【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。更多还原

【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.更多还原