Magnetic field enhanced plasma (MFEP) deposition of inner surfaces of tubes

This paper describes a newly developed technique, magnetic field enhanced plasma (MFEP) deposition, by which inner diameter of tubes or pipes can be deposited with various coatings. Deposition of hard coatings onto inner diameter (ID) of tubes with high aspect ratios is always a challenging task. The MFEP technique is a novel method of plasma enhanced chemical vapor deposition (PECVD). It utilizes a magnetic field to generate hollow cathode glow discharge inside a long tube and enhance the plasma production. By proper arrangement of the magnetic field and selection of precursors, hard coatings such as diamondlike carbon and silicon carbide can be deposited on to the ID of tubes. Using this method DLC and SiC films have been deposited on the inner walls of tubes with small diameters and high aspect ratios (0.9–2.5 cm in diameter, up to 71 cm long). In this paper, we will also discuss the design and the construction of the MFEP device, properties of the plasma and characteristics of the coatings obtained. Finally, we will present some practical applications.