Coating technology based on the vacuum arc-a review

An overview of the current state of vacuum-arc-based coating technology is presented, with particular emphasis on defining those areas where further investigation would reap the greatest benefits. Particular attention is given to the `continuous´ cathodic arc, which is currently the best understood approach and which has been most successfully adapted for large-scale commercial coating in the United States. It is noted that the greatest promise of ion-based coating technology based on the vacuum arc is the potential for increased control over the coating process. Unlike the case for neutral coating atoms, the presence of a charge on coating ions gives a `handle´ to exert forces on them using electrostatic fields. One can in theory control the trajectory of these ions between the coating source and part to be coated. One can also control the energy with which they impact the substrate. It may even be possible to control the extent of their reactivity