Synthesis of Potassium Titanate Fibers for Friction Materials

摘要

Potassium hexa and octatitanate fibers have been proposed as reinforcement for friction materials. The aim of this work was to establish a calcination route to produce these fibers, using commercial anatase and potassium carbonate powders. These powders were dry mixed with TiO_2/K_2O molar ratio, n, of 3.0, 3.5, and 4.0, and then calcined at 950, 1050, and 1150℃ for 3 h. Calcined powders were milled, washed in warm water with different pHs, and heat treated to crystallize the fibers. The best conditions to growth long fibers were n=3.0 and 1050℃, in the two-fase field (liquid + K_2Ti_4O_9). Controlled ion-exchange with water removed K~+ ions from K_2Ti_4O_9 fibers resulting in potassium hexa or octatitanate fibers after the second heat-treatment. Fibers with sub-micrometer thickness (～0.6 μm) and average length of～20 μm could be prepared.