Aluminum is a material that finds its application in numerous industries. Just to mention its usefulness in interior finishing, production of food and beverage cans, or creating car bodies in passenger cars. And these are just examples. Because the material is so commonly used, there was a need to protect it from destruction. Anodizing aluminum is indispensable in this field. We invite you to read this article to learn more about the process, its application, and advantages.
What is anodizing aluminum and what is it used for?
However, we should start by explaining what the presented method is. It is a surface treatment of aluminium, specifically covering the metal with a thin layer of oxide. This is done to expand the functionality of the material. Thanks to anodizing, the parameters of the metal are improved and its aesthetic values are increased. Therefore, it meets all modern standards in this regard. It is worth adding that the process is also referred to as anodizing, although this term is mainly used in workshops and scientific discussions on this topic.
How to anodize aluminum? Popular methods
Anodizing is carried out in several, quite complicated steps. Specialized tools are required for this, as well as extensive knowledge and skills. For this reason, the process of anodizing aluminum is entrusted to professionals. An independent attempt to apply a thin layer of oxide can end in failure. Not to mention the investment in tools, which are really expensive and are not useful for anything other than anodizing. Fortunately, many companies specialize in this area, so finding professionals at a reasonable price is not a difficult task. Just take a look at the offer of the Sacher company.
So how to anodize metals? At the very beginning, they are cleaned of all solid impurities and fats. This is a very important moment, because the success of the whole process depends on the effectiveness of removing impurities. It is easy to imagine a situation where poorly washed fat prevents the coating from being applied, leaving areas sensitive to external factors. In addition, the aesthetic values of such an element leave much to be desired.
After cleaning, chemical polishing or etching should be carried out. The choice of method depends on the effect you want to achieve. Both aim to achieve a high gloss on the aluminum detail by reducing the microporosity of the surface. However, there are minor differences between them, hidden in the way of processing. Anodizing aluminum by chemical polishing involves using the flow of electric current to remove the top layer of metal. On the other hand, etching is carried out by immersing the element in an aqueous solution of sodium hydroxide.
Only now can you proceed to the actual process. Anodizing aluminum at this point requires immersing the pre-prepared element in so-called electrolytic bath. It usually consists of a solution of sulfuric acid. However, some methods allow the use of chromic or oxalic acid. Anodizing cannot be done without a constant electric current with a voltage of 12-20 V (the choice of voltage is up to the specialists). After some time, an invisible oxide layer forms on the surface of the metal. It has an uneven structure, which allows for coloring. We will mention this option in a moment.
All that remains is to perform the sealing. Thanks to it, the created coating becomes insensitive to harmful atmospheric factors, and even physical-chemical ones. To create a seal, the method of hot sealing (through boiling water) or cold (through a special passivator) is used.
Between each of the mentioned stages, rinsing is necessary. It removes impurities resulting from the processes. It is also necessary at the end. This is how anodized aluminum with new, extremely useful properties is created.
It is worth knowing that anodizing aluminum is divided into two subtypes. The first is referred to as soft. The coating created as a result has between 5 and 25 μm (micrometers). It is mainly used for decorative purposes, as it enhances aesthetic values. Unfortunately, the layer is too thin to provide as good protection as in the case of the second subtype. The process of hard anodizing results in a coating with a thickness of 25-120 μm.
What colors can an anodic coating take?
The coating created as a result of anodizing takes on a gray color, similar to the basic color of aluminum. However, placing untreated metal next to treated metal allows one to notice that anodizing gives the surface a pleasant sheen and slightly deepens the color. In a word: aluminum becomes more beautiful.
But the possibilities for changing the appearance of the material do not end there. When it comes to anodizing dyeing, aluminum is wide open. And it does not carry too many restrictions. In practice, the metal can be dyed almost any color. Standard colors such as black, red, green, yellow, as well as their combinations and shades, are particularly popular.
It should be noted that dyeing does not take place after the anodizing process, but during it. This is due to the way the coating is created. The anodized layer is dyed during the electrolytic bath. Compounds of other metals are introduced into the metal structure, which changes the color of the oxide coating. All it takes is to use a variety of pigments for the pore structure to retain the color tone. In matters such as dyeing aluminum, anodizing is one of the proven methods. The metal in its basic version is not suitable for painting, as it is too smooth.
What are the benefits of anodizing?
As already established, the method is used to improve the parameters of the metal and enhance its aesthetic values. Let's highlight the most important benefits, for which customers decide to use anodizing:
- increasing the hardness of the aluminum surface to protect against mechanical damage,
- smoothing the metal surface for a decorative appearance,
- limiting the adhesion of contaminants,
- increasing the hygiene of surfaces,
- limiting electrical conductivity,
- gaining corrosion resistance.
Where is aluminum anodizing most useful?
Due to its numerous advantages and the possibility of coloring, anodized aluminum has a very wide range of applications. As mentioned in the introduction, it is used to create vastly different products and components. Aluminum for anodizing is particularly popular in certain industries. It is worth mentioning them to realize how widespread this method has become worldwide.
Aluminum with an oxide coating can be seen virtually at any moment. Just look around your own apartment. There are certainly some aluminum products in it, e.g. handles, furniture parts, lamp fittings or decorative strips. It is an excellent material for finishing interiors due to its great appearance. The ability to give anodized aluminum any color, which greatly facilitates its matching to the decor, is not insignificant. It should also be noted that even fragments of facades, terraces or winter gardens are made from the metal after processing.
Another popular use of the process is to protect electronic components. The anodic coating does not conduct electricity, thus protecting both the user and the device from shock and damage to components.
A good example is also the food industry. It uses aluminum anodizing to ensure a high level of hygiene for its products, as well as to facilitate their cleaning. Pots or pans with an oxide layer are allowed to come into contact with food. In addition, kitchen utensils made in this way are very affordable.
Interior fittings of cars are also created using this type of aluminum. The main advantage behind this choice is of course the attractive looking shine and the high resistance of the material to damage.
What is the cost of anodizing?
It is impossible to establish a rigid price list for the service. This is related to the very nature of the process, which requires the adjustment of many details. Anodizing aluminum can - and even must - be planned in terms of the dimensions of the element, the desired color, and the method used (e.g., decorative or technical). The number of details subjected to processing is also of great importance. These factors change with each project. Therefore, a predetermined price would simply be unfair.
Professionals always opt for individual pricing. Therefore, the cost of anodizing will depend on the aspects of the project mentioned above. In addition, you can count on a discount for very large orders.
Summary
Not without reason, anodizing aluminum has become one of the most frequently performed services worldwide. The method is universal, and its advantages allow for providing products with an excellent appearance combined with a high level of protection against external factors.