PCB8 is planted finishing craft encyclopedia

The purpose with PCB the most primary finishing is to assure good solderability or electric function. Because the copper of nature is in air,apt exists with the form of oxide, maintain for a long time unlikely for former copper, because this needs,undertake other processing to copper.

1, sirocco is whole smooth (gush stannum)

Sirocco is whole smooth renown sirocco solder is whole smooth (common calls gush stannum) , it is to be in stannum of melt of Fu of PCB surface besmear (lead) solder is used heat compress air to rectify (blow) smooth craft, make its form to fight cupreous oxidation already, can offer the coat of good solderability again. Sirocco is whole at ordinary times solder and copper form the compound between cupreous tin metal in combinative department. PCB undertakes sirocco is rectified should sink at ordinary times in the solder in melt; Wind knife blows the solder of smooth liquid state before solder is caky; Wind knife can get on cupreous range the curved month state of solder is the smallest change and prevent solder bridge to receive.

2, organic solderability protective agent (OSP)

OSP is printed circuit board (a kind of accords with RoHS instruction requirement craft of finishing of PCB) Copper Foil. OSP is the abbreviation of Organic Solderability Preservatives, interpret is in organic the film that protect solder, say to protect cupreous agent again, the Preflux that English also weighs. Say simply, OSP is in namely spotless naked copper apparently, grow film of an organic skin with chemical method. This film has antirust, heat-resisting is pounded, be able to bear or endure wet sex, surface of copper of protection of in order to continues to rust no longer in normal environment (oxidation or vulcanization) ; But soldering follow-uply in high temperature, this kind of diaphragm must be aided very easily again welding flux place keeps clear of quickly, the clean copper surface that just can make show so is able to be united in wedlock to be nodded for firm solder instantly with melt soldering tin inside cutty time.

3, complete gold of board plating nickel

Gold of board plating nickel is in PCB surface conductor first after a nickel again a gold, plating nickel basically is to prevent Jin Hetong between diffuse. Present eletroplate nickel gold has two kinds: Plating soft gold (bullion, golden surface does not shine it seems that) with plating hard gold (the surface is flowing and hard, wear-resisting, contain the other element such as cobalt, golden surface looks more shining) . Soft gold basically is used at chip is enclosed to make golden line; Hard gold basically is used in the electric sex that is not weld to interrelate.

4, turmeric

Turmeric is lap on cupreous range thick, the nickel gold alloy with electric good sex, this can protect PCB for a long time; The to the environment enduring sex that additionally it also has place of other finishing craft to be not had. In addition what turmeric also can prevent copper is deliquescent, this will is beneficial to assemble without lead.

5, heavy stannum

Because at present all solder are a foundation with stannum, so stannic layer can match with the solder photograph of any types. Heavy stannum craft can form the compound between even cupreous tin metal, this character makes heavy stannum is had and sirocco rectifies the good solderability like making the same score and whole without sirocco make the same score headachy even sex problem; Heavy latten cannot store too long, when assembling, need fibrous root occupies heavy stannum undertake orderly early or late.

6, heavy silver

Interpose of heavy silver-colored craft is mixed at organic besmear Fu chemical plating nickel / between turmeric, technology is simpler, fast; Although expose,be in hot, wet in the environment with pollution, silver still can maintain good solderability, but can lose luster. Heavy silver does not have chemical plating nickel / because the good physical strength that turmeric place has does not have nickel below silver layer.

7, gold of chemical nickel palladium

It is much between nickel and Jin Zhi that gold of chemical nickel palladium and heavy metallographic are compared a palladium, palladium can prevent what occurrence displacement reaction brings about corrode a phenomenon, had made sufficient preparation for turmeric. Golden criterion is enclothed cheek by jowl it is above palladium, offer good interface.

8, eletroplate hard gold

To improve product wear-resisting performance, increase insert unplug frequency and eletroplate hard gold.