Applied like paint
MoniPlex® ceramic and metallic coatings are applied as liquid slurry which naturally flows over the surface of almost any shape, including internal diameters as small as 0.5 mm. They are totally dense, pore free and the coating exhibits a spinel-like bond layer with the component. MoniPlex® coatings can be applied to a variety of ferrous and non-ferrous materials, including carbon steels; nickel based alloys, titanium alloys, aluminium and its alloys and copper alloys. MoniPlex® has a proven track record in oil, steel, textile and engineering applications. The coatings can be super-finished and exhibit a hardness of between 1800 and 2900 Vickers.
The slurry coating process is unlike thermal spray, PVD and CVD techniques, where difficult geometries and small internal bores are difficult or impossible to coat. Slurry coatings are applied like paint consequently there are no “line of sight” problems as with other techniques. Deposition techniques include pressure spraying for most external surfaces, dipping for complex shapes and draining for internal surfaces such as cylinder liners. The thickness of the deposited slurry can be controlled within the range of 1-250 µm depending upon the geometry and application criteria. Once the deposition of the slurry is complete, the component is heated to a temperature at which the thermo-chemical reaction takes place. At this stage the coating is prepared for final conversion, which produces a totally dense, pore free coating that incorporates a spinel-like bond layer between the coating and the component.
Very smooth, dense pore-free structure
The as-coated surface texture is very smooth, typically 0.5 to 1.5 µm Ra and is often used in this condition. When finishing is necessary for dimensional or surface texture considerations, the coating can be ground, honed or lapped in a similar manner to other ceramics. MoniPlex® coatings are particularly suitable for applications in corrosive environments. The totally dense pore free structure of a MoniPlex® coating provides an excellent corrosion barrier and the coating itself is inert to most forms of chemical attack. This differs from flame sprayed ceramics which can contain micro cracks and are inherently porous due to the thermal strain created by hot particles cooling quickly on impact with the relatively cool substrate.
MoniPlex® has excellent resistance against wear and solid particle erosion. The average adhesive dry rubbing wear factor is 10-15 M3/Nm, as determined from a pin-on-plate sliding test using a polished hardened steel pin rubbing against the treated plate surface at a loading of 10 Nm-2. The average high stress abrasive wear factor is comparable to carburised steel at 4000 (no units) and the average erosive wear factor indicated by 1,000 parts per million of silica in water with an impact velocity of 25 ms-1 is 1500 (no units), which in turn is comparable to a PVD coating of titanium nitride. Frictional characteristics also influence the wear resistance of a coating. The naturally low friction characteristics of MoniPlex® coatings contribute significantly to their superior wear performance over other materials: - Electroplated hard chrome 0.50 Plasma sprayed ceramics 0.35 MoniPlex® ceramics 0.26