tribology basics

1 Tribology and Applications, 08-2003

Balzers Surface Technology

Challenging the Leading Edge

PVD-Technology

A Design Partner


PVD Thin Film Technology

A Fast Innovation Cycle Continues

• PVD Technology in Industrial Applications

• Coating Technology

• Tribology Systems

• Surface Engineering

• Future Trends

in Coating-Assisted Surface Engineering

• Applications as of Today

• Quality Methods & Analytic


Areas of Application


Types of movement

C.B1.01 (0303) e

Sliding motion Area contact

e.g. guide ways, bushings

Rolling motion Point contact

e.g. roller bearings

Rolling motion Line contact

e.g. gears


BALINIT® - coating

• Only a few

thousandths of

a millimetre thin

• Fidelity of

contours

C.B5.02 (0204) e


How big is a micron ?

1 micron 0.001 mm

Hard coating 0.003 mm

Cigarette paper 0.03 mm

Human hair 0.05 mm

Newspaper 0.08 mm

Pig’s bristle 0.1 mm

C.B5.01 (0304) e


Schematic presentation of friction:

Stribeck curve

C.B2.01 (0205) e

Friction coefficient µ

Viscosity x Sliding speed

Normal force

FN

v

FN

v

FN

v Counterbody

Medium

Body

Surface roughness R

d

Boundary friction

(d < R)

Mixed friction

(d R)

Fluid friction

(d >> R)


Wear Mechanisms

• Adhesive

• Abrasive

• Fatigue

• Tribooxidation

Holmberg, Matthews, Coatings Tribology


Adhesive wear

C.B3.02 (0205) e

Cause

Cold welding with material

transfer

Appearance

Cavities, galling and material build up


Abrasive wear

C.B3.01 (0205) e

Cause

Hard particles score the surface

Appearance

Scores, scratches


C.B3.04 (0303) e

Cause

Material fatigue with crack

formation by dynamic or cyclic

load

Appearance

Cracks, pitting

Surface fatigue (pitting)


Tribooxidation

C.B3.03 (0205) e

Cause

Formation of chemical oxidation

reaction products together with

oscillating movements

Appearance

Fretting corrosion


PVD- Coatings for Precision Components

Adapted from Ullmann, ency.

Friction Coefficient

Ab

ras

ive W

ear

Re

sis

tan

ce

0.5

1

2

3

4

5

6

7

8

CrN

DLC

Me C:H

Me C:H

0.1 0.2 0.3 0.4 0.5

Carbon Group

Non Carbon Group

TiN

TiAlN


Dry running properties of sliding materials

Sliding distance [m]

Coefficient of friction

C.B3.07 (0303) e

0

0.1

0.2

0.3

0.4

0.5

0.6

0 500 100 200 300 400 600 700

Coating

with PTFE

Coating

with MoS2

MoS2

PVD

BALINIT® C (WC/C) nearly no wear

x x x

x x

CuSnPb

bronze

Ni-PTFE

x End of test due to adhesive wear


Friction reduction of valve train with carbon coating

C.C1.02 (0205) e

Engine speed [rpm]

Friction torque [Nm]

0 1000 2000 3000 4000 5000 6000 7000

0.5

1.0

1.5

2.0

2.5

3.0

phosphated

WC/C

Method: cylinder head test rig

Source: Ford, INA


Fuel saving by minimisation of friction in engines

C.C1.01 (0205) e

86

88

90

92

94

96

98

100

70 75 80 85 90 95 100

Valve train

coated

All friction related

parts coated

uncoated

Fuel consumption [%]

Theoretical engine friction [%]


Properties of BALINIT® Coatings

Friction Coefficient against Steel (dry)*

Protection against Surface Fatigue

Coating Material

Coating Type

Microhardness (HK 0,01) (typical)*

Typical Thickness (µm)

Coating Temperature (°C)

Protection against Abrasive Wear

Protection against Adhesive Wear

Protection against Tribooxidation

BALINIT®

DLC

C1500 C1000

BALINIT®

C BALINIT®

CNI BALINIT®

D BALINIT®

A

*depending on Testing Conditions / **no reliable results available

WC/C a-C:H CrN CrN TiN

1.000 > 2.000 1.750 1.750 2.300 1.500

1 - 4 0,5 - 3 1 - 4 1 - 4 1 - 4

0,1 - 0,2 0,1 - 0,2 0,5 0,5 0,4

< 250 < 250 < 250 < 500 < 500

+ ++ +++ ++ ++ ++

+++ +++ ++ ++ ++

++ ++ ++ ++ ++

++ + + ** ** **

C.B5.04 (0204) d

Abrasive Wear Coeff.* [10-15 m3 /Nm] 5-8 0.5-1 >7 >7 2-5 2-5


Material - Wear Mechansims Map

Abrasive

Adhesive Fatigue

Tribooxidation

BALINIT® DLC

BALINIT® C, C1500

BALINIT®CNI


BALINIT® C Nanolayers

Taylored Amorphous Superstructures

W, Ti, Nb,

Cr, Si, ....

C

Cr, Ti,...

C

C

Function

Adhesion

Substrate


DLC for Valvetrain Applications:

Motorbike Tappets

Number (Date)

BALINIT C BALINIT C1500 BALINIT-DLC

,

Kawasaki S600 Racebike after 4 Races 4

Tungsten-rich

2 µm 1 µm 0,2 µm Wear: Coating:


BALINIT® DLC SEM Cross Section - Fracture

10 µm


Coatings in Machine Design ??

Environment

Speed

Counterbody

Loading

Lubrication

Fatigue

Design Geometry

Texture

Mechanical

Motion

Properties

Strength

Fatigue

Mechanical

Thermal, ....

Type Material

Process

Architecture

Thickness

Int. Stress

Composition

Structure

Layersequence

Properties

Adhesive

Abrasive

Friction

Toughness

Electrical

Mechanical

(elastic

plastic)

Tribo-System

Coating System

Perf

orm

an

ce


Running-In Behaviour


Dry Running Behaviour

BALINIT® Carbon Coatings

C.B3.08 (0204) e

0

0,2

0

0,4

0,6

0,8

1000 5000 500 1500 250 750 1250 1750

DIN 1.3505 (100 Cr 6) uncoated

BALINIT® C (WC/C)

x

BALINIT® DLC (a-C:H)

Slidelength [m]


x Test aborted because of severe adhesive wear


•Continuously increased load

•Identical contact spots for a specific load

Performance of Carbon Coatings

Crossed Cylinder Set-Up

Diploma Thesis, Magnus Hansson,

Uppsala University, 2001

29 Tribology and Applications, 08-2003 Diploma Thesis, Magnus Hansson,

Uppsala University, 2001

Lifetime for different running-in cycles

0

1000

2000

3000

4000

5000

6000

7000

8000

0,1 1 10 100 1000 10000

N (Running-In Cycles)

N (

life

tim

e)

Insufficient run-in Good running-in Wear in Run-In-Phase

240-600N RI

800N

starved Lubrication

BALINIT C


Tribometer-Testing

Reference

Pin on Disk : Load 30N

distance 2.2km

Speed 30.00cm/s

radius 12.00mm

Running In Layer

0.1

0.2

µ

Running-In Layer on a BALINIT® C type Coating


320

340

360

380

400

420

440

µm

Coating Variant

Counterbody Wear in µm

Running In Layer

Reference


Coating & Surface Topography


How Much Lubricant Does a Coated Surface Keep?

Surface Structuring

an old idea...

Source: GeoScience online Source: UCT, Electron Microscope Unit

Sharkskin

Cylinder Liner


BALINIT® CNI chromium-nitride coating

C.B5.08 (0303) e

1 µm

After coating:

Surface roughness BALINIT® CNI untreated

Roughness increase Ra < 0.02 µm

Before coating:

Surface roughness carbide polished


Coated Structure coating

Structured Surface

Coating Protects Structure

coating

Structured Coating

Coating Provides Structure

Structured Coating

Surface Morphology


Structured Coating


Structured Coating

Comparative Test

Material: 100 Cr 6,

Coating: BALINIT® DLC, 2 µm

Structuring: holes after coating; Laser;

10-20 µm deep,

Testing: Ball on disc, 100 Cr6,

3 mm ball, 30N

a=1500 MPa

e=500 MPa

dry and

starved lubrication

5W30

coating

Structured Coating

Coating Provides Structure


Pin on Disc test

Dry and Starved Lubrication

C.B3.05 (0204) d

F

v

Method

Steel Ball, Ø 3mm

DIN 1.3505 (100 Cr 6), 60 HRC

Testring:

DIN 1.3505 (100 Cr 6), 60 HRC

coated

Conditions

F = 30 N

v = 0,3 m/s

Dry, Lab air, 40% RH, 23oC

or

Starved Lubrication


Ball - on - Disc Test

0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,16

0,18

starved lubrication dry

Fri

cti

on

Co

eff

icie

nt

structured

not structured

Gegenkörperverschleiss Mangelschmierung

0

100

200

300

400

500

600

700

Structured Unstructured

Co

un

terb

od

yw

ear

[um

]

Counterbody Wear

Structured Not Str.

Ball on Disc-Test e=500 MPa

Coefficient of Friction - 20%

Counterbodywear - 30%

Dry Starved Lubrication

Fri

cti

on

Co

eff

icie

nt


Roleplay Surface

• Role of Surface Structure

– Provide favourable Surface

Texture

– Reservoir for Lubrication

– Removal of Particles in

Grooves

– Wetting Behaviour of the

Substrate on the coating

– ...

• Role of Coating

– Protect against Adhesive Wear

– Conserve Surface Structure

against (abrasive, adhesive)

Wear

– Reduce Friction

– Modify Surface Energy

– ...


Substrate Influence

Hardness & Hardening Depth

A Supporting Role


Substrate Influence

Interference Coating - Substrate Hardness

• The Eggshell-Effect


No abrasive or adhesive

Wear of Coating

Failure of Tribo-System

„Plastic Wear“

High „Point-Loads“

Soft Substrates


42CrMo4 Nitrided

BALINIT® DLC coated


Influence of Nitriding Temperature on Scratchload

Scratchtest

1N-150N

Lc2

42CrMo4, nitrided 670K

20-180 min

620-770 K

60 min

High Temperature = Hard Compound Layer

= High Breakthroughload

Influenceing Factors; Coating Support and Plastic Behaviour

500

550

600

650

700

750

800

850

20 40 60 80 100 120

Scratchload Lc2 [N]

Nit

rid

ing

Tem

pera

ture

[K

]


Substrate Influence

Surface Roughness

An Acting Role


42CrMo4 Nitrided

BALINIT® DLC coated

Nitrided 670K 60min

Coated BALINIT® DLC

Nitrided 830K

Coated BALINIT® DLC

Ball on Disc Testing 30N, 2200m


Influence of Surface on Counterbody

0

0,05

0,1

0,15

0,2

0,25

0 100 200 300 400 500 600 700 800

Counterbody Wear [µm]

Fri

cti

on

Co

eff

cie

nt

BOD 30N

30cm/s

100Cr6 Ball

High Roughness = High Friction

= High Counterbody Wear

Influenceing Factors; Coating Support and Shear Stress

42CrMo4, nitrided 670K

20-180 min

620-770 K

60 min


Link between Friction and Lifetime

0

2000

4000

6000

8000

10000

12000

14000

0 0,05 0,1 0,15 0,2


Lif

eti

me [

m]

BOD 30N

30cm/s

100Cr6 Ball

42CrMo4, nitrided

770, 670, 620K

20-180 min

High Roughness + Substrate Hardness

= High friction + Low lifetime

Influenceing Factors; Coating Support and Shear Stress

Not nitrided

770K

620K

670K


Good coatable materials

C.B5.11 (0205) e

• Heat-treatable steels

• Tool steels

• Austenitic steels

• Precipitation-hardened steels

• Structural steels

• Nitrided steels (after pre-treatment)

• Cemented carbides

• Nickel- and titanium alloys

• Ball-bearing steels*

• Case-hardening steels*

• Hardenable chromium steels*

*only for low temperature coatings suitable (< 250 °C)


Conditionally coatable materials

C.B5.12 (0205) e

• Cast iron

(lamellar graphite favourable)

• Chromium- / nickel-plated metals

(only for low loads because of rel. poor adhesion

between electroplated coating and substrate)

• Copper alloys

(cleaning could be challenging)

• Aluminium alloys

(low coating temperature required,

substrate has low strength and supporting ability )

• Ceramics

(electrical conductivity)


Non coatable materials

C.B5.13 (0205) e

• Sintered metals with open pores

(not suitable for vacuum process)

• Polymers

(not thermally stable and not electrically

conductive)



Leading Edge Applications

Designing History by Applications


Fuel Injection

PVD-Applications


Common Rail System

Injector and high-pressure pump

C.C2.02 (0304) e

Made possible only with

BALINIT® C and

BALINIT® DLC coating:

• Compliance with narrow

system tolerances < 1 µm

• Reliable operation at

pressures up to 1600 bar

• Long service life combined

with minimal wear


BALINIT® coated components in

fuel injection pumps

C.C2.01 (0204) e

Single cylinder or inline pump

Plunger

Roller pin

Bushing

Camshaft

Unit injector

Plunger

Roller pin

Bushing

Cam shaft

Injector needle

Distributor pump with axial piston

Plunger Roller pin

Cam ring

Roller

Piston

Shoe

Distributor pump or common rail system with radial piston


Tappets

PVD-Applications


Wrist pins for motorcycles

Uncoated Seizure between wrist pin boss (Aluminium) and wrist pin at racing conditions BALINIT® C (WC/C) nearly no wear after the whole racing season

C.C1.04 (0205) e

Wrist pin uncoated after 150 km

Wrist pin WC/C-coated after 3500 km

Wrist pin Aluminium piston

Connecting rod


Tappets and cam shafts for vehicles

Car motor test stand Oil: without additives Testtime: 16 hours Uncoated increased frictional losses of motor BALINIT C (WC/C) reduces friction and wear compared to nitrided tappets

Tappets Cams made of steel, uncoated

Wea

r [µ

m]

0

10

8

6

4

2

Cam

Tappet

Valve

BALINIT C (WC/C)

Nitrided

25.4 (9507) e


Wear reduction of valve train with BALINIT® C

C.C1.03 (0304) e

Cam

Tappet

Valve

Auto engine test stand Oil: without additives Test period: 16 hours

Uncoated Increased engine friction loss

BALINIT® C (WC/C) Reduced friction and wear compared with nitrided tappets

Wear [µm]

Nitrided

uncoated

BALINIT® C

(WC/C)

12

10

8

6

4

2

0

Tappets

Cams

Cams: steel, uncoated

Tappets Cams


BALINIT® DLC coating for motorcycle tappets

C.C1.05 (0205) e

Uncoated

Tappets of racing motorcycles have to be replaced

after each race (250 km) due to wear

BALINIT® C (WC/C) -coated

Slight wear after 4 races (1000 km)

BALINIT® DLC -coated

Nearly no wear after 4 races (1000 km)

Kawasaki Supersport (600 ccm)

Uncoated BALINIT® DLC BALINIT® C


Piston Rings

PVD-Applications


Wear of liners paired with differently treated

piston rings

C.C1.06 (0304) e

Tribometer

(Cameron-Plint TE77)

Load: 8 Mpa

Temperature: 80 °C

Test period: 6 hours

Frequency: 10 Hz

Liners: grey cast iron

Oil: Lubrizol TH 53303

Source: Scania AB

Plasma-

sprayed

Nitrided Hard chrome-

plated

Chrome

Ceramic

BALINIT® C

WC/C

Piston ring

surface

0,2

0,1

0

0,1

0,2

0,3

x

x x

0.3

0.2

0.1

0

0.1

0.2

x no wear detected

Liner wear [mg]

Piston ring wear [mg]


Bearings

PVD-Applications


Cylindrical roller thrust bearing

Bearing 81206 Load: 33 kN Cage material: PA 66 Speed: 15 rpm Dry running

C.C3.02 (0204) e

1000

100

10

1

Life time [hours]

> 250

1,5

Temperature: 30 °C Coeff. of friction: 0.004 Roller wear: 5 mg

Rings and rollers BALINIT® C - coated

uncoated

1.5


Gears

PVD-Applications


Load Bearing Capacity of Gears

Flank and Root of Gears

Testing:

FVA - Specification 05

Steel: 42CrMo4V

0

5

10

15

20

25

30

35

uncoated TiCN TiN pretreated

+ TiN

Balinit C pretreated

+ Balinit C

Facto

r of

Lifetim

e flank

root

Source:

WZL, RWTH Aachen


Working limits of gears

C.C4.01 (0204) e

Damagefree region

Circumferential velocity

External stress

Abrasive wear

limit

Pitting

limit

Tooth fracture

limit

Seizing

limit


Load capacity of the tooth base and flank

C.C4.02 (0204) e

Test-rig acc. to FVA -guideline 05 Material Case hardened steel DIN 16MnCr5E Uncoated Failure criterion: 4% single tooth wear (pitting) BALINIT® C (WC/C) Increase of service life by: factor 4 for tooth flank factor 16 for tooth base Source: WZL, RWTH Aachen Flank Base

BALINIT® C

4

16

1 1

0

2

4

6

8

10

12

14

16

18

Flank Base

Uncoated

Service life - progression factor


Gear wear by seizure

C.C4.03 (0205) e

FZG-Test Test data Speed: 1,000 rpm Surface pressure: 1,000 N/mm² Lubricant: ESSO CL46B (on biological base) Source: IMM, TU Dresden

Tolerated load changes

Uncoated

dry

Uncoated

lubricated

BALINIT® C

dry

BALINIT® C

lubricated

Oil quantity:

1 drop per Minute

29.000

150.000

1.400

106

107

105

104

103

102

10

1

Interruption after 200,000,000

150,000

29,000

1,400


Planetary gear for a concrete mixer

C.C4.05 (0304) e

Uncoated Seizure of case hardened sun wheels at low speeds and high loads

BALINIT® C (WC/C) Prevents seizure and increases load and working range of the planetary gear

uncoated

Pinion and wheel BALINIT® C - coated

Model test:

Slow running wear

Stress: 2180 MPa (316 KSI)

Sliding velocity: 0.04 m/s

Teeth characteristics: FZG-C

0

100

200

300

400

500

0 40 80 120 160 200

600 Total wear of pinion and wheel [mg]

Time [hours]


High loaded fast running gear

C.C4.07 (0205) e

Uncoated

Surface fatigue (Pitting)

despite continous oil film

BALINIT® C (WC/C)

increases load carrying

capacity (fatigue endurance

limit) of

• heat treated gears by

30 - 40%

• case hardened gears by

10 - 15%

Stress cycles

Tooth flank stress [N/mm2] 2100

2000

1900

1800

1700

1600

1500 2 2 4 6 8 107 2 4 6 8 108

BALINIT® C (WC/C)

Test method: FZG-C-test case hardened steel, 62 HRC, RZ = 3 µm

Uncoated


Spur gears for motorcycles

C.C4.08 (0205) e

Uncoated Seizure due to oil leakage and overloading BALINIT® C (WC/C) provides emergency running reserve and higher load carrying capacity Right Wear on uncoated gear after oil leakage Left No wear on BALINIT® C (WC/C) -coated gear after oil leakage

BALINIT® C (WC/C)

uncoated


Hydraulic & Compressors

PVD-Applications


Hydraulic motor with

BALINIT® C coated parts

C.C8.04 (0205) e

With BALINIT® C (WC/C) coated roller

bearings:

• no seizure

• after 58,000 revolutions nearly no wear

• static friction between roller and piston

decreased by 40 %

• losses at start-up reduced by 18 %

• less “Stick-slip”


Wear of PVD coated compressor screws

C.C6.01 (0205) e

BALINIT® C (WC/C) coated screws: Due to the low wear rate a service life of more than 20,000 hours is expected.

Source: University of Dortmund

0

10

20

30

40

50

60

70Worn surface [%]

CrN (PVD) BALINIT® C (WC/C)

• Male and female screw

coated

• Sliding velocity 50m/sec

• Test duration 1000 hours

• Water injected

60 %

3 %


Chlorine free vane compressors

C.C6.02 (0205) e

Vane

Roller

Testing conditions Time: 1000 hours Pressure: 3.5 N/mm2 (500 psi) Temperature: 100 °C (212 °F) Medium: chlorine free refrigerant Roller material: cast iron Vane material: steel

15

0,1

5

< 0,1

0,01

0,1

1

10

100Wear [µm]

Roller Vane uncoated

Roller Vane BALINIT® C (WC/C), only vane coated

0.1

0.01

0.1 < 0.1


Axial piston pump - pistons

C.C8.07 (0205) e

Nitrided: seizure damage

Nitrided + BALINIT® C (WC/C): no seizure damage

Test conditions

Pressure: 400 bar

Speed: 3000 rpm

Time: 1000 hours

Piston


Axial piston pump - sliding shoes

C.C8.08 (0205) e

Bronze: abrasive wear and deformation

Steel + BALINIT® C (WC/C): wear < 1 µm

Test conditions

Max. pressure: 350 bar

Max. speed: 2200 rpm

Time: 1000 hours

Sliding shoe


Pneumatic valves for paper machines

C.C7.01 (0205) e

0

1

2

3

4

5

6Service life [months]

Uncoated BALINIT® C (WC/C)

Working conditions Valve material: DIN 1.4112 Rotation 30°, 2 x / min. Pressure: 5 Mpa Dry running Uncoated The valves jam at lack of grease BALINIT® C (WC/C) coated The valves operate permanently even at dry running


Erosion of materials used in hydraulic

components

C.C8.02 (0205) e

Particle size: 0-20 µm Particle concentration: 100 mg/l Pressure: 150 bar Medium: HFA

Source: PhD Thesis, St. Lehner, IFAS Aachen (1996)

Sample

Medium

Particles 50

µm

Relative factor of wear compared to steel DIN St 52

0

1

2

3

4

Bronze

Brass

GGG 40

St 52

Ck 45 WC/C

CrN

Alu

WC/C = BALINIT® C

CrN = BALINIT® D


Wear behaviour of hydraulic valves coated

with BALINIT® C (WC/C)

C.C8.09 (0205) e

Gap increase h [µm]

Valve housing

Valve stem Particles

0

2

4

6

8

10

12

14

16

uncoated BALINIT® C (WC/C)

Valve stem: Steel Ck 45 / 650 HV

Standard flow rate: 50 l/min

Valve type: 4/3 way proportional valve

Valve housing: cast iron

Medium: HFA

Source: PhD Thesis, St. Lehner, IFAS Aachen (1996)

Medium

h



A QS9000 Company

PVD - Quality Standards


QS9000-Certification for

Component Production Cites

C.D3.02 (0205) e


Measurement techniques for quality control

C.D3.03 (0204) e

Destructive measurements are performed outside the functional surfaces if possible

Method Coating

Feature Accuracy Substrate

Requirements

Limits

Destructive for:

Calo test

XRF measurement

Rockwell hardness HRC

Rockwell test

Colour measurement

Profilometer

Coating thickness

Substrate hardness

Coating adhesion

Colour

Roughness

Geometry, roughness

Substrate hardness, geometry

Plane surface

Geometry

0.3 - 0.5 µm

+/- 1 HRC

+/- 0.5 HF-classification

+/- 1

yes yes

no no Coating

thickness Geometry,

chem. elements 0.3 - 0.5 µm

yes yes


yes yes

no no

no no


Measurement techniques for analysis and

specification

C.D3.04 (0304) e

Destructive measurements are performed outside the functional surfaces if possible

Method Coating

Feature Accuracy Substrate

Requirements

Limits

Destructive for:

Cross section

Microhardness

Scratch test

Calo-wear test

Tribometer

Coating thickness

Coating adhesion

Abrasive wear

coefficient

Friction coefficient,

life cycle test


Plane surface

0.1 - 0.3 µm

+/- 10%

yes yes

yes no Coating

hardness

Geometry, roughness,

coating thickness >1µm +/- 10%

yes yes

Plane surface, roughness

yes no

yes yes


C.D3.05 (0205) e

Polishing sphere

Coating

Substrate

Calculation of coating thickness D

using A, B, and sphere radius r

BALINIT®- coating after calo test

(spherical abrasion),

top view

A

B

D r v

Coating thickness measurement by calo test


Rockwell coating adhesion test

C.D3.06 (0205) e

Rockwell diamond cone

Coating

Substrate

BALINIT® -coating

with HRC indentation,

top view

Comparative assessment of

coating adhesion based on de-

formation geometries in zone A

with defined image series.

F A A


Measurement of coating adhesion with

scratch test

C.D3.07 (0205) e

Diamond stylus

Coating

Substrate

Scratch in BALINIT® -coated surface,

top view

F

v

S

Visual assessment of crack formation and

coating flaking inside track S dynamically

deformed under load F.


C.D3.08 (0304) e

Polishing sphere

Coating

Substrate

Calculation of grinding mark volume

using B and sphere radius r

Test conditions:

Humidity and temperature constant

r v

B

Measurement of abrasive wear coefficient

with calo-wear test

Abrasive slurry


Sliding wear test with tribometer

Fixed ball, diam. 3 mm,

AISI 52100 (DIN 1.3505), 60 HRC

Test ring:

AISI 52100 (DIN 1.3505), 60 HRC

blasted or ground, N4

coated

FN = 30 N

v = 0.3 m/s

dry running

C.D3.09 (0304) e

FN

v

FR Frictional force

Calculation of friction

coefficient µ by measuring

the frictional force FR v

Normal force


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