Low-temperature lead-free soldering paste

Abstract

It is used for soldering components in electronics and automotive applications. The paste has an extended shelf life and improved efficiency. The paste contains a flux comprising rosin dissolved in a solvent and dispersed in the flux, first metal powder particles containing bismuth (Bi) 58-71 wt% and tin (Sn) 29-42 wt%, and second metal powder particles of silver (Ag) 0.1-0.5 wt% of the total amount of metal powder. The flux also contains undissolved uniformly dispersed particles of graphene 0.1 - 3.0, enzyme lysozyme 0.1 - 0.4 wt%, thixotropic agent carboxymethylcellulose 6 - 12 wt%, zinc carbonate (ZnCO3) 2–5 wt%, boron carbide (B4C) 0.5–4 wt%, and zinc phosphate (Zn3(PO4)2) 3–7 wt% of the total amount of flux.