Papers by Keyword: Powder Preparation

Abstract: The purpose of this paper is to study the feasibility of nano-material (1~100nm) level powder preparation by wet ball milling. The powder was used to prepare the ceramic and the performance of the ceramic was analyzed. The experimental results show that the average particle size of the powder is close to nano-material level (around 120nm) and the ceramic possess high compactness, high dielectric constant and low dielectric loss.

Abstract: A novel process was developed to make micro-fine spherical high Nb containing TiAl alloyed powders in quantity. Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y(at%) ingot prepared by vacuum induction melting was heat-treated for homogenization, and then machined with a crusher. The chippings were refined by fluidized bed jet milling, and subsequently spheroidized with radio frequency (RF) argon plasma. The effects of processing parameters on powder characteristics were studied. By fluidized bed jet milling, the particle size and distribution uniformity both decline with the rise of classifier frequency. Above 5800rpm, the number-average diameter is lower than 20μm with a bimodal particle size distribution. The powders consist of coarse plate-shaped particles and some finer flaky debris, and with the further rise of the frequency, the amount of debris gradually increases. The plasma-spheroidized powders are found to possess good sphericity and composition homogeneity with phase dominated by supersaturated α2-Ti3Al. The granulometric characteristics of the spherical powders strongly depend on those of the feed powders. For the jet milled powders below 5800rpm, due to the relatively lower size distribution uniformity, the fine particle fraction reduces after spheroidization, which causes an obvious improvement of distribution uniformity and the corresponding increase of number-average diameter

Abstract: In the milling process, the particles experience mechanical stresses at their contact points due to compression, impact, or shear with the mill medium or with other particles. The rate of grinding depends on a number of factors, including the mill parameters, the properties of the grinding media, and the properties of the particles to be ground. SEM photomicrographs show that the mean sizes of final refined powders are about 200–400 nm, and are quite uniformly distributed by wet ball milling, so the quasi-nano powders are very suitable for sintering.

Abstract: In this review a small overview is given about methods of powder preparation and thick films tested in the field of High-Temperature-SuperConductors (HTSC). The first and very important step on the way to applications consists generally in the preparation of an adequate powder, alternatively prepared by the common ceramic way or tailor made by wet chemistry. Following, the preparation of thick films are discussed, mostly made by low cost processes in contrast to the expensive manufacturing of thick films.

Abstract: Powder library of pseudo four components Li-Ni-Co-Ti compounds were prepared for exploring the composition region with the single phase of the layer-type structure by using combinatorial high-throuput preparation system “M-ist Combi” based on electrostatic spray deposition method. The new layer-type compounds were found wider composition region than the previous report. This process is promising way to find functional multi-component materials.