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Alterate to Gold plating

M

Martin Riddle

Jan 1, 1970
0
With the price of Gold close to $1k/oz has anyone looked for alternatives?

Cheers
 
M

Martin Griffith

Jan 1, 1970
0
With the price of Gold close to $1k/oz has anyone looked for alternatives?

Cheers
Don't worry, it is not really going up, it's the dollar going down


martin
 
E

Eeyore

Jan 1, 1970
0
Martin said:
Don't worry, it is not really going up, it's the dollar going down

LOL !

What alternative anyway ? I vaguely recall something from the 80s. Some alloy
IIRC.

Graham
 
M

MooseFET

Jan 1, 1970
0
With the price of Gold close to $1k/oz has anyone looked for alternatives?

Cheers


The alternatives generally cost more and work less well. Gold can be
put on very thin and still do its job so you don't end up using enough
to really matter.

Lately, I've been looking again at gold plating the entire PCB. It
makes a nice chemically stable layer on top of the copper. With the
price of copper these days, changes are the copper on the PCB will
cost more than the small amount of gold involved.
 
S

Spehro Pefhany

Jan 1, 1970
0
LOL !

What alternative anyway ? I vaguely recall something from the 80s. Some alloy
IIRC.

Graham

Gold was much more expensive in real terms in the recent past. It's
pretty much only used now where it offers extraordinary benefits now.
Used to be there was thick gold (not just thin selective gold) on all
kinds of things that didn't really need it. Kinda like petroleum will
proably be in the future. There was a major shift away from
unnecessary use of gold in the early eighties when it hit more than
$600 US/troy oz (it peaked even higher) or about $1700 US/troy oz in
2007 US dollars.


Best regards,
Spehro Pefhany
 
S

Spehro Pefhany

Jan 1, 1970
0
The alternatives generally cost more and work less well. Gold can be
put on very thin and still do its job so you don't end up using enough
to really matter.

Lately, I've been looking again at gold plating the entire PCB. It
makes a nice chemically stable layer on top of the copper. With the
price of copper these days, changes are the copper on the PCB will
cost more than the small amount of gold involved.

It looks nice too.


Best regards,
Spehro Pefhany
 
M

MooseFET

Jan 1, 1970
0
Are there any alternatives to copper on PCBs?

Aluminum was tried for a while for house wiring. I think it would
work but there seems to be a long tail on the learning curve.

Aluminum would be big trouble on PCBs for the same sort of reasons as
it is in house wiring. It isn't soft enough, it corrodes to make a
nonconductive material and it has more resistance.
 
M

MooseFET

Jan 1, 1970
0
Ever try to solder to aluminum?

You can buy solder than works on some types of aluminum. It doesn't
work at all on other alloys.
 
M

MooseFET

Jan 1, 1970
0
No, no, a million times no. Nickel sounds cheap!


But seriously, there is a big problem with nickel plating and MRI
machines. There is nothing in the universe more magnetic than a thin
layer of nickel.
 
M

MooseFET

Jan 1, 1970
0
Nowadays the standard "gold plating" on pcb pads, called "immersion
gold", is a roughly 100 micro-inch electroless nickel plating finished
with 8-10 uin of gold. It looks good, doesn't tarnish easily, and
solders beautifully. It's very flat, so is good for fine-pitch and BGA
parts. The tiny amount of gold dissolves in the solder when the board
is reflowed, so the joint is basically solder onto nickel.

Yes, a nickel then gold plated surface solders very very nicely. Gold
over copper flash also works well. The copper flash makes a very
smooth surface on the copper.
 
P

przemek klosowski

Jan 1, 1970
0
Ever try to solder to aluminum?

Yes I did, in fact; I was successful using the oil drop method. It works
by covering up the solder pad with oil, and scratching the heck off of
the aluminum oxide layer covered by the oil. The Al2O3 layer protects the
bulk but also doesn't let the solder attach; it's hard but thin, so you
can break it up and the oil prevents reforming (it reforms in milliseconds
in air). You have to solder under oil, of course, but a simple engine oil
is resistant to soldering temperatures.

Aluminum is actually a cool idea---you can hard-anodize it, making it
pretty much any color. Since coloring in anodizing is done by introducing
the dye in an etched rough Al surface, I imagine that it should be
possible to alter other surface properties besides color (hardness,
friction properties, maybe even solderability). I have no first hand
knowledge, though.
 
L

Leon

Jan 1, 1970
0
With the price of Gold close to $1k/oz has anyone looked for alternatives?

Cheers

I've just had a board made with immersion silver plating. Levelling is
inherent in the process and solderability was OK.

Leon
 
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