本實驗以水熱法成功製備鈮酸鉀粉體，於200℃2小時的水熱條件下合成單相鈣鈦礦相。水熱合成時之KOH的濃度為重要變因，當其濃度大於8M，可合成大量鈮酸鉀粉體。合成粉末經800℃?燒後，其晶型由擬立方晶轉變成斜方晶。合成之鈮酸鉀粉體的形態與水熱反應中之鈮離子的濃度有關。當鈮離子的濃度提高時，粉體的粒徑增大，並且粉體的型態由長棒狀變化成球型。為控制鈮酸鉀粉體之形態，水熱反應中之鈮濃度必須精確調控。

　　　　　Monophasic potassium niobate powders were successfully prepared via a hydrothermal process after reaction at 2000℃ for 2h. The concentration of KOH required to be larger than 8M for the preparation of KNbO3. After calcinations at 800℃, the crystal structure of KNbO3 transformed from a pseudo-cubic to an orthorhombic structure. The morphology of prepared KNbO3 powders depended on the concentration of niobium ions during hydrothermal reactions. When the concentration of niobium ions increased, the particle size of powders increased, and the morphology of powders varied from a long-rod shape to a spherical shape. The concentration of niobium ions requires to be well adjusted for controlling the morphology of KNbO3 powders.