采用共沉淀-煅烧法制备了热障涂层用Dy2Zr2O7陶瓷粉末。通过电感耦合等离子体原子发射光谱(ICP-AES)、X射线衍射,SEM,DSC及霍尔流速计等分析方法,对粉末的化学组成、相组成、微观结构、高温相稳定性和流动性能进行了研究。通过高温膨胀仪、DSC和激光热导仪分别测定其热膨胀系数、比热系数和导热系数。结果表明,所制备粉末的组成与锆酸镝氟石结构的组成相近;高温下Dy2Zr2O7无明显相变;在高于1400℃的温度下煅烧后,Dy2Zr2O7的流动性得到显著改善;Dy2Zr2O7具有比8YSZ更高的热膨胀系数和更低的导热系数。
Abstract
Dy2Zr2O7 composite ceramic powders used for thermal barrier coating were prepared by the coprecipitation-calcination method.The chemical compositions of the powders were analyzed by means of Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES).The microstructure and crystallographic phases of Dy2Zr2O7 were determined by SEM and X-ray diffraction technique.Dfferential Scanning Calorimetry(DSC),TG and XRD were used to analyze the crystallogrphic phase and the phase stability of Dy2Zr2O7.The Hall flowmeter was performed to determine the flowability of Dy2Zr2O7 powder.High-temperature dilatometer,DSC and laser thermal diffusivity methods were used to analyze its thermal expansion coefficient(TEC),specific heat and thermal diffusivity respectively.The results showed that the compositions of the prepared ceramic powders were in the range of the synthesis of Dy2Zr2O7 with fluorite structure,the Dy2Zr2O7 powders kept the fluorite structure and there was no phase transformation for Dy2Zr2O7 at high temperatures(~1350℃).The flowability of Dy2Zr2O7 powder calcined at 1400℃ was greatly improved.The TEC of the ceramic was slightly higher than that of conventional Y2O3-8wt.%ZrO2(8YSZ) and the thermal conductivity of the ceramic was much lower than that of 8YSZ,which indicated that Dy2Zr2O7 might be a excellent material for thermal barrier coatings.This study can provide science information for this material used as thermal barrier ceramic materials.
关键词
Dy2Zr2O7 /
热障涂层 /
热物理性能 /
共沉淀-煅烧法
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Key words
Dy2Zr2O7 /
thermal barrier coat /
thermophysical prope /
coprecipitation-calc
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基金
中南大学博士后基金(76132017)
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