Linear LED PCB Aluminum Circuit Board
In order to ensure the aluminum PCB can meet customer production needs, various surface treatment will be carried out in the production process, mainly including ENIG, gold plating, HASL, immersion tin, silver plating, etc.
Immersion gold mainly uses chemical deposition in these surface treatment processes.The main process is
1, remove oil acid, oxidize copper surface and slightly remove oil;
2, micro erosion, copper surface can be coarsened in this way, so that nickel and copper can have a better binding force.
3, The percolation is used to remove the minor oxides on the copper surface to ensure that the copper surface is in a fresh state and maintains the acid content in the activation cylinder;
4, Porous activation consists of depositing a thin layer of palladium on the copper surface via a replacement reaction to provide a catalyst for the subsequent nickel deposition operation;
5. After soaking, the residues of activated liquid on the substrate are washed to prevent the occurrence of infiltration and plating of nickel.
6,Immersion nickel is formed between copper and gold to form a layer of metal diffusion barrier, thereby providing a layer of corrosion resistant, can carry out soldering and wire operation;
7, ENIG is to ensure that the nickel layer will not be corroded;
8, The last step is to dry the aluminum circuit board.
The advantage of using this method for surface treatment is that the welding is easier and has the function of antioxidant.
The gold plating is based on the principle of electrolysis. The aluminum pcb treated in this way has the characteristics of conducting electricity, heat conducting and antioxidation.HASL is a relatively common surface treatment method on PCB circuit board. HASL mainly includes vertical tin spraying and horizontal tin spraying. The reason why it is applied to the surface of aluminum circuit board is to prevent oxidation on the bare copper surface and maintain solderability. Immersion tin technology is based on the metal copper and tin ion in the solution of the displacement response, the technological process for acid pickling, washing, micro erosion, washing, presoak, immerison tin, hot water washing, water washing, DI water washing and drying, compared with HASL and ENIG, it has characteristics of lead-free, smooth surface, low cost, oxidation resistance and higher welding reliability.
In addition, there are other surface treatment methods such as silver plating. The silver-plated aluminum pcb is characterized by good thermal conductivity, electrical conductivity, easy polishing and excellent reflective performance, as well as good welding and bonding strength. It is also a common surface treatment method.