Preprocessing
Electrophoretic coatings, including polymer resins, organic solvents, color suspension particles, and water, are placed in an electrophoretic tank and stirred to form a uniform solution.
Classification of electrophoretic coatings
There are two kinds of electrophoretic coating: anode coating and cathode coating. Anode electrophoresis is sintered ndFeb magnet as anode, this way in the process of electrophoresis matrix metal and surface treatment film (such as phosphating film) are precipitated and dissolved at the same time, reduce the corrosion resistance of electrophoretic deposition film, so in most cases the use of cathode electrophoresis, namely sintered NdFeb as cathode, the use of cationic electrophoretic paint. The paint is a water-soluble coating formed by neutralizing a nitrogen-based synthetic resin with organic acids.
The cathodic electrophoretic layer is neutralized by organic acid, which has low toxicity. The mechanical strength of the wet film and its binding force to the workpiece are higher than those of the anodic electrophoretic coating. But cathode electrophoretic coating cost is high, electrophoretic tank liquid is acidic, has corrosion effect on equipment. Cathodic electrophoretic tank to use corrosion resistant materials, such as stainless steel, or acid resistant plastic.
Process flow of sintered NdFeb electrophoretic coating
The process of electrophoretic coating is mainly divided into three parts: surface pretreatment, electrophoresis and drying and curing. The specific process is blank - degreasing - washing - hole sealing treatment - washing - phosphating - washing - electrophoresis - washing - drying and curing.
Smooth and clean surface is the basis of high quality electrophoretic coating. The purpose of surface treatment is to create good surface conditions. The process of electrophoretic coating is a complicated process of chemical change. As the coating is deposited to the surface of the magnet continuously, the composition of the electrophoretic tank also changes constantly. The solid composition, ph value of the electrophoretic tank, temperature, electrophoretic voltage, electrode spacing and so on should be strictly controlled.
