Browsing by Author "Park H."

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Densification behaviour analysis of ZrO2 nanopowders for dental applications compacted by magnetic pulsed compaction
(2013-08-15) Park H.; Kilicaslan M.; Hong S.
Sintered bulks of commercial ZrO2 nanopowders were produced by combined application of magnetic pulsed compaction (MPC) and subsequent two-step sintering, and finally, their density, hardness, shrinkage and formability were analyzed. The formability tests were conducted by a CAD/CAM system. Nearly fully dense (∼98%) commercial ZrO2 bulks were successfully obtained. With increasing MPC pressure, there was a decrease in the grain size of zirconia block. The ratio of PVA did not have a remarkable effect on the grain size. The optimum compaction pressure during MPC was 1 GPa and mixing conditions included using 1.0 wt. % PVA. The optimum processing condition included MPC process, followed by two-step sintering (first at 1000 and then at 1450 C). The bulk under these conditions was found to have good formability, ∼97% density, reasonable hardness (1150 Hv) and ∼19% shrinkage© 2013 Elsevier B.V. All rights reserved.
Effect of multiple pressures by magnetic pulsed compaction (MPC) on the density of gas-atomized Al-20Si powder
(2012-07-01) Park H.; Kilicaslan M.; Hong S.
Rapidly solidified Al-20. wt.%Si alloy powders with particle size of ~. 106. μm in diameter were fabricated by gas atomization, and the powder compaction was performed by using magnetic pulsed compaction. Multiple way experiments were carried out on Al-Si powders with varying pressing time, weight and intensity of initial and final pressures. Effects of process parameters during multiple pressing such as, number of repeated pressing, initial pressure, and final pressure, on the density were investigated. It was found that density decreases with increasing weight of powder poured to the die, but it enhances with increasing pressure. The last compaction pressure has a more dominant effect on the density than the initial compaction pressure in magnetic pulsed compaction process. With increasing the number of repeated pressing, the density of the compacted product increases. © 2012 Elsevier B.V..