No abstract

The effects of the addition of surfactants and of the surface treatment upon the aqueous dispersion of silicon carbide were examined. In the case of β-SiC, the addition of nonionic surfactants having relatively longer lengths of hydrocarbon and oxyethylene chain to the β-SiC treated with a silane coupling agent enhanced the dispersion stability. On the other hand, the lack of a difference for the dispersion stability was observed between a silane coupling treated α-SiC and an untreated one by the addition of surfactants. These differences in the surface property of two kinds of SiC were confirmed by measuring the zeta potential and the heat of immersion in water.

Articles you may be interested inPreparation of baxis oriented YBa2Cu3O y thin film by laser metalorganic chemical vapor deposition and successive annealing

We have found a very effective way to control the orientation of YBCO films by MOCVD using ArF excimer laser ( A = 193 nm) irradiation on an MgO(100) substrate. It also enables u s to control crystalline orientation locally by focusing the laser. We found that the irradiated parts were stronglya-axis oriented normal to the surface of MgO(100) substrate for YBCO films prepared at 65&700"C, whereas the x-ray diffraction pattern of the unirradiated part consists of the peaks of (llO)y (001) and (h00) planes. The surface morphology of the laser-irradiated part of the films was very smooth, whereas that of t h e unirradiated part was comparatively rough. The zero-resistance temperatures of unirradiated and irradiated parts of YBCO prepared at 650°C were 45 K and 72 K respectively