Top 8 Types of Metals That Don't Rust - Tried and Trusted
Corrosion means degradation of a metal which happens when a refined metal is naturally converted into a stable form such as oxide, hydroxide, and sulphide that damages the entire surface. There are different types of corrosion; uniform corrosion, pitting corrosion, crevice corrosion, intergranular corrosion, and. galvanic corrosion. These corrosions occur in different types of metal. Corrosion generally happens due to electrochemical reactions. Normally, corrosion occurs when most atoms of the same metal surface are oxidized. There are different types of metal that tend to lose electrons easily in the air and water which results in reduced oxygen and forms an oxide with the metal.
Corrosion is dangerous and costly. It can collapse buildings and bridges, break oil pipelines, bathroom overflows, and chemical plant leaks. Corroded electrical contracts can also cause a fire. Air pollution has caused corrosion to works of art around the world. Fortunately, some metals don’t rust easily These metals can either hold on to a prolonged period or even avoid corrosion completely. Every metal indeed has its advantages; the aspect of metal being corrosion resistant is an essential property that determines its usages. Iron is known to be the most surplus present transition metal on earth; it is used for more than 5,000 years by mankind but due to its massive usage; it is prone to corrosion if exposed to water and oxygen. There are five other types of metal that do not rust easily, but before hoping to that, learn why different types of metal corrode. This article briefs you about the different types of metal and their characteristics that resist corrosion. You will get to know why does metal rust, what types of metal rust, metals that don’t rust, and steps you can take to prevent corrosion.
Why does metal rust?
Corrosion is an electrochemical reaction that appears in two forms; chemical and atmospheric corrosion. When acidic substances come in contact with iron or steel, the rusting begins. Rust happens when iron particles are exposed to oxygen and moisture e.g humidity, vapor, and immersion. The affected iron particles become a corrosion pit and are called rust.
Metals corrode due to their temporary existence in metallic form. To turn metallic from chemical compounds, metals must absorb and store up the energy required to release the metals from their original compounds. This energy is called thermodynamic which varies from metal to metal. It is relatively high for; magnesium, aluminum, and iron and low for copper, silver, and gold. The metals that don’t rust easily are as follows
#1. Stainless steel
Stainless steel contains iron, magnesium, chromium, silicon, carbon, nickel, and molybdenum. These elements react with oxygen from water and air to form a thin stable film that consists of corrosion products such as metal oxides and hydroxides. Chromium plays a dominant role as it is present in all the elements by at least 10%. When chromium reacts it forms chromium oxide on the metal surface which acts as a protective layer against corrosion. The more the chromium, the more resistance
The most renowned grades of stainless steel include 304, 316, and 430. If you are planning to buy any of the stainless steel products but thinking will stainless steel rust? then don’t worry. Along with being corrosion-free, it is durable, increases the aesthetic appeal, and is used in a range of products from kitchen utensils to kitchen sinks. Once you buy, you might stop wondering will stainless steel rust or not?
Aluminum does not contain iron or steel which reduces the chances of corrosion drastically. Aluminum is self-reliant and creates protection against corrosion. When exposed to water it creates a thin coating of aluminum oxide that shields the metal against corrosion. Aluminum remains corrosion-free when exposed to natural weather and used in different applications; car and bike parts, kitchen utensils.
According to a theory given by Leland Stanford Junior University, the Majority of the aircrafts are made of aluminum- A chemical element that resists corrosion despite being exposed to air and water. Fortunately, if aluminum metal exposes to the atmosphere a thin layer known as aluminum oxide forms on the metal surface and shields the metal from rust and corrosion.
#3. Galvanized steel
This is a type of carbon steel that has been galvanized, coated with a thin layer of zinc which acts as a barricade to oxygen and water and prevents them from reaching the steel which keeps it corrosion-free. If you are worried and questioning yourself, will stainless steel rust? This is an option to go for. If the zinc coating is scratched off either by mistake or intentionally, it still protects the nearby areas of the underlying steel through cathodic protection along with forming a protective coating of zinc oxide. Aluminum zinc reacts to oxygen and moisture and the coating protects the iron in the steel from further oxidation.
There are different grades of galvanized steel, the higher the grade number, the thicker the layer of zinc which equally makes it corrosion-free.
#4. Red metals
Red metals contain little or no iron which makes them resistant to rust or probably corrosion-free. The metals are copper, brass, and bronze. When these metals oxidize they don’t corrode but are likely to turn green due to prolonged exposure to oxygen. The Green layer formed over copper when oxidized is called green patina. This layer highly resists corrosion but looks less appealing. Red metals that remain corrosion-free are as follows
Brass oxidation happens when brass is exposed to water but it does not rust easily because of the negligible amount of iron in it. Brass oxidation is typically blackish, blue, or green that hardens over the surface. Unlike corrosion, brass oxidation does not affect the integrity of the brass. Some people also leave brass oxidation for decorative effect. This keeps it protected against rust and iron dioxide and is stronger than pure copper. The increased strength and ductility make it corrosion-free and a classic choice for marine applications. Brass is smoother, malleable, and aesthetically pleasing which makes it a popular choice for decorative items, home fitting, and musical instruments.
Bronze is another copper alloy that includes the combination of tin and adequate percentages of other metals. It remains corrosion-free due to the absence of iron which doesn’t cause rust or iron oxide. On rare occasions, it can be susceptible to a destructive chemical process known as bronze disease, caused by chlorides under conditions like submersion in saltwater.
Copper can be easily found anywhere in its pure metallic form. It is naturally brown and turns bright green when corroded. It does not rust but oxidizes if exposed to air and that green layer is called patina. As with aluminum the layer protects the metal but does not provide the desired look.
#8. Corton and weathering steel
You might not have heard about this, but weathering steel known as COR-TEN steel contains up to 21% of alloying elements; chromium, copper, nickel, and phosphorus. The blend of all these elements forms a protective rust patina which reduces the corrosion rate over time. This steel is cheaper than stainless steel.
These are some of the metals that don’t rust easily but know-how is rust different from corrosion. Why does metal rust or corrode? Many people have this question. There is a difference between rust and corrosion as stated below.
Difference between rust and corrosion
People often confuse these two terms but they are different. The primary difference is corrosion is a type of oxidation whereas rusting is a part of corrosion. Corrosion happens because of the chemical influence and affects a lot of materials while rust generally affects iron substances and paces up due to various chemicals.
- It takes place in air and moisture
- It is a slow process
- Its red-orange in nature is formed by oxidation of iron due to oxygen and moisture of water
- It badly affects the quality of metals
- It forms oxides, sulfides, and hydroxides due to elements present in the metal
How to prevent corrosion
The World Corrosion Organization estimates the overall cost of corrosion to be about US $2.5 Trillion annually, but 25% of the portion can be eliminated if the right preventive measures are taken. Corrosion alone is not a financial issue, but it is hazardous to health as well. Engineers have taken steps to use proper types of metals or alloys and collaborated with metallurgical experts. They also know about possible chemical interactions between metals used for fitting, fastenings, and surfaces. Some steps you should take for the prevention of corrosion are as follows:-
- Use corrosion-free metals such as aluminum and stainless steel. They are eco-friendly and versatile enough to be used under various conditions.
- Treat metals with lasers to give them a non-crystalline structure that resists corrosion.
- Use non-metallic coatings such as grease, carbon fiber, plastic, paint, and oil to keep it corrosion-free.
- Apply Anti- corrosion protective coating to prevent your metal from contacting harsh environmental conditions.
- Coatings are highly effective. They are resistant to UV rays and temperature, won’t chalk, fade, and require only single coat application.
- Use drying agents and make sure to keep different types of metal clean and dry
These are some of the metals that don’t rust, but a few of them corrode as every metal has different characteristics, and each functions distinctly. Taking preventive measures will expand the life of the metal and keep it in a good condition. By now you might have understood that buying different types of metal and preserving them is essential, but if you are still confused, reach us without any hesitation we will be ready to help.