17 oxidation resistant high temperature coatingshome.agh.edu.pl/~grzesik/FHTC/17_oxidation resistant...

OXIDATION RESISTANT

HIGH TEMPERATURE COATINGS

Zbigniew Grzesik

Department of Physical Chemistry and Modelling

http://home.agh.edu.pl/~grzesik

REFERENCES

1. N. Birks, G.H. Meier and F.S Pettit, Introduction to the high temperature oxidation

of metals, Cambridge, University Press, 2009.

2. P. Kofstad, „High-Temperature Oxidation of Metals”, John Wiley & Sons, Inc, New

York-London-Sydney, 1978.

3. A.S. Khanna, „Introduction to High Temperature Oxidation and Corrosion”, ASM

International, Materials Park, 2002.

4. S. Mrowec, „An Introduction to the Theory of Metal Oxidation”, National Bureau

of Standards and the National Science Foundation, Washington, D.C., 1982.

5. Wei Gao and Zhengwei Li ”Developments in high-temperature corrosion and

protection of metals”, Ed, Woodhead Publishing Limited, Cambridge, England,

2008.

6. R. Cottis, M. Graham, R. Lindsay, S. Lyon, J. Richardson, J. Scantlebury, F. Stott,

„Basic Concepts, High Temperature Corrosion”, vol. I, in „Shreir’s Corrosion”,

Elsevier, Amsterdam, 2010.

Oxidation resistance of selected metals

10-7

10-5

Cu

Mn

Co

Fe

cm-4

s-11573 1473 1373 1273 1173

T / K

6 7 810-13

10-11

10-9Mn

Ni-Li2O

Ni

Cr

.

k p /

g2 cm

T -1 104 / K-1

Oxidation resistance of selected metals

Ni-Al phase diagram

Degradation rate of noble metals at high temperatures

The influence of dopping effect on oxidation resistance

10-11

10-10

10-9

-4s-1

1573 1373 1173 973

Ni-30CrCo-35Cr

UTLENIANIE

T / K

Oxidation resistance of selected alloys

6 7 8 9 10 1110-15

10-14

10-13

10-12

.T-1 104 / K-1

k p /

g2 cm-4

chromia formersalumina formers

β-NiAl

Fe-5Cr-4Al Ni-10Cr-5Al

Fe-20Cr

The influence of Y on the oxidation rate of the Fe-25Cr-5Al alloy

The influence of Y and Sc on the degradation rate of the Fe-25Cr-5Aland Ni-20Cr alloys under thermal shock conditions

0 25 50 75 100-5

-4

-3

-2

-1

0

1very good

good

ratherbad

mas

s ch

ange

/sur

face

are

a

/ a.u

.

Number of thermal shocks

1 cycle = 2 h

extremalybad bad

0 50 100 150 200 Time / h

MATERIALS USED AS PROTECTIVE COATINGS IN OXIDIZING ATMOSPHERES

Cr – Cr2O3

Al – Al2O3

Si – SiO2Si – SiO2

MCrAlY (where M = Co, Ni, Co/Ni) – Al2O3, Cr2O3

MCrAlY-Si – Al2O3, Cr2O3

MCrAlY-RE (where RE = Y, Hf, Zr) – Al2O3

NiAl – Al2O3

Cross-section of the Ni-Cr-Al-Y coating obtained by the EB-PVD method

Surface and cross-section of the Co-Cr-Al-Y coatingobtained by the EB-PVD method on the IN-738 alloy

Micrograph of Pt modified aluminide coatingon nickel-base superalloy

PtAl2 phase (white color) in a matrix of β-NiAl

Micrograph of cross-section of an EB-PVD Co-Cr-Al-Y coating, deposited on IN-738

Micrograph of cross-section of Pt-modified aluminide coating on nickel-base single-crystal superalloy

after oxidation at 1200oC for 20 h

The original grain structure of the β-phase is evident and γ’ has begunto nucleate at β grain boundaries as a consequence of Al depletion

Micrograph of cross-section of Pt-modified aluminide coating on nickel-base single-crystal superalloy

after oxidation at 1200oC for 200 h

The coating had been converted almost completely to γ’, as a result of Al depletion. Further exposure would result in the γ’ transforming to γ.

Micrograph of cross-section of a Ni-Co-Cr-Al-Y coatingon a single-crystal Ni-base superalloy

after 200 one-hour cycles at 1100oC in air

Micrograph of cross-section of a Ni-Co-Cr-Al-Y coatingon a single-crystal Ni-base superalloy

after 1000 one-hour cycles at 1100oC in air

Cyclic oxidation data for a straight aluminide and a platinum aluminide on IN-738 at 1200oC in air

Cyclic oxidation data for a sputtered Ti-Cr-Al coating on γ−TiAl at 900oC and the cross-section

of coating after exposure

Thermal barrier coatings (TBC)

Thermal barrier coatings (TBC) are highly advanced materials systemsusually applied to metallic surfaces, such as on gas turbine or aero-engineparts, operating at elevated temperatures, as a form of exhaust heatmanagement.These coatings serve to insulate components from large and prolongedheat loads by utilizing thermally insulating materials which can sustain anheat loads by utilizing thermally insulating materials which can sustain anappreciable temperature difference between the load-bearing alloys andthe coating surface. TBC coatings can allow for higher operatingtemperatures while limiting the thermal exposure of structural components,extending part life by reducing oxidation and thermal fatigue. In conjunctionwith active film cooling, TBCs permit working fluid temperatures higherthan the melting point of the metal airfoil in some turbine applications.

Scheme of a typical TBC system

Scheme of a typical TBC system

a) before and b) after oxidation

Scheme of the structure of a thermal barrier coatingwith a temperature profile

The parts of an aircraft engine using a plasma spray coating

View of Engine Alliance GP7200 aircraft engine with photograph of aturbine blade ( ∼ 10 cm long) with thermal-barrier coating (TBC) from the

high-pressure hot section of an engine, and a scanning electron microscope (SEM) image of a cross-section of an electron beam physical vapor

deposited 7 wt% yttria-stabilized zirconia TBC.

Cross-sections of TBC coatings

Surface and cross-sections of a layer of TBC protective coating after oxidation

EB-PVD YSZ TBC

Pt-modified bond coat

Cross sections of a layer of TBC protective coating after oxidation

EB-PVD YSZ TBC

Photograph of a plasma spray physical vapor deposition (PSPVD) plumecoating (a) and (b) scanning electron microscopy images of PSPVD

microstructures from splat/cluster deposition all the way to vapor depositionobtained at different deposition rates

Progression of temperature capabilities of Ni-based superalloys and thermal-barrier coating (TBC) materials over the past 50 years. The red lines indicate progression of maximum allowable gas temperatures in

engines, with the large increase gained from employing TBCs.

Thermal conductivity summary of the emerging ceramics for thermal-barrier coatings, whose conductivities vary with temperature (a) and

temperature-independent thermal conductivities of ceramics (b)

Schematic illustration of the multilayer, multifunctional nature of the thermalbarrier coating system. The ceramic topcoat is deposited by electron beam

physical vapor deposition (EBPVD) or air plasma-spraying (APS).

Failure mechanisms typical of current thermal-barrier coatings (TBCs):delamination cracks propagating through the TBC, chemical attack of the thermally grown oxide (TGO) with concomitant loss of adherence, creep

cavitation of the bond coat below a heavily penetrated TBC

Thermal barrier coatings in automobiles

Cross section of four-cylinder in-line engine with spark ignition, Fiat

Construction of an exhaust valve

1 – mushroom - austenitic steel Cr-Ni-W-Mo in supersaturated and aged state,

2 – handle - Cr-Si-Mo steel thermally improved,

3 – place of friction welding, 4 – valve face hard coated of stellite Co-Cr-W

Working conditions of valves in car engines

• aggressive atmosphere of combustion gases

• high temperature (T ≈ 1173 K)

• rapid changes of temperature (thermal shocks)• rapid changes of temperature (thermal shocks)

Temperature distribution in the exhaust valve- petrol engine with spark ignition

Componentsof exhaust gases

Units Method of ignition Toxicity evaluationspark ignition spontaneous

Nitrogen % vol. 74-77 76-78 neutral

Oxygen % vol. 0,3-8,0 2,0-18,0 as above

Water vapor % vol. 3,0-5,5 0,4-5,0 as above

Carbon dioxide % vol. 5,0-12,0 1,0-10,0 as above

Chemical compositions of an engine gaseswith spark and spontaneous ignition (wt. %)

Carbon dioxide % vol. 5,0-12,0 1,0-10,0 as above

Carbon monoxide % vol. 5,0-10,0 0,01-0,5 toxic

Nitrogen oxides % vol. 0,0-0,8 0,002-0,5 as above

Hydrocarbons % vol. 0,2-3,0 0,009-3,0 as above

Aldehydes % vol. 0,0-0,2 0,001-0,009 as above

Soot g/m3 0,0-0,04 0,01-1,1 as above

3,4 benzopyrene g/m3 to 15,0 to 10,0 carcinogenic

Merkisz J., Ekologiczne problemy silników spalinowych Tom I i II. Wydawnictwo Politechniki Poznańskiej, Poznań 1999

a.

Exhaust valves after the 1000 hour test- engine with spontaneous ignition

The chemical composition of valve steels (% wt.)

Type of steel C Mn Si Cr Ni N W Nb S P Mo Fe

X33CrNiMn23-8 0.35 3.3 0.63 23.4 7.8 0.28 0.02 - <0.005 0.014 0.11 bal.

X50CrMnNiNbN21-9 0.54 7.61 0.30 19.88 3.64 0.44 0.86 2.05 0.001 0.031 - bal.

X53CrMnNiN20-8 0.53 10.3 0.30 20.5 4.1 0.41 - - <0.005 0.04 0.12 bal.

X55CrMnNiN20-8 0.55 8.18 0.17 20.0 2.3 0.38 - - <0.005 0.03 0.11 bal.X55CrMnNiN20-8 0.55 8.18 0.17 20.0 2.3 0.38 - - <0.005 0.03 0.11 bal.

The corrosion test of valve steels under thermal shock conditions in engine house

Hybrid reactive head

Corrosion kinetics of tested valve steelsunder thermal shock conditions

-0.15

-0.10

-0.05

0.00

0.05

combustion gases of fuel oil B5


1 cycle = 2h

air

∆m/S

/

g cm

-2

X33CrNiMn23-8T = 1173 K

0 100 200 300 400 500

-0.3

-0.2

-0.1

0.0


combustion gases of fuel oil B5 air

1 cycle = 2h

∆m

/S

/g c

m-2

X50CrMnNiNbN21-9T = 1173 K

0 100 200 300 400 500 600-0.15


0 100 200 300

-0.3

-0.2

-0.1

0.0

0.1



air

1 cycle = 2h


∆m

/S

/g c

m-2

X53CrMnNiN20-8T = 1173 K

0 100 200 300-0.3

-0.2

-0.1

0.0

0.1

1 cycle = 2h



air


∆m/S

/ g

cm

-2


0 100 200 300 400 500


0 20 40 60 80 100-0.4

-0.3

-0.2

-0.1

0.0

0.1

combustion gasesof petrol E50



1 cycle = 2h

air

∆m/S

/

g cm

-2

X50CrMnNiNbN21-9T = 1173 K

0 20 40 60 80 100-0.10

-0.05

0.00

0.05

0.10




1 cycle = 2h

air

∆m/S

/

g cm

-2

X33CrNiMn23-8T = 1173 K

Corrosion kinetics of tested valve steelsunder thermal shock conditions

0 20 40 60 80 100


0 20 40 60 80 100-0.4

-0.3

-0.2

-0.1

0.0

0.1





1 cycle = 2h

air

∆m/S

/

g cm

-2


0 20 40 60 80 100-0.4

-0.3

-0.2

-0.1

0.0

0.1





1 cycle = 2h

air

∆m/S

/

g cm

-2


0 20 40 60 80 100


-0.03

-0.02

-0.01

0.00

0.01

combustion gasesof fuel oil B5


1 cycle = 2hX33CrNiMn23-8

∆m/S

/

g cm

-2

aircombustion gasesof petrol 95Al

combustion gasesof petrol 90Al


-0.4

-0.3

-0.2

-0.1

0.0

0.1






∆m/S

/

g cm

-2

X50CrMnNiNbN21-91 cycle = 2h

air

Comparison of corrosion kinetics of valve steelsunder thermal shock conditions at different atmospheres

0 20 40 60 80 100

Number of thermal cycles

0 20 40 60 80 100-0.4


0 20 40 60 80 100-0.4

-0.3

-0.2

-0.1

0.0

0.1







1 cycle = 2hair

∆m/S

/

g cm

-2

X53CrMnNiN20-8

0 20 40 60 80 100-0.4

-0.3

-0.2

-0.1

0.0

0.1


combustion gasesof fuel oil B10 combustion gases

of petrol 90Al




1 cycle = 2hair

∆m/S

/

g cm

-2

X55CrMnNiN20-8

Images of valve steel samples corroded under thermal shock conditions in a number of aggressive atmospheres

T = 1173K

Images of valve steel samples corroded under thermal shock conditions in a number of aggressive atmospheres

outer layer of the coatingZrO2⋅Y2O3

Cross-section of valve steel covered by protective coatingwith TBC layer

steel

inner layer of the coating

Ni22Cr10AlY

Surface of TBC layer

Photographs of surfaces of coated and uncoated valve steelsafter corrosion tests at 1173 K

a) before tests

b) after 500 shocks

a) after 300 shocks

b) after 500 shocks

The results of corrosion tests of uncoatedand coated valve steels

10

15

/ g

cm-2

coated X50CrMnNiNbN21-9 steel

0 200 400 600 800 1000 Time / h

The results of corrosion tests of coatedtwo different valve steels

0 100 200 300 400 5000

5

coated X33CrNiMn23-8 steel


∆m/S

104

/ g

cm

1 cycle = 2 h

.

10-3

10-2

10-1

-4s-1

1573 1373 1173 973

Ni-30CrCo-35Cr

Oxidation

T / K

Temperature dependence of the oxidation rate of steel coated with a protective coating

6 7 8 9 10 1110-7

10-6

10-5

10-4

.T-1 104 / K-1

k p

/ g2 m

-4

chromia formersalumina formers

coated steel

β-NiAl

Fe-5Cr-4Al Ni-10Cr-5Al

Fe-20Cr

steel

THE ENDTHE END

17 oxidation resistant high temperature coatingshome.agh.edu.pl/~grzesik/FHTC/17_oxidation resistant...

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