超细Zr@NC的微尺度连续流动制备与性能表征

Microscale Continuous Flow Preparation and Characterization of Ultrafine Zr@NC

为了实现超细锆(Zr)粉表面包覆改性的制备过程安全,研究了一种在微尺度下连续流动制备核壳结构Zr粉的方法,并构建了一个由微流控单元和喷雾干燥单元组成的连续化微流控系统以验证其可行性。该系统可连续化实现组分的微尺度混合、核壳结构的形成以及样品的后处理。以Zr粉和硝化纤维素(NC)为组分,通过控制NC含量并在微尺度上调节干燥气体压力,对Zr@NC的结构调控进行了研究。采用热分析法与静电火花感度测试对Zr@NC的活性与安全性进行了分析。结果表明,连续化微流控系统可以成功制备出形貌良好、具有核壳结构的Zr粉;热分析结果表明,Zr@NC相比未包覆时的氧化增重仅降低1.04%,能量释放更为迅速;静电火花感度测试结果表明,Zr@NC的50%发火能量相比原料Zr粉从1.42 mJ提升至197.82 mJ,静电火花感度大幅降低。

In order to achieve the safety of the preparation process of ultrafine zirconium(Zr)powder,a method for preparing core-shell Zr powder by continuous flow at microscale was studied.A continuous microfluidic system consisting of microfluidic unit and spray-drying unit was established to verify the feasibility.The system can realize the microscale mixing of components,the formation of core-shell structure and the post-processing of samples continuously.Using Zr powder and nitrocellulose(NC)as composite components,the structure regulation of Zr@NC was studied by controlling content of NC and adjusting dry gas pressure at the microscale.In addition,the activity and safety of Zr@NC were analyzed by thermal analysis and electrostatic spark sensitivity test.The results show that the Zr powder with uniform morphology and core-shell structure can be prepared by the continuous microfluidic system.Thermal analysis results show that the oxidation weight gain of Zr@NC is only 1.04%lower than that of the raw Zr,and the energy release is faster.According to the electrostatic spark sensitivity test,it was found that the50%ignition energy of Zr@NC is increased from 1.42 mJ to 197.82 mJ compared with the raw Zr,which means the electrostatic spark sensitivity is greatly reduced.