Ion-beam assisted coating of tube inner walls by plasma immersion ion implantation

Tubes are often required to exhibit better performance in corrosion and wear behaviour than the material the tube is made of can offer. The situation can be improved when the tube is coated with a protective film. This is possible when sputter coating with ions is performed. A sputter target is located inside the tube. Energetic ions extracted from a plasma in which the tube is immersed (plasma immersion ion implantation PIII) are accelerated towards the tube, enter it and impinge onto the target. Thus, material is sputtered from the target onto the inner walls of the tube. Tubes made of stainless steel and of tantalum were used. A part of the stainless steel tube was cut away and replaced by a segment of a silicon wafer. A zirconium sputter target was inserted into the tube. Ions from a nitrogen plasma were accelerated into the tube. Thus, zirconium oxynitride films were formed. Tantalum tubes with a platinum sputter target inside were treated in an argon plasma. The deposited films were analysed by Rutherford backscattering spectrometry. The results show that PIII treatment of tube inner walls is an effective technique for coating inner walls of tubes with protective films.