Preparation and Characterization of Core-Shell MoSi_(2)@Nb Materials Sintered by SPS  

SPS烧结制备MoSi_(2)@Nb核壳结构材料及其表征

作　　者：Luo Jiajun Quan Ciwang Zhang Jianjun Chen Shuixiang Zhang Xitong Han Mengyao Liang Bingliang Chen Weihua 罗佳军;全慈旺;张建军;陈水香;张茜彤;韩孟瑶;梁炳亮;陈卫华(南昌航空大学材料科学与工程学院,江西南昌330063;南昌航空大学江西省航空材料表面技术工程研究中心,江西南昌330063)

机构地区：[1]School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China [2]Jiangxi Provincial Engineering Research Center for Surface Technology of Aeronautical Materials,Nanchang Hangkong University,Nanchang 330063,China

出　　处：《稀有金属材料与工程》2024年第11期3053-3063,共11页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51861026);The Graduate Innovation Special Fund of Nanchang Hangkong University(YC2022-011)。

摘　　要：Core-shell MoSi_(2)@Nb powder was prepared by electrostatic layer self-assembly method.The surfactants SDS(CHSO_(4)Na)and CTAB(C_(19)H_(42)BrN)were used to modify the surface of the two particles to make them charged,and the Zeta potential of the suspension was tested by the Zeta potentiometer.Scanning electron microscope,transmission electron microscope and energy dispersive spectrometer were used to characterize the phase,morphology,microstructure and element distribution of synthetic materials.The results show that when the SDS concentration is 2 mmol/L,the CTAB concentration is 3mmol/L and the pH value of Nb suspension is 5,the coating effect is better after secondary cladding.NbSi_(2)phase is found at the interface between Nb and MoSi_(2)after calcination at 200℃ for 2 h in Ar atmosphere,indicating that Nb is highly active and reacts with Si.Core-shell structure is still retained in MoSi_(2)@Nb material after spark plasma sintering at 1450℃ for 2 h under uniaxial pressure of 40 MPa.However,it is found that Nb reacts strongly with MoSi_(2),and most of the Nb phase is reacted.This issue needs to be addressed in subsequent studies.The fracture toughness(K_(IC))of MoSi_(2)@Nb material is significantly improved to 5.75 MPa·m^(0.5)compared with that of MoSi_(2)material(3.32 MPa·m^(0.5)).采用静电层自组装法制备了核壳MoSi_(2)@Nb粉体。采用表面活性剂SDS(CHSO_(4)Na)和CTAB(C_(19)H_(42)BrN)对2种颗粒表面进行改性,使其带电,并用Zeta电位计测试悬浮液的Zeta电位。采用扫描电镜、透射电镜和能谱仪对合成材料的物相、形貌、结构和元素分布进行了表征。结果表明:当SDS浓度为2 mmol/L,CTAB浓度为3 mmol/L,Nb悬浮液pH值为5时,二次包覆后涂层效果较好。在200℃氩气中煅烧2 h后,Nb与MoSi_(2)的界面处发现了NbSi_(2)相,表明Nb具有高活性并与Si反应。在1450℃单轴压力40 MPa下放电等离子烧结2 h后,MoSi_(2)@Nb材料中仍保留了核壳结构。然而,Nb与MoSi_(2)反应强烈,大部分Nb相发生反应,这个问题在后续研究中亟待解决。与MoSi_(2)材料的断裂韧性(K_(IC)=3.32 MPa·m^(0.5))相比,MoSi_(2)@Nb材料的K_(IC)显著提高至5.75 MPa·m^(0.5)。

关 键 词：core-shell structure electrostatic layer self-assembly spark plasma sintering fracture toughness 

分 类 号：TQ174.758.22[化学工程—陶瓷工业]