Metals are subject to destructive atmospheric and physical impact. Chromium plating allows to protect metal from corrosion, to increase wear resistance of the rubbing details, to give it hardness. On wear resistance the chromeplated metal does not concede to a covering of modern cars. Besides, chromium plating it is possible to give it an original form.
It is required to you
- - fine-grained emery paper on a fabric basis;
- - sulfuric acid;
- - the glass or enameled capacity;
- - chromic anhydride;
- - battery;
- - lead plates;
- - extinguished lime;
- - caustic potassium;
- - liquid glass.
Instruction
1. Prepare a metal surface for chromium plating. Remove the oxides and rust formed over time under environmental impact. Jam metal a fine-grained emery paper.
2. Now the surface of metal needs to be degreased. Use special mix on the basis of extinguished lime: on 1 liter of water – 35 g of extinguished lime, 3 g of liquid glass and 10 g of caustic potassium. Temperature of mix is 90 wasps. Degrease within 1 hour.
3. Wash after degreasing with warm water.
4. Prepare an electrolytic bathtub of the following structure in the enameled ware: on 1 l of water – 300 g of chromic acid and 3 g of the concentrated sulfuric acid. Heat to 50 wasps and pour a little more than a half of capacity of the distilled water. Pour chromic anhydride and mix. Then add water up to the necessary volume.
5. Place two lead plates containing up to 7% of antimony or tin on both sides of the chromeplated metal detail. If it is more lead plates, then place them around metal. By the size they have to be twice more, than the chromeplated detail. Lead will serve as the anode while the chromeplated metal – the cathode. Bathtub temperature - 60 wasps. Determine time, being guided by what result you want to achieve. Use the battery of the car for giving of current. Current has to be 1.60 – 3.10 kA/sq.m. of DC.
6. After metal is extracted by you from a bathtub, wash a detail with water and dry wipe with a piece of soft fabric. If it is necessary, polish it.
7. If you noticed that chrome does not accumulate on a metal detail, check contact at the cathode or the anode. It is possible that the surface of the anode is covered with a film of oxides. Take electrolyte temperature, reduce it if it is higher than the specified values. Make sure that the amount of sulfuric acid does not exceed admissible.