Advantages and disadvantages of nickel acetate sealing
Aluminum and its alloys form a layer of oxide film on aluminum products (anode) under the action of applied current under corresponding electrolyte and specific process conditions. If there is no special indication, anodic oxidation usually refers to sulfuric acid anodic oxidation.
In order to overcome the defects of aluminum alloy surface hardness and wear resistance, expand the scope of application, and extend the service life, surface treatment technology has become an indispensable part of the use of aluminum alloy, and anodizing technology is currently widely used and successful.
The wide application of nickel acetate sealing technology replaces part of the hot water sealing process. Nickel acetate sealing is very popular in North America, thanks to its high sealing quality. The principle of nickel acetate sealing is that after nickel ions are adsorbed by the anodic oxide film, a hydrolysis reaction occurs to generate nickel hydroxide precipitates, which are filled in the pores to achieve the purpose of sealing. In the neutral salt spray test and the acid dissolution weight loss test, the anodic oxide film sealed with nickel acetate shows excellent corrosion resistance. The nickel acetate sealant developed by someone can pass 3000h of the anodic oxide film sealed by it. Neutral salt spray test and phosphoric acid monochromic acid corrosion weight loss test of less than 1mg/dm2. For dyed oxide film, nickel acetate sealing can prevent the fading and discoloration of the oxide film. Compared with boiling water sealing, nickel acetate sealing allows higher impurity content and relatively lower sealing temperature.
The sealing effect of nickel acetate sealing process is similar to boiling water sealing, but the sealing speed and allowable amount of impurities are slightly higher, and there are also various disadvantages of boiling water sealing, such as: high energy consumption, easy to produce "frost", and reduce the hardness of the oxide film. Long sealing time, water vapor pollution and safety issues.
