Partial Chemical Plating Technique for Apertures of Aluminum Radiator

Abstract

This invention involves the technical area of chemical plating in aluminum radiators, referring specifically to the partial chemical plating technique in the inner cavity of aluminum radiator. It undergoes the inner cavity shielding before zinc impregnation and continues chemical oxidization in other parts in the chemical the based on the existing oxidization trough, making the unshielded area unable to sediment a layer of zinc and be plated with nickel and phosphors alloy. Then, it is applied with enclosure technique. The chemical oxidization and enclosure enable the sections other than the inner cavity in the aluminum radiator to be covered with a layer of oxidization film against erosion from acid and alkali, so the sections covered with a oxidization film will not accumulate a layer of zinc nor be plated with nickel and phosphor alloy in the subsequent zinc impregnation and nickel plating. Only the surface of the inner cavity is plated with nickel and phosphor alloy. The technique in this invention is simple and easy to achieve, with only the walls in inner cavity being plated with nickel and phosphor alloy, which can save up nickel and effectively cut the aluminum radiators' costs.

1 . Partial chemical plating technique for apertures of an aluminum radiator comprising the following steps:
 Step 1: pre-treatment for the aluminum radiator, then go on with oil removal, water rinsing, weak erosion, water rinsing, exposure to light and water rinsing step by step for the aluminum radiator;   Step 2: shielding the apertures of the aluminum of the radiator, take a rubber tube with greater length and smaller diameter than the aperture, Seal one end of the tube and connect the other end to an aerator, Put the rubber tube into the aperture of the aluminum radiator and charge the rubber tube with air by the aerator, the expanded tube presses to the wall of the aperture and shields the wall of the aperture;   Step 3: chemical oxidization, put the aluminum radiator with shielded apertures into a chemical oxidization trough containing solution with oxidant, after the chemical oxidization, the surface of the aluminum radiator is covered with a layer of colorless porous oxidization film, but the wall of aperture is covered nothing because of the shielding of the rubber tube.   Step 4: water rinsing;   Step 5: enclosure, put the whole aluminum radiator into the enclosure trough containing water solution with sealing compound, after the aluminum radiator is enclosed, holes in the porous oxidization film on the aluminum radiator's surface are filled up with the sealing compound, thus a layer of oxidization film is formed on aluminum surface to against erosion from acid and alkali, there is no change for the wall of aperture of the radiator due to the shielding of rubber tube, which remains of aluminum;   Step 6: water rinsing;   Step 7: remove the shielding from the aperture, get the rubber tube out of the aerator and release gas to resume the rubber tube in original shape, remove the rubber tube from the aperture;   Step 7: water rinsing;   Step 8: exposure to light;   Step 9: water rinsing;   Step 10: zinc impregnation, make first galvanizing for the radiator, than water rinsing, continue with zinc removal by washing the galvanized radiator in acid, then water rinsing, continue with second galvanization, then water rinsing, only the wall of aperture is plated with zinc, while other surfaces of the radiator do not accumulate a layer of zinc;   Step 11: chemical plating of nickel and phosphor alloy, Continue with the chemical nickel and phosphor-plating for the radiator, only the wall of the aperture is plated with nickel and phosphor alloy, while other surfaces of the radiator won't.   Step 12: post-treatment, continue with water rinsing, drying and parching for the radiator.   Step 13: finished products.   
   
   
       2 . The partial chemical plating technique of  claim 1 , wherein the aerator is connected with an air compressor for charging gas into the rubber tube. 
   
   
       3 . The partial chemical plating technique of  claim 1 , wherein the oxidants in the chemical oxidization in the Step 3 are organic amine comprising trolamine and formamine. 
   
   
       4 . The partial chemical plating technique of  claim 1 , wherein in the chemical oxidization in Step 3, the solution temperature is 80-95° C., the time for oxidization is 8-30 min, the thickness of the porous oxidization film after the chemical oxidization is 0.5-5 micron 
   
   
       5 . The partial chemical plating technique of  claim 1 , wherein in the enclosure in Step 5, the sealing compound is boric acid. 
   
   
       6 . The partial chemical plating technique of  claim 1 , wherein in the enclosure in Step 5, the temperature of the water solution with sealing compound is 85-95° C., The enclosure time is 8-30 min.