The document details advanced nano-impact testing techniques to assess the dynamic mechanical properties and performance of materials, particularly focusing on fatigue wear and failure in coatings and ceramics. It highlights the capabilities of measuring adhesion energy, dynamic hardness, and time-to-failure across various materials and conditions. The testing aims to bridge the gap between theoretical nanoindentation results and real-world applications, enabling better prediction and optimization of material behavior under fatigue conditions.

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MEASURING NANOTECHNOLOGY
MICRO
MATERIALS
NanoTest impact module
for…
• Impact testing
• Contact fatigue testing
• Erosive wear testing
• Fracture toughness
• Adhesion testing
• Dynamic hardness
The only commercial nano-impact tester available
Impact

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MEASURING NANOTECHNOLOGY
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Quasi-static tests are very useful
Nanoindentation – mechanical
properties (hardness, modulus,
creep)
Nanoscratch – tribological properties
(abrasive and sliding wear)
Importance of Nano-impact testing
Bringing nanomechanical
measurements into the real-world
Dynamic nanomechanical tests (nano-impact
and contact fatigue) have been developed by
Micro Materials to address this problem
The need for dynamic testing
Materials often fail by fatigue not
overload…
so optimisation based on
nanoindentation/scratch can be
insufficient for applications where
materials are exposed in service
and/or in processing to fatigue wear
or erosive wear (impact wear)
The solution…

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MEASURING NANOTECHNOLOGY
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Nano-impact testing - simulating fatigue wear and failure
Impact
Sample oscillation
2 different methods…
• High frequency oscillation
• High cycle fatigue
• Accurately controlled impacts
• Known energy to failure
• Wear mechanisms

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MEASURING NANOTECHNOLOGY
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Impact testing - simulating fatigue wear and failure
Impact by sample oscillation:
Operating principles
• Applied Load
• Oscillation frequency
• Oscillation Amplitude
• Sample scanning
• Probe geometry
• Impact Angle
Test parameters
• High frequency oscillation
• High cycle fatigue
• Time-to-failure
• Adhesion failure
• Fracture Behaviour
Key features

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Impact Testing of a brittle TiN coating on Si
• For bulk materials wear rates are
determined from changes in probe depth
• For coatings, time-to-failure is related to
the bonding strength to the substrate
• 100 mN applied load is
on throughout test
• 80 Hz oscillation frequency
• Oscillation on 30 s after start
• Oscillation off 30 s before end
• Film failure after 250 s
Impact by sample oscillation
SEM of test stopped
just after transition
Impact-induced
coating damage -
ring cracks spread
outwards until failure
CRAFT Project BRST-CT97-5196
Impact characterisation of single and
duplex surface engineered steels

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Contact fatigue testing of
thick ceramic glazes
80 Hz oscillation
frequency
1 N applied load
...clear differences
in time-to-failure
and overall
depth changes...
Collaboration with Ito Tecnologia Cerámica, Castellon, Spain

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MEASURING NANOTECHNOLOGY
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Glaze coating B Glaze coating C
Effect of microstructure on impact performance
small needle-like crystals
aid impact resistance
larger rounded crystals
do not help impact resistance
Contact fatigue testing of
thick ceramic glazes

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MEASURING NANOTECHNOLOGY
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MATERIALS
Contact fatigue of ceramic coatings:
comparison to other testing techniques
• Hardness and Young’s modulus did not vary
• Scratch testing frustrated by high surface roughness
• Correlation with fracture toughness data…
• Impact resistant samples had high fracture toughness
• Time-to-failure
• Change in Probe Depth
…measures of resistance to brittle fracture
“Micro-impact testing: a new technique for investigating fracture toughness” BD Beake (MML), Maria
Jesus Ibanez Garcia (ITC Spain) and JF Smith (MML), Thin Solid Films 398-399 (2001) 438-443.

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Unique points:
• Quantification of adhesion energy
• Determination of total energy delivered
to contact point
• Dynamic hardness measurement
Static Force
Impact Angle
Acceleration distance
Impact Frequency
Test probe geometry
Experimental
variables
include:
Pendulum impulse:
Operating principles

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MEASURING NANOTECHNOLOGY
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MATERIALS
Impact-induced fatigue failure
of Polymeric Coating on soft Al substrate
Fatigue-induced
surface damage
Contact changes from
impact (essentially non-
energy absorbing) to
contact fatigue (energy
absorbing) on film failure
• Time-to-failure
• Rapid high-cycle fatigue tests
Impact by sample oscillation

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MEASURING NANOTECHNOLOGY
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Unimplanted SiO2 1 x 1016 N cm-2
implanted SiO2
Damage regimes in the impact test:
1 = before impact
2 = plastic deformation
3 = slow crack growth (fatigue)
4 = abrupt failure and material removal
5 = further slow crack growth
Fracture and fatigue wear by Nano-impact testing
Ceramics and glasses: brittle behaviour
• Fatigue resistance from
time-to-failure
• Ion-implantation
improves toughness
BD Beake (MML), J Lu, Q Xue, J E and T Xu, (all Lanzhou Institute of Chemical Physics) Proc FMC8 2003
1 impact every 4 s in these tests

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Carbon coating on tool steel
• depth vs. time impact plot for
multilayered carbon coating at 1mN
• long time to failure
Coating failure
Multiple coating failures
DLC coating on tool steel
• depth vs. time impact plot for
multilayered DLC coating at 1mN
• note short time-to-failure
Nano-impact testing reveals fatigue differences
on coatings of the same hardness…
Impact

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Impact failure of 550 nm
DLC film on Silicon
Nano-impact shows how deposition conditions
influence coating performance
• Time-to-failure
• Failure mechanism
Coating debonding - adhesion failure
Abrupt depth change at failure > film thickness
Coating fracture – cohesive failure
Depth change at failure
less than film thickness
CVD Coating
Deposition
RF Power
BD Beake et al, Diamond and Related Materials, 11, 1606, 2002

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Impact failure of 100 nm
DLC films on Silicon
• Scratch test showed little difference in critical load
• Impact test shows clear difference in behaviour
1 = initial contact; 2 = plastic deformation; 3 = fatigue (slow crack growth)
4 = fast crack propagation and material removal 5 = further slow crack growth

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Damage mechanism in the impact test: before impact - plastic deformation - slow crack
growth (fatigue) - abrupt failure and material removal - further slow crack growth
Fatigue and Fracture Wear
of ta-C films
80 nm
on Si
60 nm
on Si
• time-to-first-failure to rank impact resistance
• some plastic deformation of the substrate does occur (depth at failure)
5 nm
on Si
80 nm
on Si

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Fatigue and Fracture Wear
of ta-C films
Procedure developed for analysing fracture behaviour
• Sort initial time to failure in individual tests into ascending order
• Plot time to failure vs. probability of the sample failing in that time
• Use time for failure probability of 0.5 to rank impact resistance
Fracture resistance of 80 nm ta-C films
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 50 100 150 200 250 300
Impact time (s)
Probability
of
fracture
Probability of fracture
within 300 s = 0.9
Probability of
fracture = 0.5
at 75 s
A key advantage of
nano-scale
impact is the
possibility of
repeat testing at
different locations

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MEASURING NANOTECHNOLOGY
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MATERIALS Nano-impact mapping of biomaterials
50
200
350
500
650
800
950
50
200
Impact depth
(nm)
position (microns)
position
(microns)
Mapping of fatigue properties across crab
shell
5000-6000
4000-5000
3000-4000
2000-3000
• Nano-scale ductility of crab shell varies
across the shell
• Finer “mesh sizes” can be used to
investigate this behaviour at much smaller
scale
• Initial results suggest test can be used to
identify osteopaenia (2-5 times greater risk of
osteoporosis in later life)
Grids of impacts to determine differences in toughness/ductility…
Collaboration in progress with Universities of Limerick and Lancaster Collaboration in progress with University of Maryland
100 200 300 400 500 600
100
200
300
400
500
Impact depth
(nm)
position (microns)
position
(microns)
Variation in fatigue properties across finger nail of
42 yr old woman
2500-3000
2000-2500
1500-2000
1000-1500
500-1000
0-500