The ultimate wear- and corrosion resistant pistonThe ultimate wear- and corrosion resistant pistonrod and axle coating due to the uniquerod and axle coating due to the unique

combination of characteristicscombination of characteristics

The ultimate wear- and corrosion resistant pistonThe ultimate wear- and corrosion resistant pistonrod and axle coating due to the uniquerod and axle coating due to the unique

combination of characteristicscombination of characteristics

WMV b.v.WMV b.v.The NetherlandsThe Netherlandswww.wmv.nlwww.wmv.nl

he new semi-ceramic Lunac2+ duplex coating (Hv 1200/2100) is partially a galvanic

and partially a ceramic coatingsystem that includes an interme-diate layer of very dense modifiednickel. The 70-100 µm hard Lunac2+ top layer has been applied tovarious machine parts and tools fora longer period already because ofits tough nature, friction reducingproperty, ultimate hardness,effective anti-galling property,smooth (seal friendly) surface andweld joint quality bond with steelor copper alloy substrates.

fter a long period of additionalresearch a delicately modifiednickel sub layer added an unpre-cedented synergistic corrosion

protection effect to the Lunac 2+ platingsystem in 2010. This breakthrough gene-rated a coating that was principally ableto combine the usually highly conflic-ting properties of ultimate hardness andgood corrosion protection. Moreover, astriking sub-surface corrosion inhibitioneffect has been determined and the abili-

ty to deal with even substantial plasticdeformations. An affordable coating that as able to offer this combination of allmentioned characteristics was hardlyavailable up to that moment.

Frequently applied full ceramic piston rodcoatings to dredging equipment is often notsufficiently impact resistant. Apart from theoutstanding corrosion protection, Lunac 2+duplex proved to resist most stone chipseven without any cracking

This new coating concept acquired theultimate EPQ corrosion test approval in2011, incorporated in the NBD 10300(RWS) qualification. Since its introduc-tion, the Lunac 2+ duplex coating is par-ticularly applied to infrastructure sys-tems, been operational under high loadsand in various tough offshore applica-tions. Almost none of the Lunac coatedparts have been returned for repair andno Lunac 2+ duplex coated part hasbeen claimed to show corrosion yet.

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Lunac 2+ duplex success-fully combines nearly in-

compatible characteristics

Lunac 2+ duplex success-fully combines nearly in-

compatible characteristics

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Lunac 2+ duplex encompasses all essential characte-ristics to armour (offshore) hydraulic pistons and axles

enerally, hard galvanic coatingsare rather affordable. Thescratch and wear resistance isreasonable to good, but can

hardly be compared with ceramiccoatings. Although some hard galvaniccoatings can offer sufficient corrosionprotection as well, vulnerability, delami-nation and limited chloride/salt waterresistance or pore problems are oftenrecorded. Most HVOF ceramic coatingsare notable for their effective anti-gallingproperties and high hardness as well asgood corrosion resistance in the case ofmultilayer systems. However, these cera-mic coatings frequently show seriousbond and vulnerability problems, as wellas causing increased seal-wear. Somehard coating systems based on weldingor hard metal processes meet mostrequisites, but are generally regarded tobe very expensive. For these reasonsthere continued to be a high demand foraffordable hydraulic piston rod and axlecoatings without major drawbacks.Lunac 2+ duplex is able to combine allthese essential axle and piston rodarmour properties in an as yet unprece-dented manner. Moreover, Lunac 2+duplex coatings can easily be repaired inthe case of accidents.

Lunac 2+ duplex applied to bridge and lock doorhinges offers wear and friction reduction as wellas long lasting prevention of (galvanic) corrosion

The Lunac 2+ duplexinnovation:

The Lunac 2+ duplexinnovation:

All major Lunac 2+ duplex characteristics :

All major Lunac 2+ duplex characteristics :

1. Superb (salt) water corrosion resistance if the substrate is free of defects; NBD10300 (Rijks-waterstaat 2010) EPQ corrosion testing, based on ASTM G59-97 (2003) / G61-86 (2003) and ISO 17475 standards. ASTM B117 salt spray testing > 3300 hours rating 10 and distinct sub-surface corrosion inhibition

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Ultimate hardness, supreme corrosion resistance and 100% coating bond were hard to unify for a long time

Lunac 2+ duplex applied to hydraulic pistonrods, dealing with very hard (mechanicaland corrosive) conditions after severalyears. All preceding coatings failed within 2years at this spot. These piston rods clearlypresent the Lunac 2+ dark grey appearancethat typically comes along with the Lunac 2+surface under these harsh conditions.

2. Lunac 2+ is highly resistant to adhesive and abrasive wear (Hv 1200/2100) and equals most full ceramic materials. Because Lunac 2+ is tough and harder than quartz sand, natural sand can hardly scratch Lunac 2+ 3. Full bond with steel or copper alloy substrates (similar to a weld joint). Surfaces might part-ly be deformed (dented) and the Lunac 2+ coating could develop micro cracks beginning at 0.28% elongation, but Lunac coatings will never peel off

4. Lunac 2+ can deal with very high mechanical loads (shocks up to 600 MPa)

5. Generally, in most sliding systems that incorporate Lunac 2+, friction is reduced and galling or fretting are highly inhibited

6. The smooth pore-free Lunac 2+ surface does not cause the frequently observed increased 'seal on full ceramic’ wear

7. The heat conductance of Lunac 2+ duplex is comparable

to steel, which means that Lunac 2+ (duplex) will discharge heat much better than full cera-mic coatings.

8. The Lunac 2+ surface will tarnish in response to water contact and develop a thin (0.2 µm) brown/grey film. This layer will not disturb the functionality

9. Locally damaged Lunac 2+ (duplex) coatings can be easily repaired (on location as well)

Lunac 2+ duplex plated piston rods or axles never returned because of spontaneous coating defects or corrosion spots

ubsurface corrosion highly limitsthe service time, particularly forpiston rods due to the formationof sharp (lifted) edges. The unpa-

ralleled subsurface corrosion inhibitioneffect of Lunac 2+ duplex explains whythis coating can even deal with somedamage.

Corrosion behaviour after 8 days acidifiedsalt water test in two 3.0 mm pre drilledholes. The first graphic pair shows thereaction of a duplex hard chromium coatingand the second graphic pair the reaction ofa Lunac 2+ duplex coating. The Lunac 2+duplex coating reduces the total amount ofcorrosion (red numbers) and highly inhibitssubsurface corrosion.

Lunac 2+ applied to hydro-electric powerplant shafts offers corrosion protection and

wear resistance as well as anti-galling andanti-fretting properties. The narrow toleran-ces combined with considerable dimensi-ons, pollution, corrosive environment andvibrations require a coating that can dealwith all these conditions simultaneously.

ypically, Lunac 2+ is explicitlyresistant to the abrasive action ofquartz sand. This characteristicexplains the exceptional scratch

and abrasive wear resistance in a sandyenvironment.

Almost any kind of steel softerthan HRc 50 can be plated, butsteel should be free of micro-

defects. Certified steel with a highCharpy impact value is favourable

Conditions for applying Lunac 2+ duplex

successfully :

Conditions for applying Lunac 2+ duplex

successfully :

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Lunac 2+ duplex plated pistons and axles can deal with moderate stone chips and very high mechanical loads

(examples: QT quality steel in the caseof 42CrMo4 or J2 quality or higher in thecase of S355)

The initial surface roughness mustbe less than Ra = 0.10 μm / Rz = 1.0μm before the coating can be

applied. Do not apply worn out abrasivebelts or rolling to obtain this low initialsurface roughness.

The Lunac 2+ duplex coatingthickness is 0.12 mm (up to 0.15mm, if necessary). Consequently,

the product diameter must be reducedby 0.24 mm +/- 0.01 mm below the no-minal final diameter, but by 0.21 +/- 0.01mm if the surface roughness still needsto be reduced from Ra = 0.9 µm (usuallyacquired by turning ) to Ra = 0.10 µm

Copper alloys (and stainless steel to alesser extent) in intensive contact with(salt) water and Lunac 2+ could slowlydissolve the Lunac 2+ coating locally.

After hardening at 310 °C the Lunac 2+surface will be finish-ground withdiamond to a surface roughness ofround about Ra = 0.15 µm

Common and hard fibre resins as well asmost bronze versions guiding materials,can be applied. Harder (Shore-A 95 (PU))seals are slightly preferred.

Plating capacity:Plating capacity:

Length: 3930 mmØ: 780 mmweight: 3000 Kg

To complete the total product support,WMV also offers a comprehensive tech-nical support (e.g. material research orbearing choice) thanks to the mechani-cal engineering specialisation and thematerial research department.

State of delivery and application details :

State of delivery and application details :

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Specialist in high performance alloy and ceramic precision platingSpecialist in high performance alloy and ceramic precision platingWMV b.v. Heliumstraat 1 7463 PL Rijssen

Netherlands Tel. +31 548 520681 www.wmv.nl