A Method to Study Agglomerate Breakup and Bounce During Impaction
A Method to Study Agglomerate Breakup and Bounce During Impaction
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研究撞击过程中团聚物破碎和弹跳的方法
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发表时间：
2012
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通讯作者：
J. Jokiniemi
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作者：
M. Ihalainen;T. Lind;T. Torvela;K. Lehtinen;J. Jokiniemi
团聚体的撞击行为在纳米颗粒技术中占有重要地位。为了能够评价解聚过程，团聚体被冲击到表面，并根据团聚体的破裂来估计作用力。有几项研究使用了这一原理；然而，凝聚体的同时反弹和破裂几乎没有受到关注。在这项研究中，设计了一种方法来研究撞击过程中凝聚体的破碎和反弹。在该方法中，团聚体被冲击到位于单级微孔均匀沉积冲击器中的撞击板上，并将反弹的颗粒收集到专门为此任务设计的取样室中。这样，沉积和反弹的颗粒的性质可以用透射电子显微镜来检查，此外，反弹的颗粒还可以用在线测量仪器进行分析，例如扫描迁移率粒度仪。用二氧化钛和铜粉对该体系进行了测试和验证，并利用二氧化钛团聚体获得了该体系的第一批冲击行为结果。在本研究所用条件下，颗粒在撞击过程中明显解体，颗粒直径从269 nm减小到143 nm。结果发现，有一半的粒子反弹了。被反弹的颗粒的直径和分维与未反弹的颗粒非常相似。版权所有2012美国气溶胶研究协会
The impaction behavior of agglomerates plays a significant role in nanoparticle technology. In order to be able to evaluate the process of de-agglomeration, the agglomerates are impacted onto a surface and forces are estimated from the breakup of the agglomerates. Several studies have used this principle; however, the simultaneous bounce and breakup of the agglomerates has received little attention. In this study, a method was devised to study both agglomerate breakup and bounce during impaction. In this method, the agglomerates were impacted onto an impaction plate located in a single stage micro-orifice uniform deposit impactor and the bounced particles were collected into a sampling chamber specially designed for this task. This way, the properties of the deposited and bounced particles can be examined with transmission electron microscopy, but in addition, the bounced particles can be analyzed with online measurement instruments, such as the scanning mobility particle sizer. Titanium dioxide (TiO2) and copper particles were used to test and validate the system, and the first impaction behavior results with this system were acquired using TiO2 agglomerates. It was evident that the agglomerates broke up during impaction under the conditions used in this study; the diameter of the particles decreased from 269 nm to 143 nm. It was found that half of the particles bounced. The particle diameter and the fractal dimension of the bounced particles were very similar to those of the particles that did not bounce. Copyright 2012 American Association for Aerosol Research