The latest techniques to become widely available commercially to design engineers and others who specify surface coatings are those for ionization assisted physical vapour deposition; titanium nitride being the main coating material at this time. The background to this new technology is outlined and information is provided about the main commercial processes. An indication is given of potential problems which can arise, leading to performance variability. Details of applications reported by users are included. It is intended that with the aid of this guide engineers, designers, and other potential users will have a clearer picture of the technology involved and its strengths and weaknesses.