含AgI焰剂成冰性能与物化特征的实验研究

Laboratory Study on Nucleating Properties and Microstructure of AgI Pyrotechnics

利用CAMS的1 m^3等温云室系统筛选出新型高效AgI焰剂WMC-IN-001和WMG-IN-002。检测结果表明,它们具有较高的成核率,在-15℃时达到10^(15)g^(-1)AgI量级,尤其在-7℃时WMC-IN-001的成核率仍可达到10^(14)g^(-1)AgI量级。同时给出对节银剂配方和2011年市场上主要的几种催化剂的检测结果进行对比。WMC-IN-001和WMC-IN-002的成冰速率较慢,在各检测温度的成冰速率差异较小,均在40~55 min。利用冷场发射扫描电镜和能谱仪对WMC-IN-001燃烧产生的气溶胶粒子作了物化特征分析,粒子分布在0.02~0.60μm,具有两个典型的模态:0.02~0.10μm的较小的粒子和0.20~0.55μm的较大的粒子,均立方直径为0.2472μm。WMC-IN-001气溶胶粒子明显偏大,小粒子相对较少,这可能是其成冰速率偏慢的原因之一。

Two formulations （WMC-IN-001 and WMC-IN-002） of high efficient AgI pyrotechnics used in weather modification have been obtained after a number of screen tests were carried out in CAMS 1 m^3 isothermal cloud chamber. The effectiveness can reach to 10^14 g ^-1 AgI at temperatures of -7℃ and colder for WMC-IN-001, and it can reach up to 1015 g^-1 AgI at -15℃. The foreign pyrotechnic was made according to the formulation of silver-spare （USSR）. The ice nucleating properties of silver-spare and other five formulations of AgI pyrotechnics in the marketplace in 2011 was tested in the same chamber for comparison with the new pyrotechnics. The results show that the nucleating rates are very low for WMC-IN-001 and WMC-IN-002, and change less （in 40-55 min） in the temperature range between -7 and -20℃. The aerosol particles produced by WMC-IN-001 are identified by environmental scanning electron microscope （ESEM） and energy disperse spectroscopy （EDS）. The particle sizes are within 0.02-0.60 μm in diameter, and the mean cube-root diameter is 0. 2472 μm. WMC-IN-001 aerosol has a pronounced bimodal size distribution with particles in the small diameter mode between 0.02-0.10 μm and particles constituting the mode between 0.20-0.55 μm. The relatively large particle size may be one cause for the low nucleating rates.