DOCSLIB.ORG

Thermal Spraying for Power Generation Components

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thermal Spraying for Power Generation Components Klaus Erich Schneider, Vladimir Belashchenko, Marian Dratwinski, Stephan Siegmann, Alexander Zagorski Thermal Spraying for Power Generation Components WILEY- VCH WILEY-VCH Verlag GmbH & Co. KGaA Contents Preface V The Authors of this Book VII 1 Introduction 1 1.1 Requirements for Materials and Coatings in Powcrplants 1.2 Examples of Coatings in Gas Turbines 2 1.3 Definition of Thermal Spraying (THSP) 5 1.4 Thermal-Spraying Systems 5 1.5 Coatings for Power-Generation Components 6 1.6 The Complete Manufacturing and Coating Process 7 1.7 Coating-Process Development 12 1.8 Tasks for "Target" Readers 35 2 Practica I Experience Today 17 2.1 Coating Processes J7 2.2 Basics of Thermal Spraying 21 2.3 Feedstock 23 2.3.1 Wire 23 2.3.2 Powder 24 2.3.2.1 Powder Types 24 2.3.2.2 Powder-Production Processes and Morphologies 27 2.3.2.3 Powder Characterization 33 2.3.2.4 Powders for Power-Generation Applications 36 2.4 Thermal-Spraying Equipment 40 2.4.1 Example of a Low-Pressure Plasma-Coating System 41 2.4.2 Flame and Are Spray Torches 43 2.4.3 HVOF Process 45 2.4.3.1 Comparison of HVOF Fuels 47 2.4.3.2 A Brief Overview of the Major Existing HVOF Systems 2.4.3.3 Possible [mprovements of HVOF Systems 51 2.4.4 Plasma Process 54 2.4.4.1 A Brief Overview of Plasma Torches 58 Thermal Spraying for Power Generation Components '{. E. Schneider, V. Bdashchfriko, M, Dratwinski, S. Siegrmnn, A. Zagorski Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 3-527-31337-0 X Contents 2.4.4.2 Possible Improvements of Plasma Systems 63 2.5 Work Flow and Important Coating Hardware 65 2.5.1 Powder Preparation and Powder-Dclivery System 68 2.5.1.1 Powder Preparation 68 2.5.1.2 Powder Delivery and Injection System 68 2.5.1.3 Powder Injection and Plasma/Hot Gas Jet 73 2.5.1.4 Injector Plugging and "Spitting" 75 2.5.1.5 Powder Buildup at the Front Nozzle Wall 77 2.5.2 Cooling System 77 2.5.3 Power-Supply System 79 2.5.4 Gas Supply and Distribution System 80 2.5.5 Manipulation Systems 81 2.5.6 Fixtures and Masking 83 2.6 Examples of Coated Power-Generation Components 84 2.7 Production Experience 86 2.7.1 Surfate Preparation 87 2.7.1.1 Internal Plasma and Transferred Are 89 2.7.2 Process and Systems 91 2.7.2.1 Tbe Programming of fhe Coating Process 94 2.7.3 Finishing 95 2.7.4 Repair of Turbine Parts 95 2.7.4.1 Coating Removal, Stripping 97 2.7.4.2 Restoration of the Base Materials 98 2.7.4.3 Refurbisbing, Recoating 98 2.8 Commercial 99 2.8.1 General 99 2.8.2 Surfa.ee Preparation 103 2.8.3 Coating Equipment 103 2.8.4 Finishing 104 3 Quality and Process Capability 705 3.1 Quality Assurance 105 3.2 Sources of Process Variations 105 3.2.1 Special Causesof Coating-Process Variation 107 3.2.2 Stochastic Nature of a Spray Process 108 3.2.2.1 Are and Jet Pulsations 108 3.2.2.2 Powder-Size Distribution 109 3.2.2.3 Powder Injection 110 3.2.2.4 Powder Sbape 110 3.2.2.5 Particle Bonding 110 3.2.2.6 Gun and Component Motion and Positioning HO 3.2.3 Drifting 7 77 3.2.4 S tability of the Quality Control 7 7 2 3.3 Process Capability and Stable Process 115 3.3.1 Definition of Process Capability 115 3.3.2 Definition ofa Stahle Coating Process 117 3.3.3 Operational Window 1J8 3.3.4 What Process Capability is Required? 122 3.3.5 Additional Factors that Affect the Process Capability 124 3.3.6 Case Study: Achievable Process Capability 125 3.3.6.1 Part Complexity 125 3.3.6.2 Mutual Position of the Gun and Component Fixtures 125 3.3.6.3 Powder Quality 125 3.3.6.4 Torch Pulsations and Drifting 126 3.3.6.5 lnstability of the Quality-Control Process 128 3.3.6.6 Surface Preparation and the Part Temperature 128 3.3.6.7 Conditions of the Powder-Injection System 129 3.3.6.8 Process Capability 129 3.4 Maintenance 130 4 Theory and Physical Trends 133 4.1 Coating Formation from Separate Particles: Particle Impact, Spreading and Bonding 133 4.2 Physics of Plasma Torches 138 4.2.1 Plasma Properties 139 4.2.2 Gas Dynamics of Plasma Torch 145 4.2.3 Energy Balance of the Plasma Gun 147 4.2.4 Major Trends 149 4.2.4.1 Variation of the Gun Power; the Gas Flow Rates and Composition Unchanged 149 4.2.4.2 Variation of the Plasma Composition at the Same Specific Plasma Enthalpy 149 4.2.4.3 Variation of the Plasma Flow Rate at Unchanged Gun Power and Gas Composition 150 4.2.4.4 Effect of Nozzle Diameter 151 4.2.5 Plasma Swirl 151 4.3 Structure of Plasma Jets 757 4.3.1 APS Jet 151 4.3.2 S tructure ofLPPSJet 153 4.4 Particles in Plasma 155 4.4.1 Particles at APS 156 4.4.2 Particle at LPPS 158 4.4.2.1 Particle Acceleration and Heating in the LPPS Free Jet 158 4.4.2.2 Particle Acceleration and Heating Inside the Nozzle 160 4.5 Spray Footprint (Spray Pattern) 161 4.6 Influenceof Particles on Plasma Flow 164 4.7 Substrate Surface Temperature 165 4.8 Formation of the Coating Layer 167 4.9 Useof Different Plasma Gases 168 4.10 Some Distinguishing Features ofHVOF Physics 169 XII Contents 5 Offline Simulation of a Thermal-Spray Process 171 5.1 Simulation in Production 171 5.2 Physical Background of Simulation Package 275 5.2.1 Viscoplasticity Model of a Splat and Particle Bonding 175 5.2.2 Thermodynamic and Transport Properties of Argon/Hydrogen Mixtures 176 5.2.3 Modeling of the Plasma Gun 176 5.2.4 Modeling of the Plasma Jets 176 5.2.4.1 APS Jet 177 5.2.4.2 LPPSJet 177 5.2.5 Acceleration and Heating of Parti des in Plasma 779 5.2.6 Surface Thermal Conditions 180 5.3 Spray Pattern 182 5.3.1 Calibration of the Bonding Model and Sensitivity of a Spray Pattern to the Process Parameters, Spray Angle and Bonding Model 182 5.3.2 Coating Porosity and Roughness 185 5.4 Modeling of Turbine Blades 187 5.5 Coating Thickness Optimization and Stochastic Modeling Tools 189 5.6 Simulation ofHVOF Process 195 5.7 Use of Offline Simulation in Coating Development 199 5.7.1 Application Areas of Modeling in the Coating Process 199 5.7.1.1 Coating Definition and Design for Coating 199 5.7.1.2 Coating-Process Development 199 5.7.1.3 Part Development 200 5.7.1.4 Physical Modeling and Offline Simulation as Process-Diagnostic Tools 201 5.7.1.5 Simulation as a Numerical Experiment 201 5.7.1.6 When the Offline Simulation Should Be Used 202 6 Standards and Training 205 6.1 Standards, Codes 205 6.1.1 Introduction to Standards 205 6.1.2 Quality Requirements for Thermally Sprayed Structures and Coating Shops 206 6.1.3 QuaKfication and Education of Spraying Personnel 209 6.2 Special Case: Spraying for Power-Generation Components 211 6.2.1 Coating-Process Development 212 6.2.2 Coating Production 213 6.2.3 Genera] Requirements for Coating-Shop Personnel 213 7 Monitoring, Shopfloor Experience and Manufacturing Process Development 215 7.1 Monitoring, Sensing 215 7.1.1 Introduction of Monitoring 215 7.1.2 Particle-Monitoring Devices 217 Contents XIII 7.1.3 Influence of Spray Parameters on Particle Speed and Tcmperature 218 7.1.4 Influence of Particle Velocity and Tempcrature on Microstructure 219 7.2 How to Use Monitoring for Process Control 222 7.2.1 Monitoring, Sensing from a Job Shop Point of View 222 7.2.2 Vision for Future Coating Control and Monitoring 224 7.3 Manufacturing Coating Development 228 7.3.1 Coating Development Process 229 7.3.2 Coating Definition and Coating Specification; Design for Coating 230 7.3.3 Process Development 233 7.3.3.1 Powder Selection 234 7.3.3.2 Torch Parameters 234 7.3.3.3 Spray Pattern and Standoff Distance 234 7.3.3.4 Coating Mono-Layer; Powder Feed Rate and Traverse Gun Speed 235 7.3.3.5 Spray Trials and Coating Qualification 235 7.3.3.6 Sensitivity Checks 236 7.3.4 Part Development 236 7.3.4.1 Coating Program 236 7.3.4.2 Process Qualification and Preserial Release 237 7.3.5 Serial Release 239 8 Outlook, Summary 241 8.1 Thermal Spray Torches 242 8.2 Future Offline Programming and Monitoring in Process Development and Production 244 References 245 Subject Index 261 .
Load more

Recommended publications
  • Porosity and Its Significance in Plasma-Sprayed Coatings
    coatings Review Porosity and Its Significance in Plasma-Sprayed Coatings John Gerald Odhiambo 1,2 , WenGe Li 1,*, YuanTao Zhao 1,* and ChengLong Li 1 1 Naval Architecture and Ocean Engineering, Merchant Marine College, Shanghai Maritime University, Shanghai 201306, China 2 Marine Engineering and Maritime Operations, School of Mechanical, Manufacturing & Materials Engineering, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200 Nairobi, Kenya * Correspondence: [email protected] (W.L.); [email protected] (Y.Z.); Tel.: +86-139-1799-6912 (W.L.); +86-151-2116-7661 (Y.Z.) Received: 11 June 2019; Accepted: 16 July 2019; Published: 23 July 2019 Abstract: Porosity in plasma-sprayed coatings is vital for most engineering applications. Porosity has its merits and demerits depending on the functionality of the coating and the immediate working environment. Consequently, the formation mechanisms and development of porosity have been extensively explored to find out modes of controlling porosity in plasma-sprayed coatings. In this work, a comprehensive review of porosity on plasma-sprayed coatings is established. The formation and development of porosity on plasma-sprayed coatings are governed by set spraying parameters. Optimized set spraying parameters have been used to achieve the most favorable coatings with minimum defects. Even with the optimized set spraying parameters, defects like porosity still occur. Here, we discuss other ways that can be used to control porosity in plasma-sprayed coating with emphasis to atmospheric plasma-sprayed chromium oxide coatings. Techniques like multilayer coatings, nanostructured coatings, doping with rare earth elements, laser surface re-melting and a combination of the above methods have been suggested in adjusting porosity.
    [Show full text]
  • Thermal Spraying of Polymer-Ceramic Composite Coatings with Multiple Size
    Thermal Spraying of Polymer-Ceramic Composite Coatings with Multiple Size Scales of Reinforcements A Thesis Submitted to the Faculty of Drexel University by Varun Gupta in partial fulfillment of the requirements for the degree of Master of Science in Materials Engineering April, 2006 i © Copyright 2006 Varun Gupta. All Rights Reserved. ii DEDICATION To my parents iii ACKNOWLEDGEMENTS I would like to express my gratitude to my primary advisor, Dr. Richard Knight, for his guidance, constant support and advice in many aspects of my graduate studies and research work but especially for the invaluable insights into thermal spray technology and a great influence on my professional development. I would like to thank my co-advisor, Dr. Richard Cairncross, for his always constant motivation, understanding, trust and support given throughout the course of my graduate studies. I deeply appreciate the friendship, assistance and practical help of Mr. Dustin Doss and Mr. Milan Ivosevic in working with me on this project, especially for the hands-on introduction to thermal spraying. I would also like to extend my thanks to Ms. Dee Breger for all her help during the SEM analysis and to Mr. Kishore Kumar Tenneti for assistance with the TGA analysis during the course of this project. I would like to give my special thanks to Mr. Ranjan Dash, Ms. Maria Pia Rossi, Mr. Davide Mattia, Mr. Brandon McWilliams and Mr. Stephen Niezgoda for their constant motivation and help. I also wish to thank all my friends, colleagues, faculty and staff members in the Department of Materials Science and Engineering who gave me the opportunity to learn from their advice and who have made my stay here at Drexel unforgettable.
    [Show full text]
  • Thermal Spraying Technology and Applications
    Thermal Spraying Technology and Applications Course No: T04-002 Credit: 4 PDH A. Bhatia Continuing Education and Development, Inc. 22 Stonewall Court Woodcliff Lake, NJ 07677 P: (877) 322-5800 [email protected] EM 1110-2-3401 29 Jan 99 1 EM 1110-2-3401 29 Jan 99 2 EM 1110-2-3401 29 Jan 99 DEPARTMENT OF THE ARMY EM 1110-2-3401 U.S. Army Corps of Engineers Washington, DC 20314-1000 Engineering and Design THERMAL SPRAYING: NEW CONSTRUCTION AND MAINTENANCE Table of Contents Subject Paragraph Page Chapter 1 Introduction Purpose 1-1 1-1 Applicability 1-2 1-1 References 1-3 1-1 Distribution Statement 1-4 1-1 Abbreviations and Acronyms 1-5 1-1 Neutral Language Use and Terms 1-6 1-1 Scope 1-7 1-1 Chapter 2 Thermal Spray Fundamentals Introduction 2-1 2-1 General Description of Thermal Spraying 2-2 2-1 Characteristics of Thermal Spray Coatings 2-3 2-1 Types of Thermal Spray Coatings 2-4 2-2 Thermal Spray Processes 2-5 2-3 Thermal Spray Uses 2-6 2-7 Chapter 3 Thermal Spray Materials Introduction 3-1 3-1 Specifications 3-2 3-1 Procurement 3-3 3-1 Classification 3-4 3-1 Acceptance 3-5 3-2 Certification 3-6 3-2 Sizes 3-7 3-2 Packaging 3-8 3-3 Identification and Marking 3-9 3-3 Manufacture 3-10 3-3 Testing 3-11 3-3 3 EM 1110-2-3401 29 Jan 99 Subject Paragraph Page Chapter 4 Thermal Spray Coating Cost and Service Life Introduction 4-1 4-1 Cost 4-2 4-1 Service Life 4-3 4-2 Chapter 5 Thermal Spray Coating Selection Introduction 5-1 5-1 Service Environments 5-2 5-1 Other Considerations in Coating Selection 5-3 5-4 Thermal Spray Selection for Ferrous
    [Show full text]
  • Application Notes Metallographic Preparation of Thermal Spray Coatings
    Metallographic preparation of thermal spray coatings Application Notes Thermal spraying was invented in the early 1900s using zinc for „metallizing” substrates for corrosion protection. The development of the plasma spray gun in the late 50s and 60s made it commercially viable to use high temperature materials such as ceramics and refractory metals for coating materials. In addition to fl ame and plasma spraying, today thermal spray methods include high velocity and detona- tion spraying using a multitude of different spray materials for the most diverse and demanding applications. Thermal spray coatings are applied to a substrate to give a specifi c surface quali- ty, which it originally does not have. Thus Metallography of thermal spray coatings the bulk strength of a part is given by the can have several purposes: substrate, and the coating adds superior - To defi ne, monitor and control spraying surface qualities such as corrosion, wear conditions for quality control or heat resistance. - For failure analysis Therefore thermal spray coatings are wide- - For developing new products. ly used in the aerospace and power gene- ration industry for new and refurbished The procedure normally involves coating sections and parts for jet engines and a test coupon to defi ne and optimize the gas turbines, compressors and pumps. process for the part to be sprayed. Sec- The properties of some coatings can only tions of this test coupon are then metal- be fabricated by thermal spraying, using lographically prepared and examined to mainly metals, ceramics, carbides and assess coating thickness, size and distribu- composites as well as mixtures of various tion of porosity, oxides and cracks, adhe- materials.
    [Show full text]
  • (12) United States Patent (10) Patent No.: US 6,852,433 B2 Maeda (45) Date of Patent: Feb
    USOO6852433B2 (12) United States Patent (10) Patent No.: US 6,852,433 B2 Maeda (45) Date of Patent: Feb. 8, 2005 (54) RARE-EARTH OXIDE THERMAL SPRAY 5.993,970 A 11/1999 Oscarsson et al. COATED ARTICLES AND POWDERS FOR 6,080.232 A * 6/2000 Sperlich et al.............. 106/436 THERMAL SPRAYING 6,582,814 B2 * 6/2003 Swiler et al. ............... 428/328 2002/0177001 A1 11/2002 Harada et al. (75) Inventor: Takao Maeda, Takefu (JP) FOREIGN PATENT DOCUMENTS (73) Assignee: Shin-Etsu Chemical Co., Ltd., Tokyo (JP) JP 2001-164354 A 6/2001 (*) Notice: Subject to any disclaimer, the term of this OTHER PUBLICATIONS patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. U.S. Appl. No. 10/101,612, filed Mar. 21, 2002, Takai et al. (21) Appl. No.: 10/618,679 U.S. Appl. No. 10/173,030, filed Jun. 18, 2002, Takai et al. (22) Filed: Jul. 15, 2003 U.S. Appl. No. 10/173,031, filed Jun. 18, 2002, Takai et al. (65) Prior Publication Data * cited by examiner US 2004/0013911A1 Jan. 22, 2004 (30) Foreign Application Priority Data Primary Examiner Jennifer McNeil (74) Attorney, Agent, or Firm-Birch, Stewart, Kolasch & Jul. 19, 2002 (JP) ....................................... 2002-211400 Birch, LLP (51) Int. Cl. ............................ B32B 15/04; B32B 9/04 (57) ABSTRACT (52) U.S. Cl. ....................... 428/697; 428/701; 428/702; 428/699; 428/469; 428/698 A rare-earth oxide thermal spray coated article comprising a (58) Field of Search ................................. 428/469, 701, Substrate and a coating layer formed by thermally spraying 428/702, 699, 698, 697: 106/474, 403, a rare-earth oxide thermal spraying powder onto a Surface of 479, 436 the Substrate, Said coating layer being of a gray or black color having, in the L*a*b* color space, an L* value of up (56) References Cited to 50, an a value of -3.0 to +3.0, and a b value of -3.0 to +3.0.
    [Show full text]
  • Detonation Thermal Spraying Process of Metal
    Technology Lappeenranta/Imatra Degree Programme in Mechanical Engineering and Production Technology Specialisation Andrey Vinogradov Detonation thermal spraying process of metal- ceramic coating of the inner body of a regulating valve for maintenance of turbine condensate level in a deaerator for a nuclear power plant Bachelor’s Thesis 2015 1 Abstract Andrey Vinogradov Detonation thermal spraying process of metal-ceramic coating of the inner body of a regulating valve for maintenance of turbine condensate level in a deaerator for a nuclear power plant, 41 pages, 3 appendices Saimaa University of Applied Sciences Technology Lappeenranta Degree Programme in Mechanical Engineering and Production Technology Bachelor’s Thesis 2015 Instructors: Lecturer Jukka Nisonen, Saimaa University of Applied Sciences Managing Director Zelenin Y.V., main process engineer Shvedov N.G., process engineer Karpenko D., Center of Scientific-Technical Service "Prometey" The objective of the research was to examine a process of metal-ceramic deto- nation spraying, technology and realization of the procedure and its features for the given component. The work was commissioned by main process engineer Shvedov N. G. This study was carried out at the Center of Scientific-Technical Service "Prometey". The information was gathered from internal documentation of the enterprise, manuals, literature and by interviewing process engineers. As a result of this thesis the detonation coating process was investigated for a particular unit – the regulating valve. All the stages and requirements were pre- sented. The results can be applied to any detonation coating case or surface treatment matter where complex approach is necessary. Keywords: coating, valve, deposition, spraying, mixture, powder, assembly, component, aluminum oxide, spraying gun, surface, nozzle, plunger, process.
    [Show full text]
  • Thermal Spraying of Oxide Ceramic and Ceramic Metallic Coatings
    6 Thermal Spraying of Oxide Ceramic and Ceramic Metallic Coatings Martin Erne and Daniel Kolar Institute of Materials Science, Leibniz University of Hannover Germany 1. Introduction Thermal Spraying is called a group of processes by means of that thin ceramic and ceramic metallic (cermet) coatings can be applied on a vast variety of materials, so called substrates. The goal is to reach considerably different characteristics on the surface of the component part regarding the resistance against abrasion and corrosion, the electrical conductivity and many more. This chapter intends to give an overview of the different processes, the processable feedstock materials, the different areas of application and new developments in the field of Thermal Spraying. 2. Thermal spray processes and coatings´ microstructure All together thermal spray processes make use of heat and kinetic energy to warm-up and propel feedstock material to build up a coating on the substrate. Often the goal is to melt the feedstock thoroughly due to reach a dense microstructure, but in some cases the feedstock impinges in solid state and is deformed by the kinetic energy as the particles reach supersonic velocity before impact. Dependent on the source of energy distinctly different process characteristics and therefore visibly diverse microstructure and properties of the coatings can be obtained. In the norm DIN EN 657 “Thermal Spraying” the different processes are distinguished by the means of the energy source. The processes being widely in operation are based on the energy sources flames and electric or gas discharges. Although the lasers assisted spraying techniques are coming more and more into operation, they cover only a small segment compared to the conventional techniques.
    [Show full text]
  • Thermal Spraying
    Thermal spraying Process engineering and selection of gases The right gas for the right process Because of the variety of different thermal Gases for Thermal Spraying spraying processes, almost the entire range of technical gases is used. Most of the applications are for fuel gases and oxygen. Process/ Gases Application Fuel gases Flame spraying acetylene, Grieson®, Various hydrocarbons, especially acetylene, and propane, hydrogen, also hydrogen are used. In addition to the fuel characteristics, aspects of the gas supply system oxygen are also important. Flame spraying guns can High velocity Grieson®, Mapp®, propane, often be used for different fuel gases by flame spraying hydrogen, oxygen changing the nozzles. For fusing, high acetylene performance fuel gases such as acetylene and Grieson® are generally preferred. Plasma spraying argon, helium, hydrogen, nitrogen, mixtures Conveying gases Coolant nitrogen, carbon dioxide Most guns work with an attached powder Fusing acetylene, Grieson®, container and oxygen as internal conveying gas. oxygen In order to provide greater quantities of powder, external powder conveyors are used, normally driven by compressed air which has to be HVOF*-Torch purified by means of oil and water separators. If inertization is required, argon, sometimes with added nitrogen, is used. Gas supply Flame spray guns have a fuel gas requirement up to several kilograms per hour. An acetylene supply system must be of adequate size and capacity. For high-speed flame spraying, the gases most used are propane, propene and ® 1) Cooling water * HVOF= High Velocity hydrogen. Grieson is also highly suitable. Typical 2) Cooling gas Oxy Fuel pressures are between 5 and 7 bars, with 3) Fuel gas/O2 a tendency going in the direction of 10 bars.
    [Show full text]
  • Different Coating Processes for Surface Hardening of Aluminium Kumavat Mukesh Manilal1, Prof
    International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 02 | Feb -2017 www.irjet.net p-ISSN: 2395-0072 Different Coating Processes for Surface Hardening of Aluminium Kumavat Mukesh Manilal1, Prof. Londhe B.C.2, Prof. Ghodake A.P.3, Prof. Gujrathi T.V.4 1 PG Student (Machine Design), Savitribai Phule Pune University, SND COE & RC Yeola, Maharashtra, India 2 Associate Professor, Dept. of Mechanical Engineering, SND COE & RC Yeola, Maharashtra, India 3,4 Assistant Professor, Dept. of Mechanical Engineering, SND COE & RC Yeola, Maharashtra, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Materials engineers constantly create and reason we will discuss the different types of coating for improve the properties of materials by applying the existing aluminium. knowledge of science. This is because newly developed materials can easily be used as replacement of the current 1.1 Different Coating Processes ones. The requirements of individual components with regards to properties like hardness, corrosion, wear, impact, strength, 1.1.1 Chemical vapor deposition and economic considerations finally decide the material to be preferred. Technological progresses compel the use of 1. Metal organic vapour phase epitaxy. materials in increasingly extreme and aggressive conditions, 2. Electrostatic spray assisted vapour deposition (ESAVD). such as corrosive atmospheres. Corrosion is one of the most frequently encountered causes of failure of components. 1.1.2 Physical vapour deposition Corrosion is a complex series of oxidation/reduction reactions between the metal/alloy surfaces and liquid media. Nearly all 1. Cathode arc deposition metals will corrode to some degree. Corrosion can be 2. Electron beam physical vapour deposition (EBPVD) concentrated locally to form a pit or crack, or it can extend 3.
    [Show full text]
  • Cold Spraying of Titanium: a Review of Bonding Mechanisms, Microstructure and Properties T
    Key Engineering Materials Online: 2012-12-27 ISSN: 1662-9795, Vol. 533, pp 53-90 doi:10.4028/www.scientific.net/KEM.533.53 © 2013 Trans Tech Publications, Switzerland Cold Spraying of Titanium: A Review of Bonding Mechanisms, Microstructure and Properties T. Hussain1 1 Centre for Energy and Resource Technology (CERT), School of Applied Sciences, Cranfield University, Bedford, MK43 0AL, UK [email protected] Keywords: cold spray, deposits, bonding mechanisms, titanium Abstract. Cold gas dynamic spraying (CGDS) is a relatively new branch of surface engineering that involves modification of the surface of substrates to provide specific engineering advantages, which the substrate alone cannot provide. Cold spraying, as a metal deposition technique, involves spraying of typically 10-40 μm particles which are accelerated by a propellant gas to 300- 1200 m/s at a temperature well below the melting point of material, and upon impact deform and adhere to the substrate. The deposition process in cold spraying occurs in a solid state which results in reduced oxidation and absence of phase changes; whereas, in thermal spraying deposition occurs of molten or semi molten particles. Over the last decade the interest in cold spraying has increased substantially. Considerable effort has been invested in process developments and optimization of coatings like copper. However, bonding in cold spraying is still a matter of some debate. The most prevalent theory is that when a particle travels at a minimum required velocity the particle deforms at a very high strain rate upon impact and during this deformation thermal softening dominates over work hardening in impact zone and a material jet is produced.
    [Show full text]
  • Thermodynamics and Mechanics of Thermal Spraying of Steel EN 10060 Substrate with Nicrbsi Alloy After Milling
    materials Article Thermodynamics and Mechanics of Thermal Spraying of Steel EN 10060 Substrate with NiCrBSi Alloy after Milling Jan Valíˇcek 1, Marta Harniˇcárová 1,*, Jan Rehoˇrˇ 1 , Milena Kušnerová 1, Ludmila Kuˇcerová 1 , Miroslav Gombár 1, Jaroslava Fulemová 1, Jan Filipenský 2 and Jan Hnátík 1 1 Regional Technology Institute, Faculty of Mechanical Engineering, University of West Bohemia, Univerzitni 8, 306 14 Pilsen, Czech Republic; [email protected] (J.V.); [email protected] (J.R.);ˇ [email protected] (M.K.); [email protected] (L.K.); [email protected] (M.G.); [email protected] (J.F.); [email protected] (J.H.) 2 PLASMAMETAL, Ltd., Tovární 917/1e, 643 00 Brno-Chrlice, Czech Republic; fi[email protected] * Correspondence: [email protected] Received: 16 October 2020; Accepted: 23 November 2020; Published: 25 November 2020 Abstract: The objective of this paper is to present a new way of identifying and predicting the relationship between thermodynamic and physical-mechanical parameters in the formation of a layer after spraying on a substrate with NiCrBSi alloy and its subsequent processing by milling. The milling of the spherical surface of the EN 10060 material after spraying was performed on the DMU 40 eVolinear linear milling centre. The experimental part of the article is focused on investigating the influence of cutting parameters when machining a selected combination of materials (substrate-coating: EN 10060 steel-NiCrBSi alloy). The experiment is based on the results of direct measurements of 1 three basic cutting parameters, namely: cutting speed vc (m min ), feed per tooth fz (mm), and the · − depth of cut ap (mm).
    [Show full text]
  • Thermal Spraying
    Thermal Spraying Thermal Spraying DIN 32530: Thermal spraying comprises processes that feature: - full or partial melting of spraying feedstock (or at least sufficient heat transfer in order to provide a state of high plastic deformation capability) inside or outside a spraying torch - propelling of spray particles onto a prepared substrate surface - substrate surface is (usually) not melted Definition Heat and Momentum Substrate Transfer Spraying gun Energy source -Flame -Arc -Plasma Spraying feedstock -Powder -Wire -Rod Principle of Thermal Spraying Coating formation Thermal Spraying Spraying direction Pores Oxides Heat flux Lateral spreading Contact zones Impact of spray particles on substrates Pore Oxidized particle Not fully molten particle Substrate Formation of thermal spray coatings t = 0.00 µs -50 µm 0 50 t = 0.08 µs t = 0.03 µs -50 µm -50 0 µm 0 50 50 t = 0.13 µs d = 50 µm, v = 200 m/s Spreading of a AlPart. Part. -50 µm 0 50 2 O 3 particle on a substrate t = 0.23 µs -50 µm 0 50 t = 0.62 µs t = 0.36 µs -50 µm -50 0 µm 0 50 50 t = 5.00 µs d = 50 µm, v = 200 m/s Spreading of an AlPart. Part. -50 µm 0 50 2 O 3 particle on a substrate 15 30 45 60 75 > 75 P [MPa] t = 0.04 µs t = 0.10 µs -0.1 0.1 -0.1 0.1 mm mm t = 0.06 µs t = 0.23 µs -0.1 0.1 -0.1 0.1 mm mm t = 0.09 µs t = 0.36 µs -0.1 0.1 -0.1 0.1 mm mm Pressure distribution in an Al2O3 particle during spreading on a steel substrate white dashs: t = 0.62 µs solidification boundary -0.10 0.10 [mm] Temperature [K] t = 3.00 µs -0.10 0.10 > 1550 [mm] > 1300 >1050 t = 10.00 µs -0.10
    [Show full text]