Higher performance capacity through the use of coatings€¦ · Higher performance capacity through the use of coatings ... 10 Durotect® Z (zinc phosphate) 11 ... Isotect® coating

Higher performance capacity through the use of coatings

Coated rolling bearings and precision components

Contents Coating systems and their areas of application 2Coatings · Overview 31 Main function – Anti-corrosion protection

and fretting corrosion 32 Main function – Anti-wear protection /

friction reduction 43 Main function – Current insulation 54 Main function – Surfaces subjected to high

tribomechanical stresses 5

1 Main function – Anti-corrosion protection and fretting corrosionCorrotect® coating systems:Corrotect® thin layer coating (zinc-iron alloy) 6Corrotect® ZI (zinc-iron alloy) 7Corrotect® ZN (zinc-nickel alloy) 8Corrotect® ZK (zinc, electroplated) 8Corrotect® ZF (zinc, lamellar coating) 9

2 Main function – Anti-wear protection / friction reductionDurotect® coating systems:Durotect® B (mixed iron oxide) 10Durotect® Z (zinc phosphate) 11Durotect® M (manganese phosphate) 12Durotect® CK (columnar hard chromium coating) 13Durotect® CK+ (columnar hard chromium coating

+ anti-friction coating) 14Durotect® CM (microcracked hard chromium coating) 15Durotect® NP (nickel-phosphorus coating) 16Durotect® C (copper) and Durotect® S (silver) 17Durotect® HA (hard anodising) 17Durotect® P (PTFE coating) 18

3 Main function – Current insulationIsotect® coating system:Isotect® A (oxide ceramic) 19

4 Main function – Surfaces subjected to high tribomechanical stresses

Triondur® coating systems:Triondur® C (metal-doped carbon coating) 20Triondur® C+ / CX+ (carbon coating) 21Triondur® CN (chromium nitride) 22Triondur® CNN (chromium carbonitride) 22Triondur® TN (titanium nitride) 23

Coating systems and their areas of application

2

CorrosionFretting corrosion

Wear

(abrasive)

Corrotect® A*, C, F, N*

Triondur® TNDurotect® NPCorrotect® ZI, ZN

Corrotect® ZF

Corrotect® ZK

Durotect® CK, CK+, CM

Durotect® Z

Durotect® M

Triondur®

CN, CNN, C, C+, CX+Current

insulationDurotect® C, S

Isotect® A

Durotect® HA

Durotect® BWear (adhesive)

Friction

Durotect® P

Bearings and precision components from the SchaefflerGroup offer high performance capacity and a long operating life. They provide the user with thoroughlydeveloped and economical solutions for the large majority of requirements. Nevertheless, operating conditions sometimes occur that are beyond the limitsof the standard designs. In such cases, one of the verywide range of coatings available can be a solution tothe task of increasing the operating life of a component.

Coatings are used where there are problems with:Corrosion and fretting corrosion• anti-corrosion protection• prevention of fretting corrosion Wear, friction and slippage• improvement of friction behaviour• reduction of wear, principally under mixed friction• prevention of slippage damageCurrent passage• insulation in order to prevent the passage of current.

Coatings are applied to the surfaces of componentswithout thermo-chemical diffusion taking place betweenthe coating and the base material. In the SchaefflerGroup, a large number of coatings are used. They areapplied by a wide variety of methods and give widelydiffering advantages for the component. They shouldalways be individually matched to the mounting situation.In many cases it is sufficient to coat only one of thecomponents in rolling contact or only a part thereof.This Technical Information gives an overview of thecoatings used at Schaeffler, arranged according to the main areas of use. The features, advantages andbenefits are given for each type of coating.Specific examples and references are shown.

Coatings · Overview

3

Corrotect® A* Zinc alloy/ X – Automotive, belt drives, selector

RR*; J56 shafts, bearings, bearing components,

Cr(VI)-free

Corrotect® C To be phased out X – Industrial,

bearing rings containing Cr(VI)

Corrotect® F X – Industrial, containing Cr(VI)

Corrotect® N* X – Automotive, belt drives,

detents, Cr(VI)-free

Corrotect® ZK Zinc/J32 X Simple anti-corrosion protection

applications

Corrotect® T Tin X Reduction in Automotive, bearing bushes

contact corrosion

Corrotect® ZI Zinc-iron/J44 X – Industrial, Automotive

belt drives, bearing components,

screws

Corrotect® ZN Zinc-nickel X – Industrial, Automotive

belt drives, bearing components,

screws

Corrotect® ZF Zinc lamellae, X – Industrial, Automotive, chassis

Cr(VI)-free engineering, components, screws

Designation Comment Main function Additional Main area of application

Coating system Suffix Anti-corrosion Anti-wear Friction function Special feature

protection protection reduction

1 Main function: Anti-corrosion protection – Corrotect® coating systems

Coatings ∙ Overview

4

Durotect® B Mixed iron oxide X Improvement in Industrial, Automotive,

running-in behaviour, bearing components in wind power,

reduction in full complement roller bearings

slippage damage,

slight anti-corrosion

protection

Durotect® Z Zinc phosphate/ X Temporary anti- Industrial, Aerospace,

J33B corrosion protection, linear guidance systems, bearings,

protection against bearing components

fretting corrosion,

suitable in

sliding seat fits

Durotect® M Manganese X Improvement in Industrial, Automotive,

phosphate/J33B running-in behaviour, Aerospace,

slight anti-corrosion bearing components

protection, emergency

running lubrication

Durotect® CK Columnar thin layer X Anti-corrosion protection, Industrial, Linear Technology,

chromium coating slight reduction in Aerospace, vibratory screen bearings,

(Protect A in linear friction, reduced helicopter bearings, spindle bearings

sector) / J24 fretting corrosion

Durotect® CK+ Columnar thin layer X X X Additionally good Industrial, bearing components,

chromium coating anti-corrosion protection Linear Technology

plus mixed chromium

oxide (Protect B in

Linear sector)/J46

Durotect® CM Microcracked thin X Slight Industrial,

layer chromium anti-corrosion protection, needle roller bearings

coating slight reduction in

friction

Durotect® NP Chemical nickel/J36 X X – Industrial, drawn cups,

guide ring segments

Durotect® C Copper X Emergency running Industrial, cages

lubrication

Durotect® S Silver X Emergency running Industrial, Aerospace,

lubrication linear guidance systems,

bearing components, cages

Durotect® HA Hard anodising (Al) X X Current insulation Automotive, sliding sleeves

Durotect® P PTFE/J47 X Protection against Industrial,

fretting corrosion bearing rings

Friction reduction




2 Main function: Anti-wear protection and friction reduction – Durotect® coating systems

Coatings ∙ Overview

5

Triondur® CN CrNx X X – Automotive,

valve train components

Triondur® CNN CrN/CrC X X – Automotive,

valve train components

Triondur® C a-C:H:Me/J48 X X Reduction in Industrial, Automotive,

slippage damage bearing components,

engine components

Triondur® C+ a-C:H X X – Industrial, Automotive,

engine components

Triondur® CX+ a-C:H:X X X Minimal friction Automotive,

in valve train valve train components

Triondur® TN TiN X – Aerospace,

bearing components, rib surfaces




4 Main function: Surfaces subjected to high tribomechanical stresses – Triondur® coating systems

Isotect® A Oxide ceramic/J20 X Main function Industrial, rail vehicles,

current insulation electric motors, generators




3 Main function: Current insulation – Isotect® coating systems

FeaturesColour: dependent on post-treatmentA*: iridescent silver - Cr(VI)-freeC: iridescent yellow - containing Cr(VI)F: black - containing Cr(VI)N*: silver, slightly iridescent - Cr(VI)-free

Coating structureZinc-iron coating with passivation on A*/N* or chromating on C/F.

Coating thickness0,5 – 3 μm preferably for C/F or coating thickness 2 – 5 μm preferably for A*/N*.A* = thick layer passivationN* = nanoparticle-based passivation

Advantages/benefitsAnti-corrosion protection, in accordance with salt spraytest to DIN EN ISO 9227, between 48 and 360 hoursagainst red rust formation(depending on design type).

• Economical alternative cathodic anti-corrosion protection.

Applications• Various bearings, bearing components and bearing

adjacent parts with requirement for increased corrosionresistance, e. g. bearing inner rings / outer rings / rolling elements; drawn cup needle roller bearings andthin-walled components in large quantities, e.g. detentsleeves.

1 Main function – Anti-corrosion protection

6

Corrotect® thin layer coating (zinc-iron alloy)

FeaturesColour: dependent on post-treatmentA*: iridescent silver - Cr(VI)-freeC: iridescent yellow - containing Cr(VI)F: black - containing Cr(VI)N*: silver, slightly iridescent - Cr(VI)-free

Coating structureZinc-iron coating with passivation on A*/N* or chromating on C/F.

Coating thicknessdependent on requirement, 5 μm or more. A* = thick layer passivationN* = nanoparticle-based passivation

Advantages/benefits• Anti-corrosion protection, in accordance with salt

spray test to DIN EN ISO 9227, between 120 and 600 hours against red rust formation (depending on design type)

• Economical cathodic anti-corrosion protection.

Applications• Automotive and industrial components with

requirement for increased anti-corrosion protection• Large bearings in rolling mill sector.


7

Corrotect® ZI (zinc-iron alloy)

FeaturesColour: dependent on post-treatmentA*: silver, at some points slightly iridescent

yellow; Cr(VI)-free

Coating structureZinc-nickel coating with thick layer passivation on A*.

Coating thicknessdependent on requirement, 2 μm or more.


spray test to DIN EN ISO 9227, between 360 and 720 hours against red rust formation (depending on design type)

• High quality cathodic anti-corrosion protection.

Applications• Automotive and industrial components with

requirement for very high anti-corrosion protection,such as steering and detent bushes, bearing pins,mechanical levers, etc.

Corrotect® ZK (zinc, electroplated)

FeaturesColour: dependent on post-treatment, preferablyA*: silver, at some points slightly iridescent

yellow; Cr(VI)-free

Coating structureZinc with post-treatment, preferably thick layer.

Coating thicknessdependent on requirement, 5 μm or more.


spray test to DIN EN ISO 9227, between 24 and 360 hours against red rust formation (depending on design)

Applications• Simpler adjacent parts.


8

Corrotect® ZN (zinc-nickel alloy)

FeaturesColour: silver-grey

Coating structureSoft zinc lamellar coating, partially cathodic, paint-type anti-corrosion protection.

Coating thickness8 – 15 μm

Advantages/benefits• Anti-corrosion protection

(salt spray test to DIN EN ISO 9227, up to 720 hours against red rust formation).

Applications• Principally in the automotive sector:

wheel bearings, sensor and intermediate rings,screws.


9

Corrotect® ZF (zinc lamellar coating)

FeaturesColour: jet black

Coating structureCoating comprising mixed iron oxides.

Coating thickness0,4 – 2 μm.

Advantages/benefits• Improvement in running-in behaviour of bearings• Favourable under low risk of slippage.

Applications• Rolling elements and rings for bearings in wind

turbines and railway drive bearings• Full complement cylindrical roller bearings• Ball bearings under poor lubrication conditions.

2 Main function – Anti-wear protection / friction reduction

10

Durotect® B (mixed iron oxide)

11

FeaturesColour: grey/black

Coating structure Zinc phosphate

Coating thickness 1 – 3 μm (bearing rings),3 – 10 μm (other parts).

Advantages/benefits• Anti-corrosion protection in oiled condition

(salt spray test to DIN EN ISO 9227, up to 48 hours against red rust formation)

• Prevention of fretting corrosion in the bearing seat• Friction reduction promotes displacement effect.

Applications• Tapered roller bearings in rail vehicles• Large bearings – paper industry• Expander roller eccentric bearings• Rolling bearing cages and drawn cups.


Durotect® Z (zinc phosphate)

12


FeaturesColour: matt dark grey

Coating structure Manganese phosphate

Coating thickness1 – 5 μm (bearing rings, rolling elements)3 – 10 μm (other parts)

Advantages/benefits• Improvement in sliding and running-in behaviour.

Applications• Roller coating in bearings in mixer gearboxes• Sheet steel cages • Adapter and withdrawal sleeves• Inner ring bores in crankshaft bearings• Primary layer for anti-friction paints.

Durotect® M (manganese phosphate)

13

Durotect® CK (columnar hard chromium coating)


FeaturesColour: matt grey

Coating structureChromium coating with columnar surface surface.

Coating thicknessFunctional surfaces: 1 – 3 μmSecondary surfaces: 1 – 6 μm.

Hardness: approx. 1 000 HV.

Advantages/benefits• High wear resistance (high hardness) especially at

the axial contact running points or on fit surfaceswhere fretting corrosion is expected

• Effective anti-wear protection under mixed friction for small ball or roller bearings

• Low friction factors under mixed friction due to smoothing of the pearly structure after the running-in process

• Reduced friction factors allow unconstrained displacements in non-locating bearings

• Corrosion resistance approx. 5 times higher compared with rolling bearing steel (salt spray test to DIN EN ISO 9227).

Applications• Raceways in high precision bearings• Outside diameter of spindle bearings• Complete coating of spherical roller bearings

(rings, rolling elements) running in corrosive environments

• Bore of vibratory screen bearings against fretting corrosion / vibratory wear

• Ball bearing rings for swash plates in helicopters• Linear components.

14

FeaturesColour: black

Coating structureSmooth upper layer comprising mixed chromium oxide(LC layer) in columnar chromium layer.

Coating thicknessAs Durotect® CK plus 0,5 – 3 μm LC.

Hardness: approx. 1 000 HV; the LC layer is soft.

Advantages/benefits• Improved running-in behaviour• Improved friction and wear behaviour under lubricant

starvation (the depressions between the chromium pearls act as a “lubricant reservoir” for the chromium oxide).

When the bearings are used in aggressive atmospheresand at high temperatures, the LC layer acts in a sup porting role to the lubricant compared with pure thin layer chromium coating and increases the corrosion resistance.

Due to mechanical load, the soft LC layer is compactedinto the pearly structure. The resulting grey functionallayer reveals the base layer Durotect® CK.

Applications• Traction motor bearings in rail vehicles• Wheelset bearings in kiln and furnace trucks• Back-up rollers for multi-roll cold rolling mills• Linear components.

Durotect® CK+ (columnar hard chromium coating + anti-friction coating)


15

FeaturesColour: silver – definable surface qualities

(from very fine to rough, matt to lustrous).

Coating structureSmooth, microcracked hard chromium coating.

Coating thicknesses between 0,1 and 500 μm, depending on the application (suitable for mechanical processing).

Hardness: approx. 850 – 1 100 HV.

Advantages/benefits• Improved friction and wear behaviour under

lubricant starvation (the microcracks in the coating act as a “lubricant reservoir”)

• Increased life due to hard surfaces as anti-wear protection

• Good anti-corrosion protection and high resistance tomany chemicals with coating thicknesses over 30 μm

• Temperature resistance up to +300 °C • Protection against tribocorrosion • Low friction coefficient / good sliding characteristics• Anti-adhesive characteristics.

Applications• Spherical plain bearing applications• Industrial products subjected to wear loads.


Durotect® CM (microcracked hard chromium coating)

16

FeaturesColour: metallic silver, slight yellow tinge

Coating structureChemically deposited nickel coating,with 8 – 15 % phosphorus in the deposit.

Coating thicknessDependent on requirement 8 – 15 μm,For anti-corrosion protection 15 – 300 μm.

Hardness 500 – 600 HV (increasable by heat treatment to 750 – 1 000 HV).

Advantages/benefits• Coating true to contours of component,

in some cases also in depressions• Combined characteristics of anti-wear protection

and anti-corrosion protection allow a wide range ofapplications

• High coating thicknesses give very good anti-corrosionprotection characteristics

• Suitable for mechanical processing in certain cases.

Applications• Guide rings, spherical roller bearings• Spherical plain bearings• Housings for the food industry• Usage in fresh water/salt water applications.

Special featuresDurotect® NP can be dispersed by means of PTFE orhard material particles (diamond, SiC) in order to optimise the sliding characteristics or improve the wear resistance.


Durotect® NP (nickel-phosphorus coating)

17

FeaturesColour: copper-coloured or silver-coloured

Coating structure Durotect® C CopperDurotect® S Silver with copper intermediate layer.

Coating thicknessDependent on requirement, 2 – 15 μm.

Advantages/benefits• Improvement in emergency running behaviour• Also possible as combined coating.

Applications• Sheet steel cages in two-stroke and four-stroke engines• Cages for aerospace applications.


FeaturesColour: silver to mouse grey

Coating structure Durotect® HA, aluminium oxide layer.

Coating thicknessDependent on requirement, 2 – 25 μm.

Advantages/benefits• Increase in wear resistance of aluminium• Current insulation.

Applications• Aluminium sliding sleeves in clutch bearings• Aluminium cages for aerospace applications.

Durotect® HA (hard anodising)

Durotect® C (copper) and Durotect® S (silver)

FeaturesColour: dark grey/black

Coating structure PTFE coating

Coating thickness10 – 20 μm.

Advantages/benefits• Improvement in sliding capacity on the bearing outer

ring, reduction in the friction factor to < 0,1 underaxial displacement of bearing rings.

Applications• Quadropol mills for cement production

(outer ring outside surface of spherical roller bearings)• Suction box rolls and thermo rolls in paper machinery

(outer ring outside surface of spherical roller bearings)• Main rotor bearing arrangements in wind power.


18

Durotect® P (PTFE coating)

FeaturesColour: light grey to matt beige

Coating structureCeramic coating comprising aluminium oxide Al2O3

with sealant.


Advantages/benefits• Current insulation depending on coating type –

resistance to passage of current – up to 1 000 Volt even in damp environment, anti-corrosion protection.

Applications• Bearings in threephase motors• Traction motor bearings• Wheelset bearing arrangements• Bearings in generators.

Details, Technical Information WL 43-1189/2“Current-insulated bearings prevent damage due to thepassage of electrical current”.

3 Main function – Current insulation

19

Isotect® A (oxide ceramic)

FeaturesColour: matt greyish black

Coating structureHard amorphous hydrocarbon coating of lamellar type structure with content of tungsten and tungstencarbides.The surface structure is smooth.

Coating thickness0,5 – 4 μm.Friction reduction in DLC/steel compared withsteel/steel (dry in each case) 80 percent.

Hardness: 1 100 – 1 500 HV (corresponds to TPI 115, Triondur).

Advantages/benefits• Effective anti-wear protection under mixed friction• Higher wear resistance due to high hardness• Favourable under adhesive wear due to the low

friction factor• Highly suitable under risk of slippage and for large

bearing components.

Applications• Barrel rollers in spherical roller bearings for paper

calenders• Barrel rollers in axial spherical roller bearings for

hydraulic motors• Track rollers with coated outside diameter for the

printing industry.


20

Triondur® C (metal-doped carbon coating)

FeaturesColour: black

Coating structureHard amorphous non-metallic hydrocarbon coatingwith lamellar type structure.The surface structure is smooth.

Coating thickness2 – 4 μm (corresponds to TPI 115, Triondur).Friction reduction in DLC/steel compared withsteel/steel (dry in each case) 85 percent.

Hardness: > 2 000 HV.

Advantages/benefits• Very high anti-wear protection under mixed friction• Higher wear resistance due to high hardness• Friction reduction under mixed friction• Highly suitable for components subjected to high

tribological stresses with lubricant starvation.

Applications• Reduction in wear and friction in valve train

components (e. g. tappets) • Anti-wear protection in diesel injection components• Bearing components (e. g. cages) for increased life.


21

Triondur® C+ / CX+ (carbon coating)

FeaturesColour: lustrous silver-grey

Coating structureHard nitridic chromium coating with nanocrystalline structure. The surface structure is smooth.

Coating thickness1 – 4 μm.Friction reduction in Triondur CN/steel compared withsteel/steel (dry in each case) 20 percent.

Hardness: > 2,200 HV.

Advantages/benefits• Very high anti-abrasive wear protection by high hardness• Friction reduction under adequate lubrication.


components (e. g. tappets).


22

Triondur® CN (chromium nitride)

Triondur® CNN (chromium carbonitride)

FeaturesColour: matt silver

Coating structureMulti-layer, nanodispersive, chromium-based hard material coating.

Coating thickness: 5 – 15 μm.Friction reduction in Triondur CNN/steel compared withsteel/steel (dry in each case) 15 percent.

Hardness: 1 200 – 1 800 HV.

Advantages/benefits• High anti-abrasive wear protection by high hardness• Good anti-wear protection under lubricant starvation

or oil contamination.


components (e. g. hydraulic pivot elements).

FeaturesColour: lustrous gold

Coating structure Titanium nitride


Hardness: > 2 000 HV.

Advantages/benefits• High anti-wear protection

Applications• At the rib surfaces of aircraft engine bearings.

Attention!The coating cannot be used on the bearing raceway.

23


23

TRIONDUR® TN (titanium nitride)

24

Notes

MAT

NR

0368

0539

4-00

00 /

TPI

186

/ G

B-D

/ 2

0090

53 /

Pri

nted

in G

erm

any

by M

ande

lkow

Every care has been taken to ensure the

correctness of the information contained

in this publication but no liability can be

accepted for any errors or omissions.

We reserve the right to make technical

changes.

© Schaeffler KG · 2009, May

This publication or parts thereof may not

be reproduced without our permission.

TPI 186 GB-D

Schaeffler KG

Oberflächen/Schichtsysteme

Industriestraße 1-3

91074 Herzogenaurach (Germany)

Internet www.ina.de

E-Mail [email protected]

In Germany:

Phone 0180 5003872

Fax 0180 5003873

From other countries:

Phone +49 9132 82-0

Fax +49 9132 82-4950

Schaeffler KG

Oberflächen/Schichtsysteme

Georg-Schäfer-Straße 30

97421 Schweinfurt (Germany)

Internet www.fag.de

E-Mail [email protected]

In Germany:

Phone 0180 5003872

Fax 0180 5003873

From other countries:

Phone +49 9721 91-0

Fax +49 9721 91-3435

Documents

Higher performance capacity through the use of coatings€¦ · Higher performance capacity through the use of coatings ... 10 Durotect® Z (zinc phosphate) 11 ... Isotect® coating