Applied using plasma spraying
Weak, mechanical bond between coating & surface
Rapid cooling -> coating cracking -> failure
Alloy implant supplies most mechanical properties
Difficult to predict lifetime coating bond to implant
As coating resorbs, implant-bone interface becomes unstable -> micro-motion & loosening
Ceramic-alloy bond weaker than ceramic-bone bond
Important variables: powder particle size/shape, pore size/shape, pore size distribution, specific surface area, phases present, crystal structure, density, coating thickness, hardness, roughness