ALUMAL ELOX 557
High Performance Anodizing
Anodizing is an electrochemical process that converts the metal surface into a durable, decorative, corrosion resistant, anodic oxide finish utilized in countless industries and applications around the globe. By forming a stable, porous oxide coating, anodizing can both increase performance and improve the appearance of the fabricated parts.
The structure and quality of this coating depends on various factors, such as operating temperature, current density, voltage & time, solution agitation during processing and, of course, the aluminum substrate used.
MacDermid Enthone offers a complete range of processes for standardized sulfuric acid-type anodizing. Furthermore, our portfolio holds some specially crafted anodizing chemistry additives that provide additional benefits to aluminium applicators, such as lower product consumption and substantial energy savings, to name a few.
ALUMAL Elox 557 is a specially formulated additive system that delivers the highest performance and productivity. When utilized, the quality of the anodic oxide layer is improved with increased hardness, wear resistance, ductility, dye receptivity and seal efficiency. To the applicator, energy savings and increased throughput are also key benefits.
Since anodizing involves an electrolytic dissolution of aluminum, the oxide formed is not a deposit, but rather a highly ordered nano-scale network comprised of aluminum oxy-hydroxide that grows from the surface aluminum alloy substrate itself.
The structure of this anodic coating is based on a series of hexagonal cells, each with a central pore and a thin barrier layer separating the electrolyte in the base of the pores from the underlying metal.
It is the size, structure and placement uniformity of these cells that determine the characteristics of the final coating. The more evenly the obtained cells are distributed, the more uniform and appealing the result.
KEY FACTORS INFLUENCING ANODIZING QUALITY
- Applied current/voltage
- The chemistry of the anodizing solution
- Electrolyte temperature
- Processing time
- Base metal alloy and surface condition
- Racking of the parts
Oxide Layer At It’s Best
The ALUMAL ELOX 557 anodizing additive changes the micro-structure of the oxide formed by increasing the number of the cells per given area, which yields a more even structure, higher gloss and a smoother surface finish, thus significantly improving the quality of the result.
The hardness of the anodic oxide layer formed is up to 55–85 HV units above conventional sulfuric anodized systems, resulting in improved wear performance.
Additionally, the layer is more ductile and, despite its hardness, less brittle than the oxide obtained without using the additive.
The uniformity of the oxide layer makes for easier process management for electro-coloring and organic coloring.
The enhanced color penetration in the pores results in better colour brightness and retention and increased fade resistance, with the additional benefits of reduced coloring time and decreased dye consumption.
What’s more, the sealing process is also simplified, as smaller pores are filled. As for cold sealing, the consumption of sealing additives is decreased by up to 7%.