Shear Strength of Copper Joints Prepared by Low Temperature Sintering of Silver Nanoparticles

In this work, mechanical properties of Cu-to-Cu joint samples prepared by low temperature sintering of Ag nanoparticle paste have been investigated. The silver nanopaste was prepared by a controlled thermal decomposition of an organometallic precursor. The as-synthesized Ag particles were spherical, with an average diameter of 8.5 nm. The Cu-to-Cu joint samples were made by placing a small amount of Ag nanopaste between two polished Cu plates and sintering at 150C, 200C, 220C and 350C in air. A normal load was applied to aid sintering. Mechanical properties were measured by imposing a uniform stress across the sample bond area and measuring the corresponding strain. The application of external load was found to have a positive effect on the material’s mechanical properties. Furthermore, interestingly high values of shear strength were observed.Byly zkoumány mechanické vlastnosti Cu-to-Cu spojů připravených nízkoteplotní sintrací pasty Ag nanočástic. Ag nanopasta byla připravena řízeným tepelným rozkladem organokovových prekurzorů. Syntetizované Ag NPs byly kulovité, o středním průměru 8,5 nm. Cu-to-Cu spoje byly vyrobeny umístěním malého množství Ag nanopasty mezi dvě leštěné Cu desky a sintrováním při 150C, 200C, 220C and 350C na vzduchu. Zatížení bylo použito na k podpoře sintrace. Mechanické vlastnosti byly měřeny stanovením napětí lomu a deformace. Bylo zjištěno, že aplikace vnějšího zatížení má pozitivní vliv na mechanické vlastnosti spoje

Computer simulation of up-hill diffusion in ČSN 17 242/P91 welded joint

The DICTRA software is used for simulating diffusion in multiphase diffusion couple ČSN 17242/P91 at temperature ranging 500-1100 C. The examples of calculated phase profiles, activity and concentration profiles of all species at selected condition are shown

Bimodal size distributed silver nanoparticles on copper substrate: in situ heat treating under air and protective atmospheres

Silver bimodal nano-suspension was prepared by a wet synthetic route. Organic cover protected the particles. Interaction with copper substrate was monitored. The phenomena starting with temperature activation of the free surface of metallic nanoparticles and finishing with the formation of a bulk layer of Ag in between two Cu substrate were monitored by different in situ methods of thermal analyse, microscopy and conductivity measurement. This monitoring was carried out under different outer gas conditions. An important outcome is the estimation of heat effect, which is produced during low temperature sintering and aggregation of the Ag nanoparticles