Технология PCB - преимущества и недостатки химического никелирования и гальванизации никелем

1. химический никель(ENIG)
   Nickel gold is a relatively large surface treatment process. слой никеля - фосфора. According to the phosphorus content, разделение на фосфорные и среднефосфорные никели. разное Приложение.
   
   The advantages of nickel-gold:
   Suitable for lead-free soldering-->The surface is very flat, suitable for SMT-->Through holes can also be coated with nickel and gold-->Long storage time, storage conditions are not harsh-->Suitable for electrical testing-->Suitable for switch contact design -->Suitable for aluminum wire binding, годный для толстой доски, strong resistance to environmental attacks.
   
   

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2. гальваническое никелирование

Electroplated nickel gold is divided into "hard gold" and "soft gold". Hard gold (such as goldcobalt alloy) is commonly used on gold fingers (contact connection design), мягкое золото чистое золото. Electroplating of nickel and gold is widely used on IC substrates (such as PBGA). в основном для соединения медных и золотых проводов. However, гальваническое основной платы IC подходит. область слипанных золотых пальцев требует гальванизации дополнительными проводами.

The advantages of electroplating nickel gold:

Long storage time>12 months-->Suitable for contact switch design and gold wire binding-->Suitable for electrical test

Weaknesses of nickel-gold electroplating:

Higher cost, thicker gold-->Additional design wire conductivity is needed when electroplating gold fingers-->Because the thickness of gold is not constant, из - за толщины золота, может вызвать хрупкость точки сварки и повлиять на прочность при сварке.--> The problem of surface uniformity of electroplating-->The electroplated nickel and gold do not cover the edge of the wire-->It is not suitable for aluminum wire bonding. Not suitable --> High storage conditions are required.

The advantages and disadvantages of плата PCBtin spraying
Tin spraying was a common treatment in the early days of PCBs. Теперь разделение на свинцовое и бессвинцовое олово.

The advantages of tin spraying:

Long storage time -->After the PCB is completed, the copper surface is completely wetted (the tin is completely covered before soldering)
Suitable for lead-free soldering-->Mature process-->Low cost-->Suitable for visual inspection and electrical measurement

Weaknesses of tin spraying:

-->Not suitable for wire bonding; due to surface flatness, there are limitations on SMT; not suitable for contact switch design --> Copper will dissolve when spraying tin, and the board will withstand a high temperature --> Especially thick or thin board , ограниченность орошения оловом, and the production operation is inconvenient.