Niobic alloy high temperature antioxidation silicide coating and preparation method thereof

Abstract

The invention discloses a niobium alloy high temperature antioxidation silicide coating and a preparation method thereof. Firstly, molybdenum layers, the particle size of most of which is 0.6-1.0 Mu m and the thickness of which is 50 Mu m-80 Mu m, are sintered through vacuum on a niobium alloy substrate surface layer. Under the protection of argon, a MoSi2 coating is made through the pack cementation silicification. The pack cementation silicification activator is NaF, the promoter is Al2O3, and the weight ratio of Si to Al2O3 to NaF is 35-45 to 50-65 to 3-5. The complex pack cementation process is suitable for preparing the silicide coating with high melting point and can coat the inside and the external surface of irregular structural components without the influences of the shape and the size of the components. The components and the thickness of the coating prepared through the method are uniform. The density is greatly improved compared with that of a material pulp reaction sintering method. With simple process and low requirement on equipment, the invention is a novel high temperature coating preparation technology.

Description

technical field [0001] The invention relates to a niobium alloy high-temperature oxidation-resistant silicide coating, and also relates to a preparation method of the niobium alloy high-temperature oxidation-resistant silicide coating. Background technique [0002] Niobium alloy is an excellent high-temperature structural material widely used in aviation, aerospace, electronics, metallurgy and light industry, etc., but its high-temperature oxidation resistance is poor, which strictly limits its application. Nickel-based and cobalt-based superalloys are the high-temperature structural materials with the best comprehensive performance at present, but their working temperature generally cannot exceed 1100°C; although silicon-based ceramic materials have high high-temperature strength, their working temperature can reach 1600°C, but Their room temperature toughness, fracture toughness, and reliability are still difficult to meet the requirements of aerospace structural materials...

AI Technical Summary

Problems solved by technology

[0002] Niobium alloy is an excellent high-temperature structural material widely used in aviation, aerospace, electronics, metallurgy and light industry, but its high-temperature oxidation resistance is poor, which strictly limits its application

Nickel-based and cobalt-based superalloys are the high-temperature structural materials with the best comprehensive performance at present, but their working temperature generally cannot exceed 1100°C; although silicon-based ceramic materials have high high-temperature strength, their working temperature can reach 1600°C, but Their room temperature toughness, fracture toughness and reliability are still difficult to meet the requirements of aerospace structural materials

Niobium alloys have a high melting point and high temperature strength, and are widely used in some high temperature resistant components in aviation, aerospace, electronics, metallurgy and light industry industries, but they are easily oxidized in high temperature oxidizing atmospheres, and niobium begins to form oxidation at temperatures above 600°C substances, and the volatilization of oxides accelerates rapidly with the increase of temperature, causing refractory metals not to resist oxidation

At present, the oxidation resistance of niobium alloys is mainly improved by alloying protection and surface coating protection, but although the alloying method can improve the oxidation resistance of niobium and niobium alloys, the alloying elements must exceed a certain critical value In order to protect the matrix, this will inevitably affect other properties, especially the decline in the high-temperature mechanical properties of the matrix. It can be seen that the alloying method has its own limitations.