| abstract |
An article (30) has a cavity (33) defined by an inner surface (31), the cavity (33) having a size such that a largest sphere placeable in the cavity (33) has a diameter of less than 7 cm and a smallest sphere placeable in the cavity (33) has a diameter of 0.5 mm; and a hard coating (32) on the inner surface (31), the hard coating (32) having a hardness between 18 to 100 GPa, the hard coating (32) distributed on the inner surface (31) such that a ratio of a coating thickness (t) at a first region of the hard coating (32) to that at a second region of the hard coating (32) ranges from 0.75 to 1.33. A method of deposition forming a plasma inside the cavity in a PECVD chamber comprising the step of pulsing the power supply and a method comprising the step of pulsing the electric current at a given frequency are also disclosed. |