Abstract: A hard carbon film is formed in a vacuum vessel directly or through an intermediate layer for enhancing adhesion over an inner surface of a guide bush with a uniform thickness and excellent adhesion wherein the inner surface is in sliding contact with a workpiece and the guide bush is mounted on an automatic lathe for holding the workpiece rotatably and slidably in the axial direction near a cutting tool. Accordingly, the method comprises disposing the guide bush in a vacuum vessel, inserting an auxiliary electrode into the center bore forming the inner surface of the guide bush to be at a ground potential, introducing a gas containing carbon into the vacuum vessel through the gas inlet port after evacuating the vacuum vessel, and applying a DC voltage to the guide bush through a reactor, thereby producing a plasma in the vacuum vessel so that a hard carbon film of hydrogenated amorphous carbon is formed over the inner surface of the guide bush by a plasma CVD method.

Abstract: In a valve unit 10 for a water mixing valve comprising a stationary disk 11 provided with a hot water inlet, a cold water inlet, and a mixed water discharge outlet, and a rotary disk 12 slidably overlapping the stationary disk, and provided with a mixing chamber, a face 11s, 12s of at least one of the stationary disk 11 and the rotary disk 12, slidable relative to the other, is provided with a hard carbon film 15 with a first intermediate layer 13a made of titanium or chromium and a second intermediate layer 13b made of silicon or silicon carbide being interposed in-between. With the valve unit constituted as above, the hard carbon film having high adhesion strength is formed on the slidable face 11s/12s of the stationary disk 11 or the rotary disk 12, or on both the slidable faces, substantially enhancing resistance-to-wear of the valve unit.

Abstract: An auxiliary electrode which is to be connected to a ground potential or applied with a positive DC voltage is disposed in a center bore which forms an inner surface of a guide bush, and a ringlike dummy member made of a conductive material having an internal diameter equal to or larger than the diameter of the center bore of the guide bush with its both ends having a different diameter is placed on an end face of the guide bush opening the inner surface thereof so that one end having the smaller diameter contacts the end face of the guide bush with its center in alignment with the central axis of the center bore. A DLC film is formed over an inner surface of a guide bush which is in sliding contact with a workpiece held in the guide bush by disposing the guide bush in a vacuum vessel after evacuating the vessel and introducing a gas containing carbon, producing a plasma in a vacuum vessel by applying a DC voltage or a radio frequency power to the guide bush by the plasma CVD process.

Abstract: A heating roller device including a center shaft, a heat roller rotatably supported on the center shaft, and heating means provided inside the heat roller has the wear resistance of the outer surface of its heat roller outer surface increased and its availability factor enhanced by forming the outer surface of the heat roller with a hard carbon film of hydrogenated amorphous carbon. The hard carbon film is preferably formed on an intermediate layer formed on the outer surface of the heat roller beforehand so and to increase its adhesion to the outer surface. Wear resistance can be further enhanced by forming the outer surface of the heat roller with a hard layer, forming an intermediate layer on the hard layer and forming the hard carbon film on the intermediate layer.