with water molecules and away from oil; hydrophobic groups are just the opposite. Under normal circumstances, the surface active substances are disordered in the aqueous solution, and some are linked to each other to become glue; in the outer layer of the solution, the hydrophobic group points to the air. On the container wall, the hydrophobic bases point to the container wall and are arranged in an orderly manner.
There are many other degreasing methods on the surface of titanium anode. For example, when the workpiece is too large, part of the surface treatment (such as coating, etc.) or no degreasing equipment, simple brushing can also be used to remove oil. When wiping and removing oil, use a brush or rag to wipe back and forth with lime slurry, magnesium oxide, cement, soap solution, tile ash, plant ash, sodium carbonate, metal cleaning agent, surface active agent, decontamination powder, etc. Oil removed. Sometimes after brushing once, apply the oil remover and wipe again, so that the oil can be completely removed after repeated several times.
Anode degreasing is the opposite of cathode degreasing, and its advantages are as follows:
a. The matrix has no risk of hydrogen infiltration due to degreasing;
b. It can remove the residues left by pickling on the surface of the parts and some metal coatings, such as zinc, tin, lead, chromium, etc., so that the workpiece surface is particularly clean.
The disadvantage is that the degreasing power of the anode is not as high as that of the cathode. There are three reasons:
(a) The alkalinity is low due to the discharge of OH- near the anode, and the saponification reaction cannot be carried out;
(b) Under the condition of constant electricity, the oxygen generated on the anode is only half of the hydrogen generated on the titanium cathode, and the tearing effect on the oil film and the mixing effect on the solution are poor;
(c) The oxygen bubbles are larger, the ability to stay on the surface of the workpiece is small, and the ability to bring out the oil droplets is also weak.
c. Aluminum, zinc, tin, lead, copper and their alloys dissolve on the anode and suffer from corrosion. When the alkalinity of the solution is low and the current density is high, especially when the solution is contaminated with chloride ions, the steel parts can also suffer from pitting corrosion.
To make full use of the respective advantages of cathode degreasing and anode degreasing, the combined degreasing method of first cathode degreasing and then anode degreasing is currently used.
