高熵稀土铪酸盐热障/环境障涂层材料的制备与性能研究

Synthesis and Property of High-Entropy Rare Earth Hafnate as Thermal/Environmental Barrier Coating Material

综合性能优异的热障/环境障涂层是先进航空发动机涡轮叶片等高温部件的关键热防护材料。本研究通过两步烧结法制备了高熵稀土铪酸盐(La_(0.2)Gd_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12)和(Yb_(0.2)Lu_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12),系统研究了两种材料的力学、热学性能和CMAS腐蚀性能。多主元高熵材料具有较低的热膨胀系数和热导率,其中(Yb_(0.2)Lu_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12)表现出比(La_(0.2)Gd_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12)更高的硬度和断裂韧性。1300℃下CMAS腐蚀结果表明,(La_(0.2)Gd_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12)与CMAS的反应速率快,更容易析出磷灰石,对阻止CMAS迅速渗透是有益的。高熵稀土铪酸盐材料具有优异的综合性能,在热障/环境障涂层领域具有良好的应用前景。

Thermal/environmental barrier coating with optimized performance is critical for the application in advanced aero-engines.In this work,high-entropy rare-earth hafnates,(La_(0.2)Gd_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12) and(Yb_(0.2)Lu_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))4 Hf3O12,were prepared by a two-step sintering method.Mechanical properties,thermal properties and CMAS corrosion behavior of two materials were systematically investigated.(Yb_(0.2)Lu_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12) exhibits higher hardness and fracture toughness than that of(La_(0.2)Gd_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.2))_(4)Hf_(3)O_(12).High-entropy hafnates demonstrate reduced coefficient of thermal expansion and thermal conductivity.When corroded at 1300℃,the reaction of(La_(0.2)Gd_(0.2)Ho_(0.2)Er_(0.2)Tm_(0.3))_(4)Hf_(3)O_(12) with molten CMAS is more severe and triggers the precipitation of apatite,which mitigates the infiltration of molten CMAS into thermal/environmental barrier coatings.The rare earth hafnate has been regarded as a promising thermal barrier coating material.