Formation of the Cast Iron Coatings Plasma-Sprayed at Different Substrate Temperatures

2010 ◽  
Vol 44-47 ◽  
pp. 2144-2147
Author(s):  
Ya Zhe Xing ◽  
Chao Ping Jiang ◽  
Hong Chen ◽  
Jian Min Hao
Keyword(s):  
Cast Iron ◽  
Substrate Temperature ◽  
Phase Structure ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Atmospheric Plasma ◽  
Cross Sectional ◽  
The Cross ◽  
Plasma Sprayed ◽  
Iron Coatings

In this work, three cast iron coatings were produced by atmospheric plasma spraying. During spraying, the surface temperature of three coatings (substrate temperature) was controlled to be averagely 50oC, 180oC and 240oC by changing the processing parameters. X-ray diffraction (XRD) was employed to analyze the phase structure of the starting powder and the coatings. The results showed that the powder was mainly composed of (Fe,Cr)7C3 and martensite and both the spraying processing and the substrate temperature exerted no influence on coating phase structure. An optical microscope (OM) was used to characterize the microstructure of the cross-section and surface of the coatings. It was found that the cross sectional hardness increased with the increase of the substrate temperature due to the improvement in interlamellar bonding.

Numerical Study on Rapid Solidification of a Plasma-Sprayed Cast Iron Splat on a High-Temperature Substrate

2009 ◽  
Vol 79-82 ◽  
pp. 1129-1132 ◽  
Author(s):  
Ya Zhe Xing ◽  
Qiu Lan Wei ◽  
Jian Min Hao ◽  
Can Shang
Keyword(s):  
Cast Iron ◽  
Substrate Temperature ◽  
Rapid Solidification ◽  
Numerical Study ◽  
Substrate Surface ◽  
Melt Temperature ◽  
Metallurgical Bonding ◽  
Initial Substrate ◽  
Plasma Sprayed ◽  
Iron Coatings

In this work, an experiment was performed to demonstrate the possibility of the metallurgical bonding in plasma-sprayed cast iron coatings at high substrate temperature. A quantitative analysis of splat cooling and rapid solidification of cast iron splat is then presented. The effect of the substrate temperature on the development of melt undercooling within the splat is investigated in detail. The results indicated that the initial substrate temperature has a profound effect on the development of melt undercooling in a splat, the splat bottom melt temperature, and the substrate surface temperature. A high initial temperature of the substrate restrains the cooling of the splat and leads to a high melt temperature that may promote the grain growth directly on cast iron substrate surface to form the metallurgical bonding.

Effect of Substrate Temperature on Properties of Nano-Scale Functionally Graded Calcium Phosphate Coatings

2006 ◽  
Author(s):  
Travis Blalock ◽  
Xiao Bai ◽  
Afsaneh Rabiei
Keyword(s):  
Electron Microscopy ◽  
Calcium Phosphate ◽  
Substrate Temperature ◽  
Ion Beam ◽  
Processing Parameters ◽  
Functionally Graded ◽  
Cross Sectional ◽  
X Ray ◽  
Phosphate Coatings ◽  
Calcium Phosphate Coatings

The effect of substrate temperature and processing parameters on microstructure and crystallinity of calcium phosphate coatings deposited on heated substrates in an Ion Beam Assisted Deposition (IBAD) system are being studied. The experimental procedures include mechanical testing and film thickness measurements using bonding strength and profilometery. Cross-sectional scanning transmission electron microscopy (STEM) with energy dispersive X-ray spectroscopy (EDX) through the thickness of the film as well as scanning electron microscopy (SEM) with EDX at the top surface of the film was performed to evaluate the microstructure of the film. The coating crystallinity was studied through X-ray diffraction (XRD). The information gained from current analysis on the set temperature coatings will be used to refine the processing techniques of the Functionally Graded Hydroxyapatite (FGHA) coating.

scholarly journals The Morphology Analysis of Plasma-Sprayed Cast Iron Splats at Different Substrate Temperatures via Fractal Dimension and Circularity Methods

2019 ◽  
Vol 38 (2019) ◽  
pp. 692-698
Author(s):  
Qiulan Wei ◽  
Li He ◽  
Zhang Liu ◽  
Xiao Feng ◽  
Ya-Zhe Xing
Keyword(s):  
Fractal Dimension ◽  
Cast Iron ◽  
Substrate Temperature ◽  
Solidification Rate ◽  
Molten Droplet ◽  
Characterization Methods ◽  
Different Temperatures ◽  
Molten Droplets ◽  
The Difference ◽  
Plasma Sprayed

AbstractPlasma-sprayed cast iron splats were deposited onto polished aluminum substrates preheated to different temperatures ranging from 25°C to 250°C. The morphology of single splat was observed by a field emission scanning electron microscope. Quantitative characterization methods, including fractal dimension (FD) and circularity analyses of the splat profile, were employed to identify the difference in morphology of the splats with the change of the substrate temperature. The results showed that the substrate temperature has a significant effect on the spreading of molten droplets and the morphology of resultant splats through changing the solidification rate of the droplets. With the increment of substrate temperature, the homogeneous and sufficient spreading of the droplets resulted from low solidification rate reduces the splashing of the droplets. In addition, the evaporation of adsorbed moisture on the substrate improves the wettability between the spreading droplet and the substrate, then benefits the homogeneous spreading of the molten droplet. As a result, a distinct decline in the FD value was observed. It was also suggested that the FD analysis could be used to characterize the morphology of the splat more effectively while the circularity method was heavily dependent on the area of the 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.

scholarly journals Evaluation of the quality of layers applied by LDT laser metal deposition

2018 ◽  
Vol 19 (6) ◽  
pp. 591-596
Author(s):  
Andrzej Mazurkiewicz ◽  
Andrzej Poprzeczka
Keyword(s):  
Heat Affected Zone ◽  
Heat Dissipation ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Cross Sectional ◽  
Weld Overlay ◽  
The Cross

The article presents the results of a study of C45 carbon steel hardfacing using laser metal deposition with Stellit Co-21 powder. The microstructure of the cross-section of samples prepared with different scanning speed and the amount of used powder at constant laser power was observed. Analyzing the cross-sectional areas of the samples, it was found that, at specific production parameters, cracks occur in weld overlay, which should be associated with the amount of heat supplied and discharged, especially at the unheated basis.This may be confirmed by the presence of deposits of weakly branched dendrites in the microstructure, which should be related to the directional heat dissipation process and rapid directional crystallization. It is possible to regulate these phenomena by selecting appropriate processing parameters. The microstructure analysis of cross-sectional areas of samples after hardfacing using LDT technique indicates good metallurgical quality of the deposit with a small heat affected zone of about 660÷760m. The microhardness measurements on the sample cross-sections indicated a wide micohardness distribution ranging from 510HV1 in the weld overlay, about 410HV1 in the heat affected zone, to 270HV1 in the C45 steel base.

An Improvement of Cr3C2-NiCr Sprayed Coatings Followed by Chromium Diffusion Treatment

1998 ◽  
Author(s):  
J. Takeuchi ◽  
Y. Murata ◽  
Y. Harada ◽  
T. Tomita ◽  
S. Nakahama ◽  
...  
Keyword(s):  
Bond Strength ◽  
Atmospheric Plasma ◽  
Hybrid Technique ◽  
Chromium Diffusion ◽  
Cross Sectional ◽  
Sem Image ◽  
Diffusion Treatment ◽  
Carbide Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Abstract Atmospheric plasma sprayed carbide cermet coatings have more porosity, lower hardness and bond strength compared with HVOF(High Velosity Oxy-Fuel) sprayed coatings. This paper described hybrid technique combined with plasma spraying and metal diffusion treatment in order to get improved denser, harder and higher bond strength coatings. In this study, a pure chromium carbide layer, perfomed on the top of the coating area, was evaluated by cross sectional SEM image, X-ray diffraction analyis, microhardness tests. This perfomed layer showed extremely high density with outstanding hardness values in terms of plasma sprayed carbide coatings has been achieved.

Tribological Properties of Mo/NiCrBSi Thermal Spray Deposits

1998 ◽  
Author(s):  
V. Fervel ◽  
B. Normand ◽  
C. Coddet ◽  
M. Delaet
Keyword(s):  
Cast Iron ◽  
Adhesive Wear ◽  
Tribological Behavior ◽  
Optical Microscope ◽  
Atmospheric Plasma ◽  
Wear Process ◽  
Dry Conditions ◽  
Nicrbsi Coating ◽  
The Difference ◽  
Nicrbsi Coatings

Abstract The tribological behavior of Mo/NiCrBSi coatings obtained by atmospheric plasma spray was studied under dry conditions using an Amsler machine. Discussion is made on the effects of the plasma gas mixture and of the preheating of the substrate. The wear process of Mo/NiCrBSi in situation of dry rolling-sliding contact versus cast iron was observed using a profilometer, an optical microscope, and a scanning electron microscope. It was found that the wear mechanism could be divided into two steps : the first one corresponds to an abrasive wear; it results from the difference in hardness between the counter-specimen and the Mo/NiCrBSi coating. The second one corresponds to an adhesive wear resulting from the transfer of cast iron from the counter-specimen to the coating.

scholarly journals Effect of Vacuum Annealing on the Nickel-Based Coatings Deposited on a CGI Cast Iron through Atmospheric Plasma Spraying

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 963
Author(s):  
Peihu Gao ◽  
Baiyang Chen ◽  
Shencong Zeng ◽  
Zhong Yang ◽  
Yongchun Guo ◽  
...  
Keyword(s):  
Cast Iron ◽  
Adhesion Strength ◽  
Room Temperature ◽  
Vacuum Annealing ◽  
Atmospheric Plasma ◽  
Compacted Graphite ◽  
Graphite Cast Iron ◽  
Nickel Based Alloy ◽  
Sprayed Coating ◽  
Plasma Sprayed

Plasma-sprayed nickel-based self-fusion alloy coatings were annealed in a vacuum at 990, 1020 and 1050 °C for 20 min to increase the bonding between the compacted graphite cast iron substrate and coating, as well as the inner cohesion of the coatings. It was found that nickel and chromium diffused between nickel-based alloy coatings and compacted graphite cast iron substrate. A metallurgical translation zone with a thickness up to 1145 μm formed during the vacuum annealing, which resulted in an enhancement of the adhesion between the coating and substrate. The adhesion strength at room temperature was increased from the as-sprayed coating of 33.4 MPa to the annealed one of 163 MPa. Meanwhile, the adhesion strength at 500 °C reached 146 MPa. Conversely, the inner cohesion of the coating was improved with the particles’ interfaces healed after vacuum annealing. The micro-hardness of the annealed coatings was increased to 902 HV from the as-sprayed one of 578 HV.

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