Preparation method of multi-layer composite high-temperature corrosion-resistant coating based on high-temperature nickel-based alloy

Abstract

The invention belongs to a high-temperature corrosion resisting coating preparing technology, and particularly relates to a preparing method for a multi-layer composite high-temperature corrosion resisting coating based on a high-temperature nickel-base alloy. The multi-component coating technology is adopted, the embedded type nano Si3N4 film technology is adopted in the outer surface, the extremely high oxidization resisting capability is achieved, a four-layer matching layer structure including a base plate transition layer (Al-Si), a connecting layer (Ti3Si(Al)C2), a gradient layer (Al-Ti-Si-Cr-N) and an embedding layer (nano Si3N4) is adopted, and the thermal shock resistance of the composite coating is greatly improved through chemical bonds formed through diffusion of common atoms between the matching layers and the mutually close thermal expansion coefficient.

Description

technical field [0001] The invention belongs to a high-temperature corrosion-resistant coating preparation technology, in particular to a preparation method of a multi-layer composite high-temperature corrosion-resistant coating based on a high-temperature nickel-based alloy. Background technique [0002] High-temperature alloys can have high high-temperature strength at high temperatures (generally referring to 600°C to 1100°C), good oxidation resistance and thermal corrosion resistance, good fatigue properties, fracture toughness and plastic alloy materials. In the actual application process of high-temperature alloys, the working environment and performance of the alloy require that the alloy not only have excellent high-temperature mechanical properties, but also have excellent corrosion resistance. At present, with the increase in the operating temperature of aero-engines, the operating environment is becoming increasingly harsh. , the traditional high-temperature nicke...

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Problems solved by technology

[0004] 1. Metal aluminide coating (including modified aluminide coating): metal aluminide is the earliest protective coating on the alloy surface, which mainly uses the dense alumina generated on the surface of the high-temperature coating to prevent further high-temperature oxidation. At the same time, the aluminum-rich or chromium-rich oxide on its surface can have certain high-temperature corrosion resistance, and it has long-term reliability in the salt spray state below 650 ° C, but it can be used in molten salt and salt spray conditions above 700 ° C Corrosion marks will appear obviously after use, and its corrosion resistance will be greatly reduced in the complex environment of high-temperature oxidation and reduction atmosphere changes

[0005] 2. Metal silicide coating (including composite metal silicide coating): metal silicide mainly refers to the compound coating formed by refractory metal and silicon, which is mainly dense SiO formed by high temperature oxidation surface 2 In order to prevent further oxidation, the glassy coating has self-healing properties and is a good anti-corrosion material, but the biggest problem with this coating is that silicon diffuses quickly in most alloys, and the interaction between silicon and alloys is easy The formation of low-melting point phase and brittle phase makes the surface of the alloy embrittled, and it is easy to crack and fall off under long-term high-temperature thermal shock conditions, so the service temperature is relatively low

But it also has chromium oxide volatilization above 900°C and strong salt spray corrosion at high temperature above 700°C

[0007] 4. Precious metal coating: a protection method that mechanically isolates materials from the environment through precious metal coating (platinum, niobium, etc.), which has strong oxidation resistance and corrosion resistance, but its biggest problem is its high temperature The internal diffusion is serious, and the matrix elements are easy to diffuse to the surface to make the coating invalid

However, this kind of barrier coating usually has a large gap between the mechanical properties and the substrate, and it is easy to crack and fall off under long-term thermal shock conditions.

[0009] At present, the operating temperature of aero-engines is increasing day by day, and the operating environment is becoming increasingly harsh. Not only does it require the operating temperature of superalloys to reach above 950°C, but also to meet the requirements of thermal shock resistance, high temperature resistance (above 700°C) salt spray corrosion, and compatibility with oxidative atmospheres ( Full combustion) and reducing atmosphere (incomplete combustion) long-term (more than 100h) use requirements, there is no one type of coating that can fully meet the above application conditions

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