Efficacy of graphene nanoplatelets on splat morphology and microstructure of plasma sprayed alumina coatings

2019 ◽  
Vol 366 ◽  
pp. 54-61 ◽  
Author(s):  
Xiaolong Lu ◽  
Sadhana Bhusal ◽  
Guangyu He ◽  
Dong Zhao ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Graphene Nanoplatelets ◽  
Splat Morphology ◽  
Alumina Coatings ◽  
Plasma Sprayed

Relationship between Splat Morphology and Property of Plasma Sprayed Alumina Coatings

2004 ◽  
Vol 449-452 ◽  
pp. 925-928 ◽  
Author(s):  
Sachio Oki
Keyword(s):  
Surface Morphology ◽  
Splat Morphology ◽  
Alumina Coatings ◽  
Spray Pattern ◽  
Coating Property ◽  
Microscope Images ◽  
Plasma Sprayed ◽  
The Relationship ◽  
Scanning Electron

New method for characterization of coating microstructures and for evaluation of coating property by means of surface morphology has been proposed. In this paper, the distribution of shape and dimensions of splat was examined using quantitative analysis of scanning electron microscope images from the surface of spray pattern as well as the surface of coating. Results obtained in this study indicate that it is necessary to analyze the spray pattern as well as the surface morphology in order to estimate the coating property by means of the distribution of splat which composes the coating. Moreover, the splats, which are in the interface between the substrate and the coating, should have the same morphology as those of the coating surface. The relationship between splat morphology and the property of coatings was discussed.

Alumina Coatings by Plasma Spraying of Monosize Sapphire Particles

1998 ◽  
Author(s):  
L.C. Erickson ◽  
T. Troczynski ◽  
H.M. Hawthorne ◽  
H. Tai ◽  
D. Ross
Keyword(s):  
High Hardness ◽  
Processing Parameters ◽  
Raw Material ◽  
Splat Morphology ◽  
Alumina Coatings ◽  
Spray Coatings ◽  
Dense Microstructure ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Abstract In an effort to obtain a series of plasma sprayed coatings of controlled microstructure, three mono-sized sapphire powders were deposited using an axial injection torch in which the plasma gas composition and nozzle diameter were the only processing parameters varied. The effects of changes in these parameters on the resultant coating splat morphology, porosity, angular crack distribution and hardness are reported. The uniform, dense microstructure and high hardness of 14 GPa - a level usually only associated with chromia thermal spray coatings - of the best alumina coatings results from use of the combination of tightly controlled processing conditions and mono-disperse precursor powders. The microstructural quality of plasma sprayed coatings and, hence, their properties can be improved significantly by minimizing variations in processing and raw material parameters.

scholarly journals Enhancing Graphene Retention and Electrical Conductivity of Plasma-Sprayed Alumina/Graphene Nanoplatelets Coating by Powder Heat Treatment

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 643
Author(s):  
Xiaoyu Wu ◽  
Shufeng Xie ◽  
Kangwei Xu ◽  
Lei Huang ◽  
Daling Wei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Structural Integrity ◽  
Ceramic Coatings ◽  
Treatment Temperature ◽  
Graphene Nanoplatelets ◽  
Structural Defects ◽  
Temperature Plasma ◽  
Heat Treated ◽  
Plasma Sprayed

Burning loss of graphene in the high-temperature plasma-spraying process is a critical issue, significantly limiting the remarkable performance improvement in graphene reinforced ceramic coatings. Here, we reported an effective approach to enhance the graphene retention, and thus improve the performance of plasma-sprayed alumina/graphene nanoplatelets (Al2O3/GNPs) coatings by heat treatment of agglomerated Al2O3/GNPs powders. The effect of powder heat treatment on the microstructure, GNPs retention, and electrical conductivity of Al2O3/GNPs coatings were systematically investigated. The results indicated that, with the increase in the powder heat treatment temperature, the plasma-sprayed Al2O3/GNPs coatings exhibited decreased porosity and improved adhesive strength. Thermogravimetric analysis and Raman spectra results indicated that increased GNPs retention from 12.9% to 28.4%, and further to 37.4%, as well as decreased structural defects, were obtained for the AG, AG850, and AG1280 coatings, respectively, which were fabricated by using AG powders without heat treatment, powders heat-treated at 850 °C, and powders heat-treated at 1280 °C. Moreover, the electrical conductivities of AG, AG850, and AG1280 coatings exhibited 3 orders, 4 orders, and 7 orders of magnitude higher than that of Al2O3 coating, respectively. Powder heat treatment is considered to increase the melting degree of agglomerated alumina particles, eventually leaving less thermal energy for GNPs to burn; thus, a high retention amount and structural integrity of GNPs and significantly enhanced electrical conductivity were achieved for the plasma-sprayed Al2O3/GNPs coatings.

Use of Different Process Gases for Manufacturing Isolating Alumina Coatings by Flame Spraying with Cords

2021 ◽  
Author(s):  
M. Hauer ◽  
M. Meyer ◽  
D. Billieres ◽  
C. Bricquet ◽  
F. Gerstgrasser ◽  
...  
Keyword(s):  
Volume Resistivity ◽  
Alpha Phase ◽  
Flame Spraying ◽  
Flame Spray ◽  
Alumina Coatings ◽  
Spray Coatings ◽  
Aluminum Hydroxides ◽  
Fine Microstructure ◽  
Plasma Sprayed ◽  
Aluminum Substrates

Abstract This study assesses the quality of flame-sprayed alumina coatings produced from recently developed alumina cord using argon and compressed air as atomizing gases. Coatings of different thicknesses were deposited on aluminum substrates and then analyzed using optical microscopy, X-ray diffraction, and resistivity measurements. The coatings, particularly those sprayed with argon, had fine microstructure and higher surface and volume resistivity than flame-spray coatings made from alumina cord in the past. They were also found to have higher alpha phase content than plasma-sprayed coatings, regardless of the atomizing gas used. The effect of humidity and the possible formation of aluminum hydroxides are also addressed.

Ultrasonic technique for measuring porosity of plasma-sprayed alumina coatings

1997 ◽  
Vol 6 (4) ◽  
pp. 486-488 ◽  
Author(s):  
S. Parthasarathi ◽  
B. R. Tittmann ◽  
E. J. Onesto
Keyword(s):  
Ultrasonic Technique ◽  
Alumina Coatings ◽  
Plasma Sprayed

A Definition of the Topography of Grit-Blasted Surfaces for Plasma Sprayed Alumina Coatings

1999 ◽  
Vol 121 (1) ◽  
pp. 49-53 ◽  
Author(s):  
B. J. Griffiths ◽  
D. T. Gawne ◽  
G. Dong
Keyword(s):  
Surface Topography ◽  
Raw Material ◽  
Height Distribution ◽  
Alumina Coatings ◽  
Definition Of ◽  
The Individual ◽  
Plasma Sprayed ◽  
Individual Particles

This paper describes the topographical implications of grit blasted surfaces on plasma sprayed alumina. The transition of the grit blasted surface from raw material to correctly blasted is described in terms of surface heights, height distribution, spacings and texture. The influence of embedded grit is shown to be significant. The individual particles of alumina impacting the surface are classified into two types, these being disc splats and splash splats. Their deposition relationships with regard to surface topography and adhesion is explained with reference to the two types of splat.

Plasma Sprayed Alumina Coating on Ti6Al4V Alloy for Orthopaedic Implants: Microstructure and Phase Analysis

2012 ◽  
Vol 510-511 ◽  
pp. 547-553 ◽  
Author(s):  
M. Khalid ◽  
M. Mujahid ◽  
Aamer Nusair Khan ◽  
R.S. Rawat ◽  
I. Salam ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Atmospheric Plasma Spraying ◽  
Ti6al4v Alloy ◽  
Atmospheric Plasma ◽  
Alumina Coating ◽  
Splat Morphology ◽  
Cross Sectional ◽  
Arc Current ◽  
Plasma Sprayed ◽  
Sectional Analysis

Alumina was coated on Ti6Al4V alloy by atmospheric plasma spraying. Surface and cross sectional analysis of the coating by SEM showed that diameter and thickness of splat was greatly influenced by arc current and stand-off distance. In turn, this variation in splat morphology had effect on evolution of α-Al2O3 and γ-Al2O3 phases as revealed by XRD. Higher proportion of required γ-Al2O3 phase was achieved at stand-off distance of 130 mm and arc current of 500A.

Sign in / Sign up

Export Citation Format

Share Document