Articles which can be used in implantable prostheses have an outer surface that bears at least two layers of metal particles. An outermost layer consists essentially of aspherical metallic particles having a mean particle size of 50 to 500 µm. An intermediate layer consists essentially of substantially spherical metallic particles having a mean particle size of from 50 to 500 µm. The outer surface has a volume porosity of between about 20% and about 80%.