What is fake gold plating on connectors made of? Is it better than nickel?

[dusan]

I see some yellow plating on some connectors that are imho not real gold plating, what is it made of? I need cheap connector, is it better to choose nickel then? Which has better contact resistance and lower oxidation, nickel or fake gold plating?

[Psi]

It's probably gold. 
Thin gold plating is not that expensive, we're talking under 2000 atoms thick.
The difference between a cheap aliexpress gold plated connecter verses something from Molex or TE is more the thickness of the gold. Rather than actually having gold or not.

But assuming it really has no gold in it, it's probably just brass or phosphor bronze or some other copper containing alloy.

[AndyBeez]

In engineering gold colour is often Phosphor Bronze.
https://en.m.wikipedia.org/wiki/Phosphor_bronze

Alloys of Copper Tin and Copper Zinc are used in the jewellery industry to create a 'gold' finish, often over a Silver or Nickel base.

[Gyro]

I remember seeing some phono connectors once on the CPC website that claimed to be "colden" plated. 

[DavidAlfa]

Some time ago I bought some connectors from Aliexpress, supposedly "gold-plated" but some had cyan-coloured corrosion, so no way it was gold, maybe bronce or a similar alloy.
Nordic Gold rarely corrodes as it protects itself.

[magic]

I have seen some cheap "gold" connectors from dodgy sources tarnish and turn brown, even unused.
When new, they weren't as shiny as gold plating normally is.

Fake gold plating does appear to be a thing.

[MikeK]

Tin melts at 232C (450F), gold melts at 1064C (1947F).  Is this something that can be tested with the average kitchen oven?

[wraper]

A bit late but if it's about something like golden shell of HDMI or Displayport connector, then it seems to be just brass with no plating for best looking shiny parts that look close to real gold. They are non magnetic unlike nickel plated parts that are made of steel and removing surface layer makes no color change.  Some quite a bit worse looking dull connectors I have are magnetic, so I assume it's just a brass plated steel. FWIW imitation gold leaf for gilding are made of brass https://www.goldleafsupplies.co.uk/schlag-metal-no-2-5-loose-leaf/

[LinuxHata]

That material is called titanium nitride.

[Berni]

When you see gold things turn to silver with use that will tend to be real gold plating, just that it is super thin so it wears off. As said above this is not as expensive of a process as you might think since such thin plantings have so little gold in them that the value of the gold is less than a US cent.

The silver colored metal you get to see once the gold wears off is usually nickel. It is commonly put on before the gold plating step as a surface preparation (provides a nice smooth surface and helps it adhere better)

There is also the ENIG coating that is often used on PCBs to protect pads from corrosion using gold. However that coating is incredibly thin and delicate so it would not hold up to any sort of wear. For example gold card edge connectors use a different plating method that makes a thicker and more solid layer of gold that can hold up to the contacts dragging across it (The PCB fabs tend to call this 'hard gold plating')

[radiolistener]

I see some yellow plating on some connectors that are imho not real gold plating, what is it made of?

It is made from brass (copper zinc alloy). It has color similar to gold, so Chinese guys mark its color as "Gold". 

This is why Chinese connectors get tarnished areas after some time...

I also hear that Chinese connector are covered with a layer of titanium nitride for yellow color.

I found that white Chinese connectors (silver color) is better than yellow...

[JustMeHere]

If they can put gold flakes into this awful stuff, gold plating can't be that expensive.

https://en.wikipedia.org/wiki/Goldschl%C3%A4ger

[magic]

This awful stuff costs more than jack connectors.

I found that white Chinese connectors (silver color) is better than yellow...

True. Chinese gold is a gimmick which manages to simultaneously make connectors more expensive and worse.

[tooki]

I got some “gold-plated” headers on eBay or Ali a while back that wouldn’t solder. Whatever it was, it was NOT gold. I ended up throwing them out.

[tooki]

If they can put gold flakes into this awful stuff, gold plating can't be that expensive.

https://en.wikipedia.org/wiki/Goldschl%C3%A4ger

It is when you consider a) how cheap the Chinese products are, and b) that gold-plating adds production steps that add cost, even aside from the cost of the gold itself.

[shapirus]

I got some “gold-plated” headers on eBay or Ali a while back that wouldn’t solder. Whatever it was, it was NOT gold. I ended up throwing them out.

OTOH, I bought pin headers on Ali that soldered very nicely and willingly. Still not sure if it was gold, but whatever it was, the coating did its job. I guess even there many variations of quality exist. Typically, better quality products are found in stores that care about details such as e.g. using their own branded packaging, which also suggests that they are probably more picky about their suppliers.

[beanflying]

If they can put gold flakes into this awful stuff, gold plating can't be that expensive.

https://en.wikipedia.org/wiki/Goldschl%C3%A4ger

I have some remnants of memories from a Chicago work trip and Goldschlager. The first bottle wasn't enough to get the deal done 

[tooki]

I got some “gold-plated” headers on eBay or Ali a while back that wouldn’t solder. Whatever it was, it was NOT gold. I ended up throwing them out.

OTOH, I bought pin headers on Ali that soldered very nicely and willingly. Still not sure if it was gold, but whatever it was, the coating did its job. I guess even there many variations of quality exist. Typically, better quality products are found in stores that care about details such as e.g. using their own branded packaging, which also suggests that they are probably more picky about their suppliers.

Of course. I didn’t say all Ali gold headers are unsolderable, it was just the one lot. The problem is that you never know what you’re gonna get. Definitely agree about choosing shops that show signs of care (like having actual datasheets available).

[Kleinstein]

That material is called titanium nitride.

Titanium nitride has a golden color, but it is also not so easy to apply. For the thin film this usually needs reactive sputtering and would be more expensive than a thin gold layer. For highly abrasive uses it may be an option, but I would not expect it with cheap parts. One can still find it with drills and here it makes perfect sense.

The more obvious choices are brass, bronze (Cu-Sn) and aluminum bronze (Cu-Al , which give a good color and relative good corrosion resistance, but also not that great contacts).

[beanflying]

We sort of did this some years ago. There is also some other threads but this is one that turned up in a search.

https://www.eevblog.com/forum/metrology/gold-plated-banana-plugs-and-integrated-swivels/

[Doctorandus_P]

The yellowish euro coins are apparently made of: 89% copper, 5% aluminium, 5% zinc, and 1% tin

https://en.wikipedia.org/wiki/Nordic_Gold

I just had a look at some cheap 0.1" male headers and they do look a bit yellowish, but not the yellow of gold. Also they (barely) stick to a (strong) magnet. Maybe there is some steel in the alloy on purpose, maybe it's a "contamination"  or "don't care".  The yellowish euro coins don't stick to a magnet at all.

The "copper" 5ct euro coins do stick to a magnet vehemently. Those are copper plated steel.

[wraper]

I just had a look at some cheap 0.1" male headers and they do look a bit yellowish, but not the yellow of gold. Also they (barely) stick to a (strong) magnet. While the yellowish euro coins don't stick to a magnet at all.

Yellowness of those depends on plating thickness. A few decades ago nearly all of them had a thick gold plating of tens of µin and were really yellow. These days so called "gold flash" is way more common, and it's like <3µin.

[Jwillis]

It likely is gold but very thin. Typical plating thickness for electronics is 0.1um-25um. Very thin “flash” gold deposit of less than 0.25um, the gold is a very porous. The plating may look continuous but because of the micro pores it tends to allow corrosion of the underlying material.
The short distance of gold contacts makes little difference to the total conductivity within the circuit. Corrosion prevention is the main purpose of gold plating because of its natural resistance to oxidization. Plating to thin kind of defeats the main purpose of gold plating and becomes more of a cosmetic sales pitch. 
If you buy cheap you get cheap. Your better off getting nickel plated instead of gold plated if the lower cost is more attractive.

[5U4GB]

That material is called titanium nitride.

That's used on cutting tools, not connectors.

Also in some cases it's actually Chinesium and not real titanium nitride.

[beanflying]

Likewise because it is 'Gold' coloured it isn't always actual Gold on connectors. If you want actual Gold best to stick to known sources. If it can be faked and save a $ over thousands of units then it will be.