晶种法合成硼化铪粉体及其生长机理研究  

Synthesis and Growth Mechanism Research of HfB_(2)Powders Prepared by Crystal Seed-Mediated Method

作　　者：王振 胡晨光 李可为 胡梦恩 张瀚文 黄竹林 胡小晔 WANG Zhen;HU Chenguang;LI Kewei;HU Mengen;ZHANG Hanwen;HUANG Zhulin;HU Xiaoye(Institute of Solid State Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China)

机构地区：[1]中国科学院合肥物质科学研究院固体物理研究所,合肥230031

出　　处：《航空制造技术》2025年第3期84-91,共8页Aeronautical Manufacturing Technology

基　　金：国家自然科学基金(52222208,52072373);中国科学院合肥物质科学研究院院长基金(BJPY2021B04,YZJJ202202-CX)。

摘　　要：硼化铪(HfB_(2))超高温陶瓷因其高熔点、高抗氧化性和优异的耐腐蚀性成为热防护领域的最佳候选材料之一,而研制粒径可控的陶瓷粉体对其应用至关重要。以氧化铪(HfO_(2))、氧化硼(B_(2)O_(3))和活性碳(C)为原料,通过晶种辅助的硼/碳热还原法合成了高纯HfB_(2)陶瓷粉体,研究了晶种粒径对陶瓷粉体粒径的影响规律,探究了晶种法合成HfB_(2)粉体的生长机制。通过X射线衍射分析粉体物相、扫描电子显微镜观察粉体形貌,并测定粉体中C、O杂质的含量。结果表明,晶种辅助的硼/碳热还原反应合成HfB_(2)粉体的最佳反应温度约为1500℃,保温1 h即可获得纯相HfB_(2)。通过调控初始晶种粒径,制备的HfB_(2)陶瓷粉体平均粒径在1.08~2.33μm之间,且粉体粒径随晶种粒径的增大而增大。激光粒度分析表明,添加晶种大幅提高了陶瓷粉体的分散性且促进了粒径的窄分布。此外,试验确定了HfB_(2)陶瓷粉体的生长过程分为两个阶段:首先晶种HfB_(2)表面被HfO_(2)晶粒包覆,HfO_(2)晶粒表层形成较小的HfB_(2)晶粒;再通过碳和硼的传质由外到内实现HfO_(2)到HfB_(2)的转化。Hafnium boride(HfB_(2))ultra-high temperature ceramics have become one of the best candidate materials in the field of thermal protection due to their high melting point,high oxidation resistance and excellent corrosion resistance.The fabrication of ceramic powders with precisely controlled particle sizes is paramount for their effective application.Highpurity HfB_(2) ceramic powders were prepared by crystal seed-mediated boro/carbothermal reduction method using hafnium oxide(HfO_(2)),boron trioxide(B_(2)O_(3)),and carbon(C)powders as raw materials.The influence of crystal seed size on the particle size of HfB_(2) powders was studied,and the growth mechanism of HfB_(2) powders synthesized by crystal seed-mediated method was explored.Phase and morphology of the obtained powders were analyzed and observed by X-ray diffraction and scanning electron microscope;the contents of C and O impurities in the powders were measured as well.The results show that the optimal reaction temperature for synthesizing pure HfB_(2) powders by crystal seed-mediated boro/carbothermal reduction is approximately 1500℃(holding for 1 h).HfB,ceramic powders with average particle size of 1.08-2.33μm were obtained by controlling the initial crystal seed size.Generally,the particle size of HfB,increases with the increase of crystal seed size,and laser particle size measurements indicate that the addition of crystal seeds improves the dispersibility and narrows distribution of HfB_(2) particle size.It is confirmed that the growth process of HfB_(2) ceramic powders is divided into two stages:the cladding of HfO_(2) grains on HfB_(2) surface with formation of tiny HfB_(2) grains,and conversion of HfO_(2) to HfB_(2) through mass diffusion of carbon and boron from the outside to the inside of HfO_(2) particles.

关 键 词：硼化铪(HfB_(2)) 晶种 硼/碳热还原 粒径 陶瓷粉体形貌 

分 类 号：V25[一般工业技术—材料科学与工程]