I think that we should also be careful not to compare relay contacts with sliding switch contacts.
The spark-hardening treatment that relay contacts get is pretty useless for sliding contacts.
If I look at gold-plated legs of 70's/80's semiconductors (noble FETs, BJTs and ICs), then they look a 1000x better than the legs and contact surfaces of those default Alps switches above. So I tend to agree with Mr. Yahama that the surfaces of these switches do not have any form of gold plating.
Which does not mean that they have not received any treatment, who knows.... But that would need to be done after the parts had been punched out of the metal sheet, which would be an expensive manufacturing process given the many small parts inside one switch.
EDIT: we should also not compare PCB-style pots with sliding switches. It is relatively easy to give the PCB surface an after treatment at low cost, like silver plating. And silver..... becomes black in open air....
Hi Guys,
all I am saying is that these switches are plated with eiteher, silver, gold or a combination of the two. Most likely the later. I am saying this based on my observations, not because of some scientific study.
please try this experimant:
take an uncleaned switch, use a plain jane eraser and rubb an area clean, than take the sand paper and rub right next to it. In my experince, you will have two colors afterwords.
I know my camera sucks, but the contacts of my switches still have a gold patina to their color. If I were to uese sand paper, they start to look silver...just saying.
I am definetly not talking about relay contacts, component pins or PCBs, those are also plated for some components, which suppoets the hypothesys that even though plating with precious metals is expensive, certain manufacurers will do it for certain products.
Back to the swithces,
these are not pots, but low power switces. eve though they are physically linear, they have clearly divided points of contact.
I did not have time to look for speciffic models or Alps examples, just a quick search on the net. Here is a quick article, but there re many more explaininng why manufacurers would use precious metal aloys on certain low current or data switches.
http://www.nkkswitches.com/pdf/switchcontactmaterial.pdf
again, I could be tottally wrong about the material, but as far as the plating, my hypothesys is that it is there.
Edit:
one additional observation,
let's say I am tottally wrong and there is no plating on any of these contacts, still, wouldn't sand paper or fiberglass pen alter the physical surface?