Chemical Vapor Synthesis of Nonagglomerated Nickel Nanoparticles by In-Flight Coating

Abstract

Nickel (Ni) nanoparticles (NPs) prepared through vapor-phase synthesis (VPS) are preferred for multilayer ceramic capacitor electrodes due to their high purity and crystallinity advantages. Agglomerated Ni NPs are usually generated using VPS but are undesirable because they cause various problems such as low packing density and electrical shorts. This study proposes the use of coating-assisted chemical vapor synthesis (CVS) for agglomerate inhibition using NaCl or KCl as a coating agent. We have found that the agglomeration ratio, 34.40%, for conventional CVS, can be reduced to 4.80% in the proposed method by in-flight coating with KCl at 900 °C by image analysis using field-emission scanning electron microscopy. Furthermore, the X-ray diffraction and X-ray fluorescence analyses confirm that the NaCl and KCl coating agent can be removed by washing with distilled water. We believe that this coating process can be used to inhibit the formation of agglomerates during the CVS of Ni NPs.

A statistical method to optimize the chemical etching process of zinc oxide thin films

“…Open Sci. 9: 211560 [36]. The ratios of zinc Kβ ray to zinc Kα ray intensities from our baseline and from 5%, 10%, 15% and 20% etchant concentrations are 13.3%, 13.3%, 14.6%, 13.6% and 13.3%.…”

“…The peaks above 20 keV are indicative of Rayleigh peaks that are originated from the elastic scattering of the X-ray detector. The absence of the chlorine peak at around 2.5 KeV is a positive indication there is no chlorine contamination from the NH 4 Cl [36]. A decrease in the ratio of zinc Kβ ray to zinc Kα ray intensities suggests a shortening of the interatomic distance and, therefore, indicates crystallization royalsocietypublishing.org/journal/rsos R. Soc.…”

“…The absence of the chlorine peak at around 2.5 KeV is a positive indication there is no chlorine contamination from the NH 4 Cl [ 36 ]. A decrease in the ratio of zinc K β ray to zinc K α ray intensities suggests a shortening of the interatomic distance and, therefore, indicates crystallization [ 36 ].…”

“…The absence of the chlorine peak at around 2.5 KeV is a positive indication there is no chlorine contamination from the NH 4 Cl [ 36 ]. A decrease in the ratio of zinc K β ray to zinc K α ray intensities suggests a shortening of the interatomic distance and, therefore, indicates crystallization [ 36 ]. The ratios of zinc K β ray to zinc K α ray intensities from our baseline and from 5%, 10%, 15% and 20% etchant concentrations are 13.3%, 13.3%, 14.6%, 13.6% and 13.3%.…”

Pure copper nanoparticles prepared by coating-assisted vapor phase synthesis without agglomeration

“…We calculated the Gibbs free energy change for the hydrogen reduction reaction of several metal chlorides, namely CuCl(g), ZnCl 2 (g), KCl(g), LiCl(g), MgCl 2 (g), NaCl(g), CaCl 2 (g), and NiCl 2 (g), using Thermo-Calc DB. 24 Fig. 1 shows the Gibbs free energy changes with the temperature (500-1000 C) of the hydrogen reduction for various metal chloride reactions.…”