Microstructure and mechanical properties of plasma sprayed Al2O3 - 13%TiO2 Ceramic Coating (original) (raw)
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Microstructure and mechanical properties of plasma sprayed Al2O3– 13%TiO2Ceramic Coating
MATEC web of conferences, 2016
This paper focused on the effect of deposition conditions on the microstructural and mechanical properties of the ceramic coating. In this study, Al2O3-13%TiO2 coated mild steel were prepared by using atmospheric plasma spray technology with different plasma power ranging from 25 kW to 40 kW. The as-sprayed coatings consist of γ-Al2O3 phase as the major phase and small amount of the titania phase existed in the coating structure. High degree of fully melted region was observed in the surface morphology for the coating sprayed with high plasma power, which lead to the high hardness and low percentage of porosity. In this study, nanoindentation test was carried out to investigate mechanical properties of the coating and the results showed that the coatings possess high elastic behaviour, which beneficial in engineering practice.
Materials Today: Proceedings, 2021
The present work deals with tribological investigation of Al 2 O 3-40% TiO 2 coating deposited using plasma spraying. The structural characterization of coating was done using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). The micro hardness was measured by vickers micro hardness tester whereas fracture toughness was determined by Indentation Fracture Toughness Test (IFT) method. The sliding wear tests were carried out at different test conditions involving simultaneous variation of load (P) ranging from 5 to 30 N and sliding velocity (V) ranging from 0.1 m/sec to 0.6 m/sec. The sliding wear rate increased with increasing parameter P Â V and friction coefficient displayed minima at a load of 20 N and sliding velocity of 0.4 m/sec. The flash temperature showed the increasing trend with P Â V parameter. The variation in coefficient of friction and wear rate with varying test conditions was associated with change in wear mechanism from plastic grooving to delamination of splats & splat fracture and formation & removal of tribo layer of Ti 2 O 3 and Ti 3 O 5 on worn surface.
Surface and Coatings Technology
Al 2 O 3 /xTiO 2 (where x = 0, 3, 13 and 20 wt%) composite coatings were deposited onto mild steel substrates by atmospheric plasma spraying of mixed micron-sized Al 2 O 3 and nano-sized TiO 2 powders. Phase transformation from mainly stable α-Al 2 O 3 and anatase-TiO 2 in the powders to predominant metastable γ-Al 2 O 3 and rutile-TiO 2 in the coatings was observed. Reaction between Al 2 O 3 and TiO 2 phase also occurred producing Al 2 TiO 5 phase. Microstructural investigation showed that well separated TiO 2 lamellas were homogeneously dispersed between Al 2 O 3 lamellas. Hardness was found to decrease with increasing TiO 2 content while fracture toughness increased. The average wear rates of composite coatings determined by sliding wear test were lower than that of monolithic Al 2 O 3 coating by approximately 40%. This was mainly attributed to an increase in fracture toughness and reduction of friction coefficient due to a presence of TiO 2 splats.
Impact of Critical Plasma Spraying Parameter (CPSP) on Plasma-Sprayed Al2O3-3 TiO2 Coatings
Acta Physica Polonica A, 2020
Atmospheric plasma spray (APS) coatings are successfully used in many industrial applications, where high wear and corrosion resistance with thermal insulation are required. Critical plasma spraying parameters (CPSP) is a key factor to control the quality of coatings. In this study, alumina-3 wt% titania coatings were prepared by APS torch at three different CPSP conditions (384.09, 469.44, and 563.33) on AISI 304 L stainless steel substrate. The microstructure, sliding wear rates, and porosity of the alumina-3 wt% titania composite coatings were investigated and correlated to CPSP conditions. The obtained results show that increasing the critical plasma spraying parameters increases the hardness and anti-wear behaviour of alumina-3 wt% titania coating.
Characterisations Of Al2O3-13% Wt TiO2 Deposition On Mild Steel Via Plasma Spray Method
2011
To date, plasma sprayed alumina titania have been widely used as wear resistance coatings in textile, machinery and printing industries. Previous studies showed that the coating microstructures and properties were strongly depended on various parameters such as ceramic composition, grain size powders and spray parameters, thus, influencing the melting degree of the alumina titania during the deposition process. The aim of this study focuses on the evolution of the micron sizes of alumina-13%wt titania at different plasma spray power, ranging from 20kW to 40kW. It was noted that the coating porosity of alumina-13%wt titania were decreased from 6.2% to 4% by increasing the plasma power from 20 to 40 kW. At lower power value, partially melted powders were deposited, generating over 6% porosity within the microstructures. Percentage of porosity about 5.6% gave the best ratio of bi-modal structures, providing the highest microhardness value. Furthermore, the effect of microstructure and porosity formation on wear resistance was also discussed. Coatings with less porosity exhibited better resistance to wear, in which the wear resistance of coated mild steel possessed only ~5 x 10 -4 cm 3 /Nm with 4% of porosity.
Surface and Coatings Technology, 2008
The goal of this study is to compare two Atmospheric Plasma Spraying (APS) systems for elaborating alumina/titania coatings with good wear resistance. Both torches used were a common d.c. current Gas-Stabilized Plasma gun (GSP) with argon and hydrogen as plasma forming gases, and a Water-Stabilized high-throughput Plasma gun (WSP) working with water as plasma forming substance. The feedstock were either cladded alumina/titania powder or a mixture of conventional fused and crushed Al 2 O 3 powder with agglomerated TiO 2 nanometric particles, the resulting mean size in both cases being about 50 µm. Feedstock material phases were α-alumina and anatase titanium dioxide and the composition of both powders was 13 wt.% of TiO 2 in Al 2 O 3. Coatings obtained were analyzed by scanning electron microscopy (SEM). They presented lamellar structures with titania uniformly distributed in the alumina matrix, for both spray techniques. X-ray diffraction showed that anatase phase of titania was converted into rutile phase. The wear resistance tested by slurry abrasion (SAR) has shown that the best coating was that obtained with cladded powder sprayed by GSP process. This finding matched with the highest microhardness of this coating (Vickers indentation). It is worth noting that with these two relatively dissimilar torches similar results were obtained for the wear resistance of alumina-13 wt.% titania coating.
Acta Materialia, 2002
The development of constituent phases and microstructure in plasma sprayed Al 2 O 3 -13wt.%TiO 2 coatings and reconstituted nanocrystalline feed powder was investigated as a function of processing conditions. The microstructure of the coatings was found to consist of two distinct regions; one of the regions was completely melted and quenched as splats, and the other was incompletely melted with a particulate microstructure retained from the starting agglomerates. The melted region predominantly consisted of nanometer-sized γ-Al 2 O 3 with dissolved Ti 4+ , whereas the partially melted region was primarily submicrometer-sized α-Al 2 O 3 with small amounts of γ-Al 2 O 3 with dissolved Ti 4+ . The ratio of the splat microstructure to the particulate microstructure and thus the ratio of the γ-Al 2 O 3 to α-Al 2 O 3 can be controlled by a plasma spray parameter, defined as the critical plasma spray parameter (CPSP). This bimodal distribution of microstructure and grain size is expected to have favorable impact on mechanical properties of nanostructured coatings, as has been observed before.
Thermal Spray 2005: Proceedings from the International Thermal Spray Conference
Alumina-titania coatings deposited by air plasma spraying (APS) are widely used to protect components against wear at low temperatures. It is known that microstructures formed by the post-laser remelting of as-sprayed coatings exhibit a densification but also numerous macrocracks due to the rapid cooling and thermal stresses. By using the laser-assisted air plasma spraying (LAAPS), the laser beam interacts simultaneously with the plasma torch in order to increase coating surface temperature and possibly superficially remelt the coating. As a result, the microstructure is partially densified and macrocracks, which are generally produced in the post-laser irradiation treatment, can be inhibited. In addition, this hybrid spraying can be done without the post-treatment of coating. In this paper, LAAPS was performed to improve the mechanical properties of Al2O3-13%TiO2 coatings. The coating microstructure was characterized by SEM and X-ray diffraction. The mechanical characterization was...
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.
The improvement of steel properties using Al2O3 coatings deposited by plasma spraying
Journal of Physics: Conference Series, 2020
It is well-know that the numerous functions of use of materials can be realized at a high level of performance by using plasma jet coatings, with the reduction of the consumption of important strategic metals. These are determined by the excellent resilience to extreme temperatures, corrosion and wear of the coatings. This paper aims to characterize coating layers based on Al2O3 realized by plasma jet spray by examining its hardness, thermal shock resistance, traction resistance.