Melting and Recrystallization of Copper Nanoparticles Prepared by Microwave-Assisted Reduction in the Presence of Triethylenetetramine

• Published in: Materials Vol. 13; no. 7; p. 1507
• Main Authors: Jheng, Li-Cheng, Wang, Yen-Zen, Huang, Wen-Yao, Ho, Ko-Shan, Tsai, Cheng-Hsien, Huang, Ching-Tang, Tsai, Huang-Shian
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.03.2020; MDPI
• Subjects: Agglomeration; Atoms & subatomic particles; chelation; Copper; Diffraction patterns; Electron beams; Heat; Irradiation; Melt temperature; Melting; Metals; Microscopy; microwave-assisted; Microwaves; nanocopper; Nanoparticles; Phase transitions; Pictures; Recrystallization; Solvents; Temperature gradients; triethylene tetramine; United States > US; Japan; melting; recrystallization; chelation; microwave-assisted; nanocopper; triethylene tetramine
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma13071507

The small sized copper nanoparticles (Cu-NPs), prepared in the presence of triethylene tetramine (TETA) and assisted with microwave irradiation, have an extremely low melting temperature. Melting of the small sizezd Cu-NPs can be triggered by the heat generated from the e-beam irradiation during SEM and TEM image construction. The dispersed Cu atoms around the agglomerated big Cu particles can undergo recrystallization immediately due to the strong driving force of the huge temperature difference to normal melting temperature (T = 1085 °C). Some of the Cu-NPs with bigger sizes also recrystallize and agglomerate into dense, big particles. According to X-ray diffraction patterns, these particles can agglomerate into compact, ordered Cu crystals in less than five minutes at 60 °C. The melting and recrystallization related endothermic and exothermic phase transitions of Cu-NPs can be found from differential scanning calorimeter (DSC) thermograms and optical microscopic pictures.