摘要
用ＴＮＴ／ＲＤＸ炸药爆炸所产生的瞬间高温高压制备了纳米金刚石粉体．用Ｘ射线衍射和透射电子显微镜测定金刚石微晶的尺寸约５～１０ｎｍ．晶胞常数比常规大块金刚石有所增大．化学活性增高．红外吸收光谱表明其含有－ＣＯＯＨ，＞Ｃ＝０，－ＯＨ等基团．它们来自纳米金刚石表面的大量悬键吸附和晶粒中大量缺陷．用差热分析和热失重分析研究了它在空气和氮气氛中的热稳定性．结果表明其表面吸附的水、氧、氮和某些有机物，在高于１００℃的热处理中可以脱去．在低于４００℃时，纳米金刚石受热会缓慢氧化．高于４００℃时，氧化速率大大增加．在工业纯氮气氛保护下，它仍可迅速氧化．这是气氛中含有少量氧造成的．在氢气氛中纳米金刚石可以在８００℃高温下热处理数小时不发生氧化，晶粒也不长大．常温下的化学活性和还原气氛中的热稳定性使得我们可以用化学改性和热处理有效地改变纳米金刚石的化学和物理性质．
Pure nanocrystalline diamond was prepared by detonation of TNT/RDX. The sizes of grains were about 5～10nm measured by XRD and TEM. The parameter of cell was larger than that of normal diamond.Its reactivity was higher than normal. IR spectra indicate the existence of -COOH, >C=O, -OH. They are due to the adsorption of surface and great number of defects. The thermal stability was stadied by DTA and TW in air and N2. The results indicate the surface water, O2, N2 and other organic groups can be removed at higher temperature than 100℃. The nanocrystalline diamond can be oxidated slowly at lower temperature than 400℃. When the temperature is higher than 400℃, the velocity of oxidation is very fast. It still be oxidated although in the industrail pure N2 for the small amount of O2. In the H2 gas nanocrystalline diamond can be thermal treated at 800℃, and no oxidation or grain growth happened.Its chemical reactivity at room temperature and thermal stability in reducing atmosphere makes possible chemical modification and thermal treatment to change its physical or chemical properties.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第3期281-287,共7页
Journal of Inorganic Materials
基金
国家基金
冲击波物理
爆炸物理实验室的资助
关键词
金刚石
纳米粉体
爆炸法
微结构
稳定性
diamond
nanocrystalline materials
detonation
microstructure
