炸药爆炸冲击波合成纤锌矿型氮化硼

EXPLOSIVE SHOCK SYNTHESIS OF WURTZITE TYPE BORON NITRIDE

本文报道了用国产石墨型氮化硼(gBN)为原料在炸药爆炸产生的冲击波作用下合成纤锌矿型氮化硼(wBN)的技术。对冲击波作用后的回收产物进行化学分离,得到杂质含量低于0.5％的wBN产品;回收产物的wBN的转化率高于50％;单发试验产量达11—12g。目前已经利用这一技术生产出少量wBN产品。 在相同的冲击波条件下,对四种不同来源的gBN进行了合成试验。发现wBN的转化率强烈地依赖于原始gBN的结晶特性。比表面积测量及X射线衍射观察表明,冲击波合成的wBN是一种多晶微粉,平均颗粒度约0.1μm,平均晶粒度约17.5nm。差热分析显示放热反应起始温度为1055K,峰顶温度1238K。

Reported in the paper are techniques of wurtzite type boron nitride(wBN) synthesis from graphite type BN(gBN) by means of shock compressions created via explosive detonation. Recovered samples after shock processing are treated with molten alkalis and hydrochloric acid. Inspite that the domestic gBN materials we used are far inferior, both in the crystallinities and particle sizes, to those used in foreign countries for the purpose of shock synthesis of wBN, the yield of our wBN reaches 11 to 12 g per shot, with a convertion tatio over 50%; X-ray diffraction and X-ray fluorescence spectrometry analyses reveal that the total impurity content of this chemically extracted wurtzite type boron nitride product is less than 0. 5%.Four different starting gBN from different manufacturers were used in the experiments to synthesis wBN under the same conditions of shock compressions. It is found that the yield of wBN is closely related to the crystallinity of the starting gBN materials. Specific area measurements and XRD analysis indicate that our wBN is a polycrystal surper-fine powder material with average particle size of 0. 1 μm, which consists of many primary crystallites of 17. 5nm in dimension. Thermal stability of our wBN powder is characterized by the emergence of an exothermic peak in the atmospheric gas condition from DTA analysis. Initial temperature of this exothermic reaction is about 1 055K and peak temperature 1238K.