Cold spraying is a new emerging coating technology.In this process,a coating is formed through plastic deformation or pseudo-deformation upon high velocity impact of spray particles in a completely solid state.The temperature of spray particle prior to impact is much lower than the melting point of spray materials.Therefore,spray materials experience little microstructure change,oxidation or decomposition.Consequently,metallic coatings with a high purity of less oxidation can be easily deposit.Moreover,the meta-stable structure of feedstocks including nanostructure can be completely retained into resultant deposit.The investigations up to date have demonstrated that most metals and their alloys including Zn,Al Cu,Ni,Ta,MCrAIY,Al-Si can be deposited by cold spraying.Through controlling of particle structure,and temperature and velocity,nanostructured WC-Co cermet with a high hardness comparable to sintered bulkcan be deposited.