• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.66-74
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• 2004

The sliding wear behavior of $ZrO_2-22wt\%MgO\;(MZ)\;and\;ZrO_2-8wt\%Y_2O_3\;(YZ)$ deposited on a casting aluminum alloy with bond layer (NiCrCoAlY) by plasma spray against an SiC ball was investigated under dry test conditions at room temperature. At all load conditions, the wear mechanisms of the MZ and the YZ coatings were almost the same. The wear mechanisms involved the forming of a smooth film by material transferred on the sliding surface and pullout. The wear rate of the MZ coating was less than that of the YZ coating. With an increase normal load the wear rate of the studied coatings increased. The SEM was used to examine the sliding surfaces and elucidate likely wear mechanisms. The EDX analysis of the worn surface indicated that material transfer was occurred from the SiC ball to the disk. It was suggested that the material transfer played an important role in the wear performance.

• Journal of Powder Materials
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• v.5 no.1
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• pp.28-34
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• 1998

Plasma sprayed ceramic coatings are widely used in various industrial fields to improve their properties or to reduce the production cost. The ceramic powders for plasma spray coating have been mainly manufactured by spray drying or fused+crushed process. In this study, chromium oxide which has better mechanical properties than those of the other ceramic was selected and agglomerated chromium oxide powders for plasma spray coating were produced by spray drying process with a various processing condition. The large hollow powders and the harsh surfaced powders are formed at high slurry feed rate more than 163 g/min. and low binder concentration less than 2wt%, respectively. These powders cause the considerable decrease of flowability and apparent density. The powders produced by spray drying process have the spherical shape with the mean size of 45 ${\mu}m$, but these are shown lower apparent density and flowability than the powders produced by fused+crushed powders. The plasma spray coated layers by spray dried powders are shown a different microstructure with that by fused+crushed powders in porosity shape, but their properties such as density, hardness and bond strength are similar.