What is Anodizing?

Anodizing is an electro-chemical process that can converts the ordinary metal surface into a decorative & durable surface with corrosion resistive property by generating anodic-oxide in process. Anodizing successfully combines science with nature to create the best material finish.

Merits of Anodizing are as follows-

1. Durability

2. Maintenance

3. Colour Stability

4. Aesthetics

5. Health & Safety

Aluminum anodizing

Aluminum anodizing is basically classified in Three Types (As per MIL -A-8625)

1. Type I- Chromic Acid Anodizing (Out dated so don’t provide it anymore)

2. Type II - Sulphuric Acid Anodizing

Class 1(un-dyed)

• Class 2 (dyed)

3. Type III - Sulfuric Acid Hard Anodizing

• Class 1 (un-dyed)

• Class 2 (dyed).

Use of Anodizing

Anodizing is widely used in Cutlery, Machinery, Electronics, Microelectronics, Automobiles, Aerospace, Petrochemicals, Textile, Food, Defense, Medical, Watch, Optical, Hydraulics, etc.

Elcoats & Allied Industries provides a variety of anodizing services like:

• Normal Anodizing

• Clear anodizing

• Colour Anodizing

• White Anodizing

• Silver Anodizing

• Milky Anodizing

• Hard Anodizing

• Titanium Anodizing etc.

Type – III Sulphuric Anodise (Hard)

Hard coat Anodise processing of Aluminium using the Elcoats Process creates a fine and durable finish.

Titanium Anodizing

Titanium Anodizing is an electrolytic finishing process which can be implemented for both decorative as well as Functional purposes. Titanium Anodizing is a voltage controlled anodizing process using acidic solution to create a very thin transparent oxide layer on metal surface.

Titanium Anodizing are Two Types

• Type 2

Type2 is used in Medical Industry. It helps patients, with orthopedic implants by improving mobility of joints by providing a resistance free metal surface. It also applied in aerospace industry as well, where type 2 anodizing parts are completed with aircraft fluids and withstand extreme temperatures- range of 70°C to 260 °C. Its availableility color is Grey.

• Type3 titanium Anodizing is also know as Colour Anodizing. It is widely used in medical world for quick visual identification. It is less common in the aerospace industry. Its also used in jewelry manufacturing industry as well. Its available colors are silver, bronze, rose, blue, light blue, green teal purple & magenta.

Silver Anodizing

is a process which creates a natural oxide layer on the surface of metal without using any paints or colours. The process is controlled through passing electricity in the electrolyte solution to achieve silver kind of desire finish using propriety chemistry. Silver Anodizing increases the corrosion and wear resistance property & durability over the raw surface. e.g.: In camera, the top plate, base plate and top control elements are silver anodized.

Colour Anodizing

known for it’s organic and chemical dyes process which is applied directly after the anodizing process on metal surface. During this process the components are coated with Aluminium Oxide layer and dipped into colored dye as per the requirements. Usually this process to used for identifying the components or for aesthetic look of the component

White Anodizing

White Anodizing is an electrolyte system which consist of our proprietary chemical, this process is suitable for thermal control application requirement. White anodizing surface is smooth and film thickness is relatively thin that's why it’s suitable for decoration purpose.

Clear Anodizing

Clear Anodizing is an electrolytic anodizing process where the coating is transparent in colour with soft oxidise layer. In this process the physical property of the material remains unchanged. Clear Anodizing is usually used where you want to retain the natural looks of Aluminium finish and at the same time prevent it from getting it oxidise. The coating range for good clear anodizing start from 15-25 microns which will last for decades. However, to based on your application requirements, coated thickness can be reduced up-to 5 microns.

Normal Anodizing

Normal Anodizing is an electrolytic process which is also called as Natural Anodizing. This give the Aluminium natural finish over the component. This process is also similar to clear Anodizing but some region people also refer as Normal Anodizing. The usually coating thickness is between 10-20 microns.

Milky Anodizing

Milky Anodizing is an electro-chemical process that creates a controlled oxide film on the surface of aluminum. Milky Anodizing combines science with nature to create best material finish. The aluminum oxide is fully integrated with the underlying aluminum substrate to produce milk color coating which is for aesthetic purpose. During this process the chemistry is controlled using proprietary chemical and finished is obtained.

Hard Anodizing

is an advance technology in the field of surface finish, during this process the physical property of the metal is changed. This kind of process are used where you can use Aluminium kind of light weight and soft alloy to give any shape, design, etc. as per your requirement and hardened the material as equal to stainless steel. In Hard Anodizing process we can achieve hardness up to 400 Hv. The process is tightly controlled with the chemistry using high voltage rectifier. The process is expensive compare with usually Anodizing due to use of high end rectifier up to 120 Volts and operating temperature below 0(zero) °C. We are specialized in hard Anodizing and have in house lab facility like Wicker Hardness Tester, Coating testing, Conductivity test, etc. which is required for processing the components. Hard Anodizing gives thicker and harder layer on Aluminum than usual Anodising. The layer can be around 30-70 μm thick(based on the alloy). The abrasive wear resistance of Hard Anodized layer is better than that of hard chrome, Electroless nickel and Nitride steel.

Type II - Sulphuric Anodise (Clear & Dye)

Conventional coatings formed from a sulphuric acid bath. Sulphuric Anodising is the most commonly used and most suitable process for colouring.

MIL-A-8625 Type III, Class 1

MIL-A-8625 Type IB, Class 2

MIL-A-8625 Type II, Class 2

MIL-A-8625 Type IIB, Class 2

MIL-A-8625 Type III, Class 2

Black Hard Anodizing

is an advance technology in the field of surface finish, during this process the physical property of the metal is changed. This kind of process are used where you can use Aluminium kind of light weight and soft alloy to give any shape, design, etc. as per your requirement and hardened the material as equal to stainless steel. In Hard Anodizing process we can achieve hardness up to 400 Hv. The process is tightly controlled with the chemistry using high voltage rectifier. The process is expensive compare with usually Anodizing due to use of high end rectifier up to 120 Volts and operating temperature below 0(zero) °C. We are specialized in hard Anodizing and have in house lab facility like Wicker Hardness Tester, Coating testing, Conductivity test, etc. which is required for processing the components.

Aluminum finishing

In Cookware Industry we provide Aluminum finishing which is the process that works well with all aluminum items. Aluminum finishing will give a shiner and brighter look to almost every aluminum product.

The resistance to corrosion of aluminum and aluminum based alloys are improved by aluminum finishing. Aluminum finishing is the process in which aluminum is cleaned and dipped in different acids. Further the electricity is applied to aluminum which results in its oxidation. It is carried out when aluminum is rinsed. After that, different colors could be given to aluminum metal by adding chromate in it.

Die Casting Hard Anodizing

Die Casting Hard Anodizing is a special process used on either PDC, ADC, etc. aluminium die casted components to provide corrosion resistance to the component. Coating on these components are uneven due to the high concentration of silicon and other impurities present in the material. The coating range from 3 microns to 20 microns and Hardness is limited as compared with pure aluminium alloy. The process is recommended for components which required minimum coating thickness of 5-10 microns in Die casting with hardness of 150-250 Hv.

Hard Anodizing with Di-Chromate Sealing

Hard Anodizing with Di-Chromate Sealing is process where Hard Anodizing of the component is doing as per Mil Standards and for additional corrosive resistance the components are chemically treated with Di-Chromate sealing to close the pores of the component. This process is a special requirement only for industry specific, also alternative to standard sealing process.

Clear Chromatizing

Clear Chromatizing is an alternative to Yellow Chromatization which is chrome free, it provides a clear iridescent film of low contact resistance. The corrosion performance of our aluminium chromate conversion coating is consistent with that of traditional hexavalent processes and is largely a function of the specific alloy that the aluminium chromate conversion coating is applied to. Aluminium chromate conversion coating improve the corrosion resistance of wrought, heat treatable and cast aluminium alloys while providing an excellent base for subsequent painting or power coating services. We provide as per Mil & ASTM standards.

In the process a thin oxide layer is formed to provide corrosion resistance to the bare aluminium. Instead of using bare Aluminium this process is recommended to prevent oxidisation. It can also be used instead of primer to provide strong adhesion for further coating like powder coating or paints. The coating thickness is very thin usually counted in nano microns. At our place we can provide the dye testing to feel the difference bare aluminium and clear chromatized component.

Hexavalent Chromate Conversion Coating

Hexavalent Chromate Conversion Coating is a type of conversion coating used to passivate aluminium. It provides high corrosion resistance and paint adhesion properties to aluminium surface, it is well known that the visual desirability may be improved by forming a chromate coating by contacting the surface with an aqueous conversion coating solution containing chromium ions and other additives.

Aluminium Bright Finishing

Aluminium Bright Finishing is chemically treated to give extra brightness to the aluminium components. Usually Anodizing is a dull/matt finish, and in order to give the shiny finish we do the additional chemical treatment.

Non Hexavalent Chromatization

Non Hexavalent Chromatization specification covers the requirements relating to rinsed and non-rinsed non-hexavalent chromium conversion coatings on aluminum and aluminum alloys intended to retard corrosion; as a base for organic films including paints, plastics, and adhesives; and as.a protective coating having a low electrical contact impedance. Coatings are categorized into four classes according to corrosion protection and finish. The type of conversion coating depends on the composition of the solution and may also be affected by pH, temperature, duration of the treatment, and the nature and surface condition. Films are normally applied by dipping. Coatings shall adhere to specified electrical resistance, adhesion, and corrosion resistance requirements.

Electroless Nickel Plating

Electroless Nickel Plating is also known as ENP. Its is a chemical process which deposit Nickel Phosphorous layer on the components without of the use of electric current during the process. The major advantage of this process is that it provide even surface coating across the bath on all the components. So there is no uneven coating issue from one component to another component. Also the chemistry has proven the hardness achieved in the coating thickness is minimum 350 Hv to 1000 Hv(based on the base alloy)

The Electroless Nickel process has several advantages over Electrolytic electroplating:

Virtually unlimited throwing power Little or no excess deposit at high points Deposits of excellent physical and chemical properties Reduced hydrogen charging (hydrogen embrittlement) Ability to coat surfaces which would be difficult or impossible by electroplating