Development & Characterization of Alumina Coating by Atmospheric Plasma Spraying

2018 ◽  
Vol 877 ◽  
pp. 104-109 ◽  
Author(s):  
Jobin Sebastian ◽  
Abyson Scaria ◽  
Don George Kurian
Keyword(s):  
Plasma Spraying ◽  
Elevated Temperatures ◽  
Steel Substrate ◽  
Oxide Coating ◽  
Ceramic Coatings ◽  
Substrate Material ◽  
Atmospheric Plasma ◽  
Flame Spraying ◽  
Alumina Coating ◽  
Spray Process

Ceramic coatings are applied on metals to prevent them from oxidation and corrosion at room as well as elevated temperatures. The service environment, mechanisms of protection, chemical and mechanical compatibility, application method, control of coating quality and ability of the coating to be repaired are the factors that need to be considered while selecting the required coating. The coatings based on oxide materials provides high degree of thermal insulation and protection against oxidation at high temperatures for the underlying substrate materials. These coatings are usually applied by the flame or plasma spraying methods. The surface cleanliness needs to be ensured before spraying. Abrasive blasting can be used to provide the required surface roughness for good adhesion between the substrate and the coating. A pre bond coat like Nickel Chromium can be applied on to the substrate material before spraying the oxide coating to avoid chances of poor adhesion between the oxide coating and the metallic substrate. Plasma spraying produces oxide coatings of greater density, higher hardness, and smooth surface finish than that of the flame spraying process Inert gas is often used for generation of plasma gas so as to avoid the oxidation of the substrate material. The work focuses to develop, characterize and optimize the parameters used in Al2O3 coating on transition stainless steel substrate material for minimizing the wear rate and maximizing the leak tightness using plasma spray process. The experiment is designed using Taguchi’s L9 orthogonal array. The parameters that are to be optimized are plasma voltage, spraying distance and the cooling jet pressure. The characterization techniques includes micro-hardness and porosity tests followed by Grey relational analysis of the results

scholarly journals Preparation and Degradation Characteristics of MAO/APS Composite Bio-Coating in Simulated Body Fluid

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Zexin Wang ◽  
Fei Ye ◽  
Liangyu Chen ◽  
Weigang Lv ◽  
Zhengyi Zhang ◽  
...  
Keyword(s):  
Simulated Body Fluid ◽  
Composite Coating ◽  
Body Fluid ◽  
Composite Coatings ◽  
Degradation Process ◽  
Ceramic Coatings ◽  
Immersion Test ◽  
Substrate Material ◽  
Atmospheric Plasma

In this work, ZK60 magnesium alloy was employed as a substrate material to produce ceramic coatings, containing Ca and P, by micro-arc oxidation (MAO). Atmospheric plasma spraying (APS) was used to prepare the hydroxyapatite layer (HA) on the MAO coating to obtain a composite coating for better biological activity. The coatings were examined by various means including an X-ray diffractometer, a scanning electron microscope and an energy spectrometer. Meanwhile, an electrochemical examination, immersion test and tensile test were used to evaluate the in vitro performance of the composite coatings. The results showed that the composite coating has a better corrosion resistance. In addition, this work proposed a degradation model of the composite coating in the simulated body fluid immersion test. This model explains the degradation process of the MAO/APS coating in SBF.

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.

scholarly journals Selected Properties Of Thermally Sprayed Oxide Ceramic Coatings

2015 ◽  
Vol 15 (3) ◽  
pp. 17-32 ◽  
Author(s):  
A. Czupryński
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Calcium Oxide ◽  
Zirconium Oxide ◽  
Steel Substrate ◽  
Ceramic Coatings ◽  
Abrasive Wear Resistance ◽  
Flame Spraying ◽  
Oxide Ceramic ◽  
Wide Range

Abstract The article presents the results of the study on exploitation properties of flame sprayed ceramic coatings produced by oxide ceramic material in the form of powder on the aluminum oxide Al2O3 matrix with 3% titanium oxide TiO2 addition and also on the zirconium oxide (ZrO2) matrix with 30% calcium oxide (CaO) on the substrate of unalloyed structural steel of S235JR grade. As a primer powder, metallic powder on the base of Ni-Al-Mo has been applied. Plates with dimensions of 5×200×300 mm and also front surfaces of ∅40×50 mm cylinders have been flame sprayed. Spraying of primer coating has been done using RotoTec 80 torch and external specific coating has been done with CastoDyn DS 8000 torch. Investigations of coating properties are based on metallography tests, phase composition research, measurement of microhardness, coating adhesion to the ground research (acc. to EN 582:1996 standard), abrasive wear resistance (acc. to ASTM G65 standard) and erosion wear resistance (acc. to ASTM G76-95 standard) and thermal stroke study. Performed tests have shown that the flame spraying with 97%Al2O3 powder containing 3% TiO2 and also by the powder based on zirconium oxide (ZrO2) containing 30% calcium oxide (CaO) performed in a wide range of technological parameters allow to obtain high quality ceramic coatings with thickness up to ca. 500 μm on a steel substrate. The primer coating sprayed with the Ni-Al-Mo powder to the steel substrate and external coatings sprayed has the of mechanical bonding character. The coatings are characterized by high adhesion to the substrate and also high erosion and abrasive wear resistance and the resistance for cyclic thermal stroke.

Effect of Plasma Spray Process on TiO2 Coating over Mild Steel Substrate

2015 ◽  
Vol 766-767 ◽  
pp. 590-593
Author(s):  
I. Arul Raj ◽  
S. Ramachandran
Keyword(s):  
Mild Steel ◽  
Surface Characterization ◽  
Steel Substrate ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Average Roughness ◽  
Spray Process ◽  
Atomic Force ◽  
Plasma Spray Process ◽  
Mild Steel Substrate

Coatings are applied for protection of mild steel against corrosion. The paper deals at development of TiO2 coatings onto mild steel substrate by Atmospheric plasma spraying. The coating thickness was taken as 250μm. Surface characterization was analysed by Scanning Electron Microscope. The surface roughness was determined by Atomic Force Microscope. The average roughness was found to be 459.009 nm.

scholarly journals Testing of Flame Sprayed Al2O3 Matrix Coatings Containing TiO2

2016 ◽  
Vol 61 (3) ◽  
pp. 1363-1370 ◽  
Author(s):  
A. Czupryński ◽  
J. Górka ◽  
M. Adamiak ◽  
B. Tomiczek
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Steel Substrate ◽  
Aluminium Oxide ◽  
Ceramic Coatings ◽  
Abrasive Wear Resistance ◽  
Flame Spraying ◽  
Oxide Ceramic ◽  
Al2o3 Matrix ◽  
External Coating

Abstract The paper presents the results of the properties of flame sprayed ceramic coatings using oxide ceramic materials coating of a powdered aluminium oxide (Al2O3) matrix with 3% titanium oxide (TiO2) applied to unalloyed S235JR grade structural steel. A primer consisting of a metallic Ni-Al-Mo based powder has been applied to plates with dimensions of 5×200×300 mm and front surfaces of Ø40×50 mm cylinders. Flame spraying of primer coating was made using a RotoTec 80 torch, and an external coating was made with a CastoDyn DS 8000 torch. Evaluation of the coating properties was conducted using metallographic testing, phase composition research, measurement of microhardness, substrate coating adhesion (acc. to EN 582:1996 standard), erosion wear resistance (acc. to ASTM G76-95 standard), and abrasive wear resistance (acc. to ASTM G65 standard) and thermal impact. The testing performed has demonstrated that flame spraying with 97% Al2O3 powder containing 3% TiO2 performed in a range of parameters allows for obtaining high-quality ceramic coatings with thickness up to ca. 500 µm on a steel base. Spray coating possesses a structure consisting mainly of aluminium oxide and a small amount of NiAl10O16 and NiAl32O49 phases. The bonding primer coat sprayed with the Ni-Al-Mo powder to the steel substrate and external coating sprayed with the 97% Al2O3 powder with 3% TiO2 addition demonstrates mechanical bonding characteristics. The coating is characterized by a high adhesion to the base amounting to 6.5 MPa. Average hardness of the external coating is ca. 780 HV. The obtained coatings are characterized by high erosion and abrasive wear resistance and the resistance to effects of cyclic thermal shock.

Wear of the Al2O3-Based Multi-Ceramic Coatings Produced by SHS Flame Spraying

2007 ◽  
Vol 280-283 ◽  
pp. 1123-1126 ◽  
Author(s):  
Xin Kang Du ◽  
Jian Jiang Wang ◽  
Ming Hui Ye ◽  
Jun Yan
Keyword(s):  
Transfer Rate ◽  
Steel Substrate ◽  
Ceramic Coatings ◽  
Flame Spraying ◽  
Resistance Decrease

Based on the CuO+Al system with the additives of additional aluminum and Al2O3 + 13%TiO2, the SHS Flame Spraying coatings were produced on the surface of the steel substrate. The wear quality of the coatings was measured and the micro fabric of the coatings was analyzed. It was shown that by using the 3-6% additional aluminum, high reactive transfer rate and coatings with good micro-fabric and high abrasion quality were acquired. Adding the Al2O3 + 13%TiO2 additive could increase the content of the ceramics, but too much additive would lead to the coarse fabric and make the porosity of the coatings improve, which made the abiding strength and the wearing resistance decrease. 10% Al2O3 + 13%TiO2 additive is suitable to produce the coatings with good properties, and adding 6%(Ti+C) additive gives rise to coatings of high abrasion performance.

Effect of Arc-Current and Particle Morphology on Fracture Toughness of Plasma Sprayed Aluminium Oxide Coating

2017 ◽  
Author(s):  
Simanchal Kar ◽  
P. P. Bandyopadhyay ◽  
S. Paul
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Oxide Coating ◽  
Atmospheric Plasma ◽  
Alumina Powder ◽  
Low Carbon ◽  
Powder Morphology ◽  
Arc Current

Alumina powder was sprayed on low carbon steel substrate using atmospheric plasma spray process. Two different powders namely crushed and agglomerated powders were used and current was varied to study their effect on fracture toughness. Theoretically, with increase in arc current, melting of ceramic oxide shall increases and in turn dense coating should form. However, it was observed that if the arc power is too high and particle size of the powder being small (∼ 30 μm), the particles tend to fly away from the plasma core. Similarly, particle size distribution and powder morphology also affects the coating properties. Smaller particle should allow more melting resulting in dense coating and agglomerated powder allows flowability as well as better coating efficiency. Conversely, smaller particles tend to fly away from the plasma making the process difficult while the agglomerated particles showed a bimodal structure marked by presence of unmelted region in the splat core. All these factors lead to substantial variation in the fracture toughness of the coating. The present paper attempts to correlate plasma spraying parameters and microstructure of the coating with fracture toughness of the same.

Contact Wear Studies over Idlers Sprayed with Ni Al Si Powder Using Atmospheric Plasma Spraying Method

2014 ◽  
Vol 1036 ◽  
pp. 184-188
Author(s):  
Petru Avram ◽  
Bogdan Istrate ◽  
Marius Stelian Imbrea ◽  
Catalina Axinte ◽  
Constantin Paulin ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Surface Engineering ◽  
Steel Substrate ◽  
Mining Industry ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Basic Material ◽  
Material Surface ◽  
Wear Properties ◽  
Machine Elements

In military and mining industry are many machine elements – in our case idlers (for tanks, conveyors, and any others machineries which are using transmissions system which are subjected of coverage with a high wear rezistance powder. These machine elements (idlers) must have high wear proprieties, because the functionality of the entire transmissions systems depends on them. Also the maintenance costs are very high, that is why we proposed to studies how to improve the performances of this machine elements. Researches in surface engineering allow the obtaining of new systems of materials by coating the basic material surface with other material having superior high wear properties. In order to improve the machine elements durability, wear resistance, friction, we proposed to obtain a new system of materials using Atmospheric Plasma Spraying – with Sulzer 9MCE equipment. We have chosen the steel type 34CrNiMo6, MOCN class, STAS 691 - 880 as basic material and we coated it with NiAlSi powder. We made the samples and we tested them. The analysis has been made with Tribometre, which produces some data which link us to a high wear rezistance.The NiAlSi coating deposited on steel substrate is dense and very tought. The results showed that the new material has a better microstructure than the basic material and its physical and mechanical properties have been improved.

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