Composite coating with high temperature resistance and oxidation resistance and low infrared emissivity and preparation method thereof

Abstract

The invention discloses a high temperature resisting anti-oxidation low infrared emitting ability composite coating. The composite coating is of a multifunctional overlapped structure and comprises an oxidation partitioning layer, a low emitting ability functional layer and a protecting film from inside to outside in sequence, wherein the layers are connected in a main combination mode of mechanical combination and solid phase diffusion connection; the oxidation partitioning layer is a NiCrAlY composite film; the low emitting ability functional layer is a Pt film; the protecting film is a MgO film. A preparation method comprises the following steps: pretreating an alloy substrate, sequentially depositing the NiCrAlY composite film and the Pt film by using a direct-current megnetron sputtering method, and finally reacting and deposting the MgO film, thereby obtaining a product. The product is simple in process, the product can be continuously used for more than 500 hours in a high temperature environment of 800 DEG C, and the emitting ability and the high temperature stability are remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of functional coating materials and their preparation, and in particular relates to a high-temperature-resistant and low-red emissivity composite coating that can be used on alloy surfaces and a preparation method thereof. Background technique [0002] The infrared detector collects the infrared signals of the target in the 3μm-5μm and 8μm-14μm bands, and then uses the difference in infrared radiation energy between the target and the background to identify the target through imaging. According to the calculation formula of infrared radiation energy difference: In the formula, ε 目 is the infrared emissivity of the target, ε 背 is the infrared emissivity of the background, T 目 is the surface temperature of the target, T 背 It can be seen that reducing the surface temperature of the target can make the radiation intensity of the target and the background similar, and preparing a low-emissivity functional co...

AI Technical Summary

Problems solved by technology

The low-emissivity functional coating of the organic system is not used at a high temperature, and the organic systems that can withstand above 200°C include: modified epoxy systems, organic silicon systems, modified phenolic systems, etc., but organic coatings that can work above 400°C Few, so not suitable for harsh use on aircraft

Low-emissivity functional coatings of inorganic systems have a wider temperature range, but most systems do not work well in high-temperature environments

The main reasons for the above defects are that there are few low-emissivity materials with stable performance in high temperature environments, and the second is that the materials are more likely to diffuse at high temperatures, resulting in deterioration of the performance of the functional phase.

The current new high-temperature-resistant and low-emissivity materials include lead oxide coating, bismuth oxide coating, high-quality tin-doped indium oxide (ITO) coating and aluminum-doped zinc oxide (AZO) coating, etc. Low emissivity, but there are still defects such as material diffusion between coatings and unstable material properties in high temperature environments, resulting in increased emissivity of coatings in high temperature environments

Existing researchers have prepared composite coatings such as Ni / Au / Pt, Ni / Au, and Pt on the surface of Ni alloys. The results show that the noble metal film has low emissivity and excellent high-temperature oxidation resistance. The diffusion of elements is serious, and the metal surface is easily stained, so it is not suitable for use at the end of the engine and high-temperature exhaust system

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