This invention provides an apparatus, method, and application for forming a uniform
coating on the inner wall of a
pipe to be plated, belonging to the field of
metal surface protection technology. The apparatus includes a
vacuum chamber, an
electric field generating component, and a
magnetic field generating component. The
electric field generating component includes a
pulse power supply, an auxiliary
anode, and first and second
extension tubes. The
extension tubes and auxiliary
anode are coaxially arranged to fix the corresponding
pipe to be plated. The
extension tubes and the
pipe to be plated have the same inner
diameter and are conductive. The auxiliary
anode portion is located inside the extension tube. The negative terminal of the
pulse power supply is connected to the pipe to be plated, and the positive terminal is connected to the auxiliary anode. During operation, the pipe to be plated and the extension tube are connected to form an integral cavity, and the
cavity wall forms a continuous
equipotential cathode surface. The
electric field generating component and the
magnetic field generating component respectively generate a radial electric field and an axial
magnetic field inside the tube. This invention, through the integrated structure of "extension tube-pipe to be plated-extension tube," regulates the electric field, magnetic field, and
airflow field inside the tube, achieving uniform deposition of
a diamond-like
carbon coating on the inner wall of the
metal pipe.