Q. Hello,. My questions are: 1. What is the difference between Alodine and Alocrom ? 2. How can I get information (technical data) for these two. Alocrom is ideal for coating all types of aluminium and aluminium alloys including high silicon pressure die-castings. It should be used on. Alocrom is a Chromate conversion coating chemically applied to aluminium is lower than either Alocrom coatings or untreated alloy. Alocrom is not.
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Outside the UK, the Alocrom range of products are marketed under the Alodine trade name. Flexible adherent aloccrom Alocrom coatings are integral with the metal and will withstand bending and deformation of the surface. Maximum paint adhesion Alocrom provides an excellent foundation for paint. Simple to apply Alocrom requires no expensive equipment or skilled labour; it can be applied by brush or swab.
USES The Brush Alocrom process is designed for treating aluminium and aluminium alloy surfaces which are too large for normal dip or spray washing plant 11200, or for use where production does not justify the installation of expensive equipment.
Alocrom should be applied be applied by dip or spray washer wherever practicable as this gives a more uniform coatings. Details of these applications methods are given in the relevant Product Data Sheets. To make up the working solution mix equal volumes of Parts A and Part B in a plastic container.
Stir to ensure thorough mixing. If the surface is oxide free thorough solvent wiping is usually satisfactory provided the Alocrom wets the surface when it is applied. Where Alocrom is to be used for touching up machined, abraded or damaged areas on anodized or Alocrom treated surfaces, clean the areas by solvent wiping.
Do not apply by spray-gun or any equipment which atomises the solution into the atmosphere. Always apply evenly and liberally, working upwards on vertical surfaces. Issue 2 ; page 3 of aloceom in the solution. Treat small areas at a time, making sure that the area being treated is uniformly wetted and apply fresh solution if necessary.
If there is poor wetting or bare areas remaining after treatment, then the precleaning was inadequate and some oxide is probably still present. Reclean such surfaces with Deoxidine or Scotchbrite and treat again with Brush Alocrom Allow the Alocrom to act on the surface until an iridescent golden to golden yellow coating is obtained.
This will take minutes depending on the activity and temperature of the surface. Rinse finally with demineralised water wherever possible.
Chromate Conversion Coatings
Oven drying for approximately 10 minutes at C is beneficial if 2-pack Epoxy Primer is subsequently applied. The freshly formed Alocrom coating is quite soft and care must be taken not to damage it alkcrom rinsing and drying. When dry, Alocrom treated parts may be painted or put into service without further treatment.
There is no time limit before which paint must be applied, but if parts are to be painted this should be done as soon as possible to minimise contamination.
EQUIPMENT Containers for the Alocrom solution should be alocroj of stainless steel, plastic, synthetic rubber or other acid resistant material; lead, glass, tin and galvanised iron are not suitable. The mixed solution should not be stored See 6 below. Brush Alorcom Part B contains potassium ferricyanide. Mix only sufficient Brush Alocrom for use during the subsequent 24 hour period. If the mixture alocrm Parts A and B are stored for longer than 24 hours small quantities of toxic cyanide gas may be formed.
Discard any of the unused mixture after 24 hours. Issue 2 ; page 4 of 4 When handling and applying Brush Alocrom wear Laocrom or rubber gloves, apron and rubber boots. If Alocrom solution gets on to the skin, immediately drench with water and continue washing with soap and water.
Get medical attention if irritation or a skin rash develops. Do not allow rags, sponges or any organic material eg. Hose any spills of Alocrom to drain with plenty of water.
Store the Alocrom liquids, in a cool, dry, well ventilated area away from foodstuffs, oxidisable, organic or flammable materials.
The details given in this data sheet reflect our current technical knowledge and experience, and are not a legally binding assurance of characteristics or suitability for a specific purpose. Users must satisfy themselves that there are no circumstances requiring additional information or safety precautions relating to details given herein and must not practise or use any patented invention or trademark without prior approval.
This information is based on our current level of knowledge. It is given in a good faith but it is not intended to guarantee any particular properties.
The users must satisfy themselves that there are no circumstances requiring additional information or precautions or the verification of details given herein.
Flexible Adherent Coatings Alocrom coatings are integral with the metal and will withstand bending and denting of the surface. Maximum Paint Adhesion Alocrom provides an excellent foundation for paint and other organic finishes. Short Immersion Time Alocrom requires only a few minutes for coating formation. Negligible Heating Costs Alocrom operates at room temperature and the work can be air dried where convenient.
Low Electrical Resistance Light to medium Alocrom coatings have minimum effect on surface electrical resistance. The contact electrical resistance is less than micro-ohms per square inch measured under an applied alocrpm pressure of pounds per sq inch. Outside the UK the process is known as Alodine ; Alocrom and Alodine are chemically identical. USES Alocrom is ideal for coating all types of aluminium and aluminium alloys including high silicon pressure die-castings.
It should be used on aluminium wherever maximum corrosion resistance is required, and is suitable for articles which are aloceom be painted or left unpainted.
Its uses include general industrial work, electrical components, domestic appliances, car body parts and aircraft components. Alocrom is unaffected by steel, brass or copper inserts in the articles being processed and can be used for treating zinc and aluminium in the same bath.
Alocrom is unsuitable for producing a decorative effect on unpainted alloys which are subject to exterior weathering since some change in colour may occur under these conditions. The process should not be used to treat foodstuffs containers. For large scale continuous production, Alocrom may be applied in a conventional spray washing plant. For brush application use only Brush Alocrom liquid. 100
This product is supplied as a two pack product. Do not use the powder to make up Alocrom for brush application and especially do not store working strength brush Alocrom solution as toxic cyanide fumes can accumulate in a closed container.
C F Immersion Time: Nitric Acid may also be required Bath Make-up: Deionised or distilled water is recommended to prevent calcium or magnesium salts precipitating alocrrom and reducing the efficiency of the bath. Slowly add 8 kg of Alocrom powder per litres aloccrom water 8 lbs per glns and stir well until the powder has completely dissolved. The tank extract system must be running during bath make-up.
For the best results, a new bath should age for 24 hours and it should therefore be made up at least a day before production commences. Take care that none of the solution is spilt throughout the test. Leave to stand for about 1 minute. A blue-black colour will be obtained. Continue the titration to the colourless end point. The number of cm 3 of sodium thiosulphate added is the strength titration of the bath and this should be maintained at cm 3.
Add 2 kg of Alocrom powder per litres of bath for each cm 3 below the required value. If the coating takes longer to form than normal and is lighter coloured or non-adherent, this indicates that the ph is rising and it should be lowered by adding concentrated nitric acid when. The amount of nitric acid added must be kept as low as possible and the maximum must not be exceeded.
After each addition of acid, wait for several hours before adding more acid to ensure the bath has reached equilibrium.
If preferred, the ph can usually be lowered by increasing the Alocrom concentration rather than adding concentrated nitric acid. To do this add Alocrom in 1 gram per litre increments until consistent coating are obtained. The total Alocrom concentration must not exceed 14 kg per litres which corresponds to a titration of 7 cm 3.
Once the optimum operating strength for a particular plant has been established, the bath should be maintained at that strength by small additions of Alocrom powder as indicated by titration.
A Guide to Alocrom Plating
If the oxide skin is very light no further precleaning is 1200. However, if the oxide skin is heavier eg. Such alloys are best solvent degreased and given a light etch in Deoxidiser 1 before the Alocrom treatment. After removing the work from the bath allow it to drain over the tank for 15 seconds.
This will avoid unnecessary contamination of the rinse and reduce drag out losses. Typical coating weights are in the range 0. If the coating does not form or is too light or too iridescent, the cause may be one or more of the following: This can permanently upset the chemical balance of the solution. If the coating is too heavy or dark, the causes may be one or more of the following: If the coating is powdery, the cause may be alocro, or more of the following: If any sludge 2100 and begins to interfere with the processing, the bath should be cleaned out.
To do this allow the sludge to settle, siphon or pump the clear solution into the emptied rinse tank and discard the sludge. Wash out the Alocfom tank and return the solution. Fill the bath up to its operating level with water and add Alocrom to bring the bath to its working strength. Alocrom baths have a very long life and for all practical purposes need never be discarded.
The rinse water flowing to drain will contain a low concentration of chromates hexavalent chromium. Details of a simple effluent treatment method will be supplied alocrrom request. If the work it to be painted, rinse finally in water containing Deoxylyte see the relevant Product Data Sheet for details. To help dry the work this rinse can be heated to Alocron F. Deoxylyte in the final rinse counteracts the effects of any hardness in the final rinse water and improves the corrosion resistance.
It also acidifies the surfaces before drying and thereby ensures good aalocrom adhesion even under prolonged humid conditions.
Alternatively, Alocrom can be used for the same purpose. Add grams of Alocrom per litres of final rinse.