Study of the Splat Microstructure, Splat-Substrate Interface, and the Effects of Substrate Heating on the Splat Formation for Ni-Cr Particles Plasma Sprayed on to Aluminum Substrates

2010 ◽  
Vol 19 (5) ◽  
pp. 1115-1130 ◽  
Author(s):  
S. Brossard ◽  
P. R. Munroe ◽  
A. T. T. Tran ◽  
M. M. Hyland
2021 ◽  
Author(s):  
M. Hauer ◽  
M. Meyer ◽  
D. Billieres ◽  
C. Bricquet ◽  
F. Gerstgrasser ◽  
...  

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.


Author(s):  
V. Pershin ◽  
I. Thomson ◽  
S. Chandra ◽  
J. Mostaghimi

Abstract Individual splats are the building blocks of any thermal spray coating. Near the coating-substrate interface, they affect coating properties like adhesion strength. This article examines the effect of substrate heating on droplet splashing. Nickel powder was plasma-sprayed onto a polished stainless steel substrate at various temperatures and the resulting splats were analyzed. Droplet splashing was observed experimentally for three different cases: low substrate temperature, high substrate temperature, and droplet-splat interaction. Mechanisms for splashing were explained with the help of computer-generated nickel droplet impacts. The article proposes that the jetting of molten metal is not triggered by the formation of a central splat but rather a solidified ring on the periphery of the splat. It was observed that, on substrates below 350 deg C, splashing is triggered by solidification at the edge of the spreading droplet. Interactions with previously deposited splats also cause droplets to splash.


Author(s):  
S. Sampath ◽  
J. Matejicek ◽  
C.C. Berndt ◽  
H. Herman ◽  
A.C. Léger ◽  
...  

Abstract This is the second paper of a two part series based on an interdisciplinary research investigation between the University of Limoges, France, and the State University of New York, Stony Brook, USA, aimed at fundamental understanding of the plasma-particle interaction, deposit formation dynamics and microstructure development. In this paper, the microstructure development during plasma spraying of zirconia is investigated from the point of view of deposition parameters and splat formation (part I). Splats and deposits have been produced at Limoges and Stony Brook under controlled conditions of particle parameters and substrate temperatures. The zirconia splat microstructures thus obtained are examined for their shape factors, grain size, crystallographic texture and defects. Further the deposits were analyzed for phases, porosity and mechanical properties in an effort to develop a process-microstructure property relationship. The results suggest a strong role played by the deposition temperature on the microstructure and properties of the deposit.


2013 ◽  
Vol 717 ◽  
pp. 84-89
Author(s):  
Ming Der Jean ◽  
Maw Tyan Sheen

The surface properties of plasma-sprayed partial Y2O3 stabilized ZrO2 coatings with different travel speed and powder-feeder rate of sprayed gun on aluminum substrates have been reported. Several coatings analytical parameters were studied and these factors affecting coating properties were carried out in the plasma-sprayed experiments. Experimental results have shown that the structure of the sprayed coatings that makes relatively diverse in texture for most of the coatings was examined by a SEM. The hardened strength with a low level of a slant of powder-feeder rate became significantly weaker as the travel speed was decreased. Interestingly, the structure of the specimens for the travel speed of 30mm/s is more homogenous than that of the others, indicating a coating with good homogenous structures, while the interfaced structure of the specimens for the powder-feeder rate of 25 mm/s is more homogenous than that of the others, indicating a coating with good adhesive structures. The tendency of the effect of travel speed of sprayed gun on the hardened surface of coatings at powder feeder rate of sprayed gun varied to 30g/min from 20g/min seems to be apparent.


1997 ◽  
Vol 305 (1-2) ◽  
pp. 35-47 ◽  
Author(s):  
L. Bianchi ◽  
A.C. Leger ◽  
M. Vardelle ◽  
A. Vardelle ◽  
P. Fauchais

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