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

R. Venkataraman, S. Pabla Singh, B. Venkataraman, D. K. Das, L. C. Pathak, S. Ghosh Chowdhury, R. N. Ghosh, D. Ravichandra, G. V. Narasima Rao, Keasavan Nair, Rajesh Kathirkar

Research output: Contribution to journalArticle

6 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)5074-5083
Number of pages10
JournalSurface and Coatings Technology
Volume202
Issue number21
DOIs
Publication statusPublished - 30-07-2008
Externally publishedYes

Fingerprint

plasma spraying
Plasma spraying
Aluminum Oxide
Alumina
aluminum oxides
titanium
Titanium
Scanning
coatings
Coatings
arcs
scanning
Electrons
Poles
Plasma Gases
Plasmas
Rapid solidification
electrons
Metastable phases
poles

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Venkataraman, R. ; Pabla Singh, S. ; Venkataraman, B. ; Das, D. K. ; Pathak, L. C. ; Ghosh Chowdhury, S. ; Ghosh, R. N. ; Ravichandra, D. ; Narasima Rao, G. V. ; Nair, Keasavan ; Kathirkar, Rajesh. / 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. In: Surface and Coatings Technology. 2008 ; Vol. 202, No. 21. pp. 5074-5083.
@article{b961e6858cf64f8d8b24f561b9d7d578,
title = "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",
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.",
author = "R. Venkataraman and {Pabla Singh}, S. and B. Venkataraman and Das, {D. K.} and Pathak, {L. C.} and {Ghosh Chowdhury}, S. and Ghosh, {R. N.} and D. Ravichandra and {Narasima Rao}, {G. V.} and Keasavan Nair and Rajesh Kathirkar",
year = "2008",
month = "7",
day = "30",
doi = "10.1016/j.surfcoat.2008.03.039",
language = "English",
volume = "202",
pages = "5074--5083",
journal = "Surface and Coatings Technology",
issn = "0257-8972",
publisher = "Elsevier",
number = "21",

}

Venkataraman, R, Pabla Singh, S, Venkataraman, B, Das, DK, Pathak, LC, Ghosh Chowdhury, S, Ghosh, RN, Ravichandra, D, Narasima Rao, GV, Nair, K & Kathirkar, R 2008, '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', Surface and Coatings Technology, vol. 202, no. 21, pp. 5074-5083. https://doi.org/10.1016/j.surfcoat.2008.03.039

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. / Venkataraman, R.; Pabla Singh, S.; Venkataraman, B.; Das, D. K.; Pathak, L. C.; Ghosh Chowdhury, S.; Ghosh, R. N.; Ravichandra, D.; Narasima Rao, G. V.; Nair, Keasavan; Kathirkar, Rajesh.

In: Surface and Coatings Technology, Vol. 202, No. 21, 30.07.2008, p. 5074-5083.

Research output: Contribution to journalArticle

TY - JOUR

T1 - 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

AU - Venkataraman, R.

AU - Pabla Singh, S.

AU - Venkataraman, B.

AU - Das, D. K.

AU - Pathak, L. C.

AU - Ghosh Chowdhury, S.

AU - Ghosh, R. N.

AU - Ravichandra, D.

AU - Narasima Rao, G. V.

AU - Nair, Keasavan

AU - Kathirkar, Rajesh

PY - 2008/7/30

Y1 - 2008/7/30

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=46949092252&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=46949092252&partnerID=8YFLogxK

U2 - 10.1016/j.surfcoat.2008.03.039

DO - 10.1016/j.surfcoat.2008.03.039

M3 - Article

VL - 202

SP - 5074

EP - 5083

JO - Surface and Coatings Technology

JF - Surface and Coatings Technology

SN - 0257-8972

IS - 21

ER -