高熵硼化物含量对Si_(3)N_(4)陶瓷显微结构与性能的影响  

Effect of High-Entropy Boride Content on Microstructure and Mechanical Properties of Silicon Nitride Ceramics

作　　者：林锐霖 顾乾坤 罗嗣春 张岩 郭伟明[1] 林华泰 LIN Ruilin;GU Qiankun;LUO Sichun;ZHANG Yan;GUO Weiming;LIN Huatai(School of Electromechanical Engineering,Guangdong University of Technology,Guangzhou 510006,China)

机构地区：[1]广东工业大学机电工程学院,广州510006

出　　处：《硅酸盐学报》2022年第6期1499-1503,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金面上项目(5217020162)。

摘　　要：氮化硅(Si_(3)N_(4))陶瓷具有广泛的工业应用潜力,但其硬度和断裂韧性往往难以兼顾,这会限制到Si_(3)N_(4)陶瓷的应用。为了获得兼具高硬度和高韧性的Si_(3)N_(4)陶瓷,以高熵硼化物(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2)为添加剂,使用放电等离子烧结法在1600℃制备了Si_(3)N_(4)陶瓷材料。研究了(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2)对Si_(3)N_(4)陶瓷的相组合、致密度、显微组织和力学性能的影响。结果表明:与未添加(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2)的Si_(3)N_(4)陶瓷相比,在较低的烧结温度下(1600℃),仅添加1.0%(体积分数)的(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2)就能将β-Si_(3)N_(4)的质量分数从38%提高到53%,获得双峰显微结构。因而,Si_(3)N_(4)基陶瓷的断裂韧性从(5.4±0.3)MPa·m^(1/2)提升到(6.9±0.2)MPa·m^(1/2),而硬度维持在(20.2±0.2)GPa。随着高熵硼化物的含量增加到2.5%和5.0%,Si_(3)N_(4)基陶瓷致密度降低且相变进一步增加,导致硬度降低。Silicon nitride(Si_(3)N_(4))ceramics have a wide potential application in industrial processes,but high fracture toughness and hardness are always difficult to be handled,thus affecting the application of Si_(3)N_(4) ceramics.In this paper,silicon nitride ceramics were fabricated via spark plasma sintering at 1600℃with high-entropy boride phase(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2) as sintering aids.The effect of(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2) on the phase assemblage,densification,microstructure and mechanical properties was investigated.Compared with(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2)-free Si_(3)N_(4) ceramic,the addition of only 1.0%(in volume fraction)(Hf_(0.2)Zr_(0.2)Ta_(0.2)Cr_(0.2)Ti_(0.2))B_(2) in the ceramic can increase the mass fraction of β-Si_(3)N_(4) from 38% to 53%at 1600℃,showing a bimodal microstructure.As a consequence,the fracture toughness of Si_(3)N_(4)-based ceramic increases from(5.4±0.3)MPa·m^(1/2) to(6.9±0.2)MPa·m^(1/2),and the hardness maintains(20.2±0.2)GPa.The relative density of Si_(3)N_(4)-based ceramics decreases and the phase transformation enhances with increasing the high-entropy boride fraction to 2.5%and 5.0%,thus leading to a decrease in the hardness.

关 键 词：氮化硅陶瓷 高熵硼化物 相组成 显微结构 力学性能 

分 类 号：TB321[一般工业技术—材料科学与工程]