Aluminum Plates are suitable industrial products beneficial for a wide range of projects and applications. These panels’ unique characteristics, including being lightweight and having extreme corrosion resistance, make them versatile and durable materials for construction. They come in both forms of sheets and plates, which are recyclable while maintaining their properties. These plates provide a wide range of advantages for designers and builders to construct the perfect facility for any demanding project. Manufacturers move the aluminum between rolls under particular pressure to make it longer and thinner to achieve the practical plates. However, making these plates is not that simple and requires professional equipment and factories. It is a fact that aluminum is the most abundant metal existing on the earth. Thus, there is no wonder that with our propensity of exploiting any industrial or non-industrial products, it is common to find something made of this material. Cleaning Aluminum Plates is a process that is essential to know if there is possession of aluminum products.
Why is it Crucial to Clean Aluminum Plates?
For most projects and applications, the aluminum plates require a chemical or electrochemical cleaning process. The process involves removing residual mill oil, surface oxides, smut, and most importantly, the disturbed layer of the near-surface to provide a uniform surface to apply pretreatment. The cold and hot rolling process of making aluminum plates generates the disturbed layer due to the severe shear strain from the interaction between the aluminum and the steel roll.
The disturbed surface consists of nano-sized grains that have grain boundaries pinned by oxide particles and lubricant substances. The removal of this layer is crucial for the pretreatment process to obtain its best potential and efficiency increment. The better the pretreatment, the better the aluminum plate’s properties will be. The properties include corrosion resistance after coating and long-term durability of finishes and adhesive bonding. Thus, effective cleaning is an essential process for the performance of these industrial products.
Different Methods of Aluminum Plates Cleaning
Aluminum plate cleaning is either a batch or coil process, and the primary difference between these two is in the processing time they provide. Most manufacturers prefer coil cleaning because it is way faster than the other method. This method varies in terms of solution chemistry used, applying the substance, and utilizing and applying an external current.
Acid or Alkaline Solutions
The acid cleaning process is often based on phosphoric acid or sulphuric acid surfactants or solutions. However, experts add hydrofluoric acid as an activator. The operating temperature of this process is usually in the range of fifty to seventy centigrade degrees while having a contact time of five to sixty seconds.
On the other hand, the alkaline cleaning process is based on hydroxide surfactants. The operating temperature of this method is in the range of fifty to seventy centigrade degrees and the contact time of five to twenty seconds. Thus, this system is a fast-etching method compared to the acid cleaning method used for the aluminum plates. However, it is essential to manage the solid precipitate forms in the waste and bath known as aluminum hydroxide. Some of the intermetallic and oxide particles insoluble in the second method solution can form a smut layer, attaching to the surface. Thus, alkaline aluminum plate cleaning is followed by an acid de-smutting stage.
Immersion or Spray
The immersion method, also known as spraying, is another cleaning method that combines acid and alkaline systems. This method utilizes the solutions as a spray. Individuals who prefer this process use multi-step water rinse after the cleaning stage to remove the cleaning substance from the product’s surface thoroughly.
Chemical or Electrolytic System for Cleaning Aluminum Plates
The Alkaline and the acid methods are both chemical processes and relatively efficient cleaning agents on their own. However, using an electrolysis system increases their power and efficiency considerably. The mechanism and strategy of the electrolytic cleaning method are similar to anodizing. The anodizing process generates the characteristic anodized oxide film with a regular pore structure on the surface of the aluminum plates. Creating the oxide film is considered a competition between the dissolution and the film growth. Controlling the acid temperature and concentration and the voltage of anodizing makes it possible to produce an aluminum oxide dissolve at a formation rate.
The electrolytic cleaning method of aluminum plates does not require HF, meaning it is an efficient system for health and safety both for workers and the environment. Additionally, this system is flexible and fast. For instance, effective cleaning with minimum residual oxide can work in 0.5 to 3 seconds. Another benefit of this method is the equipment can work as anodizing pretreatment lines. The disappointing news is that most manufacturers do not utilize this perfect system despite its various advantages.