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Brass

Understanding Corrosion and the Metal Polishing Process

metal sugar bowls and jugs

Corrosion refers to the natural or forced destruction of metal. Different metals corrode in different ways. Iron, for instance, corrode by transforming into iron oxide or rust when exposed to oxygen, while zinc forms a layer of zinc oxide on its surface, which later hardens and turns into zinc carbonate when exposed to atmospheric carbon dioxide.

The chemical agent that prompts corrosion affects each metal differently, too, as elucidated through the above-mentioned examples. Oxygen remains the most influential of all corrosion-causing elements due to its abundance, but various compounds, particularly acids, are many times more potent.

Corrosion impacts not just a metal’s appearance, but also its longevity. Especially if the metal has an assigned structural function, identifying and eliminating factors that could trigger corrosion is necessary to prevent accidents.

Stages of Corrosion

There’s a vast range of factors that affect the rate and manner by which a metal corrodes. These include metal type, chemical agent, metal composition, temperature, pressure, and a plethora of environmental factors. It is therefore safe to say that each metal type undergoes unique stages of corrosion when exposed to the same chemical.

To make it easier for us to understand how metals corrode, let us categorize them based on their iron content, since iron is a key player in the corrosion of many of today’s extensively utilized metals. Let’s call those that contain iron “ferrous metals” and those that do not “non-ferrous metals”. Assuming the chemical agent is oxygen, here’s how these two types of metals react.

  • Ferrous Metals

    – Oxygen is present in the atmosphere, so unless placed in a vacuum, ferrous metals are bound to corrode. When a ferrous metal corrodes, oxygen molecules latch onto iron molecules, forming iron oxide. This continues until all of the iron within the metal leaches out.

  • Non-Ferrous Metals

    – Metals like copper, bronze, and brass corrode almost the same way as iron and steel, except the damage stays on the surface. When oxygen molecules combine with the molecules of non-ferrous metals like these, a layer of oxide forms. Over time, this oxide combines with carbon dioxide to form a carbonate, which later becomes the metal’s protective layer.

The Noble Metals

There’s a group of metals that neither tarnish nor rust when exposed to oxygen. They are called noble metals. Platinum, gold, silver, and palladium belong to this group. Even prominent non-ferrous metals like copper and titanium don’t make the cut, because they, too, corrode. Want to know if your gold jewelry is authentic? Try not polishing it for days. If it stays shiny, it means it’s authentic.

Metal Polishing Process

Thankfully, corrosion can be fixed, depending on the metal type and the severity of damage. This isn’t the case with ferrous metals in which corrosion has already cut deep. Like a rotten tooth, there’s a limit to how much of a piece of ferrous metal has been consumed by rust so it can be considered non-salvageable.

It’s a different story when you are dealing with non-ferrous metals. As explained, the damage left by corrosion on these metals are only skin-deep, because the patina acts as a shield against further damage. Such shield can preserve the metal inside for a long time. To give you an idea how long, the oldest metallic artifact discovered was a copper awl, which dates back to 5,100 B.C. It’s surface is heavily corroded but the inside is intact.

Of course, it’s difficult to remove patina and restore a metal’s luster, which is why you should polish a metal when it’s just starting to tarnish. Tarnishing is the first stage of corrosion and it’s just a thin layer that can easily be polished by scrubbing with a homemade or commercial metal polish. Besides, scraping away the patina might damage the metal underneath, especially if it’s the soft type, so don’t wait for the metal to patinate before you polish it.

Then again, if you really need to polish a severely corroded metal item but you don’t have the right tools and polishing agent, opt for professional metal polishing services. They use cutting edge-technology, including powerful substances to eradicate even thick layers of corrosion.

Whether it’s a jewelry item or a raw metal piece you bought from one of the bronze or brass suppliers in your area, if it’s made of a non-ferrous metal like copper, brass, or bronze, it can be polished back to its shimmering self. Here are some simple tips you can follow.

  1. Wash the metal piece with soap and water very carefully to remove dust and grease. Excess dust may contain tiny pieces of stones that can scratch the surface of your metal piece when you start scrubbing.
  2. Dry the metal piece properly until it’s totally stripped of moisture. Water may not go well with the metal polish. Buffing while the surface is still slightly wet may not yield the result you desire.
  3. Choose between a homemade polish and a commercial one. It would be easy to just buy over-the-counter metal polish, but if you’re the exploratory type, you can make your own metal polish by mixing boiled water, baking soda, and salt.
  4. Rub the surface of the metal item with the metal polish mixture and let it sit for a few minutes. Then buff it with a clean cloth until the shiny surface emerges. Do this repeatedly until all surfaces have been fully buffed.

If ever you are interested in making metal furniture yourself, consider using any of the 100 different copper alloys. They’re not just rust resistant, but they are also visually appealing. Some brasses even have a gold-like shade, which makes them so elegant-looking. Just remember to buy your supplies from one of the top bronze and brass suppliers in North America, such as Rotax Metals. They offer some of the highest quality copper alloy supplies in the country.

Difference Between Brass and Bronze

bronze statue

Most people have heard of “bronze” at least once—in a museum, in a church, or in an Olympic ceremony. It’s a metal used to make a variety of things, including sculptures, bells, and medals. Brass?—Not a lot. Only those in the manufacturing and construction industry are well aware of it.

Truth is even though brass is as useful, if not more, as bronze, it isn’t as popular. One apparent reason for this is because its history is not as remarkable as bronze’s. Unlike brass, bronze was discovered at a time when there are no other metals that could rival it yet.

It didn’t take long, though, before brass could make a name for itself. And at one point in history its existence begged the question “Are brass and bronze the same?”or “Can brass substitute bronze?”

While brass and bronze are both alloys of copper, their properties are not the same. Neither metal can substitute the other at least in highly specialized applications.They must be treated as different metals with different values.

Composition

To better understand the difference between brass and bronze, let’s take a close look at their composition. After all, an alloy’s properties can change dramatically when at least one of its contents is altered. In fact, adding even just a miniscule amount of a different element to the composition could produce an entirely different kind of alloy.

As previously mentioned, brass and bronze are both alloys of copper. This means that copper is their base metal content and they differ in their secondary metal content. Brass is an alloy of copper and zinc, while bronze is an alloy of copper and tin.

Unlike bronze, which was discovered when copper and tin-rich rocks were combined to build campfire rings, the discovery of brass was almost totally unintentional. For some time it wasn’t regarded as a copper alloy because zinc vapor hadn’t been recognized as a metal yet. It wasn’t even called brass until zinc qualified as a metal.

Properties

Due to their difference in composition, brass and bronze also possess different properties. Anyone working with these metals must take note of this fact because they are generally not interchangeable.Here’s to help you more easily distinguish between brass and bronze.

  • Color

    – Bronze has a reddish-brown or reddish-gold color, which turns into dark brown or green as it oxidizes. Brass, on the other hand, has a bright gold, copper, or even silver color, depending on the type and amount of other metals added to the mixture.

  • Workability

    – Brass is more malleable than bronze. Meaning, it’s less likely to break when hammered or rolled into thin plates than bronze. In fact, bronze is almost as brittle as cast iron and melts longer than brass. Depending on their composition and the output quality desired, however, both bronze and brass may need to be worked hot.Whether you are extruding brass or bronze bars or drawing them into wires, they need to be heated for easier metalworking.

  • Conductivity

    – When it comes to heat and electrical conductivity, there’s not much difference between the two alloys. They are both effective conductors, and that’s why they’re suitable for machines that run on electricity.

  • Corrosion Resistance

    – Both brass and bronze are resistant to corrosion because they are mostly made of copper. However, they react differently to oxidation. Bronze develops a protective layer called patina when exposed to the air, while brass simply tarnishes and loses its luster. Some types of brass are especially resistant to galvanic seawater corrosion, making them ideal for sea vessel covering and pipes for desalination systems.

  • Acoustic Property

    – The sound created by bronze is much duller and deeper than that created by brass, which explains why it isn’t compatible for high-pitched musical instruments. It’s just right for cymbals and bells, though, because its resonance does not disappear fast. Brass, on the other hand, is capable of creating the smooth, wide-ranging tone expected from musical instruments like trumpet and horn.

Where to Purchase Brass and Bronze

Despite being widely used in the construction, communication, and transportation industries, copper alloys are not as easy to come by as more abundant metals like iron and aluminum. There are only very few bronze and brass suppliers in North America that can provide authentic, high-quality products.

It’s easy to tell if a supplier can deliver the right grade of metal for your project. First, find out how long they’ve been in the business. The older the company, the wider its network of sources is, so it’s also highly that they produce superior products. Rotax Metals, which was established many decades ago, is the perfect example. Having their own foundry is also a meritas it means they have full control of the manufacturing and quality assurance process.

Sources:

https://www.diffen.com/difference/Brass_vs_Bronze

What Is Brass Made of and What Are Its Properties?

telescope with brass components

When you think of brass, the first thing you would probably imagine is a musical instrument, particularly a trumpet or a saxophone. While many musical instruments are indeed made of brass, they are not the only items made of such material. There are countless others, some of which are everyday objects, such as doorknobs, drawer pulls, and handrails.

Brass is quite a common metal but very few people are truly familiar with it, and it’s not difficult to understand why. Apart from having a plain appearance, brass also comes in numerous varieties. Furthermore, the color of brass can be engineered to suit a wide range of design applications, which is why it is almost always mistaken for other shiny metals.

What is brass made of?

Brass is the resulting alloy when you combine about 67% copper and 33% zinc. This standard composition can be altered to produce different types of brass. Minute amounts of other metals, such as lead, phosphorus, aluminum, manganese, and silicon can be added to the mixture to further improve the properties of brass. For instance, adding up to 2% lead could give brass better machinability.

Not all combinations, however, produce useful versions of brass. Some make brittle and soft kinds, while others too difficult to cold work. Another problem that may arise is dezincification, which is characterized by the gradual increase in porosity of brass due to an excessive amount of zinc.

Useful Properties of Brass

If you are familiar with copper and zinc, it will be easy for you to understand the nature of brass. We know that copper is extremely durable, able to last for thousands of years due to its ability to form patina, a green layer of material that protects its surface from weathering. Zinc, on the other hand, is known for its high corrosion resistance and density, which makes it incredibly impermeable. Now, let’s take a look at brass and its useful properties.

  • Corrosion Resistance

    – Like copper, brass is also resistant to corrosion. It’s no wonder manufacturers prefer brass channel and tube products to other metal supplies. With the right composition, brass can even hold out in seawater, which is ten times harsher than tap water. Unfortunately, brass tarnishes quickly, which is why brass furniture and accessories must be regularly polished to stay shiny.

  • Workable

    – Standard versions of brass are prized for their malleability. Meaning, they can be molded into different shapes and thicknesses without applying heat. Compared with bronze, brass is easier to cold work, weld, and braze. Adding a little bit more zinc helps improve this metal’s machinability.

  • High Conductivity

    – Like copper, brass also has a considerable heat and electrical conductivity, around 40% that of copper. It doesn’t quickly burn under high voltage like silver and other conductive metals. This is why brass is the preferred material for machine parts that function as conductors.

  • Germicidal Properties

    – Brass is also anti-bacterial, a property that is characteristic of most non-ferrous metals. Their molecules produce ions that target a certain protein in single-celled microorganisms, resulting in their demise. The entire process takes about two to four hours depending on the type of metal involved. This is the reason why copper alloys, such as brass, are ideal for filtration systems.

  • Aesthetic Appeal

    – There’s no denying the majestic appearance of standard brass. Its glittery yellow tone rivals that of authentic gold. Those who are looking for a cheaper alternative to gold in their crafts must consider brass.

Major Classifications of Brass

    There are currently over 60 types of brasses available commercially. They are classified according to the ratio of their copper and zinc content. As mentioned, by changing the ratio of what brass is made of, you can produce brasses of varying properties. To better identify each brass type and measure their performance, they are methodically classified into three forms.

  • Alpha Brasses

    – More commonly known as soft brasses, these are brasses with 65% copper and 35% zinc. This much copper is what makes these brasses malleable and easy to work cold. They also look more gold-like than the other forms of brasses.

  • Alpha-Beta Brasses

    – Brasses with 55-65% copper and 35-45% zinc are classified as semi-hard or alpha-beta brasses. They are slightly harder than alpha brasses, which is why they are usually worked hot. This slight change in composition gives these brasses a brighter, less golden hue. Additionally, alpha-beta brasses are also less resistant to corrosion than alpha brasses.

  • Beta Brasses

    – The hardest types of brasses belong to the beta group. Theses brasses have 50-55% copper and 45-50% zinc. Due to their hardness, they are quite impossible to work unless they are heated. The high amount of zinc also poses the risk of dezincification.

When purchasing brass for your projects, always be precise about the composition to make sure you’ll get the exact quality you need. The last thing you want is to use soft brass for structural applications. You must always consult with a metal expert before choosing a specific grade of brass. You may also get your supplies from top brass suppliers like Rotax Metals, especially because they supply North America with superior copper products.

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