[PDF]    http://dx.doi.org/10.3952/lithjphys.49114

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 49, 85–90 (2009)

Ž. Kavaliauskas, K. Brinkienė, J. Čėsnienė, and R. Kėželis
Lithuanian Energy Institute, Breslaujos 3, LT-44403 Kaunas, Lithuania
E-mail: zydrunas@mail.lei.lt

Received 26 September 2008; revised 2 February 2009; accepted 19 March 2009

The paper describes a process for preparation of yttria stabilized zirconia (YSZ) coatings by plasma spray technique employing non-equilibrium plasma spray technology at atmospheric pressure. Yttria-stabilized zirconia (10–15 wt.% Y2O3) powders (10–105 μμm in diameter) have been used. Plasma sprayed coatings have been characterized using scanning electron microscope (SEM) and X-ray diffractometer (XRD) for the microstructural study and phase analysis as a part of a process optimisation study. The dependence of microstructure of coatings on initial powder characteristics and the influence of deposition temperature in the range of 3000–3350 \circC on the structural characteristics of plasma sprayed coatings were investigated. By the data of XRD analysis, all samples were obtained with cubic crystal orientation. It has been found that crystallite size has tendency to decrease with increasing the deposition temperature. YSZ deposited at 3150–3350 \circC are found to have a nanocrystalline structure with average crystallite size of 75 nm. The samples sprayed using coarse-grained powder feed are characterized by larger grain size and crystallite size. The main parameters influencing the coating formation are the properties of the initial powder and the plasma process temperature. The SEM analysis showed that the best temperature region for the deposition of YSZ coatings was about 3200–3350 \circC.
Keywords: coatings, plasma spraying, microstructure-final, XRD, ZrO2
PACS: 52.77.Bn, 68.55.J-, 68.90.+g

Ž. Kavaliauskas, K. Brinkienė, J. Čėsnienė, R. Kėželis
Lietuvos energetikos institutas, Kaunas, Lietuva

Tirti plazminių itriu stabilizuoto cirkonio oksido (YSZ) dangų formavimo ypatumai ir vertintos dangų struktūros charakteristikos. Cirkonio oksido dangos gautos plazminio purškimo būdu, taikant nepusiausviros oro plazmos technologiją. Purškimui naudoti 44–105 μm dydžio YSZ (10–15 svorio % Y2O3) milteliai. Dangos analizuotos rentgeno difrakcijos (XRD) ir skenuojančios elektroninės mikroskopijos (SEM) metodais. Pateikta gautų dangų struktūros, fazinės sudėties bei kristalitų dydžio priklausomybė nuo plazmos srauto temperatūros ir žaliavos miltelių smulkumo. Nustatyta, kad dangų struktūrą sudaro kubinės gardelės nanometrinio dydžio cirkonio oksido kristalitai, kurių dydis mažėja, didėjant plazmos srauto temperatūrai. Pastebėtas nedidelis kristalitų dydžio padidėjimas naudojant stambesnės frakcijos YSZ miltelius. Nustatyta, kad didžiausią įtaką plazminiu būdu formuojamų YSZ dangų struktūrai turi purškimui naudojamų miltelių charakteristikos bei plazmos srauto temperatūra. Remiantis atliktais tyrimais, optimali plazmos srauto temperatūra YSZ dangoms formuoti yra 3200–3350 \circC.

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