Production, characterisation and application of monosize alloy droplets

Abstract

Monosize alloy droplets are produced by controlled capillary jet break-up, a droplet generating process, also used in ink jet printing technology. With Rayleigh instability controlled through the decoupled process parameters of jet diameter, mass flowrate and perturbation frequency, monosize droplets of desired diameter can be generated at high rates with essentially full yield. The uniform size of droplets assures nearly identical solidification paths for all the droplets generated under fixed process conditions. This permits precise prediction of the motion and thermal and solidification behaviours of the droplets through rigorous process and metallurgical modelling, which is applicable to industrial thermal spray processes as well. Uniform droplets can be in-flight solidified or deposited on a substrate to produce various forms of materials with novel rapid solidification microstructures. Areas of industrial applications are discussed.

Flux-less direct soldering of aluminum by ultrasonic surface activation

“…The present work used discs of lead-free solder (SN100C ® ), 4 mm in diameter and 0.2 mm in thickness, fabricated from 50 μm mono-disperse solder balls by ultrasonic powder consolidation (UPC), a rapid low-temperature powder consolidation technique described elsewhere (Gunduz, 2006; under conditions optimized for the solder balls (consolidation temperature: 100 °C, consolidation time: 3 s, vibration amplitude: 9 μm, uniaxial pressure: 100 MPa). The mono-disperse solder balls were prepared by a capillary molten jet breakup process described in previous study (Ando, 2012).…”