Yep, as would say your gran-granfather. Inge ----- Original Message ----- From: "John Maxwell" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, March 19, 2007 5:06 PM Subject: Re: [TN] "Greenish colour on traces" > Ingemar, > We must also remember that nickel is magnetic as well increasing its > impedance at high frequencies. That is a reason that many GHz passive > components do not use a nickel barrier on their terminations. > > John maxwell > > >>That's something else! You did not tell what purpose. It's right, for >>some multiGHZ bands, where low losses are wanted, we don't use nickel >>plating because it's higher resistivity. Some nickel platings can have >>10 times higher losses than Copper and Gold! In these cases, we use just >>copper (no plating at all)if it's possible in environmental point of >>view, or we use tinned copper lines. So, silver over copper is >>theoretically right. And metallurgically spoken, silver on copper has >>been used for centuries. What I don't understand is why add gold. Maybe >>to avoid silver tarnish, if the package is not hermetic. >>Resistivity microOhm x cm : >> >>Electronic solder 17-20 >>Pure Tin 9-11 >>Electroless nickel 50-100 >>Electrolytic nickel 8-10 >>Electrolytic Gold 2.5 >>Copper lines 1.8 >>Electrolytic Silver 1.6 >> >>When you look at the above table, you will understand why Silver. >> >>Inge >> > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at [log in to unmask] or > 847-615-7100 ext.2815 > ----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------