Thermal spray coating having improved adherence, low residual stress andimproved resistance to spalling and methods for producing same

Abstract From the Canadian patent

Method of thermal spray coating a substrate by projecting heat-softened particles onto said substrate including the steps of contacting particles to be projected and coated onto the substrate with a body of hot gases, heating the particles in the hot gases to a temperature near at, or above their melting point and impinging the heated particles against the substrate to provide a coating having the desired thickness wherein said particles are first heated to a relatively higher temperature and impinged onto the substrate to provide a first layer having a thickness that is a fraction of the desired thickness and thereafter heating coated particles to a lower temperature in the hot gases and …