The Manufacture of SiC Fiber Reinforced ΑI2O3 Coatings by Plasma Spraying

1996 ◽  
Author(s):  
H.-D. Steffens ◽  
M. Brune ◽  
E. Müller ◽  
R. Dittrich
Keyword(s):  
Plasma Spraying ◽  
Composite Coatings ◽  
High Strength ◽  
Ceramic Coatings ◽  
Ceramic Composites ◽  
Composite Powders ◽  
Pure Alumina ◽  
High Oxygen Content ◽  
Sic Fiber ◽  
Plasma Sprayed

Abstract Oftentimes, the application of bulk ceramics and ceramic coatings is limited by their poor fracture toughness and low strength. The mechanical properties of ceramics can be significantly improved by the incorporation of fibres, whiskers or particles of high strength, like SiC. Due to the high oxygen content of commercially available SiC fibers in combination with the elevated process temperatures, the SiC decomposes during plasma spraying. Therefore commercial SiC fibres were coated for temporary oxidation protection with C, TiN or Al2O3. By different agglomeration techniques using an organic binder SiC/Al2O3 composite powders were produced. Powder mixtures consisting of coated fibres and pure alumina as well as agglomerated powders have been successfully sprayed to form deposits. Recent results of the manufacture of SiC fibre-reinforced ceramic composites by plasma spray technology are presented. The properties of the composite coatings are compared to plasma sprayed pure alumina.

Wear Performance of the Plasma Sprayed Fine WC-Co Composite Powders Coatings

2012 ◽  
Vol 454 ◽  
pp. 144-147
Author(s):  
Lian Wei Yang ◽  
Jin Hui Li ◽  
Yun Dong ◽  
Xiao Ping Lin
Keyword(s):  
Wear Resistance ◽  
Brittle Fracture ◽  
Composite Coating ◽  
Plasma Spraying ◽  
Composite Coatings ◽  
Composite Powders ◽  
Wear Performance ◽  
Wear And Friction ◽  
Plasma Sprayed ◽  
Increasing Load

WC/Co; Composite coating; Plasma spraying; Friction and wear Abstract: WC- Co composite powders were synthesized by direct mechanical grinding in a rotary-vibration mill under 8h, and then analyzed by SEM and XRD. WC and WC/Co composite coatings were prepared by supersonic plasma spraying fine WC-Co composite powders. The wear and friction properties of both coatings were evaluated. The results showed that the wear resistance of the WC/Co composite coating was superior to that of the WC coating. The improvement in wear resistance of the WC/Co composite coating was attributed to its higher fracture toughness and adhesion strength as well as better thermal diffusivity. As for the WC/Co composite coating, the mechanism was mainly adhesion with micro-abrasion and fatigued-induced brittle fracture within splats, and the delamination along splat boundaries only occurred at high load. However, the failure of the WC coating was predominantly detachment of transferred film and brittle fracture within the splats and delamination along splat boundaries, which were enhanced with the increasing load.

Electron microscopy studies of plasma-sprayed materials

1983 ◽  
Vol 41 ◽  
pp. 70-71
Author(s):  
K.R. Subramanian ◽  
A.H. King ◽  
H. Herman
Keyword(s):  
Plasma Spraying ◽  
Substrate Surface ◽  
Flame Temperature ◽  
Ceramic Coatings ◽  
Metallic Substrates ◽  
Hot Plasma ◽  
Almost All ◽  
Plasma Sprayed ◽  
Hostile Environments ◽  
Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

scholarly journals Wear Behavior Analysis of Al2O3 Coatings Manufactured by APS and HVOF Spraying Processes Using Powder and Suspension Feedstocks

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 879
Author(s):  
Monika Michalak ◽  
Paweł Sokołowski ◽  
Mirosław Szala ◽  
Mariusz Walczak ◽  
Leszek Łatka ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Wear Behavior ◽  
Ceramic Coatings ◽  
Suspension Plasma Spraying ◽  
Atmospheric Plasma ◽  
Hvof Spraying ◽  
The Coefficient Of Friction ◽  
Wear Mode ◽  
Α Al2o3 ◽  
Plasma Sprayed

Thermally sprayed ceramic coatings are applied for the protection of surfaces that are exposed mainly to wear, high temperatures, and corrosion. In recent years, great interest has been garnered by spray processes with submicrometric and nanometric feedstock materials, due to the refinement of the structure and improved coating properties. This paper compares the microstructure and tribological properties of alumina coatings sprayed using conventional atmospheric plasma spraying (APS), and various methods that use finely grained suspension feedstocks, namely, suspension plasma spraying (SPS) and suspension high-velocity oxy-fuel spraying (S-HVOF). Furthermore, the suspension plasma-sprayed Al2O3 coatings have been deposited with radial (SPS) and axial (A-SPS) feedstock injection. The results showed that all suspension-based coatings demonstrated much better wear resistance than the powder-sprayed ones. S-HVOF and axial suspension plasma spraying (A-SPS) allowed for the deposition of the most dense and homogeneous coatings. Dense-structured coatings with low porosity (4 vol.%) and good cohesion to the metallic substrate, containing a high content of α–Al2O3 phase (56 vol.%) and a very low wear rate (0.2 ± 0.04 mm3 × 10−6/(N∙m)), were produced with the S-HVOF method. The wear mechanism of ceramic coatings included the adhesive wear mode supported by the fatigue-induced material delamination. Moreover, the presence of wear debris and tribofilm was confirmed. Finally, the coefficient of friction for the coatings was in the range between 0.44 and 0.68, with the highest values being recorded for APS sprayed 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.

In situ composite coatings prepared by complex reactive plasma spraying of Fe 2 O 3 -Al-Cr 2 O 3 composite powders

2017 ◽  
Vol 328 ◽  
pp. 94-101 ◽  
Author(s):  
Dian-ran Yan ◽  
Yong Yang ◽  
Zhen-hua Chu ◽  
Xue-guang Chen ◽  
Xue-rui Dai ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Composite Coatings ◽  
Composite Powders ◽  
In Situ Composite ◽  
Reactive Plasma Spraying ◽  
Reactive Plasma

Facility for Continuous CVD Coating of Ceramic Fibers

1991 ◽  
Vol 250 ◽  
Author(s):  
Arthur W. Moore
Keyword(s):  
Boron Nitride ◽  
High Temperatures ◽  
Weight Ratio ◽  
High Strength ◽  
Ceramic Coatings ◽  
Ceramic Composites ◽  
Ceramic Fiber ◽  
Ceramic Fibers ◽  
Fiber Properties ◽  
Nitride Coatings

The development of new and improved ceramic fibers has spurred the development and application of ceramic composites with improved strength, strength/weight ratio, toughness, and durability at increasingly high temperatures. For many systems, the ceramic fibers can be used without modification because their properties are adequate for the chosen application. However, in order to take maximum advantage of the fiber properties, it is often necessary to coat the ceramic fibers with materials of different composition and properties. Examples include (1) boron nitride coatings on a ceramic fiber, such as Nicalon silicon carbide, to prevent reaction with the ceramic matrix during fabrication and to enhance fiber pullout and increase toughness when the ceramic composite is subjected to stress[l]; (2) boron nitride coatings on ceramic yarns, such as Nicalon for use as thermal insulation panels in an aerodynamic environment, to reduce abrasion of the Nicalon and to inhibit the oxidation of free carbon contained within the Nicalon[2]; and (3) ceramic coatings on carbon yarns and carbon-carbon composites to permit use of these high-strength, high-temperature materials in oxidizing environments at very high temperatures[3,4].

Microstructure and properties of rare earth CeO2-doped graphene composite coatings prepared by MAO on AA7050

2020 ◽  
Vol 111 (11) ◽  
pp. 923-930
Author(s):  
Yu Zong ◽  
Renguo Song ◽  
Tianshun Hua ◽  
Siwei Cai
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Composite Coatings ◽  
High Strength ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Doped Graphene ◽  
Micropore Size

Abstract In this paper, ceramic coatings were prepared on the surface of 7050 high strength aluminum alloy using a micro-arc oxidation process in a silicate electrolyte combined with the rare earth element cerium or graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, and electrochemical measurements were used, respectively. It was shown that the micropore size of the composite coatings, which mainly consisted of α-Al2O3 and γ-Al2O3, decreases and the density improved with the simultaneous addition of 4 g · L-1 of CeO2 and 10 g · L-1 of graphene to the electrolyte. In addition, with the addition of CeO2 and graphene, the roughness was the lowest and the corrosion resistance was significantly improved.

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.

Influence of critical plasma spraying parameter (CPSP) on plasma sprayed Alumina–Titania composite coatings

2010 ◽  
Vol 36 (1) ◽  
pp. 141-149 ◽  
Author(s):  
S. Yugeswaran ◽  
V. Selvarajan ◽  
M. Vijay ◽  
P.V. Ananthapadmanabhan ◽  
K.P. Sreekumar
Keyword(s):  
Plasma Spraying ◽  
Composite Coatings ◽  
Plasma Sprayed

Electrical Discharge Machining of Alumina-Zirconia-TiC Composites with Varying Zirconia Content

2013 ◽  
Vol 554-557 ◽  
pp. 1916-1921 ◽  
Author(s):  
Richard Landfried ◽  
Frank Kern ◽  
Rainer Gadow
Keyword(s):  
Electrical Discharge ◽  
Bending Strength ◽  
High Hardness ◽  
High Strength ◽  
Ceramic Composites ◽  
Matrix Composition ◽  
Pure Alumina ◽  
Electrically Conductive ◽  
Pure Zirconia ◽  
Strength And Toughness

Ceramic injection molding (CIM) or extrusion requires molds and dies with high hardness to reduce tool wear which occurs due to processing of highly abrasive ceramic compounds. Besides the wear resistance high strength and toughness are necessary for mold materials to withstand the loads during application. Recent work of the authors has shown the high potential of electrical discharge machinable ceramic composites based on oxide ceramic matrices for high wear applications. The use of alumina zirconia composites (AZC) as matrix for electrically conductive composites enables the combination of high hardness of alumina and high strength and toughness of zirconia in order to customize the properties of the mold material. This study focuses on development of ED machinable AZCs with addition of 24 vol.-% titanium carbide as electrically conductive phase. The composition of the matrix was varied from pure alumina to pure zirconia in 5 steps. Disks for mechanical and electrical characterization and electric discharge machining experiments were manufactured by hot pressing. Results show that hardness, strength and toughness can be almost linearly correlated to composition from pure alumina matrix with a 4-point bending strength of 430 MPa, a hardness of 2250 HV10 and a toughness of 3.7 MPa√m to pure zirconia matrix with 1020 MPa bending strength, 1490 HV10 and a toughness of 5.9 MPa√m. Variation of matrix composition also leads to significantly different EDM characteristics. The material removal rate shows a maximum at 19 vol.-% zirconia and 58 vol.-% alumina while surface roughness of the machined composites decreases significantly with increasing zirconia amount. SEM and EDX analysis were made to identify removal mechanisms of each ceramic matrix phase. It was found that alumina tends to be removed by vaporization due to electrical discharges. Zirconia, which has a higher melting and vaporization point than alumina melts during the formation of the plasma channel. Zirconia cannot be removed in total from the surface but forms a smooth and compact amorphous layer of resolidified material on both sample and electrode.

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