Levitation: engineering + science at 11 ID-C

Rick Weber, STA at 11 ID-C, XSD.

17 September, 2009

2

Means of Support

nChris Benmore, Kevin Beyer, XSD 11 ID-CnJoerg Neuefeind, SNSnMartin Wilding, U. Aberystwyth, John Parise, Stony

Brook.nInternal funding: IPNS, Art Shultz, XSD, Brian Toby

and Pete ChupasnExternal funding: ORNL

Joan Siewenie,2001 GLAD tests

3

Outline

nWhy levitate things?nIssues specific to levitation experimentsnMethodsnSome applicationsnSummary

4

Containerless processing/levitation

F = -mg

Using containerless methods accesses:• high purity• non-equilibrium liquids• pristine liquid surfaces • eliminates sample “holder”

Material

Atmosphereevaporation

equilibration

Container

contamination reactions

nucleation

Tendency for chemical reactions increases exponentially with T

5

Issues

n You can’t touch the sample with anythingn Non-contact measurements

• Beams• Optical probes• Spectroscopy

– Non-contact temperature control• Lasers/beams – surface heating• EM – bulk heating• Microwave – bulk heating

n Sample sizes are limited

n Compositions and materials may be specific to the method

6

Scientific applications of levitation (containerless techniques)

n Avoid contamination of materials at extreme temperaturesn Control melt chemistry under extreme conditionsn Investigate surface reactions with reactive environmentsn Avoid nucleation to access deeply supercooled and non-equilibrium liquids

and glassesn Expose pristine liquid surfacesn Scientific and technological interest derives from:

– Geo-materials community: planetary evolution, carbon sequestration, waste storage

– Fundamental condensed matter physics: glass transition, fragile liquids, nucleation and ordering in supercooled liquids

– Bio-materials community: supersaturated solutions, bio-active phases– Energy materials: materials at extreme temperatures in chemically

active gases– Measurement of thermophysical properties of hot liquids: surface

tension, viscosity, heat capacity

7

“Transient” methods: Shot tower, William Watts, England, 1782

A shot tower in Dubuque, IA

Free fall time:gh

t2

=

0

10

20

30

40

50

0.01 0.1 1 10 100 1000 10000

Free fall distance (m)

Fre

e fa

ll ti

me

(s)

vt 4.4 44 440 ms-1

h

KC-135

8

Aero-acoustic Levitation

UHV Electrostatic levitation

Electromagnetic LevitationHigh pressure electrostatic levitation

Aerodynamic levitation

Acoustic levitation

Magnetic levitation

Some methods for “steady-state” containerless or levitation

9

Comparison of levitation techniques

3-8*

10

Aerodynamic levitation

Antonov-225, payload 550,000 lbsTakeoff wt. ~4 x 108 grams

Plenty of force availableSize limit results from fragmentation of liquids

γρ 2gL

Bo =0

0.05

0.1

0.15

0.2

0.25

0.05 0.075 0.1 0.125 0.15

Radius (cm)

Bo

nd

Nu

mb

er

STABLE LEVITATION OF LIQUIDS

11

Operated as a Class I laser system with embedded 250 Watt (Class IV) CO2 laser in the lab and at 11 ID-C

12

X-ray set up

Mar 345, PE 1600, GE Revolution

1 mm square beamArea detectorHigh energy

13

Desirable features of an APS research levitation system

n Beamline and lab. based systems to enable sample synthesis and testingn Non-contact temperature measurement

– Optical diagnostics and beam probesn Class I laser operation

– Enhanced safety– More accessible to users

n Ability to change process atmospheres– Oxidizing, neutral, reducing, reactive

n Basic lab support:– semi-micro balance, density meas., mixing and grinding equipment,

technical support

14

Some examples of reluctant glass formers made using levitation melt processing

n Al2O3-CaO 50-75 % CaOn Al2O3-RE oxide 20-50 % RE oxide (includes RE garnets and perovskites)n Al2O3-SiO2 up to 67 % Al2O3 (includes 60/40 mullite)n CaO-SiO2 up to 50% CaOn MgO-SiO2 up to 67 % MgO (includes enstatite and forsterite)n Calcium phosphatesn Zr-Cu-Ni-Al-Ti alloys Cooling rate limited by surface area:volume

A67S33 Mg2SiO4 ErAG YAG LAG

1000 300 100 30 K/s @ 1300K

3 mm

15

Temperature dependent structure of liquids

Liquid 1600oC

Mei, et al, PRL, 98, 057802 (2007).

SiO2

16

Acoustic Levitation D BE

CA

G

F

H

X-ray beam

I

B

D BE

CA

G

F

H

X-ray beam

I

B

RSI, 80, 083904 (2009).

VIDEO

17

Acoustic Levitation

-40

-35

-30

-25

-20

-15

-10

-5

0

100 110 120 130 140 150 160

Time (s)

Tem

per

ature

(oC

)

heater off heater on

0

10

20

30

40

0 5 10 15 20 25 30

Heater Power (W)

Tem

per

ature

Incr

ease

(oC

)

18

What the image plate “sees”

-15°C-15°C +16°C+16°C

Small (sub-millimeter) sample motion does not measurably affect the data quality

19

Electromagnetic levitationn Need skin depth, d, < sample x-sectionn Force is proportional to (field gradient)2

n Heating is proportional to (induced (current) field)2

n Typically 450 kHz generator (Lepel, Inductotherm, Ameritherm)

n Need to match impedance of loadn Need to avoid FCC frequenciesn Heating and levitation are coupledn Cooling gas or beam heating can extend T rangen Used in a demo expt. at GLAD ~1993

νρ

δ C∝ 2BHeat ∝dz

dBForce

2

∝

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Non-contact temperature measurement

5,6 carboxyfluorescein rhodamine B

Inframetrics 760, 8-12 µm thermal imaging camera

FL emission ratio measurements Ross et al, Analyt. Chem., 4117-23, 73 (2001).

0

10

20

30

40

50

60

70

80

0 20 40 60 80 100

Inte

nsity

(A

.U.)

Temperature (ºC)

Peak in thermal emission spectrum at 300 K is ~10 µm

Low T High T

Optical pyrometry at a wavelength where emissionis strong. Peak ~3000/T (in K)

Emissivity correctionsmay be needed.

2.

)ln(11CTT appabs

λελ=−

-30

-20

-10

0

10

20

30

-30 -20 -10 0 10 20 30

Thermocouple (oC)

IR Im

ager

(oC

)

21

Summary

• Good coverage of “sample environment space”

• Ability to investigate liquids under non-equilibrium conditions and at high purity

• Class I laser system maximizes safety, minimizes user training requirements

• Complementary bench top facility enables characterization and synthesis

• Neutron + X-ray needed to deconvolute structure and constrain models

• Work needed on low T measurement• Work needed on fast measurements

in transient conditions – high flux is essential

Acoustic Aerodynamic

0

1

2

3

4

-50 450 950 1450 1950 2450 2950

Temperature (C)

Sam

ple

siz

e (m

m)

sample environment space