Mechanofusion Processing of Metal-Oxide Composite Powders for Plasma Spraying

AbstractComposite particles destined to build plasma sprayed coatings, are prepared by the mechanofusion process (MF). These particles consist of a stainless steel core particle coated by finer particles of alumina. Changes induced by the MF process are monitored by SEM, DRX, and laser granulometry, revealing that the dry particle coating process is governed by agglomeration and rolling phenomena. Simultaneously, the MF performance is controlled by the operating parameters such as the compression gap, the mass ratio of host to guest particle, and the powder input rate. The mechanical energy input leads to a nearly rounded shape of the final composite particles; however, no formation of new phases or components decomposition is detected by XRD analysis. The resulting composite powder features optimal characteristics, concerning particle shape and phases distribution, to be plasma sprayed in air.

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Dry Coated Particle for Plasma Spraying

Materials Science Forum ◽

10.4028/www.scientific.net/msf.534-536.37 ◽

2007 ◽

Vol 534-536 ◽

pp. 37-40 ◽

Cited By ~ 2

Author(s):

C. Briones-Rodríguez ◽

Vicente Mayagoitia ◽

Ricardo Cuenca-Alvarez

Keyword(s):

Metal Oxide ◽

Plasma Spraying ◽

Mechanical Energy ◽

Chemical Properties ◽

Xrd Analysis ◽

Carbide Powder ◽

Composite Powders ◽

Coated Particle ◽

Particle Coating ◽

Dry Particle Coating

The performance of an in-house designed mechanofusion process and the preparation of composite powders for plasma spraying are investigated in a variety of powdered mixtures including metal/oxide, carbide/oxide, carbide/metal and metal/oxide/carbide. Scanning electron microscopy shows that dry particle coating depends on the thermo-mechanical and chemical properties of the powdered system. In the metal/oxide, carbide/oxide and metal/oxide/carbide powder mixtures, fine ceramic particles coat the surface of the metallic or ceramic coarser particles with no need of binders or solvents. However with the carbide/metal powdered system, an intimate mixture of components is achieved with an incipient dry particle coating. A nearly rounded shape of the final composite particles is induced by the mechanical energy input with no formation of new phases as confirmed by XRD analysis. It is suggested that the coating mechanism is governed by agglomeration and rolling phenomena. Finally these types of powders feature characteristics to be plasma sprayed in air.

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Novel Zro2-Mullite Composites Produced by Plasma Spraying

Thermal Spray 1998: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc1998p1233 ◽

1998 ◽

Author(s):

K.A. Khor ◽

Y. Li

Keyword(s):

Plasma Spraying ◽

Structural Integrity ◽

Plasma Jet ◽

Distilled Water ◽

Composite Powders ◽

Plasma Flame ◽

Amorphous Phases ◽

Plasma Sprayed Coatings ◽

Plasma Sprayed ◽

Sprayed Coatings

Abstract Zirconia can induce enhanced fracture toughness to a number of ceramics when introduced as a reinforcement either in the form of particulates, dispersed phase or whiskers because of its unique tetragonal-monoclinic (t-*m) transformation. This paper presents the preparation of Zr0 2 reinforced mullite by plasma spraying a mixtures of zircon and alumina. The dissociation of zircon into zirconia and silica in a plasma flame is well-known. Pre-mixed powders of zircon and alumina are injected into a dc plasma jet. The plasma sprayed particles are collected in distilled water and analyzed. The results indicate that the plasma sprayed powders consist of zirconia, zircon and alumina. It was found that fine, mostly amorphous and chemically homogeneous composite powders can be obtained by ball milling and plasma spraying. Recrystallization of amorphous phases and formation of mullite occurred at about 1000 °C in plasma sprayed powders. This value is more than 500 °C lower than the formation of mullite in as-milled powders. Uniform coatings with good structural integrity were obtained by plasma spraying. The amount of amorphous phases was much higher in plasma sprayed coatings than in spheroidized powders, and the relative quantity of mullite in coatings after heat treatment is about 4 times as much as that obtained in the spheroidized powders.

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Effect of the composition of composite powders on the wear resistance of plasma-sprayed coatings

Welding International ◽

10.1533/wint.2006.3714 ◽

2006 ◽

Vol 20 (11) ◽

pp. 918-920

Author(s):

V V Kozyrev ◽

M Yu Petrov ◽

L V Kozyreva

Keyword(s):

Wear Resistance ◽

Composite Powders ◽

Plasma Sprayed Coatings ◽

Plasma Sprayed ◽

Sprayed Coatings ◽

Effect Of The Composition

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Properties of the Ni-Al Composite Powders Prepared by the Mechanofusion Process and their Plasma Sprayed Coatings.

Journal of the Japan Society of Powder and Powder Metallurgy ◽

10.2497/jjspm.40.241 ◽

1993 ◽

Vol 40 (2) ◽

pp. 241-246 ◽

Cited By ~ 2

Author(s):

Mikio Umakoshi ◽

Hiroshi Ito ◽

Ryozo Nakamura ◽

Tohei Yokoyama ◽

Kiyoshi Urayama ◽

...

Keyword(s):

Composite Powders ◽

Al Composite ◽

Plasma Sprayed Coatings ◽

Plasma Sprayed ◽

Sprayed Coatings

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Microstructure and Properties of Thermally Sprayed TiC-Ni and (Ti,Mo) C-NiCo Coatings

Thermal Spray 1996: Proceedings from the National Thermal Spray Conference ◽

10.31399/asm.cp.itsc1996p0729 ◽

1996 ◽

Author(s):

P. Vuoristo ◽

T. Stenberg ◽

T. Mäntylä ◽

L.-M. Berger ◽

M. Nebelung

Keyword(s):

Wear Test ◽

Xrd Analysis ◽

Binder Phase ◽

Hard Phase ◽

Wear Properties ◽

Spray Detonation ◽

Plasma Sprayed Coatings ◽

Detonation Gun ◽

Plasma Sprayed ◽

Sprayed Coatings

Abstract Hardmetal-like coatings on the base of titanium carbide as a hard phase and nickel as a metal binder were prepared from agglomerated and sintered powders by plasma spray, detonation gun spray and high-velocity oxygen-fuel spray processes. The powders used in the spray experiments were plain TiC-Ni type and alloyed (Ti,Mo)C-NiCo type powders with different binder content. The coatings were characterized by optical and scanning electron microscopy, microhardness measurements, XRD analysis and in an abrasion wear test. The results showed that the sprayability of these novel hardmetal-like powders is good in all spray processes studied and the coatings deposited were found to have dense microstructures and good properties. The XRD analysis showed that the coatings have a phase structure similar to that found in the spray powder. The amount of retained carbides in the coatings was high. Some regions in which the carbides had dissolved with the metallic binder phase during spraying were also found, especially in plasma sprayed coatings. In such microstructural regions submicron size reprecipitated carbides were detected. These were clearly detectable in detonation gun sprayed coatings. HVOF sprayed coatings were found to contain a very high content of retained carbide phase. In this process the heat effect to the material seemed to be the lowest. The wear tests clearly showed the importance of alloying the hard phase and the binder phase in order to improve the wear resistance of the coatings. All studied spray processes produced coatings with nearly similar coating wear properties.

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