Synthesis and magnetism of hierarchical iron oxide particles

Iron Oxide Nanoparticles for Next Generation Gas Sensors

“…Recently, Prof Satoshi Hirosawa, the leading researcher, has carried out the studies of interesting topics of soft and hard magnetic Febased oxides and alloys via heat treatments with various kinds of specific gases, such as N 2 , H 2 , Ar/H 2 etc at high temperature [90,91], at national Institute for Materials Science (NIMS), Japan. In the wide temperature range from room to about 1000°C, the prepared Fe -based particles with the microscales and good sizes, shapes, and morphologies were proved to be kept in existence of grain and grain boundary structures [78][79][80][81][82][83]87,88].…”

“…In new Fe oxide based micro/nanoscale materials, it can also lead to better predict an improvement of high-performance energy conversion and storage of battery, potential biomedical applications [79,83] in the efficient treatments of dangerous tumors and cancers as well as potential applications of photocatalyst and chemical sensors [70,79,[83][84][85][86]. In his main contributions [26][27][28][29][33][34][35][36][39][40][41][42][78][79][80][81][82][83]87,88], Dr Nguyen and co-workers have developed the new definitions and concepts of self-attachment, elastic and inelastic self-collision, self-aggregation, and self-assembly phenomena of the nanoparticles according to chemical synthetic processes [78,94], and the very complex issues of atomic arrangements in order or disorder inside metal, bimetal, and alloy nanoparticles with defects, stacking fault, dislocation, twin planes etc at 10 nm by HRTEM/STEM methods [36,42]. In addition, the critical roles of heat treatment to the prepared particle products led to particle deformation, i.e.…”

“…the levels of the deformation of size, shape, morphology, surface, internal structure, composition, other crystal parameters during sintering and final densification, leading to plastic, elastic, and inelastic deformation on both the surface and inside the solidified particles leading the undiscovered new properties for various practical applications [36]. The high durability, high stability, and better strength of the prepared oxide particles after heat treatment at high temperature significantly enhanced are all the best chemical and physical properties of the particles with both micro-and nanostructures with the very complicate issues of atomic arrangements inside the grains of one particle as well as the grain arrangements of grain and grain boundary textures [78][79][80][81][82][83]87,88]. These important improvements and modifications are the keys for discovering new functional nanoparticles for life, biomedicine, energy, and environment.…”

“…The products of the nano and microparticle powders have been introduced for practical applications for life, such as gas sensor technology in Figure 12 [87,88]. Thus, Fe, FeO, Fe 2 O 3 , Fe 3 O 4 oxide particles in Figure 10 in respect with their applications can facilely be prepared according to the following equations from 13 to 22 etc, and via efficient heat treatment and gas(g)-liquid (l)-solid (s) chemical reactions in physical and/or chemical metallurgy [8,70,96] As we can know, the pure Fe particles can be prepared in H 2 gas at 900°C according to Equation 19, which are different from the Fe particles prepared in liquid-phase chemical reactions.…”

Effects of γ-Fe2O3 on γ-Fe2O3/Fe3O4 composite magnetic fluid by low-temperature low-vacuum oxidation method

“…It is because that γ-Fe 2 O 3 grain comes into nano-size, it gets more excellent magnetic properties than the usual structure, its coercive force is also greatly improved, the magnetic recording materials made by the γ-Fe 2 O 3 powder can significantly improve the signal-to-noise ratio and improve image quality, and can achieve highdensity information recording. The γ-Fe 2 O 3 nanoparticles were prepared by many methods, such as gas sensing electrode, solid-state reaction with low heating and sol-gel method [14][15]. However, most of these preparation methods are complex and costly.…”