Classifications: (HASL) / lead-free HASL, OSP, immersion gold, selective gold, hard gold, immersion silver, immersion tin.
1. Price: Hard gold > selection gold > immersion tin > immersion gold > immersion silver > OSP>HASL.
2. HASL advantages: good solderability, easy to store up. Disadvantages: Tin flatness is poor, non-environmental materials.
3. Advantages of OSP: The film can be quickly removed by dilute acid or flux before soldering, and the bare copper surface can still be displayed good solderability instantly. It protects the copper surface from oxidation by external influences. Disadvantages: It can not resist high temperature and acid alkali.
4. Advantages of immersion gold: chemical nickel gold is increasingly becoming an important way of PCB delivery, its low surface contact resistance, flat soldering surface and high solderability, etc which are unparalleled compare with HASL & OSP. Disadvantages: higher medicinal liquid prices, unmanageable chemical characteristics, and higher product scrap rates are factors that is beset ENIG.
5. Advantages of selective gold (gold + OSP): It has all the advantages of nickel gold and OSP. Disadvantages: It is easy for the gold surface to be black due to the problem of sparing hole caused by the treatment of the OSP process caused by the attack of the micro-etching liquid or the sulfuric acid liquid.
6. Advantages of flash gold: The appearance is bright and dazzling, its good weld and conductivity, corrosion resistance, uniform color distribution, and long-lasting discoloration. Disadvantages: expensive.
7. Advantages of silver: anti-magnetic. Anti-interference increases stability, temperature resistance and good heat dissipation, environmental protection and beautiful,and delay aging time. Disadvantages: The standard conditions on the appearance inspection are strict and easy to oxidation.
8. Advantages of tin: It can reduce the oxidation reactivity of IMC growth and PCB of tin-copper alloy and improve the stability of temperature storage. Disadvantages: The solder resist is weak to resist-corrosion and is easy to produce tin.
In summary, the classification and shortcomings of the common surface finish of the PCB board. I hop this article can help you!
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