In order to address deficiencies in thermal spray coatings applied using air plasma spraying (APS) and high velocity oxygen fuel (HVOF) namely; line of sight application, adhesion, cohesion and porosity, novel hybrid coatings were developed using post and pre-spray chemical vapor deposition (CVD). Tungsten carbide-cobalt and chrome carbide-nickel chrome were thermally sprayed followed by boron or chrome diffusion for severe service pump and valve applications. CoCrAlY sprayed followed by aluminum silicon diffusion was developed  for hot gas corrosion (Type II) in gas-turbine applications. Aluminum diffusion onto copper followed by HVOF Hastelloy C and a subsequent low temperature braze was developed for heat exchanger plates in sulfur environments. Testing and evaluation of the coatings included life cycle tests in field applications, molten salt exposure and immersion testing. Microstructural and microhardness testing was also carried out.