Novel Zro2-Mullite Composites Produced by Plasma Spraying

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.

Mechanofusion Processing of Metal-Oxide Composite Powders for Plasma Spraying

2010 ◽  
Vol 1276 ◽  
Author(s):  
Ricardo Cuenca-Alvarez ◽  
Carmen Monterrubio-Badillo ◽  
Hélêne Ageorges ◽  
Pierre Fauchais
Keyword(s):  
Mechanical Energy ◽  
Xrd Analysis ◽  
Composite Particles ◽  
Composite Powders ◽  
Steel Core ◽  
No Formation ◽  
Particle Coating ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

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.

Method For Producing Prealloyed Chromium Carbide/Nickel/Chromium Powders and Properties of Coatings Created Therefrom

1983 ◽  
Vol 30 ◽  
Author(s):  
David L. Houck ◽  
Richard F. Cheney
Keyword(s):  
Chromium Carbide ◽  
Binder System ◽  
Properties Of Coatings ◽  
Plasma Flame ◽  
Nickel Chromium ◽  
Bearing Materials ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings ◽  
Individual Particles

ABSTRACTA unique process for producing powder whose individual particles contain both chromium carbide and nickel/chromium is discussed. This process involves agglomeration of fine chromium carbide with nickel/ chromium-bearing materials using a proprietary binder system. The agglomerates are subsequently sintered, melted in a plasma flame, and sized. This powder does not exhibit the segregation and inhomogeneity problems associated with conventional mechanical blends of chromium carbide and Nichrome powders. Jet Kote* coatings created from the prealloyed powders have uniform microstructures, high hardnesses, and wear characteristics superior to those of plasma-sprayed coatings from the conventional blends.

Study of the Adhesion Strength of Plasma-Sprayed Coatings Using Statistical Methods

2020 ◽  
Vol 897 ◽  
pp. 56-60
Author(s):  
Nikolay Kuleshov ◽  
Nikolay Dolgov ◽  
Igor Smirnov ◽  
Leonid Vinogradov ◽  
Vladimir Shestakov
Keyword(s):  
Plasma Spraying ◽  
Adhesion Strength ◽  
Ceramic Coatings ◽  
Optimization Criterion ◽  
Alumina Powder ◽  
Nano Powder ◽  
Plasma Sprayed Coatings ◽  
Tensile Adhesion ◽  
Plasma Sprayed ◽  
Sprayed Coatings

The adhesion strength of plasma-sprayed ceramic coatings was studied. Alumina powder was used for plasma spraying. A titanium oxide Nano powder with a particle size of 40-50 [nm] was used as a modifier. The optimal conditions of plasma spraying of coatings are established. The adhesion strength was used as an optimization criterion. Coating adhesion was determined by tensile adhesion testing. A mathematical model is obtained that allows one to determine the effect of spraying conditions (lens current, arc current, and the position of the solenoid relative to the nozzle) on the adhesion strength.

Coating Materials Characteristics for Plasma Treatment of Metals, Obtained through Diffusion Doping of Powders Based on Austenite Class Steels

2020 ◽  
Vol 843 ◽  
pp. 141-146
Author(s):  
Fiodar I. Pantsialeyenka ◽  
Andrzej Kuczumow ◽  
Aliaksei F. Pantsialeyenka ◽  
Vyacheslav A. Okovity
Keyword(s):  
Atmospheric Precipitation ◽  
Plasma Jet ◽  
Austenitic Steels ◽  
Resource Saving ◽  
Coating Materials ◽  
Develop Technology ◽  
Plasma Sprayed Coatings ◽  
Through Diffusion ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Due to the increasing of the price of different materials and resource saving it is very promising to develop technology of creation cheap coatings with specified properties. We developed a diffusion-doped powder based on austenitic steels for producing plasma-sprayed coatings. In comparison with Ni-based powders our materials have better adhesion, they are cheaper, they have better mechanical machinability, it is possible to produce coatings with required properties. In our work, the features of diffusion doping of microparticles of powder, the behavior of the powder in the plasma jet were studied. The significant decreasing of porosity, increasing of adhesion of the plasma-sprayed coatings after laser processing were marked. The substantial increase of wear-resistance in 2,5-3,0 times in comparison with untreated coatings when working in conditions of abrasive wear and atmospheric precipitation was revealed.

Influence of RF Plasma Jet Surface Treatment on Wetting Behavior of Yttria Stabilized Zirconia SPS Coatings

2020 ◽  
Vol 405 ◽  
pp. 423-429
Author(s):  
Pavel Komarov ◽  
David Jech ◽  
Ladislav Čelko ◽  
Barbora Pijáková ◽  
Da Peng Zhou ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Plasma Jet ◽  
Yttria Stabilized Zirconia ◽  
Rf Plasma ◽  
Stabilized Zirconia ◽  
Water Contact ◽  
Wetting Behavior ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

According to the value of water contact angle (WCA), the surfaces can be roughly defined as hydrophilic (with WCA less than 90°) or as hydrophobic (with WCA higher than 90°). Water wetting behavior plays important role and surfaces with special wettability (hydrophobic-superhydrophobic; hydrophilic-superhydrophilic) can be used both in the daily life (solar cells, smartphones, car windows, etc.) and in the industry (corrosion resistance, self-cleaning, anti-icing properties, etc.). Nowadays, the development of hydrophobic surface treatment that may be applied in the industry is very interesting topic. Therefore, it was decided to estimate the influence of radiofrequency (RF) plasma jet in atmosphere on wetting behavior of ceramic plasma sprayed coatings. As the initial material for surface treatment, yttria stabilized zirconia suspension plasma sprayed coatings were used. The influence of RF plasma jet on suspension plasma sprayed coatings was estimated on both hydrophilic and hydrophobic surfaces, and resulted water contact angle and free surface energy of modified samples were measured by sessile droplet method. Microstructure, phase composition and topography investigation were carried out by means of light microscopy, X-ray diffraction techniques and non-contact profilometry.

Self-Lubricating Composite Plasma Sprayed Coatings

1996 ◽  
Author(s):  
D. Niebuhr ◽  
M. Scholl ◽  
P. Clayton
Keyword(s):  
Plasma Spraying ◽  
Solid Lubricants ◽  
High Energy ◽  
Contact Conditions ◽  
Steel Coating ◽  
Contact Loads ◽  
Soft Metal ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Abstract Composite self-lubricating coatings were developed using high-energy plasma spraying (HEPS). These coatings would be potentially used in high contact pressure rolling/sliding systems. The coatings are based on a steel coating deposited by high energy plasma spraying using wire feedstock. Solid lubricants such as graphite and soft metal were investigated. Twin roller rolling/sliding tests were performed at 5% and 35% creep and contact loads of 700 N to 1700 N on a 5 mm contact face. Reduced friction, compared to a steel coating-steel or 1080 wrought steel couple was observed under these rolling-sliding contact conditions.

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 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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