Single-nanosize pulverization of solid oxide by means of a wet planetary-bead-milling

Abstract

The single-nanosizing of a ceramics by a topdown method was demonstrated using a "wet planetary bead-milling" method, which is the combination of bead milling and planetary milling. By using the planetary bead-milling, single-nanoparticles (about 2 nm) of BaZr 0.9 Y 0.1 O 3¹¡ , which is one of the perovskite type oxides, was obtained with the combination of 0.05 mmº zirconia beads as pulverization media and ethanol as dispersion media.©2012 The Ceramic Society of Japan. All rights reserved.Key-words : Single-nanosizing, Perovskite oxide, Planetary bead-milling, Top-down method, Proton conducting oxide [Received October 4, 2011; Accepted October 6, 2011] It has been widely known that various characteristics of materials change drastically from those of the bulk when nanosized. This is primarily attributed to the quantum size effect: Nanosizing leads to the decrease in the degeneracy of electronic band and its structure returns to discrete condition. In addition, the surface area increases, and thus the surface properties become pronounced. As a result, the various unique properties are developed in nanosized materials. For example, fluorescence characteristic of CdSe significantly changes in response to the reduction of the particle size. 1)3) Some non magnetic materials such as Au show ferromagnetic property when nanosized.4) The sinterability of a material increases by the reduction of the particle size due to the increase in the surface free energy. 5) Superplasticity seen in a yttrium doped zirconia prepared through low temperature sintering of starting nano powder is another example of the benefit of ascendant surface properties. 6),7) Since the unique properties become more pronounced as the particle size becomes smaller, methods to prepare nano materials, especially those for the preparation of "singlenanometer" materials, are extremely attractive; spherical 2-nmradius particles with typical density of metal oxide (e.g., 5 g cm ¹3) must have an extremely high specific surface area (higher than 10000 m 2 g ¹1). However, the development of the preparation method for single-nano materials cannot be easily achieved.There are two different approaches for nanosizing: One is based on the topdown methods that prepare nano-materials by breaking down a bulk material and the other is based on the bottom-up methods that prepare nano-materials by building up in atomistic scale. The methods that have been succeeded in preparing nano materials are mostly based on the latter; the typical methods are the coprecipitation method, 8),9) the reverse micelle method, 10) the hot soap method, 2) the chemical vapor deposition (CVD) method, 11)13) the solgel method, 14)17) the salt assist spray pyrolysis (SASP) method, 18),19) etc. Especially, the single-nano particle could be obtained in the hot soap method and reverse micelle method.2),3),10) However, these bottom-up methods have restrictions in the choice of starting materials and/or preparation conditions. In addition, these methods have a difficulty in the application to co...

Anomalous gelation of self-assembling ethanol molecules

“…In this case, the sample was obtained by adding BaZrO3 (BZO) powder to ethanol and milling the mixture with very small zirconia beads in a high-speed planetary mill (see Extended Data Figs. 1 and 2) [14][15][16][17][18][19] . When 0.05 mmdiameter (50 μm) zirconia beads were used, a finely dispersed BZO nanoparticle-ethanol slurry with a most common particle size on the order of several nanometers was obtained 14,18 .…”

“…1 and 2) [14][15][16][17][18][19] . When 0.05 mmdiameter (50 μm) zirconia beads were used, a finely dispersed BZO nanoparticle-ethanol slurry with a most common particle size on the order of several nanometers was obtained 14,18 . In fact, as shown in Fig.…”

Preparation of Nano-Structured La_0.6Sr_0.4Co_0.2Fe_0.8O_{3−δ} Cathode for Protonic Ceramic Fuel Cell by Bead-Milling Method

“…16,17) The authors found that planetary bead-milling was important in grinding the solid oxides into nanoparticles sizes. 18,19) In contrast to bottom-up methods, such as the sol gel methods, hydrothermal synthesis and so forth, planetary bead-milling is categorized as a top-down approach that prepares nanoparticles by crashing the starting coarse particles and thus can be used for various solid materials. This important aspect of planetary bead-milling is advantageous to a wide range of solid oxide and is particularly useful to prepare nanoparticles for electrode materials, which usually have complicated chemical compositions and thus difficult to be prepared by bottom-up methods.…”

Electrode Properties of Bi-Sr-Fe-Based Perovskite-Type Oxides Coated with Nano-Structured PrBaCo2O5+δ

“…Regarding oxide nanoparticles, Sakai et al have recently reported that singlenanosized ceramics powder can be prepared by using a top-down method, i.e. a wet planetary bead milling with submillimeter-diameter beads (15). In this study, we focus on the preparation of nanosized PrBaCo 2 O 5+δ (PBCO) particles by means of the wet bead milling and depositing the nanoparticles on porous backbone of Bi 0.5 Sr 0.5 FeO 3-δ (BSF55).…”