Preparation method of SiC nanowire toughened HfC-SiC complex phase coating by chemical vapor co-deposition

Abstract

The invention relates to a preparation method of a SiC nanowire toughened HfC-SiC complex phase coating by chemical vapor co-deposition. The preparation method adopts a three-step method and comprises the following steps: firstly, preparing a SiC inner coating by using an embedding method, then, introducing free silicon on the surface of the SiC inner coating by using a vapor siliconizing technology, carrying out chemical vapor deposition on HfC on the surface of a C / C sample with the SiC-SiC inner coating, and enhancing the interface bonding strength between the inner coating and the outer coating through in-situ reaction and diffusion of free silicon in the vapor deposition process. The SiC / HfC-SiC coating which is uniform in thickness, compact in structure, controllable in component and high in binding force can be prepared. On the basis of a mechanical bonding interface of a traditional method, an interface diffusion layer is introduced for diffusion to form diffusion bonding. And the coating process is simple, the reaction period is short, the cost is low, and the development prospect is wide.

Description

technical field [0001] The invention belongs to a method for improving the bonding strength of an HfC-Si coating, and relates to a preparation method of a SiC nanowire toughened chemical vapor co-deposition HfC-SiC multiphase coating. Background technique [0002] C / C composite materials are one of the most potential materials for thermal structural parts in the aerospace field. They have a series of advantages such as low density, high thermal conductivity, friction resistance, thermal shock resistance and low thermal expansion coefficient. In addition, C / C composites are also lightweight materials that can still maintain excellent mechanical properties at 2200 °C. However, C / C composites are prone to oxidation under aerobic environment, which severely limits their application and development. Especially in the aerospace field, the key thermal structural parts have to withstand the harsher airflow erosion and ablation environment. In order to solve this problem, anti-abla...

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Problems solved by technology

However, most of the thermal structural parts in practical applications are shaped

Simply relying on the mosaic method to improve the interface bonding strength can no longer fully meet the requirements of the thermal protection coating on the surface of the heterogeneous component. Li et al prepared SiC / ZrC on the surface of the wedge component by combining the embedding method and plasma spraying -SiC coating, but after the component was ablated, the coating showed obvious peeling failure [B.Li,H.Li,X.Hu,et al.Effect of the curvature radius of sharp leading edgeparts made of a SiC / ZrC-SiC coated C / C composite on their ablation resistance. 40(2020)2768-2780】

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