Andozing
process video
What is anodizing?
The process by which metals and their alloys form a layer of oxidized film (protective, decorative) on metal products (anode) as a result of an applied electric current in a corresponding electrolyte and under specific process conditions. (Cathode: clich)
Oxide film: its thickness is 5 to 30 microns . Anodic oxidation if not specifically indicated, usually refers to sulfuric acid anodizing.
Generally 10%~20% sulfuric acid is used as the electrolyte, the current density is 100~200A per flat square meter, and the voltage is in the range of 10~20V.
Non-ferrous metals or their alloys (such as aluminum, magnesium and its alloys, etc.) can be anodized, and this method is widely used in mechanical parts, aircraft and automobile parts, precision instruments and radio equipment, daily necessities and architectural decoration.
After anodic oxidation of aluminum or its alloys, improve its hardness and wear resistance, good heat resistance; oxide film thin layer with a large number of microporous, can adsorb a variety of lubricants, suitable for the manufacture of engine cylinders or other wear-resistant parts; film microporous adsorption capacity can be colored into a variety of beautiful and colorful colors.
Purpose: In order to overcome the defects of aluminum alloy surface hardness, abrasion resistance, etc., to expand the scope of application and prolong the service life, the surface treatment technology has become an indispensable part of aluminum alloy, and the anodic oxidation technology is the most widely used and the most successful.
Standard Process
Degreasing→cleaning→alkaline etching→cleaning→chemical polishing→cleaning→dust removal→cleaning→anodizing→cleaning→coloring→cleaning→sealing→cleaning
Reasons for color tinting
Anodic oxidation is composed of a large number of hexagonal cells perpendicular to the metal surface, with a membrane pore in the center of each cell and an extremely strong adsorption force.
When the oxidized aluminum products are immersed in the dye solution, the dye molecules enter into the membrane pores of the oxidized film through diffusion, and at the same time form difficult to separate common order bonds and ionic bonds with the oxidized film.
Types of Anodizing
There are three main categories, defined by MIL-A-8625 as:
Type I: Chromic Acid Anodizing
Type II: Sulfuric Acid Anodizing
Type III: Hard Sulfuric Anodizing
Chromic Acid Anodizing (Type I) produces the thinnest oxide coating, typically at 0.00002”-0.0001”. Although extremely thin, this coating imparts corrosion protection in line with other types of anodizing without major dimensional changes. Chromic acid anodizing is not readily accepting of dye due to the thin nature of the coating.
Sulfuric Acid Anodizing (Type II) is the most commonly used application. The coating is typically 0.0001”-0.001” thick and is harder and more wear-resistant than chromic acid anodizing. It is also easily dyed to produce parts of an endless variety of colors. Parts can be sealed to further protect the color and base material from corrosion.
Hard Sulfuric Anodizing (Type III) utilizes special techniques to form a thicker, more wear and abrasion-resistant coating, typically in the 0.001”-0.002” range. Due to the coating formed, parts that have been hard anodized are usually dyed black, although recent advances in technique have allowed for a greater variety of colors to be utilized in the hard anodizing process.
Benefits of Anodizing
Anodizing is a common coating because of the numerous benefits it offers. These advantages include but are not limited to:
Durability – The wear and corrosion resistance extends the life of the parts which have been anodized without any chipping or peeling.
Health and Safety – The naturally occurring oxides produced during the process is chemically stable, non-toxic, and will not decompose.
Aesthetics – The availability of a virtually unlimited color pallet ensures a visually appealing surface.
Environmental – Parts that are recyclable remain recyclable after the process without stripping or other materials removal processes.
Ease of Maintenance – Parts that have been anodized can easily be cleaned with mild soaps and water without damaging the anodized surface.
anodizing Products
FAQs
What is the Importance of Anodizing?
Anodizing provides many key benefits to metals. The most important benefits are increased wear resistance, increased corrosion protection, and aesthetic improvements. Anodizing creates a thin layer of oxide on the surface of a metal, which is much more resistant to wear and tear, as well as protecting against corrosion. The surface created by the anodizing process also makes metals more suitable for dyeing and painting, allowing metal surfaces to be transformed into a variety of colors. Unlike other metallic finishes, anodizing allows the metal to retain its metallic appearance.
What Types of Materials Can be Anodized?
The most common anodized materials are aluminum and aluminum alloys, but the anodizing process can be applied to other metals as well, such as copper, titanium, manganese, magnesium, zinc, and stainless steel.
Which Material is Anodized the Most?
Aluminum is the most commonly anodized material. Aluminum anodizing is a popular preventive measure that protects the metal's surface from corrosion and wear. Anodized aluminum develops a surface that is three times tougher than that of regular aluminum, and that will not flake, chip, or peel, even after being colored. The product won't ever rust, tarnish, or weather because of the controlled aluminum oxidation layer produced by anodizing.
What Are the Anodizing Colors?
Anodized surfaces can be dyed to produce any shade. However, not all dyes are equal, and there are a few colors that are used more commonly than others. Red, blue, green, black, yellow, purple, and orange are some of the most commonly used anodizing colors. Their popularity is mostly due to their low cost and ease of manufacture.