scholarly journals Axial Plasma Spraying of Mixed Suspensions: A Case Study on Processing, Characteristics, and Tribological Behavior of Al2O3-YSZ Coatings

2020 ◽  
Vol 10 (15) ◽  
pp. 5140
Author(s):  
Sneha Goel ◽  
Stefan Björklund ◽  
Nicholas Curry ◽  
Sivakumar Govindarajan ◽  
Urban Wiklund ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Comprehensive Evaluation ◽  
Tribological Behavior ◽  
Thermal Spraying ◽  
Dry Sliding Wear ◽  
Solid Loading ◽  
Exciting Opportunity ◽  
Mixed Suspension ◽  
Plasma Sprayed

Thermal spraying deploying liquid feedstock offers an exciting opportunity to obtain coatings with characteristics vastly different from those produced using conventional spray-grade powders. The most extensively investigated variant of this technique is Suspension Plasma Spraying (SPS), which utilizes a suspension of fine powders in an appropriate medium. The relatively recent advent of axial feed capable plasma spray systems can enable higher throughputs during SPS, provides the possibility for spraying with longer stand-off distances, and also permit the use of suspensions with higher solid loading. The present work investigates axial plasma sprayed coatings produced using a mixed suspension of fine (submicron or nano-sized) powders of Al2O3 and YSZ as a case study. Deposition of the mixed suspension using axial injection plasma spraying, comprehensive evaluation of characteristics of the resulting coatings, and assessment of their tribological behavior were of particular interest. Evaluation of surface morphology, microstructure, and hardness of the coatings reveals that axial SPS of mixed suspensions provides an exciting pathway to realize finely structured multi-constituent coatings using suspensions with as high as 40 wt.% solid loading. The study of scratch, dry sliding wear, and erosion behavior also specifically shows that the addition of YSZ in the Al2O3 matrix can improve the tribological properties of the coating.

scholarly journals A Facile Approach to Deposit Graphenaceous Composite Coatings by Suspension Plasma Spraying

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 171 ◽  
Author(s):  
Ashish Ganvir ◽  
Stefan Björklund ◽  
Yiming Yao ◽  
Srikanth V. S. S. Vadali ◽  
Uta Klement ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Matrix Material ◽  
Suspension Plasma Spraying ◽  
Spray Parameters ◽  
Large Area ◽  
Mixed Suspension ◽  
First Time

This paper demonstrates, for the first time ever, the deposition of graphenaceous composite coatings using an easy, yet robust, suspension plasma spraying (SPS) process. As a case study, a composite coating comprising 8 wt.% of yttria-stabilized-zirconia (8YSZ) and reinforced with graphene oxide (GO) was deposited on a steel substrate. The coatings were sprayed using an 8YSZ-GO mixed suspension with varied plasma spray parameters. Establishing the possibility of retaining the graphene in a ceramic matrix using SPS was of specific interest. Electron microscopy and Raman spectroscopy confirmed the presence of graphenaceous material distributed throughout the coating in the 8YSZ matrix. The experimental results discussed in this work confirm that SPS is an immensely attractive pathway to incorporate a graphenaceous material into virtually any matrix material and can potentially have major implications in enabling the deposition of large-area graphene-containing coatings for diverse functional applications.

Titanium matrix reinforced composites produced by hot pressing of plasma-sprayed preforms

2003 ◽  
Vol 217 (4) ◽  
pp. 257-268
Author(s):  
T Valente ◽  
S Picchiotti ◽  
C Bartuli ◽  
C Testani
Keyword(s):  
Plasma Spraying ◽  
Hot Pressing ◽  
Thermal Spraying ◽  
Reinforced Composites ◽  
Titanium Matrix ◽  
Microstructural Investigation ◽  
High Pressure Range ◽  
Deposition Processes ◽  
Plasma Sprayed ◽  
Push Out

The present work is focused on the fabrication of long fibre reinforced titanium composites by hot pressing of plasma-sprayed preforms. Thermal spraying of two different metallic matrices [Ti-6Al-2Sn-4Zr-2Mo-0.08Si (Ti6242S) and Ti-4.5Al-3V-2Mo-2Fe (SP700)] onto prearranged silicon carbide long fibres was performed using controlled-atmosphere plasma spraying equipment (CAPS), allowing deposition processes also in the high-pressure range. After optimization of the plasma spraying procedure, composite multilayers were fabricated by hot pressing at 1200 bar with different combinations of process parameters (temperature in the range 850-940 °C, and application time from 30 to 45 min). Consolidated samples were characterized by microstructural investigation and tensile testing at room and high temperature (up to 600 °C). Push-out and push-back tests were performed to investigate interfacial properties.

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.

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.

Plasma Sprayed Ultra High Temperature Ceramics for Thermal Protection Systems

2000 ◽  
Author(s):  
T. Valente ◽  
C. Bartuli ◽  
G. Visconti ◽  
M. Tului
Keyword(s):  
Plasma Spraying ◽  
High Performance ◽  
Thermal Protection ◽  
Electrical Discharge Machining ◽  
High Heat ◽  
Heat Fluxes ◽  
Space Vehicles ◽  
Ultra High Temperature Ceramics ◽  
Protection Systems ◽  
Plasma Sprayed

Abstract Reusable space vehicles, which must withstand re-entry into the Earth's atmosphere, require external protection systems (TPS) which are usually in the forms of rigid surface in areas of high or moderate working temperature. High heat fluxes and temperatures related to high performance hypervelocity flights also require the use of TPS materials having good oxidation and thermal shock resistance, dimensional stability, and ablation resistance. Components by these materials are usually fabricated, starting from either billets or plate stocks, by uniaxial hot pressing, and complex parts, such as low radius edges, are then obtained by electrical discharge machining technique. This article investigates an alternative fabrication technology, based on plasma spraying, to produce near net shape components. Results of experimental activities, such as optimization of plasma spraying parameters based on a DOE approach, are reported and discussed.

Current problems of developing rare book collection at sci-tech library (case study of Central Scientific Agricultural Library)

2021 ◽  
Author(s):  
Mikhail Bunin ◽  
Keyword(s):  
Physical Condition ◽  
Comprehensive Evaluation ◽  
Rare Book ◽  
Valuable Book ◽  
Methodological Approaches ◽  
Selection For ◽  
Book Collections ◽  
Central Scientific

The issues of methodological approaches toward and criteria of publication selection for rare and valuable book collections of sci-tech libraries are discussed. Based on the experience of CSAL, the need for comprehensive evaluation of books is substantiated: by materials and facilities, level of performance, physical condition and age, circulation, periodicity, and by value in scientific and sociocultural aspects.

Plasma Spraying of Self-Lubricating Cr2O3-CaF2 Coatings

1997 ◽  
Author(s):  
F. Vos ◽  
L. Delaey ◽  
M. De Bonte ◽  
L. Froyen
Keyword(s):  
Plasma Spraying ◽  
Matrix Material ◽  
Production Method ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
The Matrix ◽  
Preparation Step ◽  
Plasma Sprayed ◽  
The Relationship ◽  
Selection Of

Abstract Results are presented of a project analysing the relationship between the production parameters of plasma sprayed self-lubricating Cr2O3-CaF2 coatings and their structural, wear and lubricating properties. The production method consists of a preparation step where a powder blend of the matrix material (Cr203) and solid lubricant (CaF2) is agglomerated, followed by atmospheric plasma spraying (APS) of the agglomerates. Selection of the most appropriate agglomeration and plasma spray parameters as well as the microstructure of the coatings will be discussed.

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