Synthesis of Submicron-Sized Spherical Silica-Coated Iron Nickel Particles with Adjustable Shell Thickness via Swirler Connector-Assisted Spray Pyrolysis

Abstract

Silica-coated iron nickel (FeNi@SiO2) particles have attracted significant attention because of their potential applications in electronic devices. In this work, submicron-sized spherical FeNi@SiO2 particles with precisely controllable shell thickness were successfully synthesized for the first time using a swirler connector-assisted spray pyrolysis system, comprising a preheater, specific connector, and main heater. The results indicated that the thickness of the SiO2 shell can be tuned from 3 to 23 nm by adjusting the parameter conditions (i.e., preheater temperature, SiO2 supplied amount). Furthermore, our fabrication method consistently yielded a high coating ratio of more than 94%, indicating an excellent quality of the synthesized particles. Especially, to gain an in-depth understanding of the particle formation process of the FeNi@SiO2 particles, a plausible mechanism was also investigated. These findings highlight the importance of controlling the preheater and SiO2 supplied amount to obtain FeNi@SiO2 particles with desirable morphology and high coating quality.

Effects of Coating Characteristics of One-Step Aerosol Synthesized–Silica-Coated FeNi Nanostructured Particles on Powder Core Properties for Electronic Machine Development

“…The higher crystal size in the low N FeNi value ( FNS-1.9–29 ) could be attributed to the heat transfer phenomenon. The lower number of FeNi cores resulted in less solvent being evaporated from the droplets, leading to increased heat transfer toward the FeNi core and triggering crystal growth. ,, Particle morphology analysis revealed spherical and hundreds of nanometer-sized particles with narrowed particle size distribution in both samples (Figure (b),(c)). However, certain detailed distinctive characteristics were observed.…”

“…The droplets were transported by 5%H 2 –Ar of carrier gas ( Q c ) at a flow rate of 5 L/min into the preheater at 900 °C ( T p ). The FeNi precursor droplets were decomposed and altered into solid particles comprising iron–nickel–oxide (FeNiO) . Second, the resulted FeNiO solid particles from the preheater were introduced by the silica precursor in the connector.…”

“…Some researchers have conducted silica-coated particle synthesis using a tubular reactor equipped with a hot-wall furnace, , photoinduction, ,, plasma and microwave radiation, , electron beam evaporation, and flame combustion. ,− These methods yielded particles ranging from nanometer to submicron sizes. Inspired by these works, our group has developed a facile nanostructuring method using a tubular reactor surrounded by a hot-wall reactor in a closed system, termed swirler connector-assisted spray pyrolysis (SCA-SP). , This system provides a reduction atmosphere and uniform mixing between the FeNi core particle and the SiO 2 shell material to successfully yield FeNi@SiO 2 particles. ,,− However, the resulting average shell thickness in our previous studies and the aforementioned methods was in a narrow range below 50 nm. Moreover, the effect of coating characteristics on the powder core electrical properties remains unexplored.…”

Controllable Synthesis of Porous and Hollow Nanostructured Catalyst Particles and Their Soot Oxidation

“…However, when the reheating process in air was directly performed in the first step, several particles in TNP0. 5-air exhibited open pores after the reheating process (Figure S3a). These open pores were formed because of the rapid decomposition of the remaining PMMA during the reheating process in air.…”

“…The development of submicron nanostructured particles with highly controlled structures and morphologies (e.g., porous, , hollow, , and core–shell , ) is important for advancing the next generation of fine particles. − Among nanostructured particles, macroporous particles have attracted considerable attention due to their unique advantages in material performance. By introduction of macropores, the particles can efficiently utilize their internal parts and concurrently improve their performance.…”