Corrosion Resistance of Al-Fe-alloy-coated Steel, Refractory ......Result- Refractory Metals C O2 =...

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Minoru Takahashi, Abu Khalid Rivai

Research Laboratory for Nuclear ReactorsTokyo Institute of Technology, Japan

Corrosion Resistance of Al-Fe-alloy-coated Steel,

Refractory Metals and Ceramics in Lead-Bismuth at 700ºC

Corrosion Resistance of Al-Fe-alloy-coated Steel,

Refractory Metals and Ceramics in Lead-Bismuth at 700ºC

Motivation

Structural materials: 400-550 ºCHigh Cr F-M steels (with Si and Al addition)

Cladding materials: 650-700 ºCHigh Cr F-M steels with Si and Al additionsAl-Fe-Surface coated steelsRefractory metalsCeramics

High boiling points of lead alloys can provide high temperature reactor with thermal efficiency higher than 40%.

Candidate materials compatible with lead alloys

Materials CompatibilityAustenitic steels SS316, SS316FR poor

Steels12Cr steels10-18Cr steels with Si and Al addition

SUH3, NTK04L, Recloy10, SUS430 excellent

Al-alloyed surface (GESA) ODS locally goodRefractory metalsCeramics

W, Mo excellent

HCM12A, etc. good

SiC, Si3N4 excellent

Flowing fluid: Pb-Bi eutectic (LBE)Temperature: 550°CVelocity: 1 or 2 m/sExposure time: 1,000 or 2,000 hrsOxygen concentration: 10-8-10-6 (wt%)

Results of previous corrosion tests

Purpose

To investigate the compatibility of materials in stirred LBE at 700 ºC

Steels: High Cr steels, Al-Fe-coated onesCeramics: SiC, Ti3SiC2,

SiC/SiC compositesRefractory metals: W, Mo, Nb

Test apparatus

Digital

ElectrometerPP

Digital Controller

Steam Generator

Moistureatmosphere

Exhaust NozzleInjection Nozzle

Ar + H2

Specimens

6Specimens

Thermocouple

Alumina Crucible

Oxygen Sensor

Mo Wire

Injection Nozzle

100 mm

Corrosion test section

Ceramic

340 mm

Experimental conditions

Run No. 1 No. 2Materials STBA26,

SiC/SiCcomposites

NTK04L, SUS316FR Recloy10, SUS430, Al-Fe-

coated steel, W, Mo, Nb, SiC, Ti3SiC2

Oxygen concentration (wt%) ~6.8x10-7 ~5x10-6

Injection Gas Ar Ar+H2 (3%) and Ar

Type of Sensor Y2O3-ZrO2

Temperature of LBE (ºC) 700Immersion time (hr) 1,000

Al-Fe coating (thickness: 21.45µm)

Target (Al) Target (SUS304)

Bulk Material

Moving Magnet Source

e- e-kinetic energy

Unbalanced Magnetron Sputtering(UBMS)

Specimens

Oxygen concentration

200 300 400 500 600 700-350

(1/3)Cr 2 O 3

(1/4)Fe 3 O 4

(1/3)Bi 2 O 3

1010-8

P H2 /P H2O

C (wt.%)

Oxygen potential in injected gas (1/2)RT ln P O2

Temperature (°C)

Oxygen potential in Pb-Bi Δ G Ox

Oxygen potentials of oxides Δ G o

5 x 10-6 wt%6.8 x 10-7 wt%

CO2 = 5 x 10-6 wt.% (NTK04L, SUS316FR)CO2 = 6.8 x 10-7 wt.% (STBA26) 700ºC

High Cr Steels (NTK04L, STBA26, SUS316FR)

Pb-Bi Penetration NTK04L matrix

6.12 µm

100µm

Pb-Bi Penetration STBA26 matrix

6.12 µm

100µm

Pb-Bi Penetration STBA26 matrix

Pb-Bi Penetration SUS316FR matrix

NTK04L 17.8Cr-0.4Si-3.34Al

STBA26 9Cr-0.2Si

SUS316FR 18Cr-12Ni

CO2 = 5 x 10-6 wt%, 700ºC

High Cr Steels (Recloy10 17.7Cr-1Si-0.9Al)

Oxide layer

SUS430 matrix

5.29 µm

3.77 µm

6.94 µm

Oxide layer

SUS430 matrix

5.29 µm

3.77 µm

6.94 µm

5.29 µm

3.77 µm

6.94 µm

resin oxide layer

10µm10µm

resin oxide layer

Al10µm10µm 10µm10µm

6.12 µm

100µm

Pb-Bi Penetration SUS430 matrix

6.12 µm

100µm

CO2 = 5 x 10-6 wt%, 700ºC

High Cr Steels (SUS430 18Cr-0.75Si)

Oxide layer

SUS430 matrix

5.29 µm

6.12 µm

40.0 µm

Oxide layer

SUS430 matrix

5.29 µm

6.12 µm

40.0 µm

5.29 µm

6.12 µm

40.0 µm

resin oxide layer

6.12 µm

Al-Fe-coated (STBA26)

oxide layer STBA26

40 µm

～20 µm

sputtered layer

gold coating

～3.7 µm

resinoxide layer STBA26

40 µm

～20 µm

sputtered layer

gold coating

resinoxide layer STBA26

40 µm

～20 µm

sputtered layer

gold coating

CO2 = 6.8 x 10-7 wt.%, 700ºC

Ceramics1000 hours, CO2 = 5 x 10-6 wt.% (SiC, Ti3SiC2)CO2 = 6.8 x 10-7 wt.% (SiC/SiC composite) , 700ºC

Ti3SiC2

SiC/SiCcomposite

resin SiC Matrix resin SiC Matrixgold coating

40 µm100 µm

resin SiC Matrix resin SiC Matrixgold coating

40 µm100 µm

resin Ti3SiC2 Matrix resingold coating

30 µm100 µm

Ti3SiC2 Matrixresin Ti3SiC2 Matrix resingold coating

30 µm100 µm

Ti3SiC2 Matrix

5.29 µm

5.29 µm 20.8 µm

33.7 µm

20.8µm

crackSiC/SiCComposite

33.7µm

100µm

SiC/SiCComposite

5.29 µm

5.29 µm 20.8 µm

33.7 µm

20.8µm

crackSiC/SiCComposite

33.7µm

100µm

SiC/SiCComposite

Weight Change of Ceramics

-80-70-60-50-40-30-20-10

0102030

SiC Ti3SiC2

Specimens

SiC/SiCComposite

Result- Refractory Metals

CO2 = 5 x 10-6 wt.%, 700ºC

resin W Matrix resin W Matrix

gold coating

20 µm50 µm

resin W Matrix resin W Matrix

gold coating

20 µm50 µm

resin Mo Matrix resin Mo Matrix

gold coating

20 µm50 µm

resin Mo Matrix resin Mo Matrix

gold coating

20 µm50 µm

resin Nb Matrixadhered Pb-Bi

Pb-Bi penetration

Nb Matrixadhered Pb-Bi

Pb-Bi penetration

40 µm100 µm

resin Nb Matrixadhered Pb-Bi

Pb-Bi penetration

Nb Matrixadhered Pb-Bi

Pb-Bi penetration

40 µm100 µm

Weight Change of Refractory Metals

-50-25

0255075

100125150175200225250

W Mo Nb

Specimens

Conclusions

1. Al-Fe-coated steel, W, Mo, SiC and Ti3SiC2exibited good corrosion-resistance in LBE at 700 ºC.

2. Nb exibited poor corrosion-resistance in LBE at 700 ºC.

3. SiC/SiC composite showed that LBE penetrated into the matrix due to high porosity of the material, and a thin crack layer appearedin LBE at 700 ºC.

Corrosion Resistance of Al-Fe-alloy-coated Steel, Refractory ......Result- Refractory Metals C O2 =...

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