Various colloid systems for drawing of aluminum oxide fibers

The aim of this study was to develop new low-cost synthesis routes to produce aluminum oxide ceramic fibers for high temperature insulation. The co-precipitation and sol gel chemistry provided the basic of the syntheses. The starting materials were varied from inorganic Al salts (nitrate and chloride) to organic Al compounds (acetate and isopropoxide). The influence of various chemical additives such as polymers, surfactants, basic and gelation agents has been determined on the fiber parameters. Important task was to find the appropriate and efficient fiber drawing technique and heat treatment. The solvent spinning technique has been proved to be an optimal device to produce fibers qualified for high temperature insulation. These fibers can be characterised by diameter of 10–20 μm and the length of 5–15 cm. The techniques as SEM, NMR spectroscopy, DLS, DTA, WAXS, the measurement of tensile strength, thermal conductivity, and heat resistance were aimed to characterise the fibers.