Personally I like silver itself (and sterling). The whiteness is
incomparable. I have seen that there are many anti-tarnish silver
alloys in the patents. Several use Pd/Ag (which love each other),
also Pt and Au. Some use Ti, Nb, Ta, and other exotics. Alot of
these are really old patents, from like the '30s. By the way, if Pd
is so hard to work with, how did they make so many rings with it
back in the '20s and '30s, using torches in many cases? Different
quality standards? Early patents for Pd melting with induction I did
not see until late '30s/early '40s.
One alloy I have seen not much work for is ruthenium and silver.
Have any of you tried mixing the two? I know the melting points are
way, way different and the Ru is close-packed hexagonal while Ag is
face-centered cubic, so many people just assume they are totally
insoluble, but the Ag-Ru phase diagram indicates some limited
solubility of Ru in Ag with the presence of a eutectic at about 3.1%
Ru in Ag. I myself have put about 5% Ru in Ag by melting the Ru
first, and adding molten Ag to it, allowing the two to mix for some
time. Borax seemed to limit the gas absorption in the Ru if applied
liberally just as the Ru melts.
I say this because a ring I made of this seems noticably more
resistant to tarnish than other silver articles I have made. I
thought about validating this with testing with potassium sulfide
solutions. The Ru hardens the Ag some too, it appears to me. The
nice thing about Ru is that you apparently wouldn’t need to add
much, and it isn’t that expensive right now. Ru is less than half
the cost of palladium right now.
I too have on occasion alloyed fine silver with ruthenium when
searching for a tarnish resistant hybrid. I found that adding the
standard refining mixture of sal ammoniac, powdered charcoal and
boric acid as borax is already lining the crucible - not using a
graphite crucible [If using a graphite crucible I do not use any
acid in it as i find it weakens the colour of gold in particular and
white gold alloys to a larger degree but as for silver there is no
distinguishable colour change just that I don’t acidify the graphite
anyway] gives enough deoxidation to the metals without having to use
a gas covered set up. Overall though it is not worth the wxpense in
my opinion of the ruthenium, fine silver on its own is brilliant
enough for my work, and is I beleive highlighted further with
whichever coloured gold alloy one chooses to make/use in designing
workpieces. Any rich high karat gold colour depending ion the origin
of the 24kt grain (African sourced gold being my favorite thus far
for a great deep yellow) from the peach-y or red-orange gold alloys
s to olive green or bluish greens are made all the more noticeable
with a fine silver contrast as sooposed to the minor differences I
notice when adding the ruthenium to the alloy. It is not cost
effective unless paired with a high karat gold as the perceived value
and what one can reasonably price a piece at is disparite with the
addition of the ruthenium and most consumers don’t know about the
alloying process as a sweepingly generalized statement, to validate
the price I would then charge for alloying Ru with silver to add a
fair degree of protection. I find it more cost effective if you want
some strength aplied to the silver in a given design to plate it
after finishing all operations with ruthenium, than to add it to the
pour. The tarnish resistance that follows plating (or better yet,
1/20 bonding if you have access to the equipment and can produce
d’ore (filled) metals) is sufficient for one off or mass produced
lines, and the savings validate that method of adding ruthenium as
opposed to alloying it with silver, particularly at todays market
price of ruthenium. If it were considerably lower in cost I would
perhaps use it regularly, but as it is definitely not the case in the
last couple decades and no lowered futures in sight, I would
recommend just a heavy plating or bondiong of Ru if you need a piece
of fine silver strengthened and the extra tarnish resistance if using
a cuprous stone (in example a cabachon of or something else that will
eventually react with not only skin but the metal the stone is
mounted on. rer