Cryo FIB-TEM sample preparation of plate rolled Zr-2.5%Nb sheets

A. Steiger-Thirsfelda, L. Whitmorea, S. Schwarza, G. Rumplmaira,K. Whitmorea, R. Hengstlerb and J. Bernardia

aVienna University of TechnologyUniversity Service Center of Transmission Electron MicroscopyWiedner Hauptstraße 8-10 1040 WienWiedner Hauptstraße 8 10, 1040 Wien

bAREVA NP G bHbAREVA NP GmbHPaul-Gossen-Straße 10091052 Erlangen

Outline

A li ti f Z ll•Application of Zr alloys•Different methods for preparing TEM samples from rolledZr alloy •Comparison of preparation methods concerning theinduced damageg•Cryo Assembly•Cryo FIB-TEM preparation

Application of Zr alloys

Cladding of fuel rods in nuclear reactors

Assessment of the Kinetics of Local Plastic Deformation of Zr-2.5%Nb CANDU Pressure Tubes,Talk by Bipasha Bose, Ontario, 2010

•Zr has a very low absorption cross-section of neutrons•Alloying components for improvement of corrosion resistance•Alloying components for improvement of corrosion resistance

Task

Samples

Plate rolled Zr-2 5%Nb alloy sheetsPlate rolled Zr-2.5%Nb alloy sheets of 0.33mm thicknessannealed at 580°C in vacuum for 2hours2hours

TEM sample of the near surface layer (~10μm) with a minimum of preparation damage andfinal sample thickness ≤100nm p

Electro-polishing

Thomson-Rusel, Edington

TenuPol-5

Unfortunately this methoddoes not allow preparation of cross-sectionsof cross-sections

Wedge shaped grinding

MultiPrep™ System

DuoMill

4kV Argon ions, LN2

Ultramicrotome

Zr has a Mohs hardness of 5

www.bio.miami.edu

PowerTome PC

FIB at RT

Quanta 200 3D DualBeam

5kV cleaning for 2minuteswith Ga ionswith Ga ions

1kV Ar ions for 1hour0 5kV Ar ions0.5kV Ar ions for 10minutes

gentle mill

Post-ion treatment

Precision Ion P li hi SPolishing System

(PIPS)

4KV Argon ionsfor 10 minutes

Quorum PP2000T Cryo Assembly(1)

SEM cooling ddewar

Cryo preparation chamber (turbo pumping system located on the floor behind the SEM)

Controls

floor behind the SEM)

Transfer deviceLiquid nitrogen slusher (for rapid sample freezing)sample freezing)

Quorum PP2000T Cryo Assembly (2)

Sample transfer

Cryo preparation chamber

Sample transfer device

y p p

Quorum PP2000T Cryo Assembly (3)

SEM cold stage

Cryo-Applications

Water ice growth on Siat -100°C

Fracture surface of citric acidin oil emulsion at -100°C

Lift out pre-preparation at RT

H-bar pre-preparation at RT

Sample holder

Cryo preparation steps

•Purging the system for 10-15 minutes with N2 gas flow of4l/min

•Cooling of the stage with the sample and the cold trap (-190°C)

T dj ( id h ll ) d•Temperature adjustment (cartridge heater, controller) andstabilizing for about 30min

R FIB ti t diti ( i 165°C)•Resume FIB preparation at cryo conditions (min. -165°C)

•Last FIB preparation step: 5kV Ga cleaning at cryo conditionsconditions

Difficulties

•Restricted sample rotation

•Sample drift through temperature instabilities•Sample drift through temperature instabilities

•Extended preparation time

•N2 consumption

Results Cryo FIB (lift out)

Results Cryo FIB (H-bar)

Summary

•Different methods for preparing TEM samples from Zrp p g p•Low energy ion beams (Ar, Ga) cause damage in Zr at RT•Cryo Assembly

•Cryo FIB-TEM preparation

Electro-polishing Cryo FIB preparation

Thanks a lot for your attention