添加剂对HNIW热诱导晶型转变的影响规律及作用机制

Influence and Action Mechanism of Additives on Heat-induced Polymorphic Transformation of HNIW

针对六硝基六氮杂异伍兹烷(HNIW)在复杂环境中容易发生晶型转变形成掺杂晶型,导致炸药结构损伤、性能下降及安全性降低的问题,采用原位X‐射线粉末衍射技术研究了复合炸药中添加剂对ε‐HNIW晶体热诱导晶型转变行为的影响,利用粉末衍射无标样定量相分析方法计算获得了复合炸药中HNIW热晶变率随温度的变化规律,获得了复合炸药中HNIW的热晶变特征参数及热晶变规律,提出了将添加剂分为易晶变体系、中间体系和难晶变体系三类。结果表明,易晶变体系中的添加剂对HNIW有微量溶解作用,在HNIW晶体表面形成界面微溶层,使得热晶变路径从固→固晶变改变为固→液→固晶变,降低了活化能垒,从而明显促进HNIW的ε→γ热晶变。难晶变体系和中间体系的添加剂对HNIW晶体有较强包覆作用,通过改变热量传递模式及表面隔热作用,提高了热晶变起始温度,在一定程度上实现了对HNIW热晶变的抑制作用。

Aiming at the problem of leading to explosive structure damage,performance reduction and safety descending due to the polymorphic transformation of hexanitrohexaazaisowurtzitane（HNIW）was easily occurred in complex environment,the ef‐fects of additives on the heat‐induced polymorphic transformation（PT）behavior of ε‐HNIW in composite explosives were stud‐ied by the in‐situ X‐ray powder diffraction（in‐situ XRD）technology. The change rule of heat‐induced PT rate of HNIW in com‐posite explosives with temperature were calculated and obtained by means of in‐situ XRD non‐standard quantitative phase analy‐sis. The heat‐induced PT characteristic parameters and PT rules of HNIW in composite explosives were analyzed and obtained. It was proposed to divide the additive into three species,including promote PT system,intermediate PT system and suppress PT system. Results show that the additives used in promote PT system have the tittle dissolution on HNIW,the interface micro‐disso‐lution layers were formed on the HNIW crystal surfaces,which makes the heat‐induced PT route change from solid‐solid PT to solid‐solution‐solid PT and reduces the PT activity barrier energy,thus the heat‐induced PT of ε→γ is obviously promoted. The additives used in the suppress and intermediate PT system have strong coating effect on the HNIW crystals. The preliminary heat‐induced PT temperature is improved through altering the thermal transfer mode and surface heat insulation,and the inhibition ef‐fect on the heat‐induced PT of HNIW is realized to a certain extent.