纳米粒子表面的大量空悬、不饱和键导致的高能量、不稳定性,使得颗粒之间极易自发形成团聚,限制了众多纳米特性的发挥.本文以银纳米颗粒的团聚体为研究对象,通过分子动力学模拟其熔化行为,采用势能-温度法获得熔点.结果表明,由于团聚,颗粒间形成了“颈部”结构,导致颗粒比表面积降低,进而引起熔点升高;相较于大颗粒团聚,极小颗粒间容易聚合成一个近似立方整体,有可能获得更高的熔点.通过X射线衍射及透射电镜对银纳米粉末进行表征,验证了团聚体的存在.采用热重 差式综合热分析仪对粉体的熔点进行了测量,与模拟结果吻合较好.
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