The invention relates to a powder composition comprising particles of a) an alkali metal tungsten bronze, b) tungsten oxide, and c) tungsten metal, a method for the preparation of said powder composition, and to the use of said powder composition in form of a dispersion in a polymer material or article for heat shielding, or to increase the heat-input amount of near infrared radiation in processes selected from laser welding of plastics, NIR curing of coatings, drying of printing inks, fixing of ink toners to a substrate, heating of plastic performs, laser marking of plastics or paper.