Rust can negatively affect various characteristics of a metal or product. It can reduce the product’s lifespan and produce holes and cracks in metals. It reduces magnetic properties and decreases its electrical and thermal conductivity.
Those are just some of the consequences of rust. Furthermore, it can also be bad for our health and the environment. It can jeopardize our safety due to the degradation of metals in infrastructures like pipes and power supplies. Bridges and buildings can also be affected.
Summary
Bronze, chrome, and nickel do not rust. Cast iron will rust, although it has a protective layer added to it that will keep it from rusting for as long as it’s intact. Tungsten does not rust, whereas Damascus steel does.
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Image source: ThoughtCo
Table of Contents
- Types of metal
- Bronze
- Image source: Construction Magazine
- Does acetone remove rust?
- How to prevent it
What causes it?
Rust is another name for the chemical called iron oxide in its hydrated form. We commonly see it as the reddish-brown or yellowish-brown coating/flaky substance on iron or steel. It is one of the most common examples of corrosion.
It happens with materials/metal made up of or containing iron or iron alloys. This phenomenon results from electrochemical reactions such as oxidation.
When the surface is exposed to moist air or wet environments, it reacts with oxygen gas in the presence of water. It forms an oxide layer, rust. Depending on the chemical composition of the oxide, its color may vary from yellow or red.
It can also be brown or orange. You’ll also find it in a green form and a mix of these colors. The most common one is the red type, which is iron oxide trihydrate or hydrated ferric oxide. It has a chemical formula of Fe2O3•H2O. In a nutshell, this is what happens:
iron + oxygen + water → iron oxide trihydrate
Water is necessary for this reaction to occur, facilitating the transfer of electrons. Feeling confused? Let me delve a bit into the chemical reaction above. I’ll be brief to prevent you from napping!
- When exposed to a strong oxidizing agent such as oxygen, the iron readily gives up its electrons. It goes into the aqueous solution as a cation.
Fe → Fe2+ + 2e–
Balanced equation: 2Fe → 2Fe2+ + 4e–
- The oxygen and water react with the surface of the metal, and the oxygen gets dissolved in the water. It forms hydroxide ions.
O2 + 2H2O + 4e– → 4OH–
- And then, the iron ion and the hydroxide ion react to form iron hydroxide.
2Fe2+ + 4OH– → 2Fe(OH)2
- Lastly, the iron hydroxide reacts with oxygen to form red rust.
This whole electrochemical reaction is summarized in the image below. The red brick represents the rust formed.
Image source: Spennemann, D.H.R. from Research Gate
The process is sped up when the metal is exposed to better electrolytes, such as saltwater and acidic solutions/environments. It is because more available oxidizing agents can attack the iron, corroding the metal faster.
Now, let’s face the other questions that are related:
Do all metals rust? If not, what are the types that do? Does acetone remove it? What can you do to prevent it from happening? Does corrosion manifest the same for all types? Or are there different types of corrosion?
Types of metal
There are various types, some of which are prone to oxidation and corrosion. Others are not.
NOBLE METALS
Noble metals are also called precious metals. They have high resistance to oxidation and corrosion, even in moist air and high temperatures. Because of these properties, they are very expensive and are widely used in making jewelry. Here are some examples:
- Silver
- Gold
- Platinum
- Ruthenium
- Rhodium
- Palladium
- Osmium
- Iridium
Other transition metals can also resist oxidation and corrosion despite not being considered noble metals. Some examples are:
- Titanium
- Niobium
- Tantalum
BASE METALS
In contrast to noble metals, these are prone to oxidation and corrosion. Here are some examples:
- Copper
- Lead
- Tin
- Aluminum
- Nickel
- Zinc
- Iron
- Steel
- Molybdenum
- Tungsten
ALLOYS
An alloy combines metal and another element, either metal or non-metal.
Humans found a way to turn metals usually easily corroded into something resistant to oxidization/corrosion. It’s done by mixing them with other metals or elements. Examples of such corrosion-resistant alloys are:
- Stainless steel
- Brass
However, not all alloys are made to resist rusting or corrosion. Here are some examples of alloys predominantly made up of base metals. Thus, they are also considered to be base metals.
- Brass – an alloy of copper and zinc
- Bronze – is an alloy of copper and tin. Metals like aluminum and manganese are examples, as are nickel and zinc. Non-metals like arsenic & phosphorus are often added. Silicon can be added as well.
Although many metals mentioned above can corrode through oxidation, bear in mind that not all oxidation processes produce rust. For example, silver tarnish is also an example of corrosion that happens due to oxidation. But for now, we’ll limit our discussion to rusting.
As mentioned earlier, it forms through the oxidation of iron. It can only occur in iron and metals that contain it, such as iron alloys.
IRON ALLOYS
These alloys have iron as their most predominant component. Due to the abundance of iron, these alloys can rust. Most of them are steels containing carbon as the major non-metal alloying element.
They may also contain small amounts of silicon and phosphorus. Sulfur and oxygen may also be present. Depending on the type of steel, the ratio or percentage of elements of their composition may differ.
Here are some examples of these alloys:
- Carbon steel
- Stainless steel
- Silicon steel
- Celestrium
- Tool steel
- Bulat steel
- Damascus steel
- Chromoly
- Crucible steel
- HSLA steel
- Maraging steel
- Wootz steel
- Anthracite iron
- Cast iron
- Pig iron
- Wrought iron
- Fernico
- Elinvar
- Invar
- Kovar
- Spiegeleisen
- Ferroalloys (alloys with names starting in “Ferro-” such as ferroboron & ferrochrome)
- Kanthal
Bronze
Bronze is an alloy traditionally composed of copper and tin but nowadays is made with the addition of other metals. Some of those include aluminum and zinc. Non-metals like phosphorus and silicon can be added. This alloy has been widely used to build sculptures, tools, weapons, and bells for millennia.
Does bronze rust?
Since bronze does not have iron in it, it will not rust. It is also much more resistant to corrosion and harder than pure iron and copper, thanks to alloying copper with tin. Although bronze does not rust and is wear- and corrosion-resistant, this does not mean that it can never be corroded.
Corrosion
A bronze disease is a form of corrosion that affects bronze, manifesting as a green fuzz. People thought it was caused by bacteria (hence the term “disease”). It is caused by a series of complex chemical reactions involving the chlorides of the copper of the bronze and water. These chemical reactions are still not fully understood.
What’s currently known is that the cuprous chloride in the bronze reacts with water. It creates hydrochloric acid that damages the bronze. It will then react with copper. It would take tens of years before this happens to bronze, but it can be sped up if the environment favors it.
Bronze disease in ancient coin
Image source: Joukowsky Institute – Brown University
However, do not confuse a layer of green patina with bronze disease! Patina is not destructive to bronze and may even protect it from further exposure to moisture. Over time, a layer of protective brown patina naturally forms on the bronze’s surface through oxidation. As more time passes, the patina becomes green.
Green patina on a bronze watch
Image source: Fratello Watches
Image source: Construction Magazine
Does acetone remove rust?
If you fail to safeguard your tools or jewelry against rusting, you can easily remove it with acetone! It is one of the easiest fixes for various surfaces. You can do it on your own without needing any special equipment.
All it takes is to let the item sit in the acetone for a few hours until the affected area chips away and then scrub off the remaining stuff. If submerging the item in acetone is not applicable, you can douse a scouring pad with acetone and use it to scrub it off. Just remember to oil your equipment afterward to protect it from further oxidation.
Bear in mind that acetone can also damage the paint. You’ll have to look for other remedies to remove rust for equipment marked with paint, such as precision tools. Acetone may react with the metal or coating and produce toxic fumes. Be careful and choose which can be exposed to acetone.
Other methods to remove it include mechanical means by using a fiber wheel/abrasive buff wheel attached to a rotary tool. You can also use chemical removal with safe options like WD-40 Rust Remover and POR-15.
How to prevent it
Prevention is better than cure, as one might say. Maybe buying rust-resistant materials is not an option for you. You’ll have to care for our jewelry equipment to avoid rusting properly.
First and foremost, avoid exposing it to moist or wet environments. Suppose you notice your home frequently gathering dust. I suggest looking into UV light sanitizers for your HVAC and furnace systems. It’ll help avoid multiple exposures of your tool to water due to frequent cleaning.
Also, it’s important to oil your tools regularly to prevent rusting. Oil protects the surface of your equipment from getting in contact with moisture, thereby avoiding oxidation. I always oil my engine-driven welder after cleaning its parts to ensure it won’t rust.
It is also important to store your equipment in proper temperature and humidity areas. If you noticed that your central home AC is not blowing cold air, you should resolve it quickly. Hot and humid areas do not bode well with avoiding rust. Our two most popular articles include this one on oxy torches and this one on gauge wire.
