Yang Wenqiang,Han Shanyu,Yin Yakun,Wang Zelong,Shi Wen,An Juan,Wang Hongdan,Xia Wentang
The production of ultralight copper powder (UCP) remains challenging due to the requisite ultralow apparent density coupled with a well-developed dendritic morphology, which greatly constrain the modulation and optimization of process parameters. In this study, we conducted a comprehensive investigation to gain deeper insights into the impact of these parameters on the performance of deposited UCPs. Our findings revealed the limitations of relying solely on conventional electrolytic parameters for tailored UCP production. To overcome this challenge, the introduction of hydrochloric acid into the electrolyte system was proposed. Upon which, remarkable improvements in UCP production were observed, including optimized dendritic morphology, enhanced current efficiency and reduced power consumption. By adjusting the amount of chloride addition, UCPs with tunable particle sizes and apparent densities were obtained. Under the benchmark factory process condition, the chloride-treated UCP exhibited an ultralow apparent density (0.47 g cm −3 ) and particle size (19.96 μm), considerably surpassing the corresponding figures for industrial copper powder (1.79 g cm −3 and 64.10 μm) and even the optimum values achieved by GGP Metalpowder AG for their UCP products (0.55 g cm −3 and < 63 μm), with 22.5% of the particles exhibiting simultaneously ultralight and ultrafine properties.
A modified vibrating screen method was employed to prepare granulated Y2O3 powders, which were used to fabricate transparent ceramics. The granulation process was carried out with yttrium-stabilized zirconia balls (5 mm in diameter) in a 200-mesh screen, which was vibrated by a Heidolph shaker. After passage through the vibrating screen, the sub-micron Y2O3 particles were converted into large granules and collected in the bottom chamber of the sieve. Compared with the original powders, the granulated powders had a smaller repose angle of 34.09° and larger apparent and tap densities with sharp rises of 50.54 and 32.07%, respectively, indicating a good flowability and filling properties. A high transmittance of 82% at 2500 nm was achieved for ceramics prepared using the granulated powders by vacuum sintering and hot isostatic pressing (HIP).