THERMAL CYCLIC BEHAVIOUR OF AIR PLASMA SPRAYED ZIRCONATE BASED COATINGS

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THERMAL CYCLIC BEHAVIOUR OF AIR PLASMA SPRAYED
ZIRCONATE BASED COATINGS

• BATCH MEMBERS G. AGORAMOORTHY
  (80107144003),
• M. ASWIN (80107144009),
• K. RAMKUMAR (80107144036),
• M. SURESH (80107144050),
• FINAL YEAR MECHANICAL ENGINEERING,
• AVCCE-MANNAMPANDAL.
• PROJECT GUIDE
• INTERNAL GUIDE EXTERNAL GUIDE
• Mr. A. Ramprakash, M.E., Prof. Dr. V.
  Balasubramanian,
• Asst Professor, Director, CEMAJOR,
• Dept of Mechanical Engg, Dept of Manufacturing
  Engg,
• A.V.C.College of Engg, Annamalai University,
• Mannampandal. Chidambaram.

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NATURE OF THE PROJECT WORK

• Project work Outside the campus.
• Location Plasma spraying laboratory,
• Centre for Material Joining and Research,
  (CEMAJOR),
• Dept of Manufacturing Engg,
• Annamalai University,
• Chidambaram.

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OBJECTIVES

• The project work is made on a thermal sprayed
  materials to study and analyze the heat
  withstanding capacity among the materials.
• Analyzation involves
• Scanning Electron Microscopy (SEM testing)
• X-ray Diffractometer (XRD testing).

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SYNOPSIS

• Substrate used here INCONEL 800.
• Coating materials Lanthanum Zirconate and Yttria
  stabilized zirconate.
• Coating systems APS plasmatron (Atmospheric
  Plasma Spray system, 40 kw)
• And HVOF spray system (High Velocity Oxy Fuel
  spray system).

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ABOUT THE SUBSTRATE

• The substrate used here is INCONEL 800, which is
  a super alloy of austenitic nickel-chromium.
• Composition
• It comprises of Nickel, Chromium, Iron,
  Molybdenum, Niobium, Cobalt, Manganese, Copper,
  Aluminium, Titanium, Silicon, Carbon, Sulfur,
  Phosphorus, Boron.
• Properties
• Oxidation and corrosion resistant.
• When heated, Inconel forms a thick, stable,
  passivating oxide layer protecting the surface
  from further attack.

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ABOUT THE SUBSTRATE (contd.,)

• Uses
• It is common in gas turbine blades, seals, and
  combustors,
• Turbocharger rotors and seals, Electric
  submersible well pump motor shafts,
• High temperature fasteners,
• Chemical processing and pressure vessels, Heat
  exchanger tubing, steam generators in nuclear
  pressurized water reactors.

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ABOUT THE CERAMIC COATINGS

• Ceramic coatings used here are
• Lanthanum Zirconate and
• Yttria stabilized Zirconate.
• Yttria stabilized Zirconate
• Yttria-stabilized zirconate (YSZ) is a
  zirconium-oxide based ceramic, in which the
  particular crystal structure of zirconium oxide
  is made stable at room temperature by an addition
  of yttrium oxide. These oxides are commonly
  called "zirconia" (ZrO2) and "yttria" (Y2O3).

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ABOUT THE CERAMIC COATINGS (contd.,)

• Applications of YSZ
• It is used
• As a refractory,
• As a thermal barrier coating in gas turbines,
• As the solid electrolyte,
• As a material for non-metallic knife blades,
  produced by Boker and Kyocera companies.,
• YSZ doped with rare-earth materials can act as a
  thermographic phosphor (Phosphor thermometry is
  an optical method for surface temperature
  measurement. The method exploits luminescence
  emitted by phosphor material).

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ABOUT THE CERAMIC COATINGS (contd.,)

• Lanthanum Zirconate
• Lanthanum zirconate (La2Zr2O7, LZ) is a newly
  proposed material for thermal barrier coatings
  (TBCs).
• Compared with the standard TBC material
  yttria-stabilized zirconia (YSZ), LZ coating has
  a lower thermal expansion coefficient, which
  leads to higher stress levels in a TBC system.
• Lanthanum Zirconate has been developed as a TBC
  using Electron Beam Physical Vapour Deposition
  (EB-PVD).

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ABOUT THE CERAMIC COATINGS (contd.,)

• TBCs deposited by EB-PVD exhibit a columnar grain
  microstructure.
• It is able to balance the difference in thermal
  expansion between the base material and TBC
  during thermal cycle and hence improve the TBC
  lifetime.

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ABOUT THE MACHINING

• There are two processes involved in thermal
  barrier coating process. They are
• HVOF (High Velocity Oxy Fuel Spray system).
• APS (Atmospheric Plasma Spray system).
• HVOF
• A mixture of gaseous or liquid fuel and oxygen is
  fed into a combustion chamber, where they are
  ignited and combusted continuously.
• The fuels can be gases (hydrogen, methane,
  propane, propylene, acetylene, natural gas, etc.)
  or liquids (kerosene, etc.).

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HVOF (contd.,)

• - The jet velocity at the exit of the barrel
  (gt1000 m/s) exceeds the speed of sound.
• - A powder feed stock is injected into the gas
  stream, which accelerates the powder up to 800
  m/s.
• - The stream of hot gas and powder is directed
  towards the surface to be coated. The powder
  partially melts in the stream, and deposits upon
  the substrate.
• - The resulting coating has low porosity and
  high bond strength.
• - it is typically used to deposit wear and corrosi
  on resistant coatings on materials due to
  oxidation.

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HVOF
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HVOF
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HVOF
Welding torch
Substrate
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APS

• Atmospheric Plasma Spraying (APS) has been used
  to deposit porous partially nano structured
  ceramic coatings.
• Initially a bond coating made is NiCrAlY
  (Nickel-Chromium-Aluminium-yttrium) coating,
• This is made by HVOF spray system to avoid
  oxidation and to provide a greater bond strength
  with the ceramic coatings.

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APS
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APS
Powder feeder
Feed motor
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APS
Welding electric torch
Substrate holding Fixture
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APS
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OVERALL PROCESS

• Initially the substrate is prepared by Sand
  blasting process to remove impurities.
• Sand blasting is essential to increase bond
  strength between substrate and coating material.
• After sand blasting, the substrate is acid
  treated for removing organic contaminants. The
  chemical used here is acetylene.

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OVERALL PROCESS (CONTD.,)

• After chemical treatment, a bond coating is made
  on the substrate by High Velocity Oxy Fuel Spray
  system.
• The bond coating applied here is Ni-Cr-Al-Y
  (Nickel-Chromium-Aluminium-Yttrium alloy powder).
• This coating increases bond strength with the
  ceramic coatings and it also reduces oxidation.
• Then the ceramic coatings are applied on the
  substrate by six various combinations using
  Atmospheric Plasma Spray System.

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OVERALL PROCESS (CONTD.,)

• After coating of ceramic materials, Scanning
  Electron Microscopy is made on the substrates to
  analyse the bonding structure among the
  substrates.
• After SEM testing, the substrates are treated in
  the furnace at various operating temperatures
  (12000c, 12300c, 12500c) and quenched.
• This process gets continued until the coating
  material peeled off from the substrate.

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OVERALL PROCESS (CONTD.,)

• After the coating material get peeled off, the
  substrates are again tested by Scanning Electron
  Microscopy.
• The results are observed and compared with the
  previous results.

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COATING COMBINATIONS

• 350 µ YSZ 150 µ NiCrAlY BOND COATING.
• 350 µ LZ 150 µ NiCrAlY BOND COATING.
• (175 µ LZ 175 µ YSZ) 150 µ NiCrAlY BOND
  COATING.
• (150 µ LZ 150 µ YSZ) 100 µ (50 NiCrAlY 50
  YSZ) POWDER 100 µ NiCrAlY BOND COATING.

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COATING COMBINATIONS (CONTD.,)

• 5. 125 µ LZ 100 µ (50 LZ 50 YSZ) POWDER
  125 µ YSZ 150 µ NiCrAlY BOND COATING.
• 6. 100 µ LZ 100 µ (50 LZ 50 YSZ) POWDER
  100 µ YSZ 100 µ (50 NiCrAlY 50 YSZ) POWDER
  100 µ NiCrAlY BOND COATING.

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RESULTS AND DISCUSSIONS

• This project work has been carried out for about
  3 months.
• The overall physical work has been finished by
  our team members and we are at the edge of our
  analysation work.
• We are awaiting for the results and conclusions.

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FUTURE SCOPE OF THE PROJECT

• The major factors that influences the future
  scope of our project work, that we consider are
  as follows
• Increased life of the material (INCONEL 800),
  against wear and corrosion.
• Enhanced protection from dusts and flying
  Aerosols.
• Enhanced heat resistance and safety of the
  material (INCONEL 800), such as turbine blades,
  pressure vessels, high temperature vessels and so
  on.

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PHOTOS AND VIDEOS
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THANK YOU