Due to the characteristics of low density and high strength, magnesium alloy can withstand impact loads greater than aluminum alloy and is known as a green metal material, and is widely used in the field of auto parts processing. However, the high-temperature performance and corrosion resistance of magnesium alloys are poor, and certain surface modification or coating treatment is required to improve the performance of magnesium alloys. So, what are the main methods of surface treatment of magnesium alloys? Let us answer for you!
Magnesium Alloy Pretreatment
Remove oil, rust and other foreign matter attached to the surface of the magnesium alloy to obtain a bottom layer with the effect of isolating the environment. Common treatment methods include mechanical cleaning and chemical cleaning.
Magnesium Alloy Electroplating/Electroless Plating
Protect the magnesium alloy matrix, improve the electrical conductivity, wear resistance, corrosion resistance and oxidation resistance of magnesium alloy
Magnesium Alloy Conversion Coating Treatment
Form a stable insoluble compound film on the surface of magnesium alloy
①Chemical conversion of magnesium alloys: simple operation and low cost, but the formed protective film is brittle and porous, which cannot be used as a long-term anti-corrosion protective film for magnesium alloys.
②Magnesium alloy anode & micro-arc oxidation: anodic oxidation uses electrolysis to form an oxide film on the surface of magnesium alloy; It is not mature enough and needs further research.
③Magnesium alloy E coating: Through this method, the surface of magnesium alloy can get good corrosion resistance
Magnesium Alloy Coating
①Magnesium alloy thermal spraying: The sprayed material is heated and melted by heat sources such as flame, laser, arc or plasma, and the surface of the magnesium alloy is sprayed at a certain speed to form a protective layer.
② Magnesium alloy organic coating, powder coating: the organic layer is thin and easy to fall off; powder coating is not easy to obtain for some hidden coatings.
③ Magnesium Alloy Vapor Deposition: Improving the Corrosion Resistance of Magnesium Alloys
Surface Modification of Magnesium Alloy
Divided into magnesium alloy diffusion and magnesium alloy ion implantation
Magnesium Alloy High Energy Beam Treatment
Namely laser treatment. There are mainly two types of laser surface heat treatment and laser surface alloying.
Laser surface heat treatment, also known as laser annealing, is actually a rapid surface solidification treatment. Laser surface alloying is a new technology based on laser surface heat treatment. Laser surface alloying can obtain alloy layers with different hardness and have a metallurgically bonded interface. Single-layer and multi-layer alloyed layers can also be prepared on high-purity magnesium alloys by using the cladding effect of laser radiation sources.
When a broadband laser is used to prepare a Cu-Zr-Al alloy cladding coating on the surface of a magnesium alloy, due to the strengthening effect of various intermetallic compounds formed in the coating, the alloy coating has high hardness, elastic modulus, and wear resistance. and corrosion resistance. However, due to the existence of the rare earth element Nd, the laser multilayer coating obtained after laser rapid melting treatment has obvious grain refinement, which can improve the compactness and integrity of the cladding layer.
Laser treatment can deal with complex geometric surfaces, but magnesium alloys are prone to oxidation, evaporation and vaporization, porosity and thermal stress during laser treatment. It is very important to design the correct treatment process.
Hope the above content can help you.
