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利用石墨层间化合物合成含硼金刚石
Synthesize B-Doped Diamond Using Graphite Intercalation Compounds
【作者】 黄浩;
【导师】 臧建兵;
【作者基本信息】 燕山大学 , 材料学, 2004, 硕士
【摘要】 通过掺杂硼,可以提高金刚石的导电性和热稳定性。本论文提出了利用含硼石墨层间化合物(GICs)高温高压(HTHP)合成含硼金刚石的新工艺。 本文以H3BO3,NH4BF4和KBH4作为插层剂,采用真空熔盐、真空渗析熔盐、加压熔盐以及电解法制备含硼的GICs。利用XRD分析GICs的阶结构,并研究了GICs的稳定性。以含硼GICs作为碳源,在高温高压下合成金刚石。对含硼金刚石在SEM下进行形貌观察,通过红外拉曼光谱、X射线荧光(XRF)分析硼掺杂的存在状态和含量。分析了含硼金刚石的差热曲线,并测量了其电阻值。 实验结果表明,真空熔盐、真空渗析熔盐、加压熔盐以及电解法可以制备H3BO3-GICs,KBH4-GICs和NH4BF4-GICs。获得的GICs是混合阶产物。GICs的阶数随着时间延长而降低。H3NO3-GICs水洗后不稳定,发生了水解脱插。利用这些GICs,在1250~1350℃、5~6GPa下合成了含硼金刚石,金刚石颜色随着硼含量增加而加深直至黑色,含硼金刚石生长成多晶颗粒,晶面发育不完整。通过红外吸收光谱分析,发现硼以取代原子或间隙硼的形式存在于金刚石中,并通过对红外光谱吸收率计算和XRF分析检测到硼含量在5ppm到2158ppm之间。含硼金刚石热稳定性和导电性随着硼含量增加而提高。含硼500ppm的金刚石抗氧化温度提高到1070℃。当含硼量为2158ppm时金刚石的电阻率为1.93Ω·cm。
【Abstract】 The conductivity and thermo-stability of diamond with boron doping could be improved. In this paper, a new method was presented that B-doped diamond was synthesized at high pressure and high temperature (HTHP) using B-doped graphite intercalation compounds (GICs).Using H3BO3, NH4BF4 and KBH4 as intercalant, GICs had been prepared by melt-salt in vacuum, melt-salt in vacuum infiltration, enhancing pressure melt-salt, and electrolyte intercalation. Structure of GICs had been analyzed by XRD, and stability of GICs had been studied. Diamond was synthesized using B-doped GICs as carbon sources by HTHP method. Morphology of B-doped diamond had been observed by SEM. Boron contents and impurity situation of B-doped diamond had been analyzed by FTIR/Raman and XRF. DTA curves of B-doped diamond had been studied, and the resistances had been measured.The experimental results showed that H3BO3-GICs, NH4BF4-GICs and KBH4-GICs had been prepared successfully by melt-salt in vacuum, melt-salt in vacuum infiltration, enhancing pressure melt-salt, and electrolyte intercalation. GICs had mixed stage. Stage number of GICs decreased with intercalation duration prolonging. It is unstable when GICs was washed, and H3BO3-GICs was hydrolyzed. B-doped diamonds were obtained under the condition of 1250℃~1350℃ and 5GPa~6GPa. Color of diamond became deep with boron contents increasing, till becoming black. B-doped diamond was polycrystalline, and crystal surface was developed incompletely. It was found by FTIR that boron existed as substitute atom or interstitial atom. Boron contents of diamond changed from 5 ppm to 2158 ppm. Conductivity and thermo-stability of B-doped diamond increased with boron contents increasing. Anti-oxidation temperature of diamond with 500 ppm boron reached 1070 ℃ Specific resistance of diamond with 2158 ppm boron was 1.93 Ω cm.
【Key words】 graphite intercalation compounds; intercalate; stage; diamond; B doping; high pressure and high temperature;
- 【网络出版投稿人】 燕山大学 【网络出版年期】2004年 03期
- 【分类号】TB321
- 【被引频次】5
- 【下载频次】237