An improved multilayer
coating for use on
molten metal holding and transfer apparatus, the
coating including a bound layer applied directly to the surface of
molten metal holding and transfer apparatus, and a
porous layer of
ceramic material produced by co-deposition of a
powder of said
ceramic material and a
powder of a suitable
organic polymer material and, after the co-deposition, heating of said
polymer material to thermally decompose the
polymer material and form the
porous layer. The bond layer preferably is formed of a metallic,
intermetallic or composite particulate materials. The
metal component may be in the metallic,
intermetallic,
oxide, clad or alloyed form consisting of any one or more of the
metal components selected from the group of Mo, Ni, Al, Cr, Co, Y and W and may be in combination with yttria,
alumina, zirconia,
boron, carbon and have a particle size in the range of 5 to 250 m, typically 40 to 125 m. The bond layer preferably has a thickness of 5 to 300 m with a substantially uniform
coating layer being provided over the surfaces to have the porous
ceramic coat applied.