PowerPointPrsentation

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G. Kaupp, M. R. Naimi-Jamal Powerpoint
Presentation of the Nanomech 5, Hückelhoven,
Germany September 5-7, 2004
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Nanoindentations




Why do we need the new quantitative treatment?
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Multiple unloadings/reloadings
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Nanoindentation to glassy polymers
 
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Polycarbonate (PC) dependence of Er on the load
Strong exponential dependence
Er values according to the standard procedure!
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Common assumptions about the indentation geometry
This is certainly not valid for most materials,
except the standards
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Some different cube corner indents
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Isotropic and far-reaching anisotropic
indentation response
SrTiO3 (100)
(rotation of the crystals)
(We will also clarify what happened under the
surface)
SrTiO3 (110)
SrTiO3 (111)
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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The common standard formulas
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Exponent of the unloading curve ?
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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An approach without use of projected area
Nanoscopic FN S2 plots for indents on fused
silica
S2 FN -1 4 p-1(Er)2 H-1
(a) cube corner, (a) defective cube corner, (b)
Berkovich, (c) 60 pyramidal indenter tip 95-
20 of the unloading curves were iterated
Furthermore, errors of stiffness are squared
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Quantitative analysis of the loading curve The
relation of lateral force and normal displacement
FN k h3/2 or FN2/3 k2/3 h k µN/nm3/2is
termed indentation coefficient
Fused quartz a-d sharp cube corner (trial plots
a and c invalid), e sharp 60 pyramid, f
conosphere (R 1 µm)
Valid for all types of materials in
nanoindentations
On the basis of Hertzian theory this exponent
would be the arithmetric mean of the flat and the
conical punchs
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Further demonstration of the FN k h3/2 relation
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Gold exhibits phase transition square plots are
invalid
Linearity up to 10 mN load and 370 nm
depth. Faulty square plots or microindentations
do not detect the pressure induced phase
tranformation
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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a-SiO2 and SrTiO3 linear plots with kinks
indicating pressure induced phase transitions
cubic SrTiO3(Pm-3m) tetragonal (I4/mcm) ?
trigonal a-quartz monoclinic coesite (gt2.2
GPa) tetragonal stishovite (gt8.2 GPa)
Also fused quartz gives a phase transition
(amorphous to amorphous). This has been
complicating the quantitative analysis of its
loading curve! The kinks are smeared out in
faulty square plots and in microindentations
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Phase transition with organic crystals
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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FN h3/2 plot of the cyclic loading curve of a
cube corner nanoindentation on PC showing two
straight lines and a kink in the loading curve
that is not seen in the FN h2 trial plot.
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Useful parameter total work of the indentation
WN tot ? FN dh µN.µm
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Appearances of nanoscratches by AFM
ramp experiment
constant normal force
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Quantitative treatment of nanoscratching
Lateral force proportional to (normal force)3/2
FL K FN3/2
K N-1/2 is the new scratch coefficient What
then about the friction coefficient FL/FN?
not correct in nanoscratching!
Our quantitative relation is valid for all types
of materials (we published on that)
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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The relation of lateral force and (fixed) normal
force
FL KFN3/2 (K scratch coefficient
N-1/2)
Fused quartz and cube corner indentation tip,
edge in front
Linear plot through the origin only with exponent
1.5 (not 1 or 2)
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
22
We use our quantitative FL K FN3/2
relation easy search for high pressure phase
transitions
SrTiO3 (100), 0, cube corner edge in front
exponent 1.5 (not 1 or 2) the steep line in (b)
corresponds to phase transformed SrTiO3
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Instead of inapplicable friction coefficient (FL
/ FN) or residual scratch resistance (which
lacks precision of the residual volume
measurement) an easily and unambiguously
obtained new parameter is defined The specific
scratch work (the work for 1 µm scratch length
following indentation with a specified normal
force)
spec WSc FL.1 µNµm
(We just multiply the lateral force value with 1
µm)
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Angular dependence of specific scratch work on
(1-100) of a-quartz and crystal packing
spec WSc FL.1 µNµm work for 1 µm scratch
length of the indented tip
Angle
µNµm (FN1482 µN) 90
206 45
223 0 225
c-direction (90) alternation of 0.5405nm Si-Si
rows the other directions are less distant and
the skew (10-11) cleavage plane is cutting in
c-direction
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Angular and facial dependence of specific scratch
work (WSc,spec FL.1 µNµm) or residual scratch
resistance (RSc,res FLl/VresN/m2) on
strontium titanate (why should we use the latter
parameter as the volume measurement is insecure?)
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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New Parameter Full Scratch Resistance (RSc full)
      Definition
RSc FL l / V Gpa (FL
lateral force l length)  
RSc full FL l / Vfull
FL/Q (Q indenter cross section)   for ideal
cube corner Q A / v3
(A FN / H projected area at
full load)   it follows
RSc full FLv3 / A H FLv3 / FN
(FN normal force)   and with
FL const.FN3/2
(our experimental relation)  
RSc full
const3/2 H FL1/3v3     2 convenient
linear plots FL K RSc full3 FN K RSc
full2
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Examples for linear FL K RSc full3 and FN
K RSc full2 plots
These lines cut close to the origin as required
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004
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Consistency of our quantitative laws
(normal force) (normal displacement)3/2 and
(lateral force) (normal force)3/2 imply the
relation (lateral force) (normal
displacement)9/4
(a) fused quartz, (b) SrTiO3, (c) Si, (d)
thiohydantoin, (e) ninhydrin and (f)
tetraphenylethylene
G. Kaupp, M. R. Naimi-Jamal, Nanomech 5, 7.-9.
September 2004