Gold Embrittlement in solder joints
Gold Embrittlement in solder joints
(OP)
Hello,
The basic question was answered in another closed thread but I just wanted to find out a little more detail about it
How exactly and why is solder used to remove the gold plating ?
What I mean is that since gold melts at much higher temperature than solder than why would the solder remove the gold ?
Is there something else going on like a chemical reaction ?
Maybe the correct word is leaching ?
But I still don't quite understand why would gold leach out in the solder. Does this work for other metals or just gold ?
I am taking the IPC 610 training and I asked the trainer about it but he did not know exactly how that happens
I know it sounds like a stupid question but I am just curious
The basic question was answered in another closed thread but I just wanted to find out a little more detail about it
How exactly and why is solder used to remove the gold plating ?
What I mean is that since gold melts at much higher temperature than solder than why would the solder remove the gold ?
Is there something else going on like a chemical reaction ?
Maybe the correct word is leaching ?
But I still don't quite understand why would gold leach out in the solder. Does this work for other metals or just gold ?
I am taking the IPC 610 training and I asked the trainer about it but he did not know exactly how that happens
I know it sounds like a stupid question but I am just curious





RE: Gold Embrittlement in solder joints
ht
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RE: Gold Embrittlement in solder joints
Thanks for the reply but that link says no document found.
Is there another link that has the information ?
RE: Gold Embrittlement in solder joints
> There's a thing called a "search engine"
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RE: Gold Embrittlement in solder joints
This is the cached version found on Google - essentially what IRStuff was pointing to...
http://2
RE: Gold Embrittlement in solder joints
Ok It's working today
From what I understand when gold is mixed with other metals it forms an alloy that has a lower melting point than pure gold
Should I assume that the gold plating on pc boards is not pure gold ?
How do I know what gold alloy is used on pc boards ?
RE: Gold Embrittlement in solder joints
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Gold Embrittlement in solder joints
So the pure gold is plated over the copper so far it's clear
"There is a slight mixing of gold into the solder during the soldering process"
That's what I am curious about
If the pure gold melting temperature is much higher than the melted solder how does the solder mix with the gold ?
If solder can do that why not mix with the copper trace too ?
"And metal alloys do not necessarily have a lower melting point than the individual metals"
Ok. So what was the point of the link about the eutectic alloys of gold then ?
RE: Gold Embrittlement in solder joints
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RE: Gold Embrittlement in solder joints
He is saying that the copper traces are plated with pure gold and follows that up with a statement that implies that gold alloys do not necessarily melt at lower temperatures Of course
he did not mention specifically gold alloys
I understand that some gold alloys have lower or higher melting point than pure gold
I am just trying to figure out specifically what is the process by which gold is removed from copper traces
Perhaps I need to understand what eutectic means
You said "gold forms eutectics with many other materials"
Could you expand on that a little bit more and be a little more specific as it relates to plated gold on copper traces ?
Which material to be more specific ?
According to the statement at the link you provided
"The melting point of an alloy of two (binary) or more metals depends on the relative proportions of the ingredients"
Assuming that the gold plating is pure how can it have other materials in it to have the right proportion ?
RE: Gold Embrittlement in solder joints
Pay less attention to the copper.
Under certain conditions, e.g. with respect to temperature and gold concentration; when tin-containing solder is applied, gold and tin will form intermetallic structures within the joint. These structures weaken the joint because they are formed differently to the solder. Note though, that this happens only under certain conditions. If you push tin and gold together with your bare hands at room temperature, it will not work.
Bear in mind that the metals do not already have to be 'alloyed' before an instance like this is possible.
I think you have enough information to explore embrittlement further.
The title of your post searched on Google brought extensive resources for you to study; e.g. http://
RE: Gold Embrittlement in solder joints
What do you think of this statement that I read somewhere ?
"Gold readily dissolves in molten solder"
Is that true ?
Assuming I have a bar of gold (I don't)and I place it in a solder pot at let's say 750F
Would the gold bar dissolve completely ,just a little bit on the surface or not at all ?
RE: Gold Embrittlement in solder joints
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Gold Embrittlement in solder joints
Gold embrittlement on a 10 inch wide solder joint (if they exist) would be the same gold embrittlement that exists in your own solder joint. If you want to disregard the microscopic level, then what you might come across on a PCB would simply be a poor solder joint with an unknown diagnosis.
RE: Gold Embrittlement in solder joints
I am starting to understand the process a little bit better now
So just to make sure I understand
If gold is heated by itself to 750F nothing happens but when solder is added then some of the gold is mixed with the solder at the microscopic level?
This gold that is mixed with the solder is it melted gold, gold molecules or gold that is flaked off the pc bd ?
I am just trying to grasp the magnitude
RE: Gold Embrittlement in solder joints
http://w
Read the article, look at the pictures and then you should grasp the magnitude and process by which it occurs. If you have any questions afterwards, please come back.
"If gold is heated by itself to 750F nothing happens but when solder is added then some of the gold is mixed with the solder at the microscopic level?" In a proverbial nut shell, yes.
RE: Gold Embrittlement in solder joints
If that was a copper trace that was plated with gold does all of the gold come of or gets mixed with the solder in one application ?
If only a small microscopic amount is mixed with the solder I would imagine it would take a long time to remove all of it
Is the procedure in IPC 610 to add solder and the remove it and doing that twice enough to remove all the gold ?
RE: Gold Embrittlement in solder joints
I am not familiar with IPC 610, and given you are on a course for such; would it not be wiser to ask your trainer?
RE: Gold Embrittlement in solder joints
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RE: Gold Embrittlement in solder joints
This would be from at least 95% of surface to be soldered to
I did ask the trainer but he did not have an answer at the time and he said that he will get back to me and I thought maybe I can research it myself in the meantime
I found it hard to believe at the time that just by tinning a gold plated surface the gold would be gone so easily without actually melting the gold
Someone said in a previous post with the same title that tinning the gold plated surface and removing it by wicking it off with solder wick is acceptable while the instructor said this must be done twice maybe as an extra step in case not all of the gold was removed in the first step
I don't have the manual with me but I don't think IPC 610 specifies what method to use to remove the gold
I read somewhere else that a double dip (two solder pots) immersion or the use of a flowing solder wave is the way to go
I guess the only way to find out for sure is to use a method and somehow analyze the solder joint under a powerful microscope to determine how much if any gold is left in the solder joint
I want to thank everyone for their comments on this subject
RE: Gold Embrittlement in solder joints
Does someone think that the gold plating is somehow bad? Can you really imagine doing this on every single solder joint?
Wouldn't this be a total waste of time and money? And wouldn't someone think that it might be more efficient to not have gold there in the first place, if all you're going to do is to remove it immediately prior to soldering?
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RE: Gold Embrittlement in solder joints
Where do you think those $700 hammers come from ?
Actually we did receive a small quantity of bds (not for NASA) that were plated with gold by accident and we ended up using it as is just soldering to it normally and haven't had any returns because of any joint failure
RE: Gold Embrittlement in solder joints
Frankly, it seems to be a perfectly stupid idea. Every additional second of heat on every joint is just increasing the probability of failure from other problems.
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RE: Gold Embrittlement in solder joints
RE: Gold Embrittlement in solder joints
You have three choices: 1) Don't put it there in the first place (masking is easy as pie during the plating process), 2) Remove it by chemical means (not ideal by a long shot, and messy, possibly dangerous/toxic), 3) Remove it by mechanical means (such as sandpaper tubes on a Dremel).
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Gold Embrittlement in solder joints
That is the instruction according to the IPC 610 standard
and the instructor
I understand your point and I have not removed any gold from any pc bd I was just trained on the IPC 610 so I was just curious about the process in theory only not in reality.
RE: Gold Embrittlement in solder joints
There is no real gold out there any place in industry.
Real gold is in gold nuggets only. Close to 100% gold.
Jewelry gold and industrial (watch cases etc.)are a tin-copper alloy with only a trace of real gold in it.
The gold content is less than 1/1000 of one percent even in
gold bullion coins.
Specific gravity of tin can be increased to match that of gold by melting the tin and letting it cool down on air--repeatedly. I am ready to do that experiment here at home and have a way to check specific gravity as well.
I learned this from God (who now wants to be called Voynich)
at age 4, looking at my real tin soldiers I was playing with.
So, now I want to prove it to myself.
I own a few gold nuggets purchased from ebay, they look like crap, not shiny like gold, but that proves they really are gold.
So, you are really not dealing with gold at all, but with compressed tin at 99 % or so. That golden tin has similar qualities to real gold, and its usefulness has been established.
Since you don't believe this, there is no point in writing any more than this.
Voynich (psychic reading)
RE: Gold Embrittlement in solder joints
But what about the cold fusion possibilities?
RE: Gold Embrittlement in solder joints
http:
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RE: Gold Embrittlement in solder joints
-AK2DM
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"It's the questions that drive us"
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RE: Gold Embrittlement in solder joints
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RE: Gold Embrittlement in solder joints
I was only asking about the gold plating on pc boards
I was not referring to jewelery or any other gold
I found another good link that explains the type of plating
and it's many uses
http://en.wikipedia.org/wiki/Gold_plating
RE: Gold Embrittlement in solder joints
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