Recension of boron nitride phase diagram based on high-pressure and high-temperature experiments  

作　　者：Ruike Zhang Ruiang Guo Qian Li Shuaiqi Li Haidong Long Duanwei He 张瑞柯;郭睿昂;李倩;李帅琦;龙海东;贺端威(Institute of Atomic and Molecular Physics,Sichuan University,Chengdu 610065,China;College of Physics and Electronic Engineering,Chongqing Normal University,Chongqing 401331,China;Key Laboratory of High Energy Density Physics and Technology of Ministry of Education,Sichuan University,Chengdu 610065,China)

机构地区：[1]Institute of Atomic and Molecular Physics,Sichuan University,Chengdu 610065,China [2]College of Physics and Electronic Engineering,Chongqing Normal University,Chongqing 401331,China [3]Key Laboratory of High Energy Density Physics and Technology of Ministry of Education,Sichuan University,Chengdu 610065,China

出　　处：《Chinese Physics B》2024年第10期450-457,共8页中国物理B（英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2023YFA1406200).

摘　　要：Cubic boron nitride and hexagonal boron nitride are the two predominant crystalline structures of boron nitride.They can interconvert under varying pressure and temperature conditions.However,this transformation requires overcoming significant potential barriers in dynamics,which poses great difficulty in determining the c-BN/h-BN phase boundary.This study used high-pressure in situ differential thermal measurements to ascertain the temperature of h-BN/c-BN conversion within the commonly used pressure range(3-6 GPa)for the industrial synthesis of c-BN to constrain the P-T phase boundary of h-BN/c-BN in the pressure-temperature range as much as possible.Based on the analysis of the experimental data,it is determined that the relationship between pressure and temperature conforms to the following equation:P=a+1/bT.Here,P denotes the pressure(GPa)and T is the temperature(K).The coefficients are a=-3.8±0.8 GPa and b=229.8±17.1 GPa/K.These findings call into question existing high-pressure and high-temperature phase diagrams of boron nitride,which seem to overstate the phase boundary temperature between c-BN and h-BN.The BN phase diagram obtained from this study can provide critical temperature and pressure condition guidance for the industrial synthesis of c-BN,thus optimizing synthesis efficiency and product performance.

关 键 词：hexagonal boron nitride phase diagram high temperature and high pressure cubic boron nitride phase transition differential thermal analysis 

分 类 号：O52[理学—高压高温物理]