1.What is an auxiliary anode?
In the process of electroplating various products and parts, some complex shapes and tubular parts that need to be plated evenly or have plating in the inner hole, etc. should add another anode in the low current density area to make the current distributed evenly as much as possible, and this additional anode is called auxiliary anode.
2. In what circumstances is it necessary to take an auxiliary anode or cathode?
In a plating solution with poor dispersion and depth capability, an auxiliary anode and an auxiliary cathode are generally adopted if equal thickness and full coverage of the plating layer are required.
The auxiliary anode is used outside the reach of the power line on the plated part, such as deep recesses or inside the tube. No matter using auxiliary anode or auxiliary cathode, it is important to make the power line of each part of the plating equal, so that a uniform coating can be obtained. Auxiliary anodes are generally insoluble anodes (such as lead plates, iron plates, etc.). Soluble ones are also available. However, attention needs to be paid to the effect of producing anode slag and the dissolution of the wire. Auxiliary cathode can be used with iron wire or copper wire guard frame, thickness and distance to be able to prevent the product from the concentration of power line and make the thickness of plating too thick, or even scorched.
3.The use of auxiliary anodes and cathodes when plating is commonly encountered.
For example, when galvanizing tubes, an iron is usually added to the tube as an auxiliary anode. In order to avoid short-circuiting between the auxiliary anode and the cathode, the auxiliary anode often wears an insulating plastic ring, and the auxiliary anode is moved periodically during operation so that the power lines are equal everywhere in the tube and the plating is evenly covered.
Sometimes plating a large area of plate parts, the middle part is often not plated or plated poorly. This is also due to the edge and the middle of the current density difference is particularly large caused by. For example: chrome plating, the edge of the plane and the middle current density difference of 4-5 times, so according to the general operation method is not easy to plating good, sometimes too much current, the edge and appear burnt.
For this large area plate plating parts, if thinner, can be slightly bent, so that its exposed concave and convex surface is not to the anode, or in turn will lead anode bending, so that its projection is located in the center of the plane. If the anode and the parts are not suitable for bending, lead can also be added to assist the anode in the center of the plane, or the upper and lower parts of the anode are wrapped and insulated, so that the current can be concentrated in the center.
4.What is cathodic protection?
In electroplating, for some cathodic current operation range is narrow or the shape of the more complex parts, in order to prevent the edges from burning, at the tip of the parts or the two ends of the cathode of the duct welding (or hanging) on the metal protection line, in order to disperse the current on the cathode. This metal protection line is called the protection cathode.