纤锌矿型氮化硼及其应用的研究(Ⅱ)——纤锌矿型氮化硼的等温状态方程

STUDY ON WURTZITE TYPE BORON NITRIDE AND ITS APPLICATIONS (Ⅱ)——ISOTHERMAL EQUATION OF STATE FOR WURTZITE TYPE BORON NITRIDE

使用两种不同的高压在位X光衍射法,研究了用爆炸法合成的纤锌矿型氮化硼(wBN)在室温下的等温状态方程。一种方法是用转靶X光角色散粉末衍射法,研究了它在0～40GPa压力范围内的等温压缩行为。结果表明,wBN在0～40GPa的压力范围内是稳定的,没有发生结构相变。通过p-V数据对Murnaghan方程拟合,得到wBN在p=0时的等温体模量B_0=335±34GPa及其对压力的一阶导数B_0=4.21;另一种是用同步辐射X光能量色散衍射法,研究了它在0～25GPa压力范围内的等温状态方程。实验中,使用了改进的自动加压的DAC高压装置,此装置保证了实验中衍射角θ_0固定不变。将获得的p-V数据仍用Murnaghan方程拟合,得到wBN在p=0时等温体模量B_0=280±56GPa,及其B_0=4.39。

In our experiments, the isothermal equation of state of wBN is studied by two different in situ high pressure X-ray diffraction methods at room temperature. The sample is obtained by shock compression. One of the methods is the rotating anode X-ray angle dispersive powder diffraction by which wBN is studied up to 40GPa. The results indicate that wBN is structurally stable below 400GPa and no phase transition is observed. The Murnaghan isothermal equation of state for the sample is fitted with the bulk modulus at zero pressure, B0 = 335±34GPa, and its pressure deviation B0-4. 21. The other method is the synchrotron radiation X-ray energy dispersive diffraction (EDXD) by which the isothermal equation is studied with improved Mao-Bell type diamond anvil cell up to 25GPa. The loading mechanism of the improved DAC is stepping and automatic, which maintains the fixed scattering angle. The Murnaghan isothermal equation is also fitted with the bulk modulus at zero pressure, B0 = 280±56GPa, and its pressure deviation B0 = 4. 39.