I can't speak to 'aerospace rules', but IPC 610/J-STD-001 soldering recommendations prescribe techniques for removing sufficient gold plating from terminals to reduce (I don't know for certain it completely eliminates it, so I won't say so) 'gold embrittlement' in solder joints. That concern would certainly apply to aerospace and perhaps automotive electronics, or any other application subject to vibrational stress screening.
For gold-plated terminals that components or wires are connected to, tinning and desoldering three times before a fourth application of solder to form the desired connection, is agreed (by industries contributing to the IPC recommendations) to eliminate embrittlement'. If a solder pot is used for the process, there are limits to the percentage of gold contaminant in the solder pot, and thus requirements in hi-rel industries for solder pot management (either test in a lab periodically, or establish some frequency of solder replacement).
If the application is not subject to levels of vibration where embrittlement can cause solder joint failure, you can sleep at night if you don't do the (OCD) tin/de-solder cycle. I only do it when completing an IPC solder-re-certification circuit board every two years. (Because I don't know if they can tell if I skipped the steps).
Y'all hopefully know that gold is inert but a significantly poorer conductor than copper and silver. It is applied where deemed necessary because it doesn't tarnish. Board-to-board connectors and certain connector contacts still have gold plating because the reduced conductivity of gold is still better than contact resistance problems over time with non-gold-plated interfaces (like solder-tinned).
In high-vibration situations, gold-on-gold contact fretting (basically loss through abrasion caused by certain vibration levels) present challenges to reliability.
Someone once told me over the phone an anecdotal story about an audio studio using silver-plated XLR connectors that was enticed to try replacing all their silver with gold and they were so immediately displeased they went back to their original cables.
i haven't looked it up in decades, but think silver has lower resistivity (inverse of conductivity) than copper, on the order of 0.94 times that of copper (ignoring very small variations in copper) and gold resistivity is about 1.42 x that of good electrical copper.
For gold-plated terminals that components or wires are connected to, tinning and desoldering three times before a fourth application of solder to form the desired connection, is agreed (by industries contributing to the IPC recommendations) to eliminate embrittlement'. If a solder pot is used for the process, there are limits to the percentage of gold contaminant in the solder pot, and thus requirements in hi-rel industries for solder pot management (either test in a lab periodically, or establish some frequency of solder replacement).
If the application is not subject to levels of vibration where embrittlement can cause solder joint failure, you can sleep at night if you don't do the (OCD) tin/de-solder cycle. I only do it when completing an IPC solder-re-certification circuit board every two years. (Because I don't know if they can tell if I skipped the steps).
Y'all hopefully know that gold is inert but a significantly poorer conductor than copper and silver. It is applied where deemed necessary because it doesn't tarnish. Board-to-board connectors and certain connector contacts still have gold plating because the reduced conductivity of gold is still better than contact resistance problems over time with non-gold-plated interfaces (like solder-tinned).
In high-vibration situations, gold-on-gold contact fretting (basically loss through abrasion caused by certain vibration levels) present challenges to reliability.
Someone once told me over the phone an anecdotal story about an audio studio using silver-plated XLR connectors that was enticed to try replacing all their silver with gold and they were so immediately displeased they went back to their original cables.
i haven't looked it up in decades, but think silver has lower resistivity (inverse of conductivity) than copper, on the order of 0.94 times that of copper (ignoring very small variations in copper) and gold resistivity is about 1.42 x that of good electrical copper.
In high-power RF amplifiers, the problem isn't vibration but thermal expansion/contraction. The RF power devices have gold-plated leads - we dipped them in a solder pot to remove it before soldering into the circuit board. Gold does take solder well, but the brittle layer in the solder joint separates with thermal cycling. For connectors, gold-to-tin contacts can be a reliability disaster. I saw many failures (burned-up RF connectors!) due to this,
I’ve been using the quad eutetic Cardas solder with good results when using silver plated copper wire, the Teflon jacket stuff. It has both copper and silver in it in small amounts. It seems to bond well to the wire and silver plated jacks I’ve been using. It’s not the cheapest but lately what is? It’s supposed to prevent leaching of the silver off the wire and jacks.