Wear behaviour of alumina plasma-sprayed coating on an AlCu alloy (original) (raw)
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Wear behavior of plasma sprayed composite coatings with in situ formed Al2O3
Materials & Design, 2009
In the present study, the wear behavior of in situ formed Al 2 O 3 reinforced hypereutectic Al-18Si matrix composite coatings have been investigated. These coatings were successfully fabricated with mechanically alloyed Al-12Si and SiO 2 powder deposited on aluminum substrates by atmospheric plasma spraying (APS). The produced samples were characterized by means of microscopic examinations, hardness measurements and wear tests. The obtained results pointed out that the amount of in situ formed Al 2 O 3 particles increased with increasing spray distance and decreasing in-flight particle velocity and temperature, which was accompanied by an improvement in hardness and wear resistance.
Sliding Wear Behavior of Alumina/Tic Coated Steel Produced by Plasma Spray Technique
Bonfring
Carbide coatings exhibit good resistance to wear and has an increased hardness which increases the service life of equipments generally when the surfaces are exposed to critical atmosphere like in thermal power plants. The hard Alumina-Titanium carbide (Al2O3/TiC) carbide coating is developed on the steel by using thermal plasma spray technique. The composition of Al and TiC are varied in the ratio of 70/30, 65/35 and 60/40. Coated samples are analyzed using optical microscope, hardness test, sliding wear and corrosion test. Hard-faced samples are shows uniform distribution of Al2O3/TiC particles on the surface of steel. Surface hardness increases with increasing volume fraction of TiC. The coating of Al2O3/TiC with volume fraction of 30% TiC shows good corrosive resistance compared to other two coating specimens and coating with 40% of TiC has shows good wear resistance than the other two coatings.
Sliding wear behaviour of plasma electrolytic oxidation coating on pure aluminium
Wear, 2011
In previous studies sliding wear behaviour of plasma electrolytic coating on pure aluminium was investigated. The effects of treated times, current density, current frequency of plasma electrolytic oxidation on the surface microstructural, mechanical and sliding wear behaviour of the ceramic coatings are conducted. Further investigations are reported regarding the sliding wear behaviour and mechanical properties of this treatment in sliding wear tests against Al 2 O 3 sand paper counter faces using a low frequency reciprocating sliding diameter of 10 mm at a load of 10 N. Scanning electron microscopy was employed to assist in the evaluation of the wear behaviour and failure mechanisms. It is shown that the ceramic coating, consisting primarily of micro-plasma sintering ceramic layer and micropores, provide improved wear resistance and enhanced load-bearing capacity for low-friction coating. The primary sliding wear mechanism observed is one of mild asperity deformation and polishing and, in extreme cases, localized delamination of the ceramic coating.
Wear of an aluminium alloy coated by plasma electrolytic oxidation
Surface and Coatings Technology, 2012
Plasma electrolytic oxidation is a technique that converts the surface of a light metal alloy into a high hardness ceramic coating. This process involves the anodic oxidation of the metallic substrate and dielectric breakdown of the layer, which takes place by subjecting the alloy to high voltages in an electrolytic bath. The plasma created by these electrochemical interactions promotes the formation of a porous ceramic coating with thicknesses up to around 150 μm. The present work deals with the study conducted on samples of an aluminium type 6061 alloy that was processed to obtain coatings of different thicknesses, aiming to assess their wear resistance in sliding conditions using a ball on disc machine. The coatings were characterised by X-ray diffraction, scanning electron microscopy, roughness measurements and microhardness tests. The X-ray analysis showed the presence of mullite, α-Al 2 O 3 and γ-Al 2 O 3 within the coatings. It was found that the friction coefficient changed along the tests, and that the weight lost depended on both, the thickness of the coating and the load applied during the test. The wear mechanisms taking place are discussed.
Microstructure, Adhesion, and Erosion Wear of Plasma Sprayed Alumina-Titania Composite Coatings
Journal of Reinforced Plastics and Composites, 2008
Plasma spray technology is being widely used for the development of protective coatings to prevent degradation of critical components working under severe conditions. Plasma sprayed alumina-titania have many industrial applications. These coatings provide a dense and hard surface which is resistant to abrasion, corrosion, cavitation, oxidation, and erosion. Plasma sprayed alumina-titania coatings are regularly used for wear resistance, electrical insulation, thermal barrier applications, etc. Alumina pre-mixed with titania powder is deposited on mild steel substances by atmospheric plasma spraying. Microstructure of the coating is analyzed by SEM. Adhesion strength of alumina-titania coatings are measured. The response of plasma sprayed alumina-titania coatings to the impingement of solid particles has been presented in this study. The erosion rate is calculated on the basis of 'coating mass loss'. It is observed that the erosion wear rate varies with erodent dose, angle of attack, the velocity of erodent, standoff distance, and size of the erodent. Cumulative coating mass loss varies with time of erosion.
2014
Thermally-sprayed alumina based materials, e.g., alumina-titania (Al 2 O 3-TiO 2), are commonly applied as wear resistant coatings in industrial applications. Properties of the coatings depend on the spray process, powder morphology, and chemical composition of the powder. In this study, wear resistant coatings from Al 2 O 3 and Al 2 O 3-13TiO 2 powders were sprayed with plasma and high-velocity oxygen-fuel (HVOF) spray processes. Both, fused and crushed, and agglomerated and sintered Al 2 O 3-13TiO 2 powders were studied and compared to pure Al 2 O 3. The coatings were tested for abrasion, erosion, and cavitation resistances in order to study the effect of the coating structure on the wear behavior. Improved coating properties were achieved when agglomerated and sintered nanostructured Al 2 O 3-13TiO 2 powder was used in plasma spraying. Coatings with the highest wear resistance in all tests were produced by HVOF spraying from fused and crushed powders.
Abrasion, Erosion and Cavitation Erosion Wear Properties of Thermally Sprayed Alumina Based Coatings
Coatings, 2014
Thermally-sprayed alumina based materials, e.g., alumina-titania (Al 2 O 3 -TiO 2 ), are commonly applied as wear resistant coatings in industrial applications. Properties of the coatings depend on the spray process, powder morphology, and chemical composition of the powder. In this study, wear resistant coatings from Al 2 O 3 and Al 2 O 3 -13TiO 2 powders were sprayed with plasma and high-velocity oxygen-fuel (HVOF) spray processes. Both, fused and crushed, and agglomerated and sintered Al 2 O 3 -13TiO 2 powders were studied and compared to pure Al 2 O 3 . The coatings were tested for abrasion, erosion, and cavitation resistances in order to study the effect of the coating structure on the wear behavior. Improved coating properties were achieved when agglomerated and sintered nanostructured Al 2 O 3 -13TiO 2 powder was used in plasma spraying. Coatings with the highest wear resistance in all tests were produced by HVOF spraying from fused and crushed powders.
Procedia Engineering, 2012
Alumina-titania coatings produced by plasma spray processes are being developed for a wide variety of applications that require resistance to wear, erosion, cracking and spallation. Consideration of parameters setting will develop reliable coatings with high performance properties for demanding coating application. Al 2 O 3 3%wt TiO 2 coating was produced onto metal substrate using Praxair Plasma Spray System with SG-100 Gun. This paper discusses the experimental and testing performance analysis of the coating which prepared based on three varied process parameters (current, powder flow rate and stand-off-distance). With the varied coating parameters, test results showed that increasing current from 550A to 650A and powder flow rate from 22.5g/min to 26 g/min increased the performance of mechanical properties of coating (adhesion strength & hardness) and gave the lowest friction coefficient value (i.e. best wear resistance) of coating. Increasing stand-off-distance from 75mm to 90mm also increased hardness performance and provided the lowest friction coefficient value of coating. However increasing stand-off-distance has decreased adhesion strength at setting powder flow rate of 26g/min and 650A current. The behavior of such parameters setting significantly influenced the production of optimum Al 2 O 3 3%wt TiO 2 coating onto metal substrate.
Wear, 2002
Effect of residual stresses on plasma sprayed alumina and chromia coatings sealed with aluminium phosphate were studied as a function of the temperature of the sealing treatment. Stresses were measured by X-ray stress analysis and high-speed circular microhole drilling method. Residual stress states were correlated with other coating properties such as microhardness, porosity, microstructure and dry abrasion wear resistance. Correlations were found between sealing treatment temperature, residual stress state and wear resistance. Wear resistance of the oxide coatings was increased at all sealing temperatures. Sealing treatment affected coatings by two mechanisms. Aluminium phosphate sealing induced compressive stresses to coatings and simultaneously bonded coating lamellar structure.