硅低温热解活化包覆超细金刚石及其抗氧化和分散稳定性  

Low Temperature Pyrolysis Activation of Complex Ultra-Fine Diamond and ItsOxidation Resistance and Dispersion Preperities

作　　者：李文生 黄晓龙[2] 成波[2] 李建军[2] 宋强[1] 赛纽特·乌拉吉米尔[3] LI Wensheng;HUANG Xiaolong;CHENG Bo;LI Jianjun;SONG Qiang;Uladzimir Seniuts(School of Materials Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,Shandong,China;State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metal,Lanzhou University of Technology,Lanzhou 730050,China;The Joint Institute of Mechanical Engineering,National Academy of Sciences of Belarus,Minsk 220072,Belarus)

机构地区：[1]山东科技大学,材料科学与工程学院,山东青岛266590 [2]兰州理工大学,有色金属先进加工与再利用国家重点实验室,兰州730050 [3]白俄罗斯国家科学院,机械联合研究所,明斯克220072

出　　处：《材料导报》2023年第11期73-78,共6页Materials Reports

基　　金：国家重点研发计划(2022YFE010462);国家自然科学基金(51901093,52075234,51674130);甘肃省高等学校产业支撑计划项目(2020C-11);兰州理工大学红柳优秀青年人才支持计划,甘肃省科技重大专项(21ZD4WA017);丝绸之路经济带金属表面工程技术国际科技合作基地(2017D01003)。

摘　　要：超细金刚石(UFD)粉体高温易氧化、分散稳定性差使其在高温、溶液等环境中的应用受到极大限制。采用硅低温热解-活化-包覆复合工艺实现了超细金刚石表面包覆改性,成功制备了具有纳米尺度核-壳结构的UFD/Si复合粉体。用拉曼和透谢电镜分别表征了包覆粉末石墨化程度,探究包覆前后粉体的相成分,复合粉体形貌及包覆层厚度;用热重分析仪和傅里叶红外光谱结合粉体在10%硫酸悬浮液中的稳定静置时间分别测定UFD包覆前后的抗氧化性和分散稳定性。结果表明,850℃时的原位热解反应使Si活化量充足,无定型硅层均匀包裹着金刚石颗粒呈椭球形,包覆层厚度为10~30 nm,物相主要为金刚石和无定型硅。核-壳结构的UFD/Si复合粉体具有抗高温氧化性,硅层阻隔了金刚石与氧气直接接触,其初始氧化温度较纯UFD从500℃提高到780℃,945℃时才被彻底氧化。包覆减少了金刚石表面的官能团,减弱了颗粒之间的吸附,包覆Si后的UFD粉体在10%稀硫酸悬浮液中的沉降时间较纯UFD提升了12 h以上。The poor solution dispersion stability and high temperature oxidation resistance limits the usage performance of ultra-fine diamond(UFD).Hereby,a combined process of silicon in-situ pyrolysis,activation,and coating was designed to achieve the surface-coating modification of UFDs,and as a result,UFD/Si composite-powders materials with a core-shell structure with nanometer Si coatings are developed.The morphology,phase,composition,graphitization and the coating thickness of the coated UFD/Si powder was characterized by TEM,XRD and Raman respectively,and the high temperature oxidation resistance and the dispersion stability in the 10%dilute sulfuric acid of UFDs and UFD/Si composite-powders were investigated by thermogravimetric analysis and Fourier transform infrared spectroscopy.The results showed that the reaction of the combined process of silicon in-situ pyrolysis,activation,and coating was sufficiently active at 850℃,and the original UFDs were evenly coated by the amorphous silicon layer with a thickness about 10-30 nm in an ellipsoidal shape The core-shell structure coated UFD/Si presented a higher oxidation resistant temperature of 780℃than that(500℃)of the original UFDs,and its settling time in 10%dilute sulfuric acid was also 12h longer than that of the original UFDs,because the coated amorphous silicon layer prevented the contact between UFDs and the environment oxygen,and reduced the functional groups on the UFDs surface and the adsorption adhesion strength between UFDs.

关 键 词：Si低温热解 核-壳结构 超细金刚石 抗高温 分散稳定性 

分 类 号：TB32[一般工业技术—材料科学与工程]