thermal cyclic behaviour of air plasma sprayed zirconate based

advertisement
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.,
Asst Professor,
Dept of Mechanical Engg,
A.V.C.College of Engg,
Mannampandal.
Prof. Dr. V. Balasubramanian,
Director, CEMAJOR,
Dept of Manufacturing Engg,
Annamalai University,
Chidambaram.
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.
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).
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).
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.
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.
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).
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).
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).
ABOUT THE CERAMIC COATINGS
– TBCs deposited
microstructure.
by
EB-PVD
exhibit
a
(contd.,)
columnar
grain
– 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.
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.).
HVOF
(contd.,)
- The jet velocity at the exit of the barrel (>1000 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 corrosion resistant coatings
on materials due to oxidation.
HVOF
HVOF
HVOF
Welding torch
Substrate
APS
• Atmospheric Plasma Spraying (APS) has been used to
deposit porous partially nano structured ceramic
coatings.
• Initially a bond coating made is NiCrAlY (NickelChromium-Aluminium-yttrium) coating,
• This is made by HVOF spray system to avoid oxidation
and to provide a greater bond strength with the ceramic
coatings.
APS
APS
Powder feeder
Feed motor
APS
Welding
electric torch
Substrate holding
Fixture
APS
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.
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 (NickelChromium-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.
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.
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.
COATING COMBINATIONS
1. 350 µ YSZ + 150 µ NiCrAlY + BOND COATING.
2. 350 µ LZ + 150 µ NiCrAlY + BOND COATING.
3. (175 µ LZ + 175 µ YSZ) + 150 µ NiCrAlY + BOND
COATING.
4. (150 µ LZ + 150 µ YSZ) + 100 µ (50% NiCrAlY + 50%
YSZ) POWDER + 100 µ NiCrAlY + BOND COATING.
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.
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.
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.
PHOTOS AND VIDEOS
THANK YOU
Download
Related flashcards

Salts

21 cards

Chemistry

20 cards

Chemical properties

18 cards

Pigments

50 cards

Dyes

45 cards

Create Flashcards