Modern surface mount techniques and small device pad sizes already has greatly
reduced the amount of solder used in circuit boards across most of the
electronic product market place. Avionics are a bit of an exception due to the
requirements of ruggedization. But vastly smaller in terms of numbers of boards
showing up in landfills as compared to cell phones. Standards like ROHAS and
the old EU LED color restrictions standards (why once dominant red LEDs
practically disappeared from the exterior of electronics) sometimes become
onerous not because of their original intent but because it becomes far cheaper
to manufacture in compliance even in situations where it is unwarranted.
Something standards writers and environmentalist rarely take into
consideration.
Sent from my iPhone
On Aug 7, 2016, at 4:11 PM, Craig Remillard <craig.rem@xxxxxxxxx> wrote:
Gold plating can reduce tin whiskers, but in return it brings the risk of
gold embrittlement of solder joints.
On Sat, Aug 6, 2016 at 9:17 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx> wrote:
On Sat, 6 Aug 2016, Jonathan Goff wrote:
Apparently you need to be careful about gold coatings of things if you're
really magnetically sensitive, they sometimes use a thin nickel undercoat
to enhance bonding...
Yeah, it's not uncommon to plate nickel as a base for other metals. If
you're *really* magnetically sensitive, you have all kinds of worries that
normal engineers don't. :-) Impurities can make tungsten or gold weakly
magnetic. Kovar (for metal-to-glass seals) is magnetic. Many
"non-magnetic" alloys are not actually perfectly non-magnetic, e.g. some
types of brass and bronze. Non-magnetic stainless can become magnetic when
machined!
(Fortunately, I've never had to deal with it to this level myself; just
happened to read the stories while researching some less-drastic issues.)
Henry
