I am not beting exact on the actual thickness of the Ni/Au as its not specified in the board report, only that the outer serfaces are plated to 1oz, part of that plating will be copper when the via and through hole connections are made.
The manufacturers report only states the plate thickness, not the proportion of Ni/Au to Cu. j. -----Original Message----- From: Brad Velander [mailto:[EMAIL PROTECTED]] Sent: 04 April 2002 20:00 To: 'Protel EDA Forum' Subject: Re: [PEDA] WANTED: PCB Expert (Off Topic) But Harry, the query was only, why there was 1.1mils associated with the NI/Au? Normal standards would call for 150 - 200 uinches of NI and upto 50uinches of Au. Not 1.1mils! Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com See us at Booth S8155 at NAB 2002 in Las Vegas April 8 - 11. > -----Original Message----- > From: H. Selfridge [mailto:[EMAIL PROTECTED]] > Sent: Thursday, April 04, 2002 10:34 AM > To: Protel EDA Forum > Subject: Re: [PEDA] WANTED: PCB Expert (Off Topic) > > > Copper on a printed circuit is subject to severe oxidation > unless coated. > Cu oxides are poor electrical conductors. > > Gold is a passive metal with excellent conductivity. > > If you plate gold directly on copper, Au/Cu intermetallics > are formed that > cause the bond to be brittle and subject to mechanical > failure under stress. > > Plating nickel over the copper forms a barrier that has desirable > intermetallic characteristics. However, Ni also oxidizes > readily. Ni > oxides are poor electrical conductors. > > Plating Au over the Ni gives the best overall metallic > structure for a pcb > (pwb). The Au is corrosion resistant, and has excellent > conductivity. The > Ni barrier under the Au prevents Cu migration into the Au. > Ni/Au and Ni/Cu > intermetallics at the bonds are both hard and relatively durable. > > That is half a semester in 5 lines that tells why nickel > plating is used > under gold on a pcb (pwb). * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
