Header menu link for other important links
X
A scanning electron microscopic study to observe the changes in the growth morphology of the α phased Alumina-13 wt.% titania coatings during plasma spraying
Keasavan Nair
Published in
2008
Volume: 202
   
Issue: 21
Pages: 5074 - 5083
Abstract
Plasma spraying of Alumina-13 wt.% titania coatings shows preferential stability of α phase, in the as sprayed conditions, to an extent of 15-40%. As reported in the literature, the quantity of this α phase can be considered to be closely related to the processing parameters of the air plasma spray process, such as arc current, plasma gas flow rate etc. Normally, a lower value of arc current, results in larger quantity of preferentially stabilized α phase. In this paper, we have attempted to measure the orientation image mapping (OIM) of these α phased Alumina-13 wt.% titania coatings with Electron Back Scattered Diffraction. From the OIM, the pole figures for the α phase were established and from appropriate pole figures, such as (0001), (0006), (01ī1) and (10ī1) the growth morphology of the α phase could be determined. For larger values of arc current, at which the growth rate is faster and due to the imposed rapid solidification conditions, the hexagonal basal plane of (0001)-H type of the α phase tends to align with the (001) type FCC faces of the metastable γ phase. This alignment can be considered to be similar to a directionally solidified chill cast texture. On the other hand, at slower growth rate and at lower arc current value not only a larger quantity of α phase forms, but for accommodation of these larger number of α grains in the thinner section of splats there appears to be a need for a change in the growth morphology. (100)-R type rhombohedral faces, with shorter axial dimensions were found to align in preference to the directional solidified (0001)-H type basal planar arrangement. This type of change in growth morphology can possibly accommodate more α grains for the same thickness of the splat as compared to a basal plane (0001)-H type arrangement. © 2008 Elsevier B.V. All rights reserved.
About the journal
JournalSurface and Coatings Technology
ISSN02578972
Open AccessNo
Concepts (43)
  •  related image
    Agricultural products
  •  related image
    Cavity resonators
  •  related image
    Ecology
  •  related image
    Growth rate
  •  related image
    Morphology
  •  related image
    ORE TREATMENT
  •  related image
    Pesticides
  •  related image
    Plasma enhanced chemical vapor deposition
  •  related image
    Plasma jets
  •  related image
    Plasma spraying
  •  related image
    Plasma stability
  •  related image
    Plasmas
  •  related image
    Poles
  •  related image
    Protective coatings
  •  related image
    Rapid solidification
  •  related image
    Scanning
  •  related image
    Sprayed coatings
  •  related image
    Spraying
  •  related image
    Steel analysis
  •  related image
    Titanium dioxide
  •  related image
    Titanium oxides
  •  related image
    TITANIUM PLATING
  •  related image
    (1 1 1) ORIENTATION
  •  related image
    (111) TEXTURE
  •  related image
    (2+1) DIMENSIONS
  •  related image
    (i ,j) conditions
  •  related image
    AIR PLASMA SPRAY PROCESS
  •  related image
    ARC CURRENTS
  •  related image
    Basal planes
  •  related image
    DIRECTIONALLY SOLIDIFIED (DS)
  •  related image
    ELECTRON BACK-SCATTERED DIFFRACTION (EBSD)
  •  related image
    ELSEVIER (CO)
  •  related image
    GROWTH MORPHOLOGIES
  •  related image
    IMAGE MAPPING
  •  related image
    Microscopic study
  •  related image
    PHASE FORMS
  •  related image
    PLANAR ARRANGEMENT
  •  related image
    PLASMA GAS FLOW RATES
  •  related image
    POLE FIGURES
  •  related image
    Processing parameters
  •  related image
    SPRAYED CONDITIONS
  •  related image
    TITANIA COATINGS
  •  related image
    Phase stability