Core-shell-structure ZrB2-SiC/Si composite powder and preparation method thereof

Abstract

The invention discloses a core-shell-structure ZrB2-SiC / Si composite powder and a preparation method thereof. The composite powder comprises an inner core and an outer shell coated outside the inner core, wherein the inner core is ZrB2 and SiC or the inner core is ZrB2 and Si, and the outer shell is a ZrB2 layer. The invention also discloses a preparation method of the core-shell-structure ZrB2-SiC / Si composite powder, which comprises the following steps: 1) refinement of the particle sizes of original powders; 2) spray drying and aggregation granulation of powder; 3) coating of powder; and 4) high-temperature sintering. The high-melting-point ZrB2 is adopted to protect the inner SiC, thereby effectively preventing the SiC from decomposition and burning loss in the plasma spraying process and implementing consistence of the coating composition and powder composition. The ZrB2 and SiC microzones in the powder are uniformly dispersed, and the coating prepared by plasma spraying can implement multiphase microzone uniform distribution and promote the enhancement of the coating performance.

Description

technical field [0001] The invention relates to the field of ultra-high temperature oxidation resistant materials, in particular to a ZrB with core-shell structure 2 -SiC / Si composite powder and its preparation method. Background technique [0002] When high-temperature structural materials such as refractory metals and alloys, ceramic matrix composites, and fiber-reinforced composites are used in high-temperature oxidizing environments, their surfaces must be protected with an anti-oxidation thermal protective coating. Non-oxides such as borides, silicides, and carbides have the characteristics of high melting point, low density, and good phase stability. They have been widely used in nose cones and wing leading edges of re-entry vehicles, space propulsion system materials, space shuttles, etc. High-temperature heat insulation protection for the hottest parts such as thermal protection systems and space aircraft thermal structural materials. [0003] At present, in the pr...

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Problems solved by technology

[0004] However, in the ZrB prepared by ordinary spray-drying agglomeration granulation technology 2 - SiC group aggregate composite powder, or mechanically mixed powder for plasma spraying ZrB 2 -SiC-based coatings, due to the high-temperature, easy-to-decompose and volatile properties of SiC, will cause a large amount of burning loss, resulting in insufficient SiC components in the coating, the two phases in the coating cannot be uniformly dispersed, and the coating is difficult to meet the high-temperature thermal protection performance requirements And other issues

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