C-Ramic's ongoing development program has perfected a new technique that can be used to coat the inside diameter of sleeves or bores.

This coating technique allows for coating thicknesses from 50 microns to 125 microns to be achieved and a variation of coating thickness of less than 25microns throughout the bore.

Sleeves coated with C-Ramic's thermochemically bonded ceramic coating have bond strengths of >77MPa and surface finish Ra values of approx 0.5microns as coated, that can be further honed to achieve smoothness down to Ra values of 0.025microns.

The low coefficient of friction coupled with high hardness and small particle pullout properties ensures a self-polishing surface that will outlast any metal in this sliding wear situation. The coating can be left with some "open porosity" to retain oil for in situ lubrication or be completely sealed where corrosion is a major factor. C-Ramic has developed a technique to sleeve the seal running area of hydraulic blocks that had become unfit for use after only a short period of time - wear caused by scoring in the bore had resulted in leakage and consequent failure to hold the designed pressure.

In this case, sleeves 700mm by 180mm with wall thicknesses of 2mm were coated with this unique C-Ramic process and then cooled to -196°C to prepare them for shrink fitting to the pre-bored blocks. The shrinking and expansion process had no effect on the strongly adhered C-Ramic coating and the tight tolerances of the final bore were readily achieved.

These C-Ramic coated sleeved hydraulic blocks have now been working for many years without interruption, extending their service life beyond all previous expectations. Avoiding costly maintenance shutdowns and/or expensive capital purchase replacements, has proved to be a very cost effective way to solve this wear problem commonly encountered with hydraulic equipment.

Other potential applications for this C-Ramic process include hydraulic cylinders, diesel engine cylinders, two stroke engine sleeves, and compressed air cylinders.

If you require increased performance or extended durability from your hydraulic equipment, contact the experts at C-Ramic.