Amorphous carbon layer for heat exchangers and processes thereof

A substrate having on at least a portion of its surface a coated layer of an amorphous carbon layer having a hardness of at least 2000 Kg/μm2, a specific resistivity of at least 105 ohm 108 cm, and a dielectric strength of at least 105 V/cm.

A process for depositing an amorphous carbon layer onto a substrate comprising the steps (a) preparing a plasma vapour deposition chamber;

• b) pumping into the chamber a carbon containing gas at a pressure range between about 10−2 and 10−5 mbar;
• c) supplying a voltage of at least 1 kV and igniting the gas to provide a self sustain a glow discharge in the gas;
• and depositing from the carbon containing gas an amorphous carbon layer on said substrate having a hardness of at least 2000 Kg/mm9, a specific resistivity of at least 108 ohm cm, and a dielectric strength of at least 106 V/cm.

A process for depositing a amorphous carbon layer into a substrate comprising the steps of preparing a PVD system;

• pumping into the system a carbon containing gas;
• operating the system at a temperature of at least 150° C. and depositing from the carbon containing gas an amorphous carbon layer on the substrate having a hardness of at least 2000 Kg/mm2, a specific resistivity of at least 108 ohm cm, and a dielectric strength of at least 106 V/cm.