摘要
稀土硅酸盐环境障涂层(EBCs)是应用于新一代高推重比航空发动机热端部件的重要材料。但在服役过程中,硅黏结层的氧化和开裂是导致EBCs失效的重要因素。对硅黏结层进行改性成为延长EBCs服役寿命的重要手段。本研究在硅黏结层中掺杂Yb_(2)O_(3)来缓解高温水氧环境下涂层开裂的问题,并提高其耐高温水氧腐蚀性能。通过真空等离子喷涂技术在SiC基体上制备了五种不同Yb_(2)O_(3)掺杂量(0、5%、10%、15%、20%,体积分数)的EBCs体系(Si-Yb_(2)O_(3))/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5),并研究其在1350℃下的耐水氧腐蚀行为和机理。结果表明,掺杂适量(5%)的Yb_(2)O_(3)能够在高温水氧腐蚀过程中反应并消耗SiO_(2),减少SiO_(2)相变(β→α)带来的应力变化,抑制混合热生长氧化(mTGO)层纵向裂纹的产生,达到提高结构稳定性的效果。另外,反应生成的Yb_(2)Si_(2)O_(7)具有合适的热膨胀系数(CTE)和化学相容性。然而,随着Yb_(2)O_(3)掺杂量提高,过量的Yb_(2)O_(3)会在黏结层内部相互联结并形成“骨架”结构,为氧化性物质提供向涂层内部扩散的直接通道,使黏结层内部发生腐蚀,导致涂层体系耐水氧腐蚀性能下降。
Rare earth silicate environmental barrier coatings(EBCs)are important materials that can be applied to hot sections for the new generation of high thrust-to-weight ratio aero engines.However,oxidation and cracking of the silicon bond layer are significant factors leading to failure during service.Modifying the silicon bond layer has become an important method to extend EBCs’service life.In this work,Yb_(2)O_(3) was doped in the silicon bond layer to mitigate cracking under high-temperature water vapor conditions,as well as to improve its corrosion resistance.Five kinds of EBC systems(Si-Yb_(2)O_(3))/Yb_(2)Si_(2)O_(7)/Yb2SiO5 with different Yb_(2)O_(3) doping(0,5%,10%,15%,20%,in volume)were prepared on SiC substrates using vacuum plasma spraying technology.Their water-oxygen corrosion behavior was studied,and mechanisms at 1350℃beneath their behavior were revealed.The results indicated that doping an appropriate amount(5%)of Yb_(2)O_(3) into silicon effectively facilitates the reaction with SiO_(2) and its subsequent consumption during high-temperature water vapor corrosion.This process reduces the stress variations associated with SiO_(2) phase transition(β→α)and inhibits formation of longitudinal cracks in mixed thermal growth oxide(mTGO)layer,thus enhancing structural stability.Furthermore,the reaction product of Yb_(2)Si_(2)O_(7) exhibits a suitable coefficient of thermal expansion(CTE)and chemical compatibility.Notably,increasing Yb_(2)O_(3) content results in formation of interconnected"skeleton"structure within the bond layer,which may provide a direct pathway for oxidizing substances to permeate into the interior of coating,thereby facilitating corrosion process within the bond layer,and ultimately diminishing the water vapor corrosion resistance of EBC systems.
作者
梁锐辉
钟鑫
洪督
黄利平
牛亚然
郑学斌
LIANG Ruihui;ZHONG Xin;HONG Du;HUANG Liping;NIU Yaran;ZHENG Xuebin(Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China)
出处
《无机材料学报》
北大核心
2025年第4期425-432,共8页
Journal of Inorganic Materials
基金
国家自然科学基金(52202075)。
关键词
环境障涂层
水氧腐蚀
黏结层改性
真空等离子喷涂
environmental barrier coating
water vapor corrosion
modified bond layer
vacuum plasma spray
