Papers by Keyword: Powder

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Authors: D.D. Green, G.S.K. Kannangara, Adriyan Milev, Besim Ben-Nissan
Authors: A. Zięba, W. Dąbrowski, P. Gryboś, W. Pawroźnik, J.R. Słowik, T. Stobiecki, K. Świentek, P. Wiącek
Abstract: Silicon strip detectors represent a new class of one-dimensional position-sensitive single photon counting devices. They allow a reduction of measurement time at the powder diffractometers by a factor up to 100 compared to instruments with a single counter, while maintaining comparable count statistics. Present work describes a 128-channel detector working with a standard diffractometer. The detector is 12.8 mm long and covers the angular range of 3.2 deg. We discuss the diffraction geometry in real and reciprocal space, the FWHM of diffraction peaks, and the background level. Measurements were made on standard samples and on complex samples of industrial importance (e. g., portland clinker). Applications of the detector to diffraction measurements of single crystals and thin films are discussed briefly.
Authors: Anna Zymla, Victor Zymla, Jean-Bernard Guillot
Authors: Zheng Xu, Shou Ci Lu
Abstract: A new electrostatic dispersion device was designed to reduce the agglomeration of fine powder in the air. This device is using the repulse force between particles which charged the same charge to prevent the particles from reuniting. The effects of charge voltage, particle size, the distant between electrode, and moisture content on the dispersion degree of the powder are discussed. The invalidation time of the electrostatic dispersion is also highlighted in the paper. The results show that the electrostatic dispersion is an effective method for the fine powders in the air. The charge voltage is the most important parameter for the dispersion. Middle size particle got best dispersion. When the distance between the electrodes is 24cm, the dispersion degree reaches the maximum. The humidity of the powder not only affects the charge of the powder, but also affects the dispersion degree of the powder.
Authors: Shi Wei Zhang, Li Yuan Hou, Yong Chao Han, Yuan Hua Xie
Abstract: In the process of manufacturing the composite materials, some of the chemical components are difficult to combine with each other. Aiming at this problem, a new method and supporting equipment of manufacturing the composite powder materials is reported which can make any two (or more) kinds of components mixing in nano-scale. This method is derived from the vacuum co-depositing technology by two (or more) vaporization sources for vacuum film coating, and some of the structures in vacuum film coil coating machine are used for reference. The principle, structure, process and characteristics of this method are introduced in detail. The models for depositing rate calculation are built respectively for both the electric resistance evaporation sources and the magnetron sputtering targets. The mixing component uniformity in the depositing powder material is analyzed by calculation.
Authors: Jiang Feng Tong, Da Ming Chen
Abstract: In this paper, a fine pure Magnesium aluminate spinel powder was synesised by Gel solid reaction,using Al(NO3)3 6H2O and Mg(NO3)26H2O as raw materials under given condition. The precursor was formed by polymer gelling.The phase changed according to heating temperatures from 700°C to 900°C.The single phase of Magnesium aluminate spinel was obtained by calcining the precursor at temperatures higher than 900°C. The phase changing process and relationship among calcination parameters, phase composition and image of particle are studied to determine the optimal conditions for the synthesis of fine Magnesium aluminate spinel powder. The powder obtained was characterized by XRD,TEM etc. The results of analysis showed that the ultrafine powder is of spinel phase, high purity, good dispersion.This process for preparing fine Magnesium aluminate spinel powder was very simple and inexpensive.The results of analysis showed that the ultrafine powder was of mullite phase, high purity, good dispersion, and the particle were homogeneous.
Authors: Dan Qing Zhang, Qi Zhou Cai, Jin Hui Liu, Rui Di Li
Abstract: Shrinkage tends to generate when loose metal powder melted in each processing layer along the direction of layer growing during selective laser melting process, resulting in an increased real layer thickness. The shrinkage model for layer shrinkage in SLM process is established. The variation of real layer thickness and the relevant mathematical explanations are discussed in this paper. The results show that the total shrinkage of metal powder layer sharply increases in the initial layers, and then reaches to a plateau value with the increased processing layers. This value is defined by the ratio of sliced layer thickness (h) to relative density (k) during selective laser melting process.
Authors: King Leung Wong, Wen Lih Chen, Shing Hae Wang
Abstract: In this study, fixed mole number proportion of CuCl, ZnCl2, SnCl2‧2H2O and sulfide compounds and the reacted solution are added to the autoclave, then the CZTS powders are prepared by changing the heating temperature and time. It is found from the experimental results that better result with less secondary phase can be obtained at the heating temperature 250°C and heated time of 36 hours.
Authors: Tang Kai, Yan Jie
Abstract: Several surfactants were studied in cemented carbides ball milling in this paper by analyzing cemented carbides mechanical properties and SEM images. Appropriate surfactants used in ball milling were selected to replace commonly used surfactant, stearic acid. Impacts of surfactants on hardness, magnetic force and magnetic saturation were also discussed. Oleic acid and AEO-3 as the better surfactant than stearic acid were selected after experiments. How containing oxygen compound affects the cemented carbide mechanical property cannot be recommended at this stage; further investigations are required.
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