Measuring Coating Mechanical Properties...Rahul Nair Fischer Technology, Inc. 2018 1 Coating...

Measuring Coating Mechanical PropertiesCTT 2019

Rahul Nair

Fischer Technology, Inc. 2018 1

Coating Mechanical Properties Characterization

2Fischer Technology, Inc. 2018

Nanoindentation Progressive Load

Scratch

Characterizing Surfaces


Treated surfaces

Coatings and Thin Films

Composites



H a r d n e s s I C r e e p I E l a s t i c i t y I U n i a x i a l M e c h a n i c a l R e s p o n s e I

Te n s i l e S t r e n g t h a n d Te n s i l e S t r e s s I S t i f f n e s s i n Te n s i o n - Yo u n g ’ s

M o d u l u s I T h e P o i s s o n E f f e c t I S h e a r i n g S t r e s s e s a n d S t r a i n s

S t r e s s - S t r a i n C u r v e s T h e r m o d y n a m i c s o f M e c h a n i c a l R e s p o n s e I

E n t h a l p i c R e s p o n s e I E n t r o p i c R e s p o n s e I V i s c o e l a s t i c i t y I

S t i f f n e s s I K i n e m a t i c s : t h e S t r a i n – D i s p l a c e m e n t R e l a t i o n s I

E q u i l i b r i u m : t h e S t r e s s R e l a t i o n s I T r a n s f o r m a t i o n o f S t r e s s e s

a n d S t r a i n s C o n s t i t u t i v e I Y i e l d a n d P l a s t i c F l o w I M u l t i a x i a l

S t r e s s S t a t e s I E f f e c t o f H y d r o s t a t i c P r e s s u r e I E f f e c t o f R a t e a n d

Te m p e r a t u r e I C o n t i n u u m P l a s t i c i t y I T h e D i s l o c a t i o n B a s i s o f

Y i e l d a n d C r e e p K i n e t i c s o f C r e e p i n C r y s t a l l i n e M a t e r i a l s I

F r a c t u r e I A t o m i s t i c s o f C r e e p R u p t u r e I F r a c t u r e M e c h a n i c s - t h e

E n e r g y - B a l a n c e A p p r o a c h I t h e S t r e s s I n t e n s i t y A p p r o a c h I

F a t i g u e

Characterizing Surfaces


Mechanical Properties of these coatings is greatly influenced by several factors

i. Chemistry

ii. Deposition Technique

iii. Curing Procedure

iv. Aging and Weathering- Thermal, Oxidative and UV

v. Environmental Conditions- Temperature and Humidity

Traditional Hardness Testing


Hardness – resistance to penetration of a hard indenter

Traditional Hardness Testing- Mohs Scale


The ability of one solid to scratch another

or to be scratched by another solid

Austrian mineralogist Friedrich Moh, 1812

References -1. http://www.hautehorlogerie.org/en/glossary/mohs-scale-187/

http://www.hautehorlogerie.org/en/glossary/mohs-scale-187/

Traditional Hardness Testing- Pencil Hardness


These alternate techniques are inexpensivePencil hardness

Handheld Hardness Testers

Scratch Testers for Scratch Hardness

BUT….

Traditional Hardness Testing- Pencil Hardness


i. Study to check the variability in the standard Pencils used in

Pencil hardness testing

ii. Our nanoindentation tester used to measure Martens

Hardness of standard Pencils

iii. At higher hardness range there is inconsistency of the pencil

hardness of the standard pencils

iv. Even at lower hardness levels pencil hardness of standard

pencils overlaps

v. Additionally, more uncertainty introduced by influence from

user

Traditional Hardness Testing- Brinell


Apply fixed load & Optical measure of the residual

print area

- Swedish engineer Johan August Brinell in 1900

2. http://en.wikipedia.org/wiki/Brinell_scaleReferences -1. http://www.precisiontestingequip.com/p1_02_3.html

http://en.wikipedia.org/wiki/Brinell_scale

http://www.precisiontestingequip.com/p1_02_3.html

Traditional Hardness Testing- Rockwell


Apply fixed pre-load, Apply fixed load & Penetration depth measurement

- Patented by Hugh M. Rockwell and Stanley P. Rockwell from CT in 1914

References -1. http://www.wilson-hardness.com/Products/RockwellTesters.aspx

http://www.wilson-hardness.com/Products/RockwellTesters.aspx

Traditional Hardness Testing- Vickers & Knoop


Application of a fixed load

References -1. http://www.instron.us/wa/applications/test_types/hardness/vickers.aspx

Optical measurement

of the indentation

Apply fixed load & Optical measure

of the residual print area

- 1921 by Robert L. Smith and

George E. Sandland at Vickers Ltd in

Britain

http://www.instron.us/wa/applications/test_types/hardness/vickers.aspx

Traditional Testing- E-Modulus (Young’s modulus)


tensile test (e.g. steel)ideal spring :

F = k.x

k: spring constant

F

x

k

k

matter constant E [Nmm-2] (Young’s Modulus, 1807)

A

F

F2

F

D

l 2Dl

l0

0

0

0

%100*

%100*)(

l

l

l

ll

D

ideal elastic behaviour of solid states : Hooke‘s law (1676)

stress :

strain :

.constE

Limitations of Traditional Hardness Testing


Coating

Base Material

Large Stress Field

• In applications where treated surfaces, coatings, thin films or composites are tested

• shows substrate influence

• indent may be too small to observe with a microscope

• (Soft) imprint on elastic materials may be too small to observe with microscope

• Testing big volumes of material can be time consuming

• Only hardness can be calculated

Principles of Nanoindentation


Force Actuator

F

Displacement Sensor

Indenter

Test Specimen

Apply a load (F) incrementally until amaximum is reached

Result: h=f(F,t)

Martens hardness HM is calculated as afunction of depth

The load decrease curve is used for thecalculation of material parametersIndentation Modulus Eit, IndentationHardness Hit

ISO14577 and ASTM E2546



h=f(F,t)

Apply a load (F) incrementally until a maximum is reached

Result: h=f(F,t)

Martens hardness HM is calculated as a function of depth

The load decrease curve is used for the calculation of material parameters Indentation Modulus Eit, Indentation Hardness Hit



h

F

F

h

F

h

ideal elastic

(rubber, spring)ideal plastic

(modeling clay)

elastic + plastic

19

Fischer Technology, Inc. 2018

hmax

Loading

UnloadingIndentation modulus

Indentation hardness : Calculation of Vicker Hardness

)0945.0*()(

maxIT

cP

IT HHVhA

FH

Martens hardness

F, applied force (load)

h,

ind

en

tati

on

de

pth

h2IT1C

h1

h2

* 100

h2IT2C

h1

h2

* 100

Indentation Creep

Indentation Recovery )(2

12

11

2

cP

r

EE

sIT

hA

SE

E

i

i

r

Dynamic Nanoindentation


Storage and loss moduli, loss tangent

Advantages of Nanoindentation


Wide variety of Materials: Applies low load - Measure shallow depths

No optical measurement: no influence of the user

The instrumented indentation test yields more information thanclassical hardness measurements

Mechanical Properties Mapping

Indentation Hardness HIT

Indentation Modulus EIT

Creep CIT

Fracture Toughness

Storage and Loss moduli

Martens Hardness

Work Done- Elastic and Plastic

Vickers and Knoop Hardness

Pop-in and Pop-out

Glass Transition

10%

Nanoindenter Form Factor – Base Instrument


Reliable, cost-effective, user-friendly instrument to measure hardness,

elastic modulus, creep and much more of coatings and bulk material

Ample load and depth range;

broad range of applications

Minimal sample

preparation due to open

layout

Solid granite base with

specialized vibration

isolation silicone feet to

reduce noise

Compact design makes the

HM2000S an ideal tool for

all environments

Automated surface

detection for higher

productivity

Nanoindenter Form Factor – Fully Equipped


Measure on smallest

structures, cross-sections

with high precision

programmable xy-table

Enhanced high

resolution optical system

with autofocus and

multiple objective turret

Motorized z-axis and

fully-automated surface

detection for higher

productivity

Custom granite structure

for enhanced frame

stiffness and low noise

Minimal sample preparation

due to large working area

and open layout

Feature-packed, user-friendly instrument to measure hardness,

elastic modulus, creep and much more of coatings and bulk material

Same measuring head as

HM2000 S

Factors that effect Nanoindentation


Advantage Cone

Protects Indenters & Speeds up Indentation

Software algorithms to auto detect surface

Factors that effect Nanoindentation


Advantage Cone

Low Thermal Drift

Low Frame Compliance

Base Instrument

Application: Automotive Paint and Clear Coats


Measurement of two 80 µm thick 2K automotive

repair paints

• Max. indentation depth < 6.5 µm

2K automotive repair

paints Samples

HM

N/mm²

E ITGPa

Mean value Sample A

Sample B

42.9

143.0

1.4

3.1

Standard deviation Sample A

Sample B

1.2

5.6

0.1

0.1

Base Instrument

Application: Wood Coating


Measurement of seven 100 µm thick coatings

Base Instrument



Base Instrument



Hard

ness(H

M)

Depth (µm)

Similar Coating but different

wood substrate

Fully Equipped Instrument- Motorized XYZ & Microscope

Application: Conformal Coatings- Cross-linking correlation


Two-component conformal coatings are often used to minimize current leakage on

PCBs and as protection against humidity and other environmental factors

HM[N/mm²]

Depth [µm]

Depth [µm]

Time [s]

10 % over cross-linked

5 % over cross-linked

Optimally cross-linked

5 % under cross-linked

10 % under cross-linked

Martens hardness Indentation Creep


Application: High Polymer Coatings


• Indenter – Spheroconical diamond• F =10mN, Loading Time = 10sec, F =80mN, Loading Time = 36sec


Heating Stage


• Temperatures up to 200°C

• Two temperature sensors (internal in the table and external to place on the

sample)

• Ceramic indenter and heat shield to eliminate thermal expansion in the head


Application: High Temp Stage – Polymer Coatings


Polyamide PA66

• Thermal properties

o Glass-transition temperature: 50 – 60 °C

o Melting point: 260 °C

o Max. operation temperature: 80 – 120 °C

Increasing

Temperature


Application: High Temp Stage – Polymer Coatings


150

100

50

Mar

ten

s h

ard

nes

s[N

/mm

²]

15010050

Temperature [°C]

60

40

20

Elas

tic

par

tn

it[%

]

15010050

Temperature [°C]

20

10

Cree

p[%

]

nitCIT1

• Coating thickness 100 µm Max. load 10 mN

• Martens hardness shows decrease with increasing temperature

• Creep and elastic behavior: extreme in the region of the glass transition temperature

Glass-transition temperatureGlass-transition temperature

Coating Adhesion- Traditional Techniques


Progressive Load Scratch Testing


Depth

SensorASTM C1624

Scratch Test- Actutors and Sensors


Programmable XY-table

Friction Table built in

Optical microscope-

Upto 5 objectives with

DIC Mode with Polarized

light filter

Motorized Z-axis and fully-

automated surface detection for

higher productivity

Custom granite structure

for enhanced frame

stiffness and low noise

Minimal sample preparation

due to large working area

and open layout

Measuring with load

system, depth and AE

Key Features


Load

Industry leading range from 0.01 to 30N with 6uN

resolution

Active Force Feedback- Capacitive Sensor

Excellent linearity of sensor Non-linearity- <= 0.02%

of FSO

Most robust design- Overload protection of 500% of

FSO

https://www.youtube.com/watch?v=BflgP7PIzYc

High overload protection protects the instrument from damage

in case of a crash


Key Features



Faster stages combined with software that quickly acquires and compiles images

results in highest productivity

X, Y & Z Stages- BLDC motors

Almost 4 times higher torque than stepper motors

Better repeatability

Scratch Length- 100mm

Stages displacement- 200 x 50 x 100mm

Programmable for multiple scratches and samples


Key Features


Microscope

Microscope with excellent video image as a result

of high quality optics with 5x and 20x objective

Easy to resolve different failure mechanisms with

DIC Mode with Polarized light filter

Optically identifying the failure is the most important for

characterizing scratches- hence we chose the best optics

for any scratch tester

Key Features


Friction Table

Use same capacitive sensor as

normal load

Very high resolution

Negligible compliance

In addition to better quality friction data, the results do not change with or without

friction table.

There is no loss of energy compared to LVDT based friction tables which can

cause 5-15% error in data.

Key Features


Depth sensor-

Pre scan and Post Scan

Range- 1600 um

Resolution- 0.2nm

Higher depth range- Test across smaller curvatures and

difficult geometries without the depth signal saturating

Application – Paint on Steel


LC1 LC2 LC3

S1 3.77 N 5.43 N 7.58 N

50µm diamond indenter



LC1 LC2 LC3

S1 3.77 N 5.43 N 7.58 N


Summary


Nanoindentation

Quantitative test for coatings on any substrate

Fundamental properties of only the coating

More than just hardness- elastic modulus, creep, etc.

Progressive Load Scratch

Simulation of real world under controlled lab conditions

Test of the entire coating-substrate system

Measure mar, crack and chip resistance and adhesion


Thank you!

Visit us at Booth #74

Application – DLC on Steel


LC1 LC2 LC3

S1 5.03 N 27.15 N 58.45 N




LC1 LC2 LC3

S1 5.03 N 27.15 N 58.45 N



Application: Cross-sections


Metallic layer

HMN/mm²

EIT/(1-vs^2)GPa

HIT

N/mm²HV

X 4734.2 151.8 6961.9 657.8

s 223.9 8.8 263.6 24.9

V/% 4.7 5.8 6.0 6.0

Load

Depth

Measuring Coating Mechanical Properties...Rahul Nair Fischer Technology, Inc. 2018 1 Coating...

Documents

Transcript of Measuring Coating Mechanical Properties...Rahul Nair Fischer Technology, Inc. 2018 1 Coating...