The Influence of Electric Current Density on Anodised Aluminium

The effect of anodized industrial aluminium extrusion has a lot to do with the electric current density. In a certain condition, with the current density increases, the growth rate anodized film increases too, but anodized time decreases and meanwhile the film is porous and easily colored, the hardness and wear resistance goes up. If the current density is too high, it will be affected by the joule heat, which will increase the temperature of the surface of the parts and the temperature of the local solution. The dissolution rate of the membrane will rise, and the possibility of burning the parts will be burned. The current density is too low, and the film growth rate will be slow, meanwhile, the film's dense, hardness and wear resistance are lower.

Under the condition of normal temperature (about 20 ℃), except the special process formulation, the electric current density of industrial aluminum profiles and industrial aluminum alloy extrusion should be controlled between 1 ~ 1.5 A/dm2 when anodizing. Selecting the electric current density should accord to the temperature, solution concentration, shapes of profile and other relevant process conditions.

Under possible conditions, the appropriate increase of current density is beneficial the formation rate of oxidation film, shorten the time of anodic oxidation, and increase the porosity of the film layer to improve the coloring effect. But when continue to increase current density, the industrial aluminum profile is affected persistently by the joule heat in the oxidation process: the endothermic effect of membrane hole is increased, and local heating is significant, which will cause the dissolution of the anodic oxide film and the membranes velocity go down. It can even result in uneven distribution of current and affect the coloring effect.

Selecting the appropriate current density can accelerate the growth rate of the film in a certain range, but when it exceeds a certain value, the membrane velocity decreases.

This article was written by Walter at https://www.linkedin.com/pulse/influence-electric-current-density-anodized-aluminium-walter-liu/

https://haluminium.com

Comments

4 Advantages of T-slotted Aluminium Extrusion Frame

Whether you are assembling a large production line, installing automation equipment, or setting up a workbench for a production line, you may need a metal framework to install robotic parts, dispensers, or other automated assembly equipment. Many factory owners choose traditional welded steel structures to enhance their strength and durability. However, aluminum extrusion frames are becoming increasingly popular for several reasons. Hoonly Aluminium Extrusion Framework is a modular solution that consists of Aluminium extrusion profiles with a unique T-slot design, and series of specialized connectors & fasteners , which allows designer or purchaser to adjust the structure frame according to their own needs. Because the framework is aluminum, it often has a higher price tag than steel (actually less than stainless steel). But don't you found that aluminum extrusion frames offer distinct advantages over other material frames (such as wood, stainless steel) systems? 1,

Application of High Strength Aluminum in Automotive Industry

The huge growing world car ownership is great influencing people's work and life, but resulting a series of problems such as energy shortage, environmental pollution is also increasingly prominent. Light-weight, energy saving, environmental protection, safety, comfort and low cost become the target of each car manufacturer, especially in energy saving and environmental protection, which is the major problem for the sustainable development of the human relationship, energy conservation, and emissions reduction has become an urgent problem in the automotive industry. Light-weight of the automobile, which means on the premise of guarantee vehicle performance is not affected, auto-manufacturers should be targeted to reduce automobile weight, to ensure the safety and comfort, and meanwhile should not improve the cost. From the life cycle of the automobile products, a fuel consumption cost is the main part of the vehicle life cycle cost, which occupies 71% of the cycle costs. A

Overview of Chemical Polishing Aluminium, Electra-chemical Polishing Aluminium and Mechanical Polishing

The general engineering application of wrought aluminium alloy material or building aluminium profile is the process of the semi-finished product. Aluminium extrusion profile manufacturers are generally able to directly put the profiles into anodize production line for anodizing. The obtained anodized film has the good protective properties in many engineering applications, which basically achieves uniform appearance requirements. However, if mechanically polished aluminium work-piece is directly anodized, only the smooth anodize oxide film could be obtained, but fails to get the coating film of high reflective. Chemical polishing and electro-chemical polishing can give aluminium profile a very shiny surface, but in terms of polishing, chemical polishing (or electro-chemical polishing) are fundamentally different from mechanical polishing: Chemical polishing and electrochemical polishing, as an advanced finishing method, can remove slight mold marks and scratches on the surface

Hoonly Aluminium - Aluminium Extrusion Profiles & Accessories Supplier

Search This Blog