Hard drives are data storage devices used in computers and other electronic devices to store digital information. They consist of one or more platters coated with magnetic material, which store data in the form of magnetized bits. Precious metals refer to rare and valuable metals like gold, silver, platinum, and palladium.
Precious metals are commonly used in hard drives and other computer components because they are highly conductive, corrosion resistant, and durable. Gold is prized for its high electrical conductivity and resistance to tarnishing. Silver has the highest electrical conductivity of all metals. Platinum and palladium are also very conductive and resistant to corrosion. Using precious metals helps maximize the performance and longevity of electronic devices like hard drives.
Gold
Gold is known as an excellent conductor that does not corrode. Gold plating is used in hard drives to coat connection points helping to conduct electricity between components of the drive (https://goldrefiningforum.com/threads/gold-in-hard-drive.21043/). The use of gold plating improves conductivity and prevents corrosion at connection points. Fine gold wire is also used inside hard drives to connect components like the actuator arm to the drive’s printed circuit board.
Gold is highly valued for use in electronics because it is one of the most electrically conductive metals and is highly resistant to corrosion. These properties make it well-suited for use in the sensitive internal components of hard disk drives. Gold coatings on connection points and gold bonding wires inside the drive help maintain the integrity of electrical signals passing between the hard drive’s components.
Silver
Silver is perhaps the most valuable metal found in hard disk drives. It has unique properties that make it very useful in the manufacture of hard disk drives (https://www.awarefiners.co.uk/hard-drives.php). Silver has the highest electrical and thermal conductivity of all metals. This high conductivity allows it to quickly transfer data in the form of electrical signals across the hard disk platters. Silver is also very reflective, which is important for the laser in hard disk drive read/write heads to function properly.
There are a few key components in a hard drive that rely on silver. The platters that store the data are typically coated with a thin layer of silver alloy. Silver is also used in the read/write heads themselves. The electrical connections that transfer data from the read/write heads are frequently silver as well. Without silver, modern high-capacity hard drives would likely not exist.
Platinum
Platinum is a precious metal valued for its durability, conductivity, and resistance to corrosion. These properties make platinum well-suited for use in computer hard drives.
Platinum is deposited in extremely thin layers on aluminum or glass hard drive platters to serve as the platter coating. This platinum layer acts as the surface that stores the magnetic data on the drive. Platinum is ideal for this coating because it is an extremely stable metal that can withstand the high speed rotation of the platters without wearing down over time.1
Platinum’s high conductivity allows it to transmit the electrical signals that read and write data on the platter surface very efficiently. Its corrosion resistance prevents the platinum layer from degrading due to moisture or oxidation over the lifetime of the drive.2
The amount of platinum used on hard drive platters is very small, typically ranging from 100-200mg per platter. But with millions of drives in circulation, recovering the platinum through recycling represents a valuable source of this precious metal.3
Palladium
Palladium is a precious metal valued for its catalytic properties and corrosion resistance. In hard disk drives, palladium is commonly used in the thin-film coatings applied to the platters. According to one source, “While almost 80% of palladium produced is used in manufacturing catalytic converters in gasoline powered vehicles, palladium also plays a critical role in the production of computer hard disks” Source. These thin-film coatings require a material that can rapidly change magnetic orientation without degrading. Palladium’s high corrosion resistance, flexibility, and durability make it well-suited for this application.
Specifically, palladium is a key component in the magnetic layer and protective overcoats on hard drive platters. The magnetic layer stores the actual data bits, while the overcoats protect the platters from corrosion and damage. Palladium alloys like nickel-palladium are often used in the magnetic layer to enable rapid magnetic switching. The overcoats also leverage palladium’s corrosion resistance to prevent the loss of data over time.
Overall, palladium plays a vital role in hard drive technology by enabling durable, high-speed data storage on platter surfaces. Its unique material properties make palladium difficult to replace for these thin-film coatings in modern hard drives.
Nickel
Nickel is used in hard drives for its ferromagnetic properties. It has a high magnetic permeability, meaning it can be easily magnetized and demagnetized. This allows data to be written and read from the platters in the hard drive. Nickel is often alloyed with iron and molybdenum to create mu-metal, which enhances its magnetic properties. Mu-metal is used to coat the read/write heads of hard drives.
Nickel is also corrosion and oxidation resistant. This allows components like the platters to resist degradation over time. The platters in a hard drive are typically made of an aluminum or glass substrate that is coated with a thin layer of nickel-phosphorus.
Other hard drive components containing nickel include the motor shaft, base plate, mounting screws and cover seal. The precise amount of nickel varies, but may be up to 16% of some components. Overall nickel accounts for around 5-10% of the materials in a typical hard drive.
Amounts Used
Hard drives contain small amounts of precious metals like gold, silver, platinum, and palladium. According to the website Shredded / Un-shredded Hard Drives, a typical hard drive contains around 0.25-0.5 grams of gold. There can also be up to 0.1 grams of silver and 0.005 grams of platinum group metals like palladium or ruthenium. The amounts vary based on the manufacturer and model of the hard drive.
Over time, the amount of precious metals used in hard drives has decreased. As technology advances, manufacturers have gotten better at using less material. For example, in the 1990s an average hard drive contained over 2 grams of gold. But by the 2000s that dropped to around 0.5 grams as platter sizes shrank. Today’s 2.5 inch laptop hard drives use even less precious metals.
While the quantities are small, with billions of hard drives in use globally it adds up. Hard drives represent an important source of precious metal recovery through electronics recycling programs.
Recycling and Recovery
There are several ways to recover precious metals from hard drives during recycling:
Physical separation – The drive is manually dismantled and components containing precious metals like circuit boards, connectors, and drive platters are removed and sorted. This is labor intensive but allows targeted extraction of high value parts.
Shredding and sorting – Drives are shredded into small pieces and sorted based on material composition using various separation techniques like gravity, magnetism, and eddy current. Precious metals can then be extracted from the sorted fractions.
Smelting – Whole drives or shredded material is fed into a furnace at high temperatures, causing the materials to melt into a molten metal mix. The precious metals can then be separated and refined.[1]
Chemical leaching – The drive material is treated with chemicals like cyanide that dissolve the precious metals. The metal-rich solution is then processed to extract the pure metals.[1]
Challenges include cost-effectively dismantling and separating the many small components in a drive, dealing with hazardous materials present like lead and mercury, and preventing environmental contamination from chemicals used.
Environmental Impact
Recycling hard drives and electronics is extremely important for recovering precious metals and reducing environmental impact. Precious metals like gold, silver, platinum and palladium are finite resources that must be reused and recycled whenever possible.
Extracting precious metals from e-waste has several benefits:
- It reduces the need for new mining, which can damage landscapes and ecosystems.
- It cuts down on electronic waste ending up in landfills.
- It allows precious metals to be reused rather than extracted newly from the earth.
However, recycling e-waste must be done properly to avoid negative consequences. Unsafe recycling can expose workers and communities to toxic materials like lead and mercury. Proper recycling uses containment, ventilation and pollution controls to minimize environmental and health risks.
Overall, recycling electronics recovers valuable and scarce materials for reuse rather than disposal. But it must be practiced responsibly to maximize benefits and minimize harm. Sustainable e-waste recycling will be crucial as use of electronics continues to grow worldwide.
Future Outlook
As hard drive technologies continue to advance, the use of precious metals may change in the future. Some key trends to watch include:
HAMR and MAMR – Technologies like heat-assisted magnetic recording (HAMR) and microwave-assisted magnetic recording (MAMR) allow for higher data densities without substantially increasing precious metal use. These technologies could enable continued growth in hard drive capacity without dramatic increases in platinum, palladium, or other metals.
Shingled magnetic recording (SMR) – SMR overlaps data tracks for higher density. Early SMR drives had challenges, but advances are making SMR more viable and economical. If adopted at scale, SMR could moderately reduce precious metals per drive.
HDD with multilayer magnetic recording (MLMR) – MLMR allows multiple magnetic recording layers within a drive. MLMR prototypes store up to 10TB per 3.5-inch disk. If commercially viable, MLMR could significantly boost density and capacity without major precious metal increases.
Overall, experts project gradual declines in per-drive precious metal use, but total demand growth as exabytes shipped increases. More data storage will likely require continued precious metal mining despite efficiency gains.1