scholarly journals Cracking caused by cutting of plasma-sprayed hydroxyapatite coatings and its relation to the structural features of coatings deposited at different initial substrate temperatures

2017 ◽  
Vol 71 (3) ◽  
pp. 241-249
Author(s):  
Bojan Gligorijevic ◽  
Miroljub Vilotijevic ◽  
Maja Scepanovic ◽  
Radovan Radovanovic ◽  
Nenad Radovic
Keyword(s):  
Phase Composition ◽  
Structural Features ◽  
Cutting Conditions ◽  
Splat Morphology ◽  
Splat Formation ◽  
Micro Cracks ◽  
Initial Substrate ◽  
Preheating Of Substrate ◽  
Plasma Sprayed ◽  
Substrate Temperatures

The present study estimated the cracking phenomenon in as-plasma-sprayed hydroxylapatite coatings (HACs) after they were being subjected to the severe cutting conditions in the direction perpendicular to the coating/substrate interface. In order to evaluate the effects of substrate preheating on the occurrence of micro-cracks, the HACs were deposited at different initial substrate temperatures (TS = 20, 100 and 200?C). The changes in phase composition and HA splat morphology with TS were observed and were correlated with the cracking occurrence. The results showed that severe cutting conditions introduced a localized cracking in the regions of HACs dominantly attributed to the brittle hydroxyl-deficient amorphous calcium phosphate (ACP) phase. This effect was particularly observable in the HACs deposited without preheating of substrate. On the other hand, the preheating of substrate reduced the presence of micro-cracks and caused insignificant changes in the average local phase composition. In HACs deposited with preheating of substrate, the HA splats (of which HACs are composed) were thinner and recrystallized HA regions seemed smaller in size and more evenly distributed. These results implied potentially important roles of the HA splat formation mechanism on the distribution of ACP and recrystallized HA regions in the as-plasma-sprayed HACs and the cracking resistance of HACs.

Generation of Alumina Plasma Sprayed Coatings on Alumina Substances

1996 ◽  
Author(s):  
L. Bianchi ◽  
A. Denoirjean ◽  
P. Fauchais ◽  
O. Postel
Keyword(s):  
Crystal Growth ◽  
Phase Structure ◽  
Alpha Phase ◽  
Splat Morphology ◽  
Splat Formation ◽  
Force Microscopy ◽  
Spraying Parameters ◽  
Splat Thickness ◽  
Influence Of Substrate ◽  
Plasma Sprayed

Abstract The influence of alumina substrate temperature and phase structure : columnar gamma phase, columnar alpha phase and granular alpha phase on splat formation and crystal growth has been studied by SEM and Atomic Force Microscopy. X Ray Diffraction at low angle has allowed to obtain informations on phase structure of layered splats according to substrate phase structure and coating thickness. Column sizes of splats are correlated to a ID model of splat cooling showing the influence of substrate thermal properties and splat thickness on crystal growth kinetic. Finally, coatings adhesion-cohesion values function of spraying parameters are in good agreement with splat morphology and microstructural evolution.

Influence of Substrate Temperature and Hydrothermal Treatment on the Phase Composition of Plasma-Sprayed Phosphate Coatings

2021 ◽  
Vol 57 (6) ◽  
pp. 598-602
Author(s):  
V. I. Kalita ◽  
D. I. Komlev ◽  
A. A. Radyuk ◽  
V. S. Komlev ◽  
V. F. Shamrai ◽  
...  
Keyword(s):  
Phase Composition ◽  
Substrate Temperature ◽  
Hydrothermal Treatment ◽  
Phosphate Coatings ◽  
Influence Of Substrate ◽  
Plasma Sprayed

Modeling of Oxidation of Plasma-Sprayed Molybdenum Coatings

2000 ◽  
Author(s):  
Y.P. Wan ◽  
X.Y. Jiang ◽  
H. Zhang ◽  
S. Sampath ◽  
V. Prasad ◽  
...  
Keyword(s):  
Spray Deposition ◽  
Mechanical Energy ◽  
Particle Surface ◽  
Conservation Equation ◽  
Type Model ◽  
Energy Conservation Equation ◽  
Thin Oxide Film ◽  
Molten Particle ◽  
Plasma Sprayed ◽  
Substrate Temperatures

Abstract A model for oxidation of molybdenum particles during plasma spray deposition is developed. The diffusion of metal an-ions or oxygen cat-ions through a thin oxidized film, chemical reactions on the surface, and diffusion of oxidant in gas phase are considered as possible rate-controlling mechanisms with controlling parameters as the temperature of the particle surface, and local oxygen concentration and flow field surrounding the particle. The deposition of molten particle and its rapid solidification and deformation is treated using a Madejski-type model, in which the mechanical energy conservation equation is solved to determine the splat deformation and one-dimensional heat conduction equation with phase change is solved to predict the solidification and temperature evolution. Calculations are performed for a single molybdenum particle sprayed under the Sulzer Metco-9MB spraying conditions. Results show that the mechanism that controls the oxidation of this droplet is the diffusion of metal/oxygen ions through a very thin oxide film. A higher substrate temperature results in a larger rate of oxidation at the splat surface, and hence, a larger oxygen content in the coating layer. Compared to the oxidation of droplet during m-flight, the oxidation during deposition is not weak and can become dominant at high substrate temperatures.

Composite ZrO2-Based Cermet Material Modified with Mo

2015 ◽  
Vol 237 ◽  
pp. 3-8 ◽  
Author(s):  
Adriana Wrona ◽  
Kinga Czechowska ◽  
Małgorzata Osadnik ◽  
Małgorzata Kamińska ◽  
Marcin Lis ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Plasma Spraying ◽  
Alloy Coating ◽  
Metallic Material ◽  
Cermet Material ◽  
Powder Composites ◽  
Annealing Procedure ◽  
Plasma Sprayed ◽  
Structure And Microstructure

The work presents studies of a new ceramic-metallic material. The base is a ZrO2-Mo cermet which is modified with metallic Mo or Mo85Re15 alloy coating. The structure and microstructure of Mo85Re15 alloy powders and the composite were characterized. The annealing procedure was found to influence phase composition of powder composites but not their morphology. The plasma sprayed powders, both metallic and alloyed, form coatings that adhere well to the cermet substrate. The coatings show a better homogeneity in comparison to powders and more favourable phase composition.Keywords: cermets, plasma spraying, corrosion resistance

Structure, Phase Composition, and Wear Mechanisms of Plasma-Sprayed NiCrSiB–20 wt.% TiB2 Coating

2015 ◽  
Vol 53 (11-12) ◽  
pp. 663-671 ◽  
Author(s):  
A. P. Umanskii ◽  
M. S. Storozhenko ◽  
I. V. Hussainova ◽  
A. E. Terentiev ◽  
A. M. Kovalchenko ◽  
...  
Keyword(s):  
Phase Composition ◽  
Wear Mechanisms ◽  
Structure Phase ◽  
Plasma Sprayed ◽  
Tib2 Coating

Phase composition and its changes during annealing of plasma-sprayed YSZ

2000 ◽  
Vol 127 (2-3) ◽  
pp. 120-129 ◽  
Author(s):  
Jan Ilavsky ◽  
Judith K. Stalick
Keyword(s):  
Phase Composition ◽  
Plasma Sprayed
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