Four surface treatment of aluminum die casting method

1, aluminum phosphide
The accelerator is studied in detail by SEM, XRD, potential time curve, film weight change, fluoride, Mn2 +, Ni2 +, Zn2 +, PO4; Fe2 + and aluminum phosphide process. : Studies have shown that the guanidine nitrate has good water solubility, low consumption, fast film-forming characteristics, the aluminum phosphide effective accelerator: fluoride can promote the film, the film weight, grain refinement; Mn2 +, Ni2 + significantly grain refinement and uniform phosphate coating, dense and can improve the appearance of the phosphate coating; Zn2 + concentration is low, can not film or film-forming, with the Zn2 + concentration, membrane weight gain O4 content of phosphate coating weight improve PO4. The content of the phosphate coating weight increased.
2, aluminum the alkaline electrolytic polishing process
Alkaline polishing solution system, compared corrosion inhibitors, viscosity, etc. polishing effect, successfully obtained good polishing effect of the alkaline solution system, and for the first time been able to reduce the operating temperature and extend the solution service life, while also improving the polishing effect of additives. The experimental results show that: in NaOH solution, adding an appropriate additive can produce good polishing effect. Exploratory experiments also found: DC constant voltage electrolytic polishing glucose NaOH solution under certain conditions, the aluminum surface reflectivity can reach 90%, but because the experiment of instability, pending further study. To explore the feasibility of using electrolytic polishing method of the DC pulse of the polished aluminum under alkaline conditions, the results show that: the pulse electrolytic polishing method can achieve the leveling effect of the DC constant voltage electrolytic polishing, but slower leveling speed.
3, aluminum and aluminum alloy environmentally friendly chemical polishing
Determining the development of phosphate, a sulfate base fluid environmentally friendly chemical polishing of new technologies, the technology to achieve the NOx zero emissions and quality defects to overcome the conventional similar techniques exist. The key of the new technology is to add some of the compounds having a special role to replace nitrate in the base fluid. To do this you first need to analyze the three-acid chemical polishing process of aluminum, with particular focus on the role of nitric acid. The main role of the nitric acid in the chemical polishing of aluminum is the inhibition of pitting corrosion, improve the polishing brightness. Incorporated in pure sulfuric acid phosphate chemical polishing of the test, that the special substances should be added in the phosphate sulfate can suppress the pitting corrosion, general corrosion mitigation, and must have good leveling shiny effect
4, aluminum and its alloys electrochemical surface hardening treatment
Aluminum and its alloys anodized sedimentary formation class ceramic amorphous composite conversion coating process, performance, morphology, composition and structure in the neutral system, explore film deposition process and mechanism. The process results show that, in Na_2WO_4 neutral mixed system, the control concentration of the film-forming promoting agent is 2.5 to 3.0g / l, the envelope synthetic film formers concentration of 1.5 to 3.0g / l, the 0.5 ~ Na_2WO_4 concentration 0.8g / L , the peak current density of 6 ~ 12A/dm ~ 2, weak stirring, can obtain the complete uniformity, gloss and good gray series of inorganic non-metallic coating. The film thickness of 5 to 10 μm, the micro-hardness of 300 ~ 540HV, and excellent corrosion resistance. The neutral system of aluminum alloy film better adaptability, rust-proof aluminum, wrought aluminum and other series aluminum alloy.