- Sulphuric Anodising Additives
- Pre – Treatment Chemicals
- Cold, Hot & Medium Seal
- Dye & Electro-colouring
- Desmut Additives
- Non- Etch Cleaners
Sulphuric Anodising Additives
Sulphuric acid is a proprietary anodizing chemical that improves the performance and result of the substrate surface, this facilitates the anodizing process and prevents the aluminium form burning, which allows for higher current densities, denser consistent coatings and quicker production times.
Pre – Treatment Chemicals
Most of the aluminium that is shipped around the world is done so as flat rolls or coils, which then requires modification to suit a particular application, ensuring a durable and high performance end product.
Aluminium surface modification requires:
- Through Cleaning to remove residual oil and oxide films, typically this include Alkaline spray or dipping, Acid spray or dipping and acid electrolytic cleaning
- Pre-treatment offers protection against corrosion and enhances adhesion capabilities for a high performance finish product, this process is either chemical or electrolytic, with chemical pre-treatment being the preferred method or industry standard.
- Protective surface coating, decorative or custom product finish.
The function Pre-treating aluminium is to form a barrier layer that restricts water, oxygen and ion from contacting the substrate. It also improves adhesion characteristic for any surface coating or finish and offers a stable platform for the resident oxide film.
Pre-treatment is a vital part of the final product, achieving the correct structure or layers will mean the difference between success and failure.
Cold, Hot Sealing & Medium Temp Seals
Sealing is the last step of the anodizing process, effectively closing the porous aluminium oxide layer. The sealing gives a maximum corrosion resistance and minimizes the wear resistance of the anodized oxide layer.
A common process is using boiling, deionized water with various sealing salt additives such as hot DI sealing, Mid-temperature sealing and cold sealing.
Dye & Electro-colouring Processes
After the anodizing process, a colour finish can be added by electro-colouring, immersing the aluminium in an organic dye solutions allowing the microscopic pores within the surface layer to absorb dyes.
An iron-free desmut / deoxidizer powder used in the aluminium anodizing process to accommodate production requirements. This product is designed to remove natural oxide film and smut formed by alkaline etching.
Non- Etch Cleaners
A process that uses a non-caustic alkaline solution to clean the parts, thereafter the items are soaked in a tank with water, phosphoric acid, wetting agents and proprietary chemicals which will activate the surface and leave a small amount of smut or oxides. The next tank contains iron and EDTA which is a powerful complexing material. The entire process removes very little material and will not hide scratches or imperfections.
Pre – Cleaning
Electro cleaning is a process whereby a controlled electric current is imposed on parts immersed in an alkaline cleaning solution, this process is common practice within the electroplating industry. Electro cleaning pre-treats parts for both rack and bulk processing, removing soils from everything and preparing the parts for the subsequent finishing of electroplating, electroless plating, painting, electro-coating, anodizing, electro-polishing, conversion coating and sealing.
De – Scalers
Descaling is the process whereby soil and contaminates are removed from the part, either in a tumbler or a separate cleaning system. Once the parts have been cleaned they are prepared by combining them with water, medium and a surface conditioner. The surface conditioner coats the parts in copper whilst the medium removes and residual scale or oxides. Accelerators, promoters and metal powder are added which provides the correct chemical environment for the plating to occur.
This refers to a material becoming “passive” which is less affected or corroded by the environment. Passivation is an outer layer of shield material, a light micro coating that is created by a chemical reaction with the substrate, such as metal oxide which creates a shell against corrosion.
Brass plating is used for industrial more than decorative purposes, its purpose is to prevent corrosion on metal finishes and provide an appealing looking surface layer of protection.
Nickel electroplating is a process of depositing nickel onto pre-treated metal parts free of soil, corrosion or any other defects. The prepared parts are dipped into an electrolyte solution and is used as the cathode. The nickel anode is dissolved into the solution, forming nickel ions. The ions travel through the solution and deposit on the cathode creating a nickel plating.
A process of electrolytically forming a layer of copper on the surface of a part, using direct electric current to dissolve a copper rod allowing the copper ions to adhere to the part in an ideal ionic solution environment.
Chrome is a technique of electroplating a thin layer of chromium onto a metal part or surface, mostly used for a decorative finish. Chrome plating does provide protection against corrosion and increases surface hardness, with an easy to clean shiny surface finish.
Silver plating is carried out in much the same fashion, coating the surface of a part to form a decorative layer of protection that increases durability and wear ability, ultimately increasing a parts lifespan.
More commonly used in the jewelry industry, gold electroplating provides good abrasion resistance to items such as watch straps and brooches, providing a layer of protection that looks luxurious.
A process of thinly coating steel with tin, the resulting product is known as tinplate. It provides a surface layer of protection and prevents rust and oxidation
Bright Cadmium Plating
Cadmium plating is a bright silvery white metal deposit used to enhance corrosion resistance and provide a good looking finish, a widely used method of surface protection, particularly in the fastening industry.
Zinc cyanide is the inorganic compound with the formula Zn(CN)2. It is a white solid that is used mainly for electroplating zinc but also has more specialized applications for the synthesis of organic compounds.
The reaction between zinc and hydrochloric acid is Zn + HCl = H2 + ZnCl2. It is a single replacement reaction where zinc metal displaces the hydrogen to form hydrogen gas and zinc chloride, a salt. Zinc reacts quickly with the acid to form bubbles of hydrogen.