The ultimate semi-ceramic coating concept
for hydraulic cylinders, rods and shafts
After 14 years of continuous development, Lunac 2+ uniquely combines all the desired properties needed for a compromise-free coating for hydraulic cylinders. This, when combined with ductile nickel, has been declared by many users to be the best and most suitable material available, especially in their offshore use and with heavy-lifting applications. Apart from |
becoming slightly tarnished after a long period of non-use, Lunac 2+ can be considered the first and only coating available that has no serious practical limitations; it is very hard, resistant to scratching and corrosion, seal-friendly, ductile, attractively priced and creates a weld-quality bond with the substrate. Early users report 12 years of uninterrupted service already. |
The hard Lunac 2+ duplex coating system on construction steel (with intermediate technical hard nickel layer) passes the ASTM B117 1000 hours Neutral Salt Spray test with no rust spot formation (rating 10) |
The corrosion resistance of the very hard (Hv eff. 2200 ) Lunac 2+ coating is very durable, partly because unique compressive stresses keep Lunac 2+ coatings micro-crack free. The exceptionally high degree of bonding with the substrate (for these types of hard coatings) makes Lunac 2+ withstand the harshest environment (chipping, point loads).
See the following picture displaying the Lunac 2+ surface after 7 years outdoor application. The resistance to scratches is remarkable. Seals (and even the hard epoxy seals) barely interact with Lunac 2+. Because of this, another important application for Lunac 2+ is on the shafts of (slurry) pumps.
The Lunac 2+ process is straightforward for these types of machine parts. Consequently the cost equals that of conventional chromium-nickel coatings and is consequently much more valuable than the most comparable HVOF ceramic plating. Normally finished Lunac 2+ coatings have a roughness of Ra = 0.1-0.3 µm (0.0039-0.0118") and do not need any post treatment. See the special report on
the application of Lunac 2+ on hydraulic systems.
Pistons up to 3800 mm / 149.6" can (partially) be plated according to the Lunac 2+ duplo system (50 + 70 µm / 1.97 + 2.76 mil) and still be cut afterwards if necessary. Welding very close to the coating zone is allowed as well as nitrogen cooling for the benefit of shrinking.
Dredging pump shaft (Ø 350 mm) coated with 250 µm Lunac 2+. The HT-HNBR seal lifetime is significantly prolonged because of the smooth Lunac 2+ surface and low interface temperature due to the low friction-coefficient .
Lock door hinge-pins (Figure left: Amerongen, the Netherlands, Figure below: Kornwerderzand, the Netherlands) coated with Lunac 2+, operational in the sweet and salt water-air interfaces.
Even this corrosion system does not inflict any extra damage to the Lunac 2+ duplex coating system. Mostly the Lunac 2+ system can be judged to be more corrosion resistant than high grade stainless steel.
An additional advantage is the possible application of high tensile steel and reduction of the galvanic corrosion potential.
Test construction lock door at TNO Delft, commissioned by Rijkswaterstaat (Dutch governmental water management).
The Lock door pivot has been coated with Lunac 2+ duplex (on mild steel) and will be tested in various salt water concentrations at various speeds. The load is approximately 53 metric ton. Lunac 2+ duplex proved to be stable in this system and no corrosion appeared.