纳米复相陶瓷SiC/(Hf_(x)Ta_(1-x))C/C的制备、微结构演变及力学性能  

Preparation,Microstructure Evolution and Mechanical Properties of SiC/(Hf_(x)Ta_(1-x))C/C Nanocomposites

作　　者：汪震越 卢丽 文青波 余兆菊 WANG Zhenyue;LU Li;WEN Qingbo;YU Zhaoju(Key Laboratory of High Performance Ceramic Fibers,Xiamen University,Xiamen 361005,Fujian,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;Key Laboratory of Electronic Ceramic Materials and Devices,Xiamen University,Xiamen 361005,Fujian,China)

机构地区：[1]厦门大学材料学院,高性能陶瓷纤维教育部重点实验室,福建厦门361005 [2]中南大学,粉末冶金国家重点实验室,长沙410083 [3]厦门大学材料学院,厦门市电子陶瓷材料与元器件重点实验室,福建厦门361005

出　　处：《硅酸盐学报》2024年第9期2757-2766,共10页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(51872246,52061135102)。

摘　　要：采用聚合物先驱体转化法结合放电等离子烧结技术,制备出近致密的SiC/(Hf_(x)Ta_(1-x))C/C纳米复相材料。通过X射线衍射仪、透射电子显微镜、扫描电子显微镜,纳米压痕仪对SiC/(Hf_(x)Ta_(1-x))C/C纳米复相陶瓷的微结构演变及其力学性能进行了表征。结果表明,通过对单源聚合物先驱体进行分子设计,改变SSP中的Hf/Ta比例,可以控制最终固溶(Hf_(x)Ta_(1-x))C的组成。最终块体SiC/(Hf_(0.2)Ta_(0.8))C/C纳米复相陶瓷的开孔率为4.87%,其纳米压痕硬度为(7.72±1.36)GPa,弹性模量为(76.71±7.89)GPa,展现出良好的力学性能。Introduction HfC and TaC are typical ultra-high temperature ceramics(UHTCs),which are important candidate materials for thermal protection components in high-speed aircraft.However,their oxidation resistance at medium and low temperatures is relatively poor.Due to the similar crystal structures of HfC and TaC,and the close atomic radii of Hf and Ta(rHf=1.585Å,rTa=1.457Å,Δr<0.15),theoretically,they can form an infinitely miscible substitutional solid solution(Hf_(x)Ta_(1-x))C(0<x<1).Among them,Hf_(0.2)Ta_(0.8)C has a melting point as high as 4300 K,which is recognized as the highest melting point carbide.Compared with single-component HfC and TaC,(Hf_(x)Ta_(1-x))C exhibits higher initial oxidation temperature and lower oxidation rate,indicating significantly improved oxidation resistance.In this work,a series of processable liquid single-source precursors(SSPs)were successfully prepared by introducing HfCl4 and TaCl5 into allylhydridopolycarbosilane(AHPCS).Through the polymer-derived ceramic(PDC)method,SiC/(Hf_(x)Ta_(1-x))C/C nanocomposites with core-shell structured SiC@C and(Hf_(x)Ta_(1-x))C@C nanoparticles were obtained,and the evolution of phase composition and microstructure during the ceramic transformation process was investigated.Combining PDC and spark plasma sintering(SPS)technology,nearly dense SiC/(Hf_(x)Ta_(1-x))C/C bulk materials were prepared,and the mechanical properties of the resulting bulk ceramic were investigated.Methods Chemically stoichiometric amounts of HfCl4 and TaCl5 were weighed and reacted with AHPCS in CHCl3 solvent at 60℃to prepare a series of SSPs.The molecular structure of the synthesized SSPs was characterized using Fourier-transform infrared spectroscopy(FT-IR,Nicolet iS10,Thermo Fisher Scientific).Thermal behavior analysis of the SSPs was conducted using a thermogravimetric analyzer(TGA,STA 449 F5 Jupiter,NETZSCH).The SSPs were heat-treated at temperatures ranging from 900℃to 1600℃to obtain SiC/(Hf_(x)Ta_(1-x))C/C nanocomposite powders.The phase composition of the ceram

关 键 词：单源先驱体 聚合物先驱体转化法 放电等离子烧结 碳化硅基复相陶瓷 

分 类 号：TB321[一般工业技术—材料科学与工程]