> "silver tarnishes easily" >So does copper, which is why standard PWB practice is to either plate >over it or solder mask it or both. Silver flash would need solder mask. >I don't think the HT semiconductors etch very well, being ceramic and >all, but if you go for the 4 Kelvin metal ones, lead traces would melt >when you tried to solder. Niobium-Tin costs more, but maybe it's more >amenable to a multilayer process. What are your other suggestions? Well, while copper tarnishes, it doesn't as easily or as fast as does silver, and silver can tarnish even UNDER certain coatings. But mostly I was trying to say, with some humor, to the OP that concentrating upon a "better" conductor material than copper is usually and largely a total waste of time and effort. Yes, there are some exceptions, e.g., CeBAF, with superconducting resonating cavities. But, usually the improvement is from conductor layout, and surface finish, and avoiding surface contamination on the conductor side, and on dielectric losses & other non-conductor related loss issues (e.g., mismatch, or excessive VSWR for RF). So, my suggestions were to NOT look at the conductor materials, but to look elsewhere, such as the many excellent suggestions in other posts. But rather than just TELLING the OP that, I thought perhaps I could provide sufficient information that OP could/would realize the truth of it directly. Knowledge gained that way means more, helps more and tends to stay with people. Just telling someone the answer is less effective (and others were doing that quite excellently). ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu