Designers of metal items sometimes believe they can avoid the danger of corrosion by specifying aluminium. It doesn’t rust in the same manner as steel. However, it does still corrode. Under some circumstances it can suffer erosion and pitting. Both harm the appearance and can result in premature failure. We want to cover what you can do to protect against corrosion. Then, if you need products like 3103 (H14) aluminium coil, you can rely on us.
What causes corrosion?
Firstly, let’s discuss what causes it. Corrosion is a reaction between materials or a material and the environment. For instance, battery acid can corrode nearly everything it touches. In the metal fabrication field, we consider corrosion a precursor to, or a form of, rust. It has close linked to oxidation. This is where metal atoms on the exterior bond with oxygen in the atmosphere. With aluminium, this creates a very thin layer of aluminium oxide. When the metal is iron or steel, the same process leads to iron oxide (rust).
Aside from air exposure, corrosion can also have other causes. Compounds like chlorides and sulphides can attack and eat away at metals. There is galvanic corrosion too. Here, a conductive liquid like sea water generates an electrical connection between unfamiliar metals. Electrons flow between them. This depends on their relative galvanic “activity”. It depletes the one that’s giving its electrons up, causing it to corrode.
Similarities to steel
For aluminium, the corrosion procedure is not unlike that of stainless steel. Aluminium atoms come with a strong oxygen affinity. Those on the exterior are fast to grab what they’re able to from the air and form aluminium oxide. From there, this layer rapidly reaches a depth where oxidation can’t occur anymore.
The oxidation procedure here is readily observable. Freshly cut aluminium comes with a shiny, bright, almost silver appearance. It turns dull grey very swiftly though. This is surface oxidation at work. Moreover, it’s self-healing. Scratch a piece and the newly exposed material grabs those oxygen atoms and turns back to grey quickly. Come to us if you need 3103 (H14) aluminium coil.
When conditions are correct, aluminium is vulnerable to attack by sulphides and chlorides. The same goes for galvanic corrosion. Chlorides reside in salt water and within the air in maritime areas. Additionally, sulphides could be a by-product of saltwater. Yet, another source is emissions from equipment burning oil, coal, and natural gas to a lesser extent.
Chlorides and sulphides
Both of these can eat through the oxide layer on aluminium’s exterior. This usually happens at specific points instead of being generalised over the exterior. The result is pitting. If you allow it to develop, it will lower the metal’s strength. It can cause failures of highly loaded areas.
Galvanic corrosion is also especially common around and in saltwater. In this scenario, when you immerse two separate metals in water, a type of weak battery or electric circuit gets created. It results in electrons flowing between the metals. What you get is the depletion of the one that’s more galvanically active.
Compare to most other metals, aluminium comes with a higher galvanic potential. Thus, if saltwater produces a circuit between mild or stainless steel and aluminium, the latter will corrode. This can happen rapidly and is something aluminium boat owners need to remember. Talk to us if you want 3103 (H14) aluminium coil.
Composition
Something crucial to note is that the particular composition of an aluminium influences the corrosion rate. In general, alloys possessing a greater copper content will corrode quicker. The 3xxx, 5xxx, and 6xxx series alloys often corrode slower than 2xxx. Copper free 7xxx alloys possess decent corrosion resistance. Those with large copper contents corrode faster.
The rate of aluminium corrosion comes down to its composition and the environment you use it in. For environmental factors, an interior industrial setting is not likely to suffer much galvanic or pitting corrosion. Although, something for outdoors use has a far higher risk.
What to do?
When you identify corrosion as a concern in the design stage, figuring out the most likely source is the ideal prevention method. For galvanic corrosion, include a sacrificial anode and utilise only a single alloy. Also, place electrical insulation between dissimilar alloys.
With pitting corrosion, you can apply a coating. Epoxy powder is a common choice. Choose an alloy from a more corrosive resistant series too. You can also put the aluminium through a passivation process; it will enhance the surface oxide layer.
We supply the best 3103 (H14) aluminium coil
At Brindley Metals, we’re committed to supplying high quality items. These include various types of aluminium and many other materials. At the same time, we work to deliver quickly. If you need to arrange processing services, we can help with that too.
We can supply 3103 (H14) aluminium coil and other products for almost any need. So, if you’re interested in working with our team, let us know.