PREPARATION OF NANOPHASE MATERIALS BY THERMAL SPRAY PROCESSING OF LIQUID PRECURSORS

Thermal spray processes were modified to spray liquid feedstocks. Nano phase Al2O3, Mn2O3, ZrO2 and Y2O3 stabilized ZrO2 powders and deposits were produced. Ceramic particles of 1-150 nm size were collected at a rate of similar to 20 mg/min., with similar to 20-35 % collection eff iciency. Organometallic precursors produced oxide deposits with a powd ery morphology, while aqueous solutions yielded hydroxide deposits, re quiring post spray heat treatments for producing oxide coatings. Spray feedstock and processing conditions affected the size, shape and phas e composition of the synthesized nanomaterials. Particles with wider d istributions of larger size grains were produced from aqueous solution s, while a narrow distribution of fine-grained materials were produced when organometallic precursors were used. (C) 1997 Acta Metallurgica Inc.