Cath Bailey

Magnetism: What Metals Are Magnetic and What Are Not?

magnet picking metals in scrapyardEver wondered how scrapyards sort mountains of junk to separate the recyclables from the non-recyclables or to identify which materials are reusable for which applications? They use a variety of techniques from manual to machine-aided segregation since they are dealing with different types of materials.

One very effective technique that almost all big scrapyards use is magnetization. By holding up a powerful magnet above junk, iron-containing or “ferrous” metals can be extracted, leaving behind “non-ferrous” metals, such as copper, brass, and bronze. Of course, plastic items won’t be magnetized as well but they are easy to identify and separate.

How Magnetism Works

Humans have known about magnetism for thousands of years, and our understanding of it has given way to various forms of technology that support some of the most important industries of our time. Because the forces at work in magnetism are invisible, it can easily be mistaken for magic or supernatural occurrence. Unsurprisingly, a lot of magic tricks involve the use of magnetism due to its physics-defying features.Disappointingly for the superstitious, magnetism is pure science.

The best way to understand how magnetism works is by looking through the electron microscope and study the motion of electrons. An atom consists mainly of three types of elementary particles—protons and neutrons, which comprise the nucleus, and electrons, which orbit the nucleus and fill the atom’s orbitals.

Electrons normally come in pairs, both of which spin but in opposite directions. Electrons spin and movement across the atom’s orbital creates a magnetic field. Because a pair of electrons spin in opposite directions, they cancel each other out, eliminating their magnetic capability. Some atoms, however, have unpaired electrons that share the same orbitals. These electrons spin in the same direction, creating a force that either attracts or repels other atoms with unpaired electrons.

Types of Magnetism

Because a lot of different things can happen to the electrons of an atom when exposed to external forces, magnetism may occur in different ways as well. Here are some of the common types of magnetism that you may encounter when trying to magnetize different types of materials.

  • Diamagnetism

    – All materials have a natural tendency to oppose an applied magnetic field, except those that possess paramagnetic properties. This reaction to external magnetization is called diamagnetism.

  • Paramagnetism

    – Some materials have a tendency to enhance an external magnetic field and in the process cancel out their diamagnetic reaction. Each of their atoms have one unpaired electron that is free to align its magnetic moment in any direction where an applied magnetic field exists.

  • Ferromagnetism

    – Like paramagnetic materials, ferromagnetic materials have unpaired electrons on their orbitals. The only difference is that the intrinsic magnetic moment of these unpaired electrons also have the tendency to orient parallel to each other to maintain a low-energy state, allowing them to maintain magnetic force even in the absence of an applied field.

  • Antiferromagnetism

    – Obviously, this is the opposite of ferromagnetism. The intrinsic magnetic moment of the unpaired electrons tends to orient opposite each other instead of parallel to each other. As a result, they don’t create their own magnetic field and are completely reliant on applied field to generate magnetic attraction.

  • Ferrimagnetism

    – Some materials have qualities of both a ferromagnet (retaining magnetization in the absence of a magnetic field) and an antiferromagnet (sometimes rely on external magnetization). Magnetite, the first discovered magnetic substance and was originally believed to be a ferromagnet, is actually a ferrite.

Types of Magnet

Now that we understand how magnetism works on a subatomic level, we can conclude that some metals are naturally magnetic and that the magnetic properties of certain metals can be manipulated. This means not all metals are magnetic but can be alloyed with other metals to become one. Magnetic metals can be classified into three types:

  • Temporary Magnets

    – These are metals that become magnetized when exposed to a magnetic field and lose their magnetism when the magnetic field is removed.

  • Permanent Magnets

    – Some metals have natural magnetic properties. They can attract metals that exhibit the same type of magnetism as they do. Best examples include alnico (an alloy of aluminum, nickel, and cobalt) and ferrites (iron oxides combined with nickel, strontium, or cobalt).

  • Electromagnets

    – When you run an electrical current through a coil with a metal core, such as copper, you create a magnetic field, which disappears when the current is shut off.

Meanwhile, there are numerous applications involving the use of metal where magnetism isn’t necessary. Therefore, it is crucial to identify not just metals that can be magnetized, but also metals not attracted to magnets. Some of the most common types of metal attracted to magnets include iron, cobalt, nickel, and some alloys of rare earth metals.

Best examples of non-magnetic metals include copper and its alloys, such as bronze and brass. In fact, they are segregated from scrap by using magnetism to extract magnetic metals like iron mixed with them. Then again, copper is also a kind of metal used in magnets, particularly in electromagnets, due to its high electrical conductivity.

If you are planning to use metals in your project, it’s important to take note of what metals are magnetic and what are not. To be absolutely sure that you are picking the right materials, consult with experts like Rotax Metals. They can give you advice not only on the most ideal type of metal to use but also the exact grade and thickness.


Beneficial Properties and True Worth of Brass

brass bowls and incenseBefore brass became one of copper’s most essential alloys, it was first thought to be just the result of a flaw in the manufacturing process, considered as either bronze or copper depending on which it resembles more. Today, brass is identified as a metal on its own just like bronze and copper as well as extensively utilized for a wide array of applications. But where does brass come from and what applications is it used for?

What is Brass?

Brass is produced by mixing zinc and copper. It is believed to have been discovered purely by accident when early metallurgists melted zinc-rich copper ore. Until the post-medieval period, the zinc vapor that such copper ore contains was not recognized as a metal. Various other metals are added into the mixture to produce a variety of brass types. Adjusting the amount of zinc also helps produce brasses of different qualities.

By adding just a little bit of other elements, such as arsenic, lead, phosphorus, aluminum, manganese, and silicon, and experimenting on their proportions, you can produce a wide variety of materials. It’s no wonder there’s an endless list of alloys under the brass category, each of which has a considerable level of industrial function.How much is brass worth?Well, the best way to understand brass’s quick ascent to popularity, and how it caught up with copper and bronze in a heartbeat, is to know its properties. After all, a metal’s usefulness is determined by how many useful properties it has.

Properties of Brass

Compared to bronze, brass has higher malleability and lower melting point, making it very easy to cast. Make no mistake, though, as this does not make brass any less durable. Brass also does not belong to the ferromagnetic class of metals. Meaning, it has a significantly low to no susceptibility to magnetization. This makes it easy to separate brass from ferrous scrap for recycling. Almost 90 percent of all brass alloys are recycled, making brass one of the most eco-friendly metals to use for large-scale applications.

Creating a ferromagnetic type of brass is also possible. You just have to mix a little bit of iron with it. This is often done when trying to increase brass’s wear and tear resistance. Of course, other elements are added along with iron, including silicon and manganese, to reach a desired durability. Otherwise, brass will only adopt iron’s ferromagnetic property without any increment in its durability. With these qualities alone, it wouldn’t make sense to keep asking “What’s brass worth?”

Because of the softness and malleability of brass, it’s very easy to cut and machine after being extruded, eliminating the need for a cutting fluid, which not only adds to the cost of manufacture, but also affects the metal’s overall quality. When mixed with aluminum or tin, brass becomes stronger and more resistant to corrosion. It forms a thin layer of oxide that acts as brass’s shield against corrosion by harsh substances. The resulting material is highly suitable for seawater applications, since seawater is ten times more corrosive than fresh water.

In case you want to force corrosion on brass to produce a particular color or texture, you can apply a variety of chlorides, acetates, ammonia, and certain acids. Unlike other metals, however, the corrosion of brass manifests as an additional layer of material called patina, as opposed to depletion of its surface. Those who are asking the question “Is brass worth anything?” can re-educate themselves of the many beneficial properties of the metal.

Classifications and Alloys

Brasses are classified according to the amount of zinc they contain. Those that contain below 35 percent zinc are called alpha brass. Having a high proportion of copper, these brass alloys are extremely malleable and resistant to corrosion. They are also recognizable in their gold-like appearance. Brasses with 35 to 45 percent zinc, on the other hand, are classified as alpha-beta brasses. They are obviously harder and stronger than alpha brasses, which is why they are often hot worked.

If you increase brass’s zinc content to a little under 50 percent, you’ll create beta brasses, which are harder than both alpha and alpha-beta brasses, and also requires a higher temperature when hot worked. It has the brightest color among all the classifications of brass as well. Increasing the zinc content of brass from this point isn’t advisable as it makes brass too brittle to use.

So far, there are over 60 different types of brass, each of which belongs to one of the classifications discussed above. The most prominent types include the admiralty brass, which has a little bit of tin to fight off dezincification; aluminum brass, which is extensively used for making heat exchanger and condenser tubes; manganese brass, the most ideal material for gold coins in the United States; Muntz metal, used as a lining on boats to prevent fouling; and nickel brass, used for making pound coins.

So is brass worth anything today? There’s your answer. As long as the industries that rely on it continue to grow, the worth of brass won’t diminish. Unlike gold and silver, brass isn’t very popular. Neither is copper and yet it is used for more applications than all famous metals combined. Brass, being an alloy of copper, will remain in demand for a long time. You just have to make sure that you’ll source your brass supplies from a reputable provider like Rotax Metals.

Properties and Applications of Copper Sheet Metal

Metals are classified into two types. Those that contain iron and are widely utilized for large-scale construction and industrial applications are classified as ferrous metals, while those that don’t contain iron and are often exploited for their electrical conductivity, corrosion resistance, and antibacterial properties are classified as non-ferrous.

The latter is regard as high-end for a number of reasons apart from the above-mentioned properties. Most of the metals that belong to that class are quite elusive or hard to come by. Their ores are either entrenched deep into the earth or simply rare. Furthermore, the industries that utilize them also belong to a sophisticated bracket, including electronics, telecommunication, and aerospace.

Of all the non-ferrous metals, copper is arguably the most influential. There’s gold and silver that everyone knows about, but when it comes to usability, they don’t come close to copper. The fact that this metal has been around for longer than all the timelines of all other metals combined is a proof of that. Man has used copper for over ten thousand years and its reign is far from over. It’s not difficult to understand why copper is still extensively used despite the emergence of numerous other non-ferrous metals. It has to do with its amazing properties.

Properties of Copper

Our dependence on copper for many of our daily necessities comes from its many properties, which allow it to be turned into materials that are valuable in manufacturing basic commodities and utilities. There are many other metals that have similar properties but they are either not as stable or far less abundant. Let’s take a look at some of the properties that make copper a great metal.

  • Malleability

    – Copper can be hammered or rolled into thin sheets or plates without breaking. In fact, there’s a vast range of thicknesses copper can be manufactured into that distributors have made an entire copper sheet thickness chart. Each option can be used for highly specific functions from machine plating to surface embellishment.

  • Ductility

    – Copper can be drawn into small wires as well. Most of the electrical cables used in buildings have a copper core. Unlike other metals that become breakable in strips, copper remains hard even when it’s drawn into strands of very small diameters.

  • Corrosion Resistance

    – Many artifacts that date back several thousands of years are made of copper, which gives us a clue how long this metal can last. Copper, surely, corrodes just like any other metal. It’s just that the substances that can corrode it aren’t as common as those that corrode other metals.

  • Electrical Conductivity

    – It’s not just copper’s ductility that makes it a favorite material for making wire cores. Copper is also known to have superior electrical conductivity. It’s the second most highly conductive metal on the planet, next to silver.

  • High Heat Capacity

    – Copper can withstand very high temperatures, including heat produced by high voltages, which is also a reason why it’s the ideal material for making electrical wires. While silver has a higher electrical conductivity, it heats up very fast, causing fire hazards.

  • Antimicrobial Property

    – Most non-ferrous metals have the ability to release ions that damage certain proteins in microbes, killing them in the process. Copper, being the king of the non-ferrous, can decimate a great deal of bacteria in a short span of time, which is why it is ideal for making tubes and containers for water distribution and food processing.

Copper Sheet Metal Applications

Copper can be manufactured into different forms but it’s most popular in sheet form. After all, there are tons of applications that require copper sheets. Regardless of the copper sheet thickness, there will always be a use for it. This metal product is so popular you have trouble identifying where to buy copper sheets whenever you find the need. Here are some of applications of copper sheet metal.

  • Welding Fixtures

    – Before welding product parts, their geometry must be secured using welding fixtures to ensure the quality of the final product. Copper alloys are ideal for such application. In case you are building your own welding setup and asking “how thick should my copper sheet be?” there are guides online that you can follow.

  • Ground Straps

    – Any system or machine that runs on electricity must have a ground strap to protect essential components and people from electrostatic discharge (ESD).

  • Plumbing Fitting

    – Copper, being resistant to corrosion, is an ideal material for flashing. It’s even perfect for roofing but, since copper is expensive, many people don’t find it practical.

  • Power Transmission

    – Most sprockets, sheaves, belt pulleys, and bushings used in power transmission systems are made of durable and wear-resistant metals. Many alloys of copper fit the criteria.

  • Heat Exchanger

    – The majority of components of heat exchangers are made of copper or its alloys, thanks to copper’s high heat capacity.

If you are planning to use metal sheet or plate in your project, copper sheet metal must be first on your list of options. Of course, it wouldn’t hurt if you get expert advice from a world-class copper sheet supplier like Rotax Metals to know which metal is most suitable for your project or whether or not the standard copper sheet thickness would suffice. Moreover, you can easily get lost in the plethora of choices available so it pays to have a detailed discussion with the supplier.


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