Hard ceramic coatings (1-5um thick) - CSM Instruments

Applications by Scratch Tester

CSM Scratch Testers
Nano Micro Macro (Revetest)
Approx. Load range* up to 1 N up to 30 N up to 200N
Max depth 2 mm 1 mm 1 mm
* depending on room noise floor, acoustic,…

Examples Scratch Test
Load Range: 1-200N
Indenter type: Rockwell Diamond, radius 50-800um
Typical materials: Hard ceramic coatings (1-5um thick)
DLC, TiN, TiCN, TiAlN, CrN, ZrO2, TiO2, Al2O3
Main application fields:
Cutting tools
Engines parts
Decorative coatings
Other applications:
Biomedical (Hip or knee prostheses)
Protective polymer coatings on Steel (100-800um)
Bulk ceramics
Turbine blades

Automotive application
RST test on a rocker arm
Double layer coating, TiN 1 �m / DLC 2 �m

Coatings for prostheses
Different hard coatings such as TiN have already been
used for some time for wear resistance in prosthetic
implants. Quality control of such materials can be
performed with the Micro Scratch Tester, even on curved
surfaces such as the ball of a ball-and-socket joint. The
instrument force feedback ensures that the applied load
remains as-programmed for the duration of the test.
Frictional data is also of importance and can be related to
the in-vivo application.
1 2
3
4

Examples Scratch Test

Polymer coating on contact lens
Progressive load range: 0 - 4 mN
Indenter radius: 2 µm
Contact lens kept flat by capillary forces
Lc1 = 1.56 mN (first cracking)
Lc2 = 3.85 mN (rupture)

Polymer varnish on ABS-PC mobile phone
First failure = 25 mN
Rupture = 33 mN

Scratch and mar resistance of paint coatings and
polymer films using the nanoscratch technique:
Viscoelastic behavior and relaxation effects
Industrial Problem:
Automotive topcoats, or varnishes, are exposed to extremely harsh
environmental conditions, yet they are expected to maintain a high
gloss finish for at least 5 years
Solution:
Develop a consistent and reproducible test method which can
measure fracture type scratch resistance of automotive topcoats and
correlate to customer quality indicators

System description
Mar resistance characterises the ability of a coating to resist damage
caused by light abrasion
The difference between mar and scratch resistance is that mar is related
only to the very fine surface scratches which spoil the appearance of the
coating
Mar resistance depends on a complex interplay between viscoelastic or
thermal recovery, yield or plastic flow, and fracture.
The mechanical properties of polymeric clearcoats are rate and temperature
dependent and viscoelastic recovery can cause scratches to change with
time
Metallic Substrate
Clearcoat ( ~ 45 - 50 µm)
Pigmented Basecoat ( ~ 12 µm)
Primer ( ~ 50 µm)

Polymer coating
20µm
Progressive normal load scratch (0 - 20 mN)
Diamond tip radius = 2 �m
20µm
Sample A
Sample B
20µm
Normal Force (mN)
20
16
12
8
4
0
Pd - A
Rd - A
Rd - B
Pd - B
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
scratch length (mm)
0
1.5
3
4.5
6
7.5
Depth (µm)
Sample A
Sample B
20µm

Permanent deformation at 5mN (µm)
//// Polymer analysis
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Better
sample B
Better
sample A
0 10 20 30 40 50
Normal force at fracture (mN)
sample C