Potassium tetratitanate (K2Ti4O9) whiskers were synthesized by the calcination and slow-cooling method. Powder X-ray diffraction (XRD) analysis and differential thermal analysis (DTA) were used to study the formation of K2Ti4O9. In the slow-cooling calcination process, the control of cooling rate was crucial to growth of K2Ti4O9 whiskers. The characterization of the whiskers was carried out by means of scanning electron microscope (SEM). (C) 2004 Kluwer Academic Publishers.