Browsing by Subject "Sprayed coatings"
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Item Wear behavior of flame-sprayed Al2O3 -TiO2 coatings on plain carbon steel substrates(2005) Kusoglu I.M.; Celik E.; Cetinel H.; Ozdemir I.; Demirkurt O.; Onel K.In this study, Al2O3-TiO2 powders were sprayed using a flame-spray technique after a NiCrMo bond layer was deposited on plain carbon steel substrate. The produced layers were characterized by X-ray diffraction (XRD), optical microscope, scanning electron microscope (SEM) including energy-dispersive spectroscopy (EDS), surface roughness and microhardness tester. Friction and wear behaviour of the coatings were also evaluated in the present study. The Al2O3-TiO2 coatings were subjected to sliding wear against AISI 303 stainless steel counter body under dry and acidic environments. A pin-on-plate type apparatus was used with normal loads in the range of 49-129 N. Wear resistance of the coatings in acid environment is better than that in dry conditions. © 2005 Elsevier B.V. All rights reserved.Item Artificial neural network-based prediction technique for wear loss quantities in Mo coatings(2006) Çetinel H.; Öztürk H.; Çelik E.; Karlik B.Mo coated materials are used in automotive, aerospace, pulp and paper industries in order to protect machine parts against wear and corrosion. In this study, the wear amounts of Mo coatings deposited on ductile iron substrates using an atmospheric plasma-spray system were investigated for different loads and environment conditions. The Mo coatings were subjected to sliding wear against AISI 303 counter bodies under dry and acid environments. In a theoretical study, cross-sectional microhardness from the surface of the coatings, loads, environment and friction test durations were chosen as variable parameters in order to determine the amount of wear loss. The numerical results obtained via a neural network model were compared with the experimental results. Agreement between the experimental and numerical results is reasonably good. © 2006 Elsevier B.V. All rights reserved.Item Wear behavior of plasma-sprayed Al-12Si/SiC composite coatings under dry and water-lubricated sliding(2009) Akgun S.; Şahin S.; Ustel F.Powders of Al-12Si with 25 and 50wt% SiC particles were ball-milled in a conventional rotating ball mill with alumina balls for 2h. The milled powders were plasma-sprayed onto aluminum and stainless steel substrates to obtain Al matrix composites with high SiC weight fraction. The microstructure characteristics of the sprayed composites were investigated by metal microscopy. Surface roughness, coating thickness and microhardness were measured. Microhardness values increased when the amount of SiC particles in Al-12Si coatings increased. The wear behavior of the coatings under dry-sliding and water-lubricated sliding with stainless steel counter material was studied using ball on disc for 10kN. Wear surfaces were investigated with scanning electron microscopy (SEM). Increasing SiC content of coatings increased the wear resistance. The highest wear resistance in coatings was observed in the coating having 50% SiC.Item Effect of sintering on mechanical properties of cold sprayed thermal barrier coatings(Taylor and Francis Ltd., 2016) Karaoglanli A.C.; Turk A.; Ozdemir I.In this study, thermal barrier coatings were deposited on nickel-based super-alloy with CoNiCrAlY bond and yttria partially stabilised zirconia top coats, using cold gas dynamic spraying and atmospheric plasma spraying techniques, respectively. High temperature oxidation behaviour and sintering effect on the mechanical properties of the coatings were studied. The main objective of this work is to explain the alteration in coating structure depending on temperature, and the mechanisms that lead to alterations in mechanical properties such as Young’s modulus and hardness. Structural examination after oxidation revealed a decrease in porosity content and crack healing on ceramic top coatings resulting from sintering effect. © 2016 Institute of Materials, Minerals and Mining.Item A comparative study of oxidation kinetics and thermal cyclic performance of thermal barrier coatings (TBCs)(Elsevier B.V., 2019) Karaoglanli A.C.; Grund T.; Turk A.; Lampke T.The present study was carried out to investigate the isothermal oxidation behavior, thermal cyclic performance and oxidation kinetics of thermal barrier coatings (TBCs) systems consisting of CoNiCrAlY metallic bondcoats produced by Atmospheric plasma spraying (APS) and high velocity oxy fuel spraying (HVOF) on Inconel 718 substrate. Yttria stabilized zirconia (YSZ) ceramic top coats was produced by APS process as for the insulation layer. The oxidation behavior of the coatings were investigated under isothermal oxidation conditions at 1000 °C, 1100 °C and 1200 °C for 8, 24, 50 and 100 h. The results of the experimental studies on the oxidation kinetics and microstructural evolution of APS and HVOF sprayed thermal barrier coatings (TBCs) are compared and discussed in the paper. The microstructural changes at the metallic/ceramic interface and growth behavior of the thermally grown oxide (TGO) layers during the isothermal oxidation and thermal cyclic tests were analyzed in detail. © 2018 Elsevier B.V.Item Investigation of in vitro behavior of plasma sprayed Ti, TiO2 and HA coatings on PEEK(Elsevier B.V., 2021) Sargin F.; Erdogan G.; Kanbur K.; Turk A.Orthopedic implants are one of the most reliable and widely used equipments to increase the quality of human life by enhancing or replacing damaged body parts and ensuring the problematic parts of the body to become operative after a short time period. Polyether ether ketone (PEEK) is a semi-crystal high-performance thermoplastic polymeric implant material which emerged as an alternative for metallic implants that used in orthopedic surgery. Although PEEK has some superior properties such as high melting point, superb wear resistance, excellent fatigue behavior, non-toxicity for bone tissue and elasticity modulus similar to human bone, PEEK has some disadvantages such as biologically inert behavior and low bioactivity. In this context, coating the implant surface to improve its osteointegration behavior is widely accepted. Coating PEEK polymers with bioactive materials such as Hydroxyapatite (HA) is among one of the solutions for this problem. In this study, in order to increase surface bioactivity of PEEK biomaterials, Titanium (Ti), Titanium dioxide (TiO2) and Hydroxyapatite (HA) powder combinations was coated on PEEK samples by using Atmospheric Plasma Spray (APS) method. Morphological and chemical characterization showed produced coatings are suitable for implantation process. Also in vitro tests performed in Simulated Body Fluid (SBF) revealed that HA, Ti + HA and TiO2 + HA coatings have bioactive property. © 2021 Elsevier B.V.