High-temperature phase-stable multi-component rare earth silicate solid solution ceramic and preparation method thereof

Abstract

The invention relates to the field of ceramic materials for extreme environments, and in particular, relates to a multi-component rare earth silicate solid solution ceramic material with excellent high-temperature phase stability and a preparation method thereof. The chemical formula of the multi-component rare earth silicate solid solution ceramic material is (REI0.25REII0.25REIII0.25REIV0.25)2Si2O7, wherein the REI, the REII, the REIII and the REIV are respectively one of rare earth elements Y, Sc, Ho, Er, Tm, Yb and Lu. The preparation method specifically comprises the preparation processes: taking corresponding rare earth oxide powder and silicon oxide powder as raw materials, performing wet mixing, and performing pressureless sintering in an air atmosphere to obtain the multi-component rare earth silicate solid solution ceramic material; and performing hot-pressing sintering in a hot-pressing furnace filled with a protective atmosphere to obtain the multi-component rare earth silicate solid solution ceramic block material with excellent high-temperature phase stability. According to the preparation method disclosed by the invention, the (REI0.25REII0.25REIII0.25REIV0.25)2Si2O7ceramic material with high purity, high density and excellent high-temperature phase stability is prepared.

Description

technical field [0001] The invention relates to the field of high-temperature structural ceramics for thermal barrier / environmental barrier coatings for extreme environments, specifically a multi-element rare earth silicate solid solution ceramic material (RE) with excellent high-temperature phase stability. I 0.25 RE II 0.25 RE III 0.25 RE IV 0.25 ) 2 Si 2 o 7 and its preparation method. Background technique [0002] With the pursuit of higher thrust-to-weight ratio of aero-engines, the environment of engine hot-end components is becoming more and more harsh. Silicon carbide fiber reinforced silicon carbide ceramic matrix composites (SiC f / SiC m ) has the characteristics of low density, high strength, excellent temperature resistance and oxidation resistance, and has broad application prospects in engine thermal structural components. SiC f / SiC m When ceramic matrix composites are used in extreme gas environments, they need to be coated with an environmenta...

AI Technical Summary

Problems solved by technology

However, the two rare earth elements Yb and Lu are the densest known rare earth elements, which conflicts with the weight reduction design requirements of new engines in the future; and the reserves and prices of these two elements (especially Lu elements) limit the Its large-scale application

[0004] Existing studies have found that: by rationally selecting and designing the type and solid solution amount of rare earth elements in rare earth silicates, the performance can be improved in rare earth-containing solid solution materials (A.J.Fernandez-Carrion, et at, Solidsolubility of Yb 2 Si 2 o 7 inβ-,γ-andδ-Y 2 Si 2 o 7 , J.Solid State Chem.184(2011)1882.), but this binary solid solution method, the proportion of other elements that can be dissolved in solid solution is limited, breaking through the "upper limit" will cause the material to change from β-type to γ-type or the transformation of the δ-type crystal form

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