The Structure of an Interlayer used to Improve the Adhesion of Plasma Sprayed Al2O3 Coatings on to a Steel Substrate

2020 ◽  
pp. 275-281
Author(s):  
J. M. Guilemany ◽  
J. Nutting ◽  
J. Portillo ◽  
M. Urban
Keyword(s):  
Steel Substrate ◽  
Plasma Sprayed

Formation of Grain Structures of Thermal Sprayed Nickel Coatings and the Coating Properties

2005 ◽  
Vol 502 ◽  
pp. 517-0
Author(s):  
Kenji Murakami
Keyword(s):  
Steel Substrate ◽  
Nickel Coatings ◽  
Grain Structures ◽  
Heat Treated ◽  
Columnar Grains ◽  
Different Temperatures ◽  
Plasma Sprayed ◽  
Equiaxed Grains ◽  
Sprayed Coatings ◽  
Lamellar Interfaces

Pure nickel powder was low pressure plasma sprayed onto a steel substrate held at different temperatures during spraying. The as-sprayed coatings consist of columnar grains whose axes are nearly perpendicular to the lamellae composing the coatings. As the coating temperature becomes higher, the length of the columnar grains increases and is longer than the thickness of the lamellae, indicating the growth of the grains across the lamellar interfaces during spraying. On the other hand, the coatings that were heat treated after spraying consist of coarse equiaxed grains. The coatings that experienced high temperatures during spraying or the heat treated coatings have large porosity and contain large globular pores. The hardness, apparent density and the tensile strength of the coating itself were the highest for the coating prepared at a low temperature and became low on heat treatment. The thermal conductivity in the direction perpendicular to the coating was the largest for the coating that consisted of long columnar grains.

Splashing of Nickel Droplets During Plasma Spraying

2000 ◽  
Author(s):  
V. Pershin ◽  
I. Thomson ◽  
S. Chandra ◽  
J. Mostaghimi
Keyword(s):  
Substrate Temperature ◽  
Nickel Powder ◽  
Steel Substrate ◽  
Spray Coating ◽  
Building Blocks ◽  
Thermal Spray Coating ◽  
Substrate Heating ◽  
Polished Stainless Steel ◽  
Plasma Sprayed ◽  
Droplet Impacts

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.

Comparative Evaluation of the Bioactive Behavior of HA and ZrO2 Reinforced Coatings

2011 ◽  
Vol 493-494 ◽  
pp. 447-452
Author(s):  
George Theodorou ◽  
Ourania Menti Goudouri ◽  
Lambrini Papadopoulou ◽  
Nikolaos Kantiranis ◽  
Subramaniam Yugeswaran ◽  
...  
Keyword(s):  
Steel Substrate ◽  
In Vitro Bioactivity ◽  
Biological Fixation ◽  
Metal Implants ◽  
Ha Coating ◽  
Biological Responses ◽  
Before And After ◽  
Sbf Solution ◽  
Plasma Sprayed

The clinical use of plasma-sprayed hydroxyapatite (HA) coatings on metal implants has been widely investigated as the HA coating can achieve the firm and direct biological fixation with the surrounding bone tissue. It is shown in previous studies that the mechanical properties of HA coatings are improved by the addition of ZrO2 particles during the deposition of the coating on the substrate. Subsequently, the cohesive and adhesive strengths of plasma-sprayed hydroxyapatite (HA) coatings were strengthened by the ZrO2 particles addition as a reinforcing agent in the HA coating (HA+ZrO2 composite coating). The aim of the present work is to investigate and evaluate the in vitro bioactivity assessment of HA and HA/ZrO2 coatings, on stainless steel substrate, soaked in c-SBF, in order to study and compare their biological responses. The coatings were produced using vapor plasma spraying (VPS). The characterization of the surface of the coatings before and after soaking in SBF solution was performed using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction analysis (XRD). All samples were smoothed before insertion in the medium and the in vitro bioactivity of all coating samples was tested in conventional Simulated Body Fluid (c-SBF) solution for various immersion times.

Processing and characterisation of plasma sprayed zirconia–alumina–mullite composite coating on a mild-steel substrate

2005 ◽  
Vol 40 (18) ◽  
pp. 5087-5089 ◽  
Author(s):  
S. Das ◽  
S. Ghosh ◽  
A. Pandit ◽  
T. K. Bandyopadhyay ◽  
A. B. Chattopadhyay ◽  
...  
Keyword(s):  
Mild Steel ◽  
Composite Coating ◽  
Steel Substrate ◽  
Plasma Sprayed ◽  
Mild Steel Substrate

Microstructure Characteristics, Tribology and Nano-Hardness of Plasma Sprayed NiCrRe Coating

2020 ◽  
Vol 405 ◽  
pp. 430-434
Author(s):  
Dávid Medved ◽  
Michal Ivor ◽  
Tomasz Chmielewski ◽  
Dariusz Golański ◽  
Katarzyna Pietrzak ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Steel Substrate ◽  
Indentation Modulus ◽  
Boiler Steel ◽  
X Ray ◽  
Spray Process ◽  
Plasma Spray Process ◽  
The Coefficient Of Friction ◽  
Continuous Stiffness Measurement ◽  
Plasma Sprayed

This paper presents the results of the investigation of NiCrRe coating deposited by plasma spray process at the atmospheric pressure on boiler steel substrate. These coatings were characterized by means of a scanning electron microscopy, and Energy-dispersive X-ray spectroscopy. The wear resistance of plasma sprayed NiCrRe coatings has been investigated under dry sliding conditions at applied load of 10 N in air. The continuous stiffness measurement (CSM) method was used for the investigation of nanohardness using Agilent G200 Nano-indenter in order to determine the mechanical properties of the coatings. Microstructural observations pointed out that the NiCr layer with white isles of rhenium possessed porosity, oxidized, un-melted and semi-melted particles, and inclusions. According to the results the thickness of the layer is 450 µm, the indentation modulus 158 ± 24.4 GPa, hardness 3.74 ± 0.76 GPa and the coefficient of friction is 0.45.

Determination of hardness of plasma-sprayed FeCrBSi coating on steel substrate by nanoindentation

2010 ◽  
Vol 528 (1) ◽  
pp. 425-428 ◽  
Author(s):  
Li-Na Zhu ◽  
Bin-Shi Xu ◽  
Hai-Dou Wang ◽  
Cheng-Biao Wang
Keyword(s):  
Steel Substrate ◽  
Plasma Sprayed

Tribological Properties of Plasma-Sprayed 20 wt. % ZrO2-Al2O3-17 wt.% TiO2 Coatings on Plain Carbon Steel Substrate

2012 ◽  
Vol 463-464 ◽  
pp. 420-424
Author(s):  
San Ming Du ◽  
Yong Ping Niu ◽  
Yong Zhen Zhang
Keyword(s):  
Carbon Steel ◽  
Tribological Properties ◽  
Steel Substrate ◽  
Plain Carbon Steel ◽  
X Ray Diffraction ◽  
Properties Of Coatings ◽  
Bond Layer ◽  
Spray Technique ◽  
Pin On Disc ◽  
Plasma Sprayed

In the present study, 20 Wt. % ZrO2-Al2O3-17 wt.% TiO2 powders were sprayed using a plasma-spray technique after a NiAl bond layer was deposited on plain carbon steel substrate. The produced coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) including energy-dispersive spectroscopy (EDS). The tribological properties of coatings against hard alloy ball were investigated by using a pin-on-disc tribo-meter under dry environments. The predominant wear mechanism of coating is fatigue.

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