Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids

Abstract

Mechanisms of the formation of nanoparticles of some B2 shape memory intermetallic compounds, glass-forming Zr-based alloy, and pure Ti obtained by spark erosion method in liquid nitrogen and argon are considered. One of peculiarity is a foam-like structure, which covers the surface of micron-sized particles that appear during spark erosion. Such morphology is related to the nanosized particles gathered in agglomerates. Detailed examination of those particles allows proposed several mechanisms of their formation. The mechanisms explains two kinds of nanosized particles: particles of several tens and even hundreds of nanometers are formed due to explosion of molten droplets while the smaller particles having in turn a different structure and morphology are formed as a result of condensation of evaporated constituents under different conditions. The latter have the composition usually different from the target composition while the composition of the former is very close to the target (master alloy) composition.

Analytical Nonlinear-Probabilistic Model of the Equivalent Electrical Resistance of a Layer of Metal Granules

“…Іскро-та плазмоерозійна обробка шарів металевих гранул (ШМГ) в робочих рідинах є основою чотирьох основних груп технологічних процесів. До першої відноситься виробництво мікродисперсних порошків металів і сплавів із спеціальними властивостями: тугоплавких і жароміцних [1], з магнітною [2] і температурною [3] пам'яттю форми, з аморфною [4] та аморфно-кристалічною структурою [5], з гігантським магніторезистивним ефектом [6], магнітом'яких [7], воденьсорбуючих, надтвердих [8], корозійно стійких [9] та ін. [10][11][12].…”

Investigation of the synthesis of nanoparticles by pulsed electrical erosion in the conditions of overvoltage of the discharge gap

“…Investigations of the influence of dielectric liquid media used in the synthesis of nanoparticles [10], including cryogenic liquids [11], have been carried out. A decrease in the size of the resulting metallic nanoparticles upon exposure to a liquid dielectric in the discharge zone by ultrasound due to cavitation and mixing has been established [12].…”