{"title":"Molecular dynamics study of sintering of faceted cubic boron nitride nanoparticles at high temperatures","authors":"","doi":"10.1016/j.jaerosci.2024.106441","DOIUrl":null,"url":null,"abstract":"<div><p>The sintering mechanisms and temperature dependence of coalescence of colliding cubic boron nitride (c-BN) nanoparticles are investigated using classical molecular dynamics (MD) simulation. Particle-particle collisions of 2.55-nm octahedral c-BN nanoparticles, consisting solely of the most stable {111} facets, with half of the surface terminations being boron and the other half nitrogen, are analyzed statistically and evaluated to assess the initial temperature range (2500 K – 3100 K) for sintering and its effect on grain growth. At these temperatures, the collision process maximizes contact surface area through interfacial sliding, thereby minimizing free energy and accommodating dangling bonds. Moreover, the exothermic formation of bonds of the coalescing nanoparticles increases the temperature. The alignment of the {111} orientation of the two collided nanoparticles occurs at a temperature slightly above the melting point, and rapid grain growth happens when the temperature is a few hundred degrees higher than that. However, phase separation also takes place at the corners away from the collision plane of the merging nanoparticles. Between 3100 K and 3250 K, crystalline alignment occurs, which aids the sintering process and allows for the formation of a well-structured nanocluster. However, above 3300 K, phase separation dominates and drives the melting of the entire sintered nanocluster.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":3.9000,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0021850224001083/pdfft?md5=f8816000fb342bf601b1bb1600ac86d5&pid=1-s2.0-S0021850224001083-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Aerosol Science","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0021850224001083","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The sintering mechanisms and temperature dependence of coalescence of colliding cubic boron nitride (c-BN) nanoparticles are investigated using classical molecular dynamics (MD) simulation. Particle-particle collisions of 2.55-nm octahedral c-BN nanoparticles, consisting solely of the most stable {111} facets, with half of the surface terminations being boron and the other half nitrogen, are analyzed statistically and evaluated to assess the initial temperature range (2500 K – 3100 K) for sintering and its effect on grain growth. At these temperatures, the collision process maximizes contact surface area through interfacial sliding, thereby minimizing free energy and accommodating dangling bonds. Moreover, the exothermic formation of bonds of the coalescing nanoparticles increases the temperature. The alignment of the {111} orientation of the two collided nanoparticles occurs at a temperature slightly above the melting point, and rapid grain growth happens when the temperature is a few hundred degrees higher than that. However, phase separation also takes place at the corners away from the collision plane of the merging nanoparticles. Between 3100 K and 3250 K, crystalline alignment occurs, which aids the sintering process and allows for the formation of a well-structured nanocluster. However, above 3300 K, phase separation dominates and drives the melting of the entire sintered nanocluster.
利用经典分子动力学(MD)模拟研究了碰撞立方氮化硼(c-BN)纳米粒子的烧结机理和凝聚的温度依赖性。2.55 纳米八面体立方氮化硼(c-BN)纳米粒子仅由最稳定的{111}面组成,其表面端点一半为硼,另一半为氮,对这些粒子间的碰撞进行了统计分析和评估,以评估烧结的初始温度范围(2500 K - 3100 K)及其对晶粒生长的影响。在这些温度下,碰撞过程通过界面滑动使接触表面积最大化,从而使自由能最小化并容纳悬空键。此外,凝聚纳米粒子的键的放热形成也会提高温度。两个碰撞的纳米粒子的{111}取向对齐发生在略高于熔点的温度下,而当温度高于熔点几百度时,晶粒会迅速生长。然而,相分离也发生在远离合并纳米粒子碰撞平面的角落。在 3100 K 到 3250 K 之间,晶体会发生排列,这有助于烧结过程,并能形成结构良好的纳米团簇。然而,在 3300 K 以上,相分离占主导地位,并促使整个烧结纳米团簇熔化。
期刊介绍:
Founded in 1970, the Journal of Aerosol Science considers itself the prime vehicle for the publication of original work as well as reviews related to fundamental and applied aerosol research, as well as aerosol instrumentation. Its content is directed at scientists working in engineering disciplines, as well as physics, chemistry, and environmental sciences.
The editors welcome submissions of papers describing recent experimental, numerical, and theoretical research related to the following topics:
1. Fundamental Aerosol Science.
2. Applied Aerosol Science.
3. Instrumentation & Measurement Methods.