TiO-based coatings prepared by plasma spraying in air of Ti + C mixtures

2006 ◽  
Vol 21 (7) ◽  
pp. 1770-1774 ◽  
Author(s):  
B. Haller ◽  
A. Grimaud ◽  
J-C. Labbe ◽  
J-P. Bonnet
Keyword(s):  
Phase Composition ◽  
Cast Iron ◽  
Liquid Metal ◽  
Plasma Spraying ◽  
Thermal Spraying ◽  
Titanium Monoxide ◽  
Optimal Conditions ◽  
Stoichiometric Mixture ◽  
Excess Carbon ◽  
Gas Tight

This work presents an original way for preparing TiO-based coatings by thermal spraying. As titanium monoxide is oxidized by the mere trace of oxygen contained in hydrogen, it is obvious that plasma spraying of TiO powder does not lead easily to the formation of a titanium monoxide coating. However, thermodynamical calculations show that the conditions necessary for the preparation of TiO can be reached, at the titanium melting temperature (Tm=1933 K), when oxygen reacts with liquid metal in the presence of excess carbon. These results have led to experiments in which TiO-based coatings have been prepared by spraying a stoichiometric mixture of graphite and titanium grains onto cast iron in air. In optimal conditions, a gas-tight hard coating (1000 ± 15 HV3) of a TiO-based phase (composition: TiO0.81±0.06C0.04±0.02) has been obtained.

scholarly journals Coatings of Carbide-Metal Systems (Cr3C2-NiCr and WC-Co-Cr) Deposited by High-Velocity Atmospheric Plasma Spraying from Specially Modified Fine-Grained Powders

2018 ◽  
Vol 1 (1) ◽  
pp. 18-23
Author(s):  
Vadim Verlotski ◽  
Keyword(s):  
Plasma Spraying ◽  
High Speed ◽  
Plasma Deposition ◽  
Thermal Spraying ◽  
Atmospheric Plasma ◽  
Metal Particles ◽  
Fine Grained ◽  
Plasma Torches ◽  
Carbide Coatings ◽  
Gas Tight

In this article, the author poses and responds to a provocative question that has practically ceased to be asked in the field of thermal spraying of carbide coatings: Is the current worldwide trend of using only unmelted metal particles to form coatings (HVOF, HVAF and cold spray methods) correct, and is the deposition of completely melted powders (plasma spraying methods) really outdated? The results of high-speed plasma deposition of new carbide powders allowed the author to prove that only coatings from molten particles can solve the main problem of such coatings, namely the problem of permeability along the grain boundaries. Through the use of modern Axial III plasma torches combined with optimized fine-grained powders, it has been possible to create Cr3C2-NiCr as well as WC-Co-Cr gas-tight layers.

Improvement of Solution Type Plasma Spraying Process

2005 ◽  
Vol 502 ◽  
pp. 505-510 ◽  
Author(s):  
Masami Futamata ◽  
Xiaohui Gai ◽  
Toyokazu Mizumoto ◽  
Kimio Nakanishi
Keyword(s):  
Mechanical Properties ◽  
Plasma Spraying ◽  
Hollow Cathode ◽  
Thermal History ◽  
Thermal Spraying ◽  
Physical And Mechanical Properties ◽  
Good Reproducibility ◽  
Solution Type ◽  
Plasma Spraying Process ◽  
Spraying Process

To fabricate thermal spraying coatings with good reproducibility, it is necessary to improve the process of the equalization of both thermal history and impacting behavior of the particles. In this study, the characteristics of the solution type plasma spraying using the hollow-cathode type torch are investigated. The physical and mechanical properties that are different from usual thermal spraying coatings are described. By using solutions including metal ingredients in a state of ion, colloid or sol, thinner coating that cannot be made by conventional plasma spraying methods is formed on various substrates. The coatings are uniform in appearance.

Peculiarities of the Structure and Phase Composition of Hydroxy Apatite Coatings Sprayed by Laminar Plasma Jet and Treated by Electron Beam

1996 ◽  
Author(s):  
V.A. Klimenov ◽  
Yu. F. Ivanov ◽  
A.V. Karlov ◽  
V.V. Trophimov ◽  
L.B. Bataeva
Keyword(s):  
Electron Beam ◽  
Phase Composition ◽  
Thermal Spraying ◽  
Medical Problem ◽  
Cyclic Strength ◽  
Titanium Implants ◽  
Hydroxy Apatite ◽  
Laminar Plasma Jet ◽  
Scientific Technical ◽  
Titanium Substrates

Abstract The covering of titanium implants by means gas-thermal spraying of hydroxyapatite powders is an actual scientific, technical and medical problem. Application of hydroxyapatite for these purposes is more preferable. However, the problem of its structural and cyclic strength under conditions of bioenvironment response determines of application areas of such coatings and reliability of them usage. Structure and phase composition of hydroxyapatite coating under plasma spraying on titanium substrates and their changing, caused as conditions of forming coating on its increasing, so and conditions of spraying an laminar and turbulent plasma streem were studied. Exact belief about the crystalline structure and phase composition of coating is obtained by methods electronic microscopy and X-ray analysis. Changing of coating structure after sintering in the vacuum and electron beam melting in the vacuum is discussed.

Thermal Spray Processing of WC-Co Nanomaterials

2000 ◽  
Author(s):  
J. Voyer ◽  
B.R. Marple
Keyword(s):  
Phase Composition ◽  
Recent Work ◽  
Phase Analysis ◽  
Thermal Spraying ◽  
Volume Percent ◽  
Wear Properties ◽  
Lower Porosity ◽  
Hvof Thermal Spraying ◽  
Spray Processing ◽  
Sprayed Coatings

Abstract WC-Co based cermets are extensively used in wear applications due to their hardness and toughness. Recent work has demonstrated the potential for using nanoscale constituents to improve the wear properties of these materials. In the present study, two WC-Co powders containing a nanosized WC phase were used to produce coatings by HVOF thermal spraying. These powders had similar properties except for the volume percent binder present: WC-8C0 and WC-12Co. The thermal spraying conditions were varied in order to identify their effect on the microstructure, properties and phase composition of the sprayed coatings. The as-sprayed coatings possess porosity values ranging between 1% and 2% and microhardness values (HV100) from 1150 to 1550, which are quite similar to values obtained for conventionally sized WC-based coatings. For all the coatings, phase analysis indicated significant degradation of the WC phase to produce W2C, W, CO3W3C and Co6W3C. For some spray conditions, even WO3 phase was found in the coatings. The JP-5000 HVOF system produces coatings with lower porosity, similar microhardness values and, more importantly, with lower WC degradation than the coatings produced with the DJ-2700.

Composite ZrO2-Based Cermet Material Modified with Mo

2015 ◽  
Vol 237 ◽  
pp. 3-8 ◽  
Author(s):  
Adriana Wrona ◽  
Kinga Czechowska ◽  
Małgorzata Osadnik ◽  
Małgorzata Kamińska ◽  
Marcin Lis ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Plasma Spraying ◽  
Alloy Coating ◽  
Metallic Material ◽  
Cermet Material ◽  
Powder Composites ◽  
Annealing Procedure ◽  
Plasma Sprayed ◽  
Structure And Microstructure

The work presents studies of a new ceramic-metallic material. The base is a ZrO2-Mo cermet which is modified with metallic Mo or Mo85Re15 alloy coating. The structure and microstructure of Mo85Re15 alloy powders and the composite were characterized. The annealing procedure was found to influence phase composition of powder composites but not their morphology. The plasma sprayed powders, both metallic and alloyed, form coatings that adhere well to the cermet substrate. The coatings show a better homogeneity in comparison to powders and more favourable phase composition.Keywords: cermets, plasma spraying, corrosion resistance

Microstructure and Phase Composition of Composite Coatings Formed by Plasma Spraying of ZrO2 and B4C Powders

2010 ◽  
Vol 19 (4) ◽  
pp. 816-823 ◽  
Author(s):  
P. Karuna Purnapu Rupa ◽  
Prashant Sharma ◽  
R. M. Mohanty ◽  
K. Balasubramanian
Keyword(s):  
Phase Composition ◽  
Plasma Spraying ◽  
Composite Coatings

scholarly journals A Study on the Microstructural Characterization and Phase Compositions of Thermally Sprayed Al2O3-TiO2 Coatings Obtained from Powders and Water-Based Suspensions

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2638 ◽  
Author(s):  
Monika Michalak ◽  
Filofteia-Laura Toma ◽  
Leszek Latka ◽  
Pawel Sokolowski ◽  
Maria Barbosa ◽  
...  
Keyword(s):  
Phase Composition ◽  
Plasma Spraying ◽  
Microstructural Characterization ◽  
Atmospheric Plasma ◽  
Coating Morphology ◽  
Liquid Feedstock ◽  
Α Al2o3 ◽  
Titania Coatings ◽  
Thermal Spray Processes ◽  
Oxygen Fuel

In this work, the alumina (Al2O3) and alumina-titania coatings with different contents of TiO2, i.e., Al2O3 + 13 wt.% TiO2 and Al2O3 + 40 wt.% TiO2, were studied. The coatings were produced by means of powder and liquid feedstock thermal spray processes, namely atmospheric plasma spraying (APS), suspension plasma spraying (SPS) and suspension high-velocity oxygen fuel spraying (S-HVOF). The aim of the study was to investigate the influence of spray feedstocks characteristics and spray processes on the coating morphology, microstructure and phase composition. The results revealed that the microstructural features were clearly related both to the spray processes and chemical composition of feedstocks. In terms of phase composition, in Al2O3 (AT0) and Al2O3 + 13 wt.% TiO2 (AT13) coatings, the decrease in α-Al2O3, which partially transformed into γ-Al2O3, was the dominant change. The increased content of TiO2 to 40 wt.% (AT40) involved also an increase in phases related to the binary system Al2O3-TiO2 (Al2TiO5 and Al2−xTi1+xO5). The obtained results confirmed that desired α-Al2O3 or α-Al2O3, together with rutile-TiO2 phases, may be preserved more easily in alumina-titania coatings sprayed by liquid feedstocks.

Separation of Lanthanides and Actinides in a Chloride Melt - Liquid Metal System: The Effect of Phase Composition

2016 ◽  
Vol 75 (15) ◽  
pp. 397-408 ◽  
Author(s):  
V. A. Volkovich ◽  
D. S. Maltsev ◽  
S. Y. Melchakov ◽  
L. F. Yamshchikov ◽  
A. V. Novoselova ◽  
...  
Keyword(s):  
Phase Composition ◽  
Liquid Metal ◽  
Metal System ◽  
Chloride Melt ◽  
Liquid Metal System
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