A process for preparing wear-resistant coating on the surface of pure aluminum and alloy castings

Abstract

The invention discloses a technological method for preparing a wear-resistant coating on a pure-aluminum and alloy casting surface and belongs to the technical field of metal base composite preparation. The method includes: adopting a self-propagating reaction formula Ti+C=TiC, weighing Ti powder and C powder according to chemometry, and adding 30%-40% of control powder for material mixing, wherein the control powder controls reaction heat and strengthens the binding phase of the coating, and the proportion of the control powder includes, by weight, 0-10% of Cu, 0-5% of Mg, 0-5% of Si, 0-5% of Ti, 0-10% of Zn, and the balance of AI; adding a binder prior to arranging the powder on the surface of plastic foam, and completing synchronous preparation of the surface wear-resistant coating and base materials by the utilization of an external ignition device and a vacuum lost foam casting technology. With the method, the self-propagating reaction of the fore-put powder on material surfaces is generated through external heat sources, metallurgical bonding of the base and the strengthening coating is realized by relying on the reaction heat and casting heat, and binding strength of the strengthening coating and the base is guaranteed; products are generated in-situ, pollution and inclusion are avoided, and mechanical and physical performances of strengthening areas are guaranteed.

Description

technical field [0001] The invention belongs to the technical field of metal-based composite material preparation, and in particular relates to a special process for preparing wear-resistant coatings on the surface of pure aluminum and alloy castings. [0002] technical background [0003] Pure aluminum and its alloys are widely used in many sectors such as aviation, aerospace and transportation due to their light weight, high specific heat and thermal conductivity. However, their low hardness and poor wear resistance limit their application range. , anti-fatigue and high-temperature air erosion resistance cannot be met. [0004] The self-propagating high-temperature synthesis method uses externally provided necessary energy to induce a thermochemical reaction to form a combustion wave, and the subsequent reaction can continue with the heat support of the previous reaction, and the required material is formed after the reaction propagation is completed. TiC has excellent phy...

AI Technical Summary

Problems solved by technology

[0006] Through literature and patent searches in the past ten years, the use of self-propagating technology and lost foam casting technology to prepare reinforced coatings mainly focuses on steel-based materials, and does not involve aluminum-based materials; Chinese patent CN201110221898.1 discloses a A method for generating a tungsten carbide-based hard alloy coating on the surface of a steel casting. Chinese patent CN201110222010.6 discloses a method for generating a titanium carbide-based hard alloy coating on the surface of a steel casting. The main bodies of the above patents are all steel castings; During the preparation of steel-based materials, due to the high melting point and casting temperature (1500-1600°C), the temperature difference between the exothermic temperature (greater than 1530°C) and the self-propagating reaction of the preset powder on the surface of the material is small, which has little effect on the coating quality. Larger, the preparation process is easier to realize; while the melting point and casting temperature of aluminum-based materials are low (700-800 ° C), the temperature difference is too large compared with the self-propagating reaction heat release on the surface of the material, which can easily cause the vaporization of the coating part of the binder phase , resulting in poor coating quality, so it cannot be directly applied to the preparation of wear-resistant coatings on the surface of aluminum-based materials