Crystallite Growth and Sintering Property of Metallic Nanoparticle

Nanoparticle has been attractive due to its low-temperature sintering property. For the large-scale production of nanoparticle, the liquid phase synthesis is a promising method because of its simple and convenient process. The nanoparticle, especially metallic nanoparticle, dispersed in a solution is generally protected by a dispersant to prevent the agglomeration. Therefore, the sintering behavior of such nanoparticles is strongly influenced by not only the material itself but also other additives like dispersant. In this work, Cu and Ag nanoparticles were synthesized using gelatin and oleic acid as a dispersant, and their crystallite growth behaviors and sintering properties were crystallographically studied. Through the heat treatment, the crystallite growth and the sintering of Cu were suppressed in an earlier stage than Ag by the oxide layer of Cu. We also clarified the gelatin formed a thick coating layer, which induced the suppression of crystallite growth and sintering. Moreover, we experimentally demonstrated that the in situ evaluation of crystallite size derived by X-ray diffraction can reflect the sintering behavior of particles.