Die-casting magnesium alloy surface modified powder infiltration process

Abstract

The invention relates to a modified powder body filtration process for the surface of die casting magnesium alloy, which forms the gradient of alloy concentration on a surface layer of a die casting magnesium alloy part through an infiltration technology. The adopted technical proposal is as follows: different modified powder bodies without adding any adhesive are directly sprayed on the surface of a parting agent of a die casting mold, and a modification layer can be formed on the surface of the magnesium alloy part by casting liquid magnesium alloy in the metal casting mold by die casting and cooling. The process substantially changes the physicochemical property and the mechanical property of the surface of the magnesium alloy; the formed surface modification layer is continuous and compact, does not contain organic substances, and has good corrosion resistance and wear resistance; and the process simplifies the prior surface modification technology of the magnesium alloy, and realizes green, environment-friendly and pollution-free production. The process is simple, has easily controlled parameters and high rate of finished products, and can be widely used for industrial production.

Description

technical field [0001] The invention relates to metal surface modification, in particular to a powder infiltration process for surface modification of die-casting magnesium alloys. Background technique [0002] Magnesium is the lightest engineering metal material (density 1.8g / cm 3 , which is 2 / 3 of aluminum and 1 / 4 of steel), has a series of unique features such as light specific gravity, high specific strength and specific stiffness, good damping and machinability, good thermal conductivity, strong electromagnetic shielding ability and easy recycling. It can meet the requirements of aviation, aerospace and modern automobile industries for weight reduction and energy saving, and can replace engineering plastics as housings and structural parts of electronic equipment to meet the light, thin, miniaturization, high integration and environmental protection of products and other requirements to improve energy utilization efficiency. However, there are still a large number of ...

AI Technical Summary

Problems solved by technology

However, there are still a large number of technical difficulties to be solved that restrict the further application of die-casting magnesium alloy parts. This is mainly manifested in the fact that magnesium is a very active metal that is resistant to atmospheric (especially humid air), acidic substances and salts. (especially chloride) has high solubility and fast corrosion rate, and the formed corrosion products are loose and poor in stability. This fatal shortcoming seriously restricts the wide application of magnesium alloys.

[0003] At present, the main methods used for surface modification of magnesium alloys are anodic oxidation, electroplating coating and other processes. Although these processes can slow down the corrosion of magnesium alloys to varying degrees, there are still many deficiencies, such as the gap between some corrosion-resistant coatings and magnesium alloy substrates. There is an obvious interface between them, the surface tissue is loose and porous, and contains more organic matter, which is easy to crack or peel off, and some process links will also cause pollution to the environment, etc.

In view of the limitations of the existing process methods, all parties are actively committed to the frontier research on the surface modification of magnesium alloys, such as vapor deposition, micro-arc oxidation, ion implantation, laser surface treatment, etc., but the above technologies are still immature. The technology and cost are difficult to be accepted by enterprises, some technologies are still in the exploratory stage, it is difficult to meet the actual requirements, and cannot be widely used in industrial production

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