Aluminum alloys are widely used in aerospace and chemical plant industries, but their low strength and poor wear resistance limit their applications. Therefore, the use of surface modification materials and specialized skills to enhance the surface properties of aluminum alloys has garnered significant attention.
Common methods generally involve organic chemical treatment or organic chemical air oxidation to enhance the bonding between the substrate and the coating, as well as the corrosion resistance of the surface. However, the air oxidation films obtained through organic chemical air oxidation are relatively thin, with weaker corrosion resistance and durability. The air oxidation film on the surface of aluminum alloys also makes it difficult to perform chemical nickel plating or electroplating processes on titanium. In comparison, micro-arc oxidation treatment is widely considered an effective method for the surface treatment of aluminum alloys today.
Micro-arc oxidation is a process that involves developing a ceramic-like air oxidation film on the surface of a material by applying high voltage (DC, alternating current, or single pulse) in an acidic or alkaline solution (usually a weak alkaline solution). This process is a collaborative effect of physical charging and discharging, photoelectrochemical air oxidation, and plasma technology air oxidation.
This specialized skill has grown and evolved from the foundation of general anodizing processing skills, further developing working voltages to exceed the electromagnetic induction law region, reaching the breakdown voltage of the air oxidation film. This will result in a corona discharge phenomenon during anodizing, forming a ceramic air oxidation film on the material surface. This not only ensures the high efficiency of the plasma technology air oxidation film in microfiltration but also maintains a persistent bond between the anodizing film and the conventional one.
This characteristic has made it a popular topic of discussion within the scope of surface engineering project skills. Using micro-arc oxidation technology, Harbin Institute of Technology in our country has added cobalt acetate to the electrolyte of lithium batteries, which then transforms into high-temperature shock-resistant micro-filtration on TC4 aluminum alloy. The bond between the film layer and the substrate exceeds 10MPa, and the aluminum alloy remains consistent and stable after 40 cycles of thermal shock. It indicates that TC4 aluminum alloy treated with micro-arc oxidation exhibits excellent high-temperature destructive resistance.
