Laser Production of Ultrafine Particles of Ceramics and Ceramic-Metal Mixtures(Fine Particles)

概要

論文の詳細を見る
This paper describes the production and characteristics of ultrafine particles of ceramics and metal-ceramic mixtures by pulsed YAG laser evaporation technique using plates and powders of various ceramics, metal+C mixtures, metals and alloys as target materials. Most particles produced were ultrafine in the size range of less than 150nm. The size was smaller with a reduction in chamber (ambient) pressure. It was observed that ultrafine particles were built-up to be larger due to the collision and condensation of atoms, clusters and super ultrafine particles. Ultrafine particles of β-SiC and γ-Al_2O_3 were produced from α-SiC and α-Al_2O_3 ceramic target plates in Ar atmosphere, and then the weight loss evaporated by one laser shot (evaporation rate for the formation of ultrafine particles) for ceramic targets of SiC and Al_2O_3 was by far greater than that for metal targets. Ultrafine particles of SiC and TiC could also be produced from SiC powders or Si and C mixed powders and TiC powders or Ti and C mixed powders in Ar. Ultrafine oxide particles could be prepared from various pure metals by laser irradiation in O_2. These types were dependent upon some groups of neighboring elements: MO type of CoO, NiO, CuO and ZnO ; M_2O_3 type of Cr_2O_3, Mn_2O_3, Fe_2O_3 and Al_2O_3 ; MO_2 type of TiO_2, ZrO_2, SnO_2 and PbO_2 ; M_2O_5 type of Nb_2O_5 and Ta_2O_5 ; MO_3 type of MoO_3 and WO_3. The formation of TiO_2 and NiO particles (of less than 10nm in size) at 50Pa (0.4 Torr) indicated that oxide powders could be easily formed even at a reduced pressure of up to 50Pa. In N_2 atmosphere, ultrafine nitride particles of TiN, ZrN, VN, Cr_2N, Ta_2N, Nb_4N_3 and Mn_4N (or δ-MnN) were formed, and ultrafine particle mixtures of Al metals and AlN nitrides were made from Al plate, but metallic particles were produced from the plates of Fe, Ni, Cu, W, Mo, Si, etc. Accordingly, for Fe-Ti and Ni-Ti alloys in N_2 atmosphere, metal-nitride mixture particles such as Fe and TiN and Ni and TiN were formed, and the mixture ratio depended upon alloy composition of Fe and Ni to Ti.
大阪大学の論文

Laser Production of Ultrafine Particles of Ceramics and Ceramic-Metal Mixtures(Fine Particles)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク