scholarly journals Effect of Shroud in Plasma Spraying on Chemical Composition and Thickness of Titanium Coatings

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 446
Author(s):  
Hong Zhou ◽  
Cheng Peng
Keyword(s):  
Chemical Composition ◽  
Plasma Spraying ◽  
Air Entrainment ◽  
Deposition Efficiency ◽  
Quantitative Chemical Analysis ◽  
Air Plasma ◽  
Lower Oxygen ◽  
Titanium Coatings ◽  
Plasma Sprayed ◽  
Steel Substrates

Titanium and its alloys are wildly used in industries. Shrouded plasma spray can be considered as a useful technology to produce low oxide containing titanium coatings. In this paper, the effect of shroud in plasma spraying on chemical composition and thickness of titanium coatings were investigated. Shrouded plasma-sprayed titanium coatings were deposited onto mild steel substrates. Air plasma-sprayed titanium coatings were also deposited for comparison under the same spraying parameters. Those titanium coatings were then studied in terms of microstructure, oxygen and nitrogen contents and coating’s thickness. The titanium coatings were assessed by scanning electron microscopy and quantitative chemical analysis. The results showed that the shroud played a key role in protecting the particles from oxidation in flight. The shrouded titanium coatings exhibited lower oxygen content and an enhanced microstructure. The reduction in air entrainment with the shroud resulted in better heating of the particles and increases in deposition efficiency and coating thickness.

scholarly journals Porosity and Micro-Hardness of Shrouded Plasma Sprayed Titanium Coatings

2019 ◽  
Vol 793 ◽  
pp. 73-77
Author(s):  
Hong Zhou
Keyword(s):  
Plasma Spray ◽  
Gas Flow ◽  
Vickers Microhardness ◽  
Air Entrainment ◽  
Optical Microscope ◽  
Oxide Content ◽  
Air Plasma ◽  
Titanium Coatings ◽  
Mechanical Properties And Corrosion ◽  
Plasma Sprayed

Titanium and its alloys are often used as key materials for corrosion protection. A promising approach to optimize both mechanical properties and corrosion resistance is the use of coating technologies. In this paper, shrouded plasma spray was used as a useful technology to produce low oxide containing titanium coatings. A solid shroud was used to plasma spray titanium coatings to reduce the oxide content. The titanium coatings were assessed by optical microscope, scanning electron microscopy and Vickers microhardness testing. The results showed that the shrouded titanium coatings exhibited an enhanced microstructure. The presence of the shroud and shroud gas flow led to a significant reduction in coating porosity because the reduction in air entrainment with the shroud resulted in better heating of the particles. The shrouded titanium coatings had a lower value of Vickers microhardness and a relative lower standard deviation than the air plasma sprayed titanium coatings.

Laser Sintering of Nano-Al2O3 Powders on Plasma Sprayed Ceramic Based Coatings

2007 ◽  
Author(s):  
Lida Shen ◽  
Yinhui Huang ◽  
Zongjun Tian ◽  
Guoran Hua
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Bond Coat ◽  
Continuous Wave ◽  
Ceramic Coatings ◽  
Laser Sintering ◽  
Al2o3 Ceramic ◽  
Plasma Sprayed ◽  
Steel Substrates

This paper describes an investigation of nano-Al2O3 powders reinforced ceramic coatings, which has included NiCrAl and Al2O3+13%wt.TiO2 coats pre-produced by atmosphere plasma spraying, implemented by laser sintering. Commercial NiCrAl powders were plasma sprayed onto 45 Steel substrates to give a bond coat with thickness of ∼100μm. The 600μm thick Al2O3+13%wt.TiO2 based coating was also plasma sprayed on top of the NiCrAl bond coat. With 2.5kw continuous wave CO2 laser, nano-Al2O3 ceramic powders were laser sintered on the based Coatings. The micro structure and chemical composition of the modified Al2O3+13%wt.TiO2 coatings were analyzed by such detection devices as scanning electronic microscope (SEM) and x-ray diffraction (XRD). Microhardness, wear resistance and corrosion resistance of the modified coatings were also tested and compared with that of the unmodified. The results show that the crystal grain size of Al2O3 had no obvious growth. In addition, due to the nanostructured Al2O3 ceramic phases, the coatings exhibited higher microhardness, better wear resistance and corrosion resistance than those unmodified counterparts. The complex process of plasma spraying with laser sintering as a potential effective way of the application of ceramic nano materials was also simply discussed and summarized in the end.

Microstructure and Oxidation Behavior of Molybdenum Disilicide Coating Prepared by Air Plasma Sprayed

2011 ◽  
Vol 686 ◽  
pp. 583-588 ◽  
Author(s):  
Jian Hui Yan ◽  
Si Wen Tang ◽  
Jian Guang Xu
Keyword(s):  
Plasma Spraying ◽  
Gas Turbines ◽  
Hexagonal Lattice ◽  
Molybdenum Disilicide ◽  
Temperature Structure ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Plasma Sprayed ◽  
Molybdenum Disilicide Coating ◽  
Oxidation Behaviors

Intermetallics molybdenum dislicied has a great potential as a protective coating in aircraft engines and gas turbines in the elevated temperature. The suit for plasma spraying MoSi2powders were prepared by spray drying process and vacuum sintered. The oxidation behaviors of the coating were determined at 1200 °C. The coatings as sprayed and oxidized were characterized by XRD, SEM and EDS. Results show that the flow ability and loose density of MoSi2powder by sintered treatment, were 17.1 s/50g and 2.1g/cm3, respectively, ideal for air plasma spraying. During the course of spraying, some of molybdenum disilicide with a tetragonal lattice was converted into molybdenum disilicide with a hexagonal lattice. Also, part of MoSi2 phase oxidized and transformed to Mo5Si3phase. A relative dense molybdenum disilicide coating was prepared by air plasma spraying. A protective SiO2layer, seems to be glassy, with a thickness about 10 μm was formed on the surface of MoSi2coating during MoSi2coating oxidized at 1200°C for 200 h. The results of the oxidation tests show that MoSi2coating prepared by air plasma spraying may be provide a protect layer for high temperature structure material.

Investigation of High Emissivity Coatings Prepared by Plasma Spraying

2011 ◽  
Vol 287-290 ◽  
pp. 2283-2287
Author(s):  
Can Wang ◽  
Quan Sheng Wang ◽  
Xian Jin Ning ◽  
Zhong Du ◽  
Yan Bo Liu ◽  
...  
Keyword(s):  
Bond Strength ◽  
Bulk Density ◽  
Plasma Spraying ◽  
Infrared Emissivity ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Feedstock Powder ◽  
Plasma Sprayed ◽  
Normal Emissivity ◽  
High Emissivity

In this study, the feedstock powder for plasma spray was prepared by spray drying and post-sintering at 1360 °C using raw metal oxides. The high emissivity coating was deposited by air plasma spraying (APS). The microstructure, phase structure, flowability and bulk density of the plasma sprayed powder were characterized. The microstructure, bond strength and infrared emissivity of the high emissivity coating were also analyzed in this paper. The results reveal that the feedstock powder present good flowability of 42.36 (sp50g) with the bulk density of 1.94 gpml and is suitable for plasma spraying. A dense coating with the bond strength of 39.6MPa and the porosity less than 5 percent was prepared successfully. The normal emissivity of the coating in all waveband is 0.88 at 300°C and 0.87 at 600°C.

THE PERFORMANCES OF TiN-TiB2 COATING PREPARED BY REACTIVE PLASMA SPRAYING

2012 ◽  
Vol 19 (03) ◽  
pp. 1250028
Author(s):  
JING MA ◽  
JIANWEN HU ◽  
DONGQING YAN ◽  
ZHENGPING MAO
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Plasma Spraying ◽  
Nacl Solution ◽  
Reactive Plasma Spraying ◽  
Reactive Plasma ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Tib2 Coating

Reactive plasma sprayed coatings were prepared on carbon steel substrates with Ti and B4C as starting materials. Two kinds of gases ( Ar and N2 ) were used as feeding gases for powders, respectively. 10 wt.% Cr was added in the powders as binder to increase the bond strength of the coating. The phases, microstructure, micro-hardness and corrosion polarization behavior in 3.5 wt.% NaCl solution of the two coatings were studied. The results show that TiN-TiB2 coatings were prepared under both conditions. The two coatings have typically laminated structure. However, the coating prepared with Ar as feeding gas has higher porosity and some unmelted Cr particles. It also contains certain content of titanium oxides. The microhardness of coating prepared with Ar as feeding gas is lower due to its higher porosity, unmelted Cr particles and some amounts of TiO2 . The corrosion resistance of TiN-TiB2 coating prepared with Ar as feeding gas in 3.5 wt.% NaCl solution is worse than that of the coating prepared with N2 as feeding gas. Yet the corrosion resistance of reactive plasma sprayed TiN-TiB2 coating is improved greatly compared with that of carbon steel. The thermodynamic analysis of reactive plasma spraying process is also discussed.

Electrical Property Characterization of Plasma Sprayed Polycrystalline Silicon

2009 ◽  
Vol 620-622 ◽  
pp. 303-306 ◽  
Author(s):  
Ya Ran Niu ◽  
Xuan Yong Liu ◽  
Yi Zeng ◽  
Xue Bin Zheng ◽  
Heng Ji ◽  
...  
Keyword(s):  
Electrical Property ◽  
Plasma Spraying ◽  
Air Plasma ◽  
Free Standing ◽  
Vacuum Plasma Spraying ◽  
Significant Difference ◽  
Plasma Sprayed ◽  
Silicon Based ◽  
Property Characterization

Silicon-based materials have been widely applied in industrial fields, such as microelectronic and solar power, for the specific electronic properties. In the present work, free-standing thick silicon coatings were fabricated by air plasma spraying (APS) and vacuum plasma spraying (VPS) technologies. The microstructure and electrical property of the coatings were characterized. It was found that the electrical resistance of APS-Si coating was higher than that of VPS-Si coating. The impedance spectroscopy results showed there was significant difference in impedance curves of APS-Si and VPS-Si coatings. The grain boundary semicircle appeared in the plot of VPS-Si coating, while did not appeared in that of APS-Si coating. It was thought that the electrical property difference of the two kind coatings was related with the oxidation and microstructure difference of the coatings.

Microstructure of Atmospheric Plasma Sprayed (Al,Cr)2O3-TiO2 Coatings from Blends

2021 ◽  
Author(s):  
Maximilian Grimm ◽  
Rico Drehmann ◽  
Thomas Lampke ◽  
Susan Conze ◽  
Lutz-Michael Berger
Keyword(s):  
Solid Solution ◽  
Plasma Spraying ◽  
Chromium Content ◽  
Defect Density ◽  
Deposition Efficiency ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Tio2 Content ◽  
Tio2 Coatings ◽  
Plasma Sprayed

Abstract This study investigates the microstructure and hardness of coatings produced by atmospheric plasma spraying using a commercial (Al,Cr)2O3 solid solution (ss) powder blended with various amounts of TiO2. The microstructures were analyzed using SEM, EDS, and XRD measurements. It was shown that blending with TiO2 reduces porosity and defect density while increasing deposition efficiency and microhardness. Small amounts of Ti in ss (Al,Cr)2O3 splats were detected in coatings prepared from blends with higher TiO2 content. Variations in aluminum and chromium content were also observed.

Comparison of Plasma-Sprayed Coatings Produced in Argon or Nitrogen Atmosphere

1997 ◽  
Author(s):  
M. Leylavergne ◽  
A. Vardelle ◽  
B. Dussoubs ◽  
N. Goubot
Keyword(s):  
Plasma Spraying ◽  
Nitrogen Atmosphere ◽  
Cryogenic Cooling ◽  
Ambient Atmosphere ◽  
Air Plasma ◽  
Spray Process ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Thick Coatings ◽  
Sprayed Coatings

Abstract When spraying is conducted in the ambient atmosphere, the entrainment of air cools down the plasma jet and affects its expansion. It may also cause the oxidation or the chemical decomposition of the sprayed materials. Inert Plasma Spraying (IPS), generally conducted in argon atmospheres, prevents these phenomena. However, the main drawbacks of IPS in comparison with air plasma spraying are the capital and apparating costs. To reduce the latter by 25 to 30%, nitrogen atmospheres may be used as a substitute for the conventional argon atmosphere. This paper presents a study in which titanium carbide and niobium powders were sprayed in argon and nitrogen atmospheres. Cryogenic cooling of the substrate was used during the spray process. This helps to maintain a low temperature in the chamber, produces thick coatings and allows the use of substrate materials that are sensitive to heat. The adhesion, roughness and microstructure of the coatings produced in both atmospheres are compared as well as their nitrogen content.

scholarly journals Corrosion and Wear Resistance of Fe-Based Amorphous Coatings

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 73 ◽  
Author(s):  
Guang Li ◽  
Youyi Gan ◽  
Chenheng Liu ◽  
Yu Shi ◽  
Yanchun Zhao ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Laser Cladding ◽  
Wear Behavior ◽  
Corrosion And Wear ◽  
Uniform Corrosion ◽  
Supersonic Plasma ◽  
Lower Porosity ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Amorphous Coatings

Fe-based amorphous coatings were prepared on the surface of 45 steel substrates via supersonic plasma spraying and laser cladding. The corrosion and wear behavior of the two different coatings were investigated. Compared with supersonic plasma spraying, laser cladding resulted in coatings with a relatively denser structure, lower porosity, less cracks, and a good metallurgical bond with the substrate. Thanks to these properties, coatings produced by laser cladding exhibit a higher ability to resist uniform corrosion and better friction and wear performance than plasma-sprayed coatings.

scholarly journals Titanium Plasma-Sprayed Coatings on Polymers for Hard Tissue Applications

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2536 ◽  
Author(s):  
Artur Wypych ◽  
Piotr Siwak ◽  
Daniel Andrzejewski ◽  
Jaroslaw Jakubowicz
Keyword(s):  
Plasma Spraying ◽  
Bending Test ◽  
Nanoindentation Test ◽  
Good Adhesion ◽  
Polymer Substrates ◽  
Appropriate Behavior ◽  
Titanium Coatings ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

The paper presents the results of titanium plasma spraying (TPS) on polymer substrates. Polyethylene (PE300), polyamide PA6, and fiber glass-reinforced polyamide (PA6.6-GF30) were used as substrates. The PE300 and PA6.6-GF30 substrates exhibited appropriate behavior during the TPS process, whereas the PA6 substrate did not “accept” Ti during plasma spraying, and the coating did not form. The TPS coatings exhibited low porosity and high homogeneity, and they had a typical multilayer structure composed of Ti and its oxides. The nanoindentation test showed good mechanical properties of the coatings and demonstrated a hardness and a Young’s modulus of approximately 400 HV and 200 GPa, respectively. The bending test confirmed the good adhesion of the titanium coatings to the polymer substrates. The Ti coatings did not fall off the substrate after its significant bending deformation.

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