00:00Because silver is the best conductor, but it's gold that's most used in electronics.
00:11Hello engineering enthusiasts. Today we'll unravel a mystery that intrigues many.
00:16If silver is the metal that conducts electricity best, why is gold the darling of electronics?
00:23And is present in almost all of our devices?
00:26Many of us learned in school that certain materials conduct electricity better than others.
00:31But what exactly makes a material a good conductor?
00:36Basically, an electrical conductor is a material that allows electric current to flow easily through it.
00:42This happens because their atoms have electrons that are not tightly bound to them, allowing them to move freely.
00:49Imagine a road full of cars.
00:51If the road is wide and without obstacles, the cars or electrons can move quickly and without problems.
00:59This width and lack of obstacles is what we call low electrical resistance.
01:05The lower the resistance, the better the conduction.
01:08And this is where Prata comes into play.
01:10It has an atomic structure that makes it the undisputed champion of electrical conductivity among all metals.
01:17Its valence electrons are very free, creating a sea of electrons that can move with minimal effort.
01:25If we measure the electrical conductivity of various materials, Prata will be at the top of the list, surpassing even
01:32copper and gold.
01:33This would theoretically make it the ideal choice for any application that requires high efficiency in current transport.
01:40But if Prata is so good, why don't we see it everywhere in electronics?
01:45Or rather, why don't we have Prata cables in our homes or Prata contacts in our cell phones?
01:51The answer to this question isn't about its initial conductivity, but rather its durability and stability over time.
01:59Prata has a major Achilles heel.
02:01It oxidizes and darkens very easily.
02:04You know those Prata jewelry pieces that get dark over time?
02:08That's oxidation, or more specifically, the formation of silver sulfide on the surface, which is the result of Prata's reaction.
02:17With sulfur compounds present in the air, this layer of silver sulfide is a terrible conductor.
02:23Imagine that your road, which was perfect for electrons, gets filled with potholes and rocks every day, making traffic difficult,
02:30just like the streets in our beloved country.
02:32An electrical contact that starts out excellent with pure silver quickly degrades when this sulfide layer forms, increasing resistance and
02:42eventually failing to conduct.
02:44Besides the oxidation that forms the sulfide layer, silver is also more susceptible to electrolytic corrosion.
02:50In humid environments, under certain conditions of electric current and moisture, silver ions can migrate and form unwanted conductive bridges
03:00in electronic components, leading to short circuits.
03:04For modern electronics needing high reliability and miniaturization, this characteristic makes silver an unviable option for most critical contacts and
03:14connections, even with its excellent initial conductivity.
03:18But if silver has these challenges, what is so special about gold that makes it the chosen one for electronics?
03:25Although it is a bit less conductive and much more expensive, the great advantage of gold lies in a property
03:32called chemical inertia.
03:34Gold is a noble metal power excellence, which means it is extremely resistant to corrosion and oxidation.
03:41Unlike silver, gold does not react with oxygen in the air, with most acids, or with sulfur compounds.
03:48It simply remains shiny and conductive, practically unchanged for decades.
03:54Think of the electron road as being made of a material that never deteriorates.
03:59No matter the time or weather conditions, it remains smooth and perfect for electron traffic indefinitely.
04:05This resistance to corrosion is fundamental for the durability of electronic components.
04:10Gold-plated connectors, for example, ensure that the electrical connection is stable and has low resistance throughout the entire lifespan
04:17of the device.
04:19This is crucial in devices we use daily, such as cell phones, computers and video game consoles.
04:25And especially in mission-critical equipment, such as avionics, medical and space equipment, where a connection failure can have catastrophic
04:33consequences.
04:35Besides being chemically stable, gold is also highly malleable and ductile.
04:40This means it can be stretched into incredibly thin wires or rolled into very, very thin layers, which is essential
04:47for manufacturing tiny components like microprocessors.
04:51But wait, gold is a noble metal. Isn't it much more expensive than silver?
04:56Yes, gold is more expensive than silver and copper.
04:59However, in electronics, it is used in tiny amounts, when we talk about gold plating.
05:05In connectors or circuit board traces, we're talking about layers with thicknesses of microns, which are fractions of a millimeter.
05:14The amount of gold in a smartphone, for example, is just a few dozen milligrams.
05:19The total cost of the gold in these components, although not negligible, is justified by the unmatched reliability and performance
05:28it provides in high-tech applications.
05:31The small savings from using an inferior material would not make up for the risk of failures or the need
05:37for frequent replacements.
05:38The cost-benefit ratio, considering longevity and performance, leans heavily in favor of gold.
05:45But where does gold really shine?
05:47In electronics, you find it in practically every important connection.
05:52The pins of processors and RAM are gold-plated to ensure fast and flawless communication with the motherboard.
05:58The internal contacts of USB, HDMI and other high-speed data cables also use gold to maintain signal integrity internally.
06:07In semiconductor chips, ultra-thin gold wires are used to make the connections between the silicon chip and the package
06:15pins,
06:15a technique known as wire bonding.
06:18Gold's ability not to oxidize is the guarantee that these millions of connections in our devices work perfectly for years
06:26on end.
06:27So, in what situations does each of these metals really shine?
06:31Copper, because it's an excellent conductor and much cheaper,
06:35silver is the king of general wiring, power cables, and the internal traces of most printed circuit boards.
06:42Its conductivity is high enough for most applications, and its cost makes it viable for large volumes.
06:49Silver is used in very specific applications, where its superior conductivity is absolutely critical,
06:56and where it can be effectively protected, like in some high-current switch contacts or in certain antennas, but always
07:03with care.
07:05Oxidation?
07:06Gold, on the other hand, is irreplaceable, where reliability, low contact resistance, and corrosion resistance are key factors.
07:15Ensuring that our devices work flawlessly for a long time.
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07:49Had you ever stopped to think about this difference between metals and electronics?
07:54Do you see why this expensive metal is in your phone?
07:57Comment below with your thoughts on this explanation, and if you already knew about it.
08:03There are two interesting videos on the side that you should watch to expand your knowledge and curiosity.
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08:16That's it.
08:17Engineering lovers, a big hug, and I'll see you in the next video.
