Powder Production Technology for Thermal Spraying

摘要

The objective of the present work is to produce Mg-PSZ(magnesia partially stabilized zirconia) powders that wereused to coat oxygen sensor tubes by plasma spraying. It is wellknown fact that zirconia based oxide thin films are the mostwidely used material as ionic conductors of oxygen. In thisstudy, MgO stabilized ZrO2 powders were produced by thesintering and crushing method. Starting powders were a highgrade ZrO2, and a natural hydromagnesite (Mg-HC) as MgOsource. ZrO2, and MgO were mixed in the compositions ofZrO2 - 9mol % MgO. The mixtures were ball milled by usingZrO2 balls. The fine powders were stabilized via thermaltreatment in air at 1540°C for 24 hours. The powders werecalibrated to the correct particle size distribution for plasmaspraying. All powder samples were characterised by a welldefinedtechniques with an exhibited an average particle sizeof 10 μm. The powders consisted of monoclinic, tetragonaland cubic phases. They were sprayed by plasma spray toproduce high temperature Mg-PSZ coatings on oxygen sensortubes. It is worthwhile to point out that high temperatures weregenerated in the plasma spray jet, and the rapid quenching ofthe molten Mg-PSZ droplets deposited on the cold substratesubsequently occurred. After this process, thermal treatmentswere carried out to improve the film density andmicrostructural stability.