Back to serious (but still very friendly, I hope): Can you provide any documentation for this? I really want to know about it. I tried reading up a bit but it isn't long before I run up against the limits of my own knowledge of chemistry. (My old chemistry-major roommate was always very frustrated with me.) From what I've read, silver sulphide has the properties of a semiconductor. But I need clarification. Here are some of the readings I've done just now:
Electrical Conductivity of Silver Sulfide
https://aip.scitation.org/doi/abs/10.1063/1.1700165#
Sulfide Corrosion of Silver Contacts during Satellite Storage
www.dtic.mil/dtic/tr/fulltext/u2/a196217.pdf
https://books.google.com/books?id=6YLL9197NfMC&pg=PA32&lpg=PA32#v=onepage&q&f=false
https://en.wikipedia.org/wiki/Silver_whiskers
Now, it's also worth mentioning that there are (for me, anyway) two entirely separate issues here: 1) does the existence of sulphide make a difference in the conductivity of silver (and silver-plated) connectors and 2) can these connections be made air-tight if so.
About Issue #2, I believe there are several ways of achieving this. First of all, a good crimping tool can produce a metal-to-metal contact (connection) which is virtually air-tight (and doubtless disrupts any plating at the same time). Secondly, the dual set-screws in the terminations I'm using clearly produce decent crimping, though the surface areas of the contacts are less; Third, solder is its own category, which has been discussed elsewhere on this forum at length (I have few issues with soldered connections except that my own skills could use work) and Fourth, it's possible that sealing the connection (e.g. with electrical tape and/or 'pants' as shown above) will eliminate or at least greatly reduce the amount of air infiltration. This (last) is generally my goal now,
in conjunction with crimping.