Magnetic and Non-Magnetic Metals: Properties and Applications
Magnetism is a physical phenomenon caused by the spin of electrons, which generates a magnetic field that allows certain materials to attract or repel other objects. This property originated from the discovery of natural magnetite by the Greek shepherd Magnes more than 4,000 years ago, and the amazing story of his shoe spikes and crutches being attracted to the black rock is still widely circulated. Today, magnetic technology has become a mainstay of modern society.
Magnetic metals:
Magnetic metals are typically ferromagnetic metals that can be magnetized by a magnetic field from outside, which in turn generates a magnetic field of high intensity. Below is a list of some of the major magnetic metals with their characteristics.
Iron: Iron is the most magnetic metal, and its body-centered cubic (α-Fe) crystal structure gives it strong ferromagnetism. As the main component of the Earth’s core, iron makes the Earth itself a huge permanent magnet.
Nickel: Nickel has ferromagnetism, and its unpaired electrons align under an external magnetic field, generating a magnetic field.
Cobalt: Cobalt is a ferromagnetic metal with a high Curie temperature of 950–990°C, making it suitable for high-temperature environments.
Steel: Steel is an iron-carbon alloy that is ferromagnetic due to its high iron content and has excellent strength and durability.
Stainless steel: Ferritic and martensitic stainless steels (400 series) are magnetic due to their high iron content; austenitic stainless steels (304, 316) are usually non-magnetic due to their high nickel content.
Rare earth metals: Rare earth metals such as neodymium and samarium have high magnetic energy products and produce the strongest permanent magnets.
Applications of magnetic metals
Scrap recycling: In scrap yards, electromagnetic cranes can efficiently separate iron-containing waste.
Data storage: Hard disk drives use the magnetism of cobalt and nickel to store data.
Medical imaging: MRI equipment relies on magnetic metals such as iron and cobalt to create strong magnetic fields to ensure high-quality imaging.
Transformers: Ferromagnetic cores enhance the magnetic field, and copper or aluminum coils generate current through electromagnetic induction.
Motors: Electric motors convert electrical energy into mechanical energy through an iron or cobalt core and copper coils.
Permanent magnet generators: NdFeB or SmCo magnets provide a constant magnetic field, and the copper coils generate current as they rotate.
Electromagnetic generators: Electromagnets control the magnetic field through current and are suitable for large facilities such as hydroelectric power stations.
Non-magnetic metals:
Non-magnetic metals are divided into paramagnetic and diamagnetic metals. They are not attracted by magnets and are suitable for scenarios where magnetic interference needs to be avoided. The following are the main non-magnetic metals:
Aluminum: paramagnetic, lightweight, high strength, corrosion resistant, good electrical and thermal conductivity.
Copper: diamagnetic, high electrical and thermal conductivity, corrosion resistant, good ductility.
Gold and silver: anti-magnetic, high electrical and thermal conductivity, corrosion resistance, and high ductility.
Titanium: non-magnetic, high strength-to-density ratio, excellent corrosion resistance.
Brass: copper-zinc alloy, non-magnetic, corrosion-resistant, excellent acoustic properties.
Zinc: non-magnetic, corrosion-resistant, low melting point, high ductility.
Platinum: non-magnetic, high density, good ductility, corrosion resistance.
Other non-magnetic metals: Bismuth, lead, tungsten, tin, chromium, manganese: non-magnetic, used in special fields such as welding, electronics, and protection.
Applications of non-magnetic metals
Aluminum housings: Aluminum’s light weight and non-magnetic properties make it a top choice for smartphone, laptop, and server housings.
Copper wires: Copper’s high conductivity and non-magnetic properties make it a core material for circuit boards, connectors, and cables. 5G base stations rely on copper for high-speed data transmission.
Titanium: Titanium’s high strength and non-magnetic properties make it an ideal material for MRI equipment, tools, and implants such as artificial joints.
Silver: Silver’s high conductivity and non-magnetic properties are used in MRI capacitors and antibacterial coatings.
Platinum: Platinum is used in pacemakers and neurostimulators because its corrosion resistance and non-magnetic properties ensure long-term stability.
Copper and brass: Copper pipes and brass fittings are widely used on ships and offshore platforms because of their resistance to seawater corrosion and non-magnetic properties.
Aluminum: Aluminum’s light weight and corrosion resistance make it a top choice for marine structures and buildings.
Gold and Silver: Used in jewelry, solar panels, and high-end electronic connectors, combining aesthetics with high conductivity.
Zinc: Used in galvanized steel sheets, batteries, and die castings, protecting building structures and supporting portable power.
Bismuth and Tungsten: Bismuth is used in welding and bullets, and tungsten is used in electronic components and high-temperature equipment, both of which are suitable for special scenarios due to their non-magnetic properties.
How to detect the magnetism of metals?
The following methods can quickly determine whether a metal is magnetic:
Compass: Magnetic objects deflect the compass needle because their magnetic field interferes with the Earth’s magnetic field.
Metal detectors: Detect magnetic or conductive metals through electromagnetic induction, suitable for security inspections, archaeology, and waste recycling.
Gaussmeter/Galvanometer: A Gaussmeter measures magnetic field strength, and a galvanometer detects induced current, suitable for precise scientific research.
Electrostatic testing: Non-magnetic metals show conductivity through frictional electrification, indirectly verifying non-magnetic properties.
Conclusion
Magnetic metals have been the life of the industrial and technological sectors, and their strong magnetic fields have been the energy sources for motors, generators, and MRI machines. Non-magnetic metals are equally important in the electronics, medical, and marine industries as they have the properties of being anti-magnetic and corrosion-resistant, which make them suitable for these sectors. Due to the fast progress of renewable energy, 5G, and the aerospace industry, magnetic and non-magnetic metals will always be the main characters in the drama of science and technology, as well as being the backbone of the green economy and the smart society in the world.
I'm dedicated to popular science writing about magnets. My articles mainly focus on their principles, applications, and industry anecdotes. Our goal is to provide readers with valuable information, helping everyone better understand the charm and significance of magnets. At the same time, we're eager to hear your opinions on magnet-related needs. Feel free to follow and engage with us as we explore the endless possibilities of magnets together!
Elite Newsletter: Delivering Top-Tier Content Exclusively
Articles you might be interested
