Five methods surface treatment of aluminum

The process of removing impurities from industrially pure aluminum to produce refined or high purity aluminum. General industrial pure aluminum refers to industrial aluminum electrolyzer using cryolite - alumina molten salt electrolysis method to produce aluminum, also known as primary aluminum, purity of 99.5% to 99.8%, is a bulk aluminum products, applications are widely used in various sectors of the national economy. However, higher purity aluminum is needed in some special areas, including refined aluminum, which has a purity of 99.99%; and high purity aluminum with a purity of 99.999% or more. Refined aluminum is usually produced by electrolytic refining of aluminum triple liquid; high purity aluminum is usually produced by directional solidification, area smelting, organic solution electrolysis, or a combination of several methods.

Aluminum die casting products are mainly used in electronics, automobile, motor, home appliances and some communication industry. The surface treatment of precision aluminum die casting parts generally adopts the following processes.

1, aluminum alkaline electrolytic polishing process

Alkaline polishing solution system has been studied, compared the corrosion inhibitor, viscosity increasing agent and other effects on the polishing effect, successfully obtained the polishing effect of alkaline solution system. The polishing effect of the additives can be improved at the same time. The experimental results showed that the addition of appropriate amount of additives in NaOH solution can produce good polishing effect. The exploratory experiments also found that the surface reflectivity of industrial aluminum profiles could reach 90% after DC polishing with NaOH solution of glucose under certain conditions. The feasibility of using DC pulse electrolytic polishing method to polish aluminum under alkaline conditions was explored. The results show that the leveling effect of DC constant voltage electrolytic polishing can be achieved by using pulse electrolytic polishing method, but the leveling speed is slower.

2、Environmental chemical polishing of aluminum and aluminum alloy

Aspire to develop a new environmentally friendly chemical polishing technology based on phosphoric acid monosulfate to realize zero NOx emission and overcome the quality defects of previous similar technologies. The key of the new technology is to add some compounds with special effects in the base solution to replace nitric acid. To this end, the first step is to analyze the triacid chemical polishing process of aluminum, especially the role of nitric acid. The main role of nitric acid in aluminum chemical polishing is to inhibit pitting and improve polishing brightness. Industrial aluminum profiles in pure phosphoric acid - sulfuric acid combined with chemical polishing tests show that phosphoric acid - sulfuric acid added special substances should be able to inhibit pitting, slow down the overall corrosion, with better leveling and brightening effect.

3, aluminum and its alloys electrochemical surface strengthening treatment

Preliminary investigation of aluminum and its alloys in the neutral system in the anodic oxidation deposition formation of similar ceramic amorphous composite conversion film process, performance, morphology, composition and structure. The results of the process study showed that in the Na2WO4 neutral mixed system, the concentration of the film-forming promoter was controlled at 2.5-3.0 g/l, the concentration of the complexing film-forming agent was 1.5-3.0 g/l, and the concentration of Na2WO4 was 0.5--0.8 g/l 1. The peak current density was 6--12 A/dm2, and under weak stirring, the gray series inorganic inorganic film layers with complete uniformity and good gloss were obtained. Non-metallic film layer. Film thickness 5--10um, microhardness 300-540HV, excellent corrosion resistance. The neutral system has good adaptability to aluminum alloy, and can form film on various series of aluminum alloys such as rust-proof aluminum and wrought aluminum.

4、Aluminum phosphating

The effects of accelerator, fluoride, Mn2+, Ni2+, Zn2+, PO4; and Fe2+ on the phosphating process of aluminum were investigated in detail by using SEM, XRD, potential-time curve, and change of film weight. The study shows that: guanidine nitrate has the characteristics of good water solubility, low dosage, rapid film formation, and is an effective promoter of aluminum phosphating: fluoride can promote film formation, increase film weight, grain refinement; Mn2+,Ni2+ can significantly refine the grain, so that the phosphate film uniformity, densification and improve the appearance of the phosphate film; Zn2+ concentration is lower, can not be a film or poor film, with the increase in the concentration of Zn2+, the film weight increases; PO4 content of the phosphating film on the phosphating process of aluminum; PO4 content of the phosphating film on the phosphating process of aluminum. PO4 content has a greater impact on the phosphating film weight, increase PO4.

5、YL112 aluminum alloy surface treatment technology

YL112 aluminum alloy is widely used in automobiles, motorcycles, structural components, the material needs to be applied before the surface treatment to improve its corrosion resistance, and the formation of a layer of easy to combine with the organic coating surface layer, aluminum surface treatment to facilitate the subsequent surface.