hello this is fountain pen researcher here, aka dovidu.
today, i experimented with my AuAg nib (approximately 60~70% silver nib, with gold etc. alloying metals)
initially i used sterling silver nib, which tarnished very badly.
then i switched to argentium silver from england.
the argentium's got a bit of germanium in the metal, which improves tarnish resistance.
while argentium did perform better than the sterling, tarnish was inevitable with time.
also, with its 93.5% silver content, the nib was a bit soft and scratch-prone.
then i started experimenting my own alloy material.
next i developed the auag nib, which has around 65% silver content, with gold & etc. metals
the auag nib was far superior in terms of tarnish resistance.
also, it was stronger and more scratch resistant.
even if it did tarnish, the tarnishing was very weak, and very easy to remove (much easier than argentium).
just several swipes and weak tarnishing was gone.
with this auag nib, i experimented the patina effect.
the patina on this particular alloy, resulted in dark blue color.
when the dark blue layer was polished, the result was quite interesting.
the dark blue color became reduced to light blue, along with nice shine.
currently i am experimenting with a method to improve the stability of production.
i will post new results if there is any progress.