Strategic oxides for thermal spraying: problems of availability and evolution of prices

Many industrial applications of thermal sprayed coatings base onto oxides such as partially stabilized zirconia, alumina or titania. Yttria and ceria stabilized zirconia are useful in such applications as thermal barrier coatings (TBC) or gas sensors as λ-sensor. Alumina is useful for such applications as corona rolls applied in polyethylene surface activation with corona discharge. Another design of corona rolls uses titania as electrically conducting coating. The key properties of these oxides related to the applications such as heat and ionic conductivity of stabilized zirconia, and electronic conductivity of alumina and of titania are briefly described. Then, the most important ores used to produce these oxides, namely (i) zircon for zirconia, (ii) different ores for rare earth oxides (REO), (iii) bauxite for alumina, and (iv) rutile for titania are shortly described and their availability and world consumption are outlined. Finally, the prices and their evolution of the ores and the final oxides are presented and related to the geographic and to the strategic considerations of exporting countries.