煅烧工艺对熔盐法合成钛钾镁片晶的影响

钛酸镁钾具有优异的力学性能,被广泛用作各类高级轿车刹车片的摩擦材料。而材料的组成及形貌对刹车效果的影响很大,传统的合成工艺无法对其进行有效地控制。本文通过对煅烧工艺的优化,从而得到结晶度和形貌俱佳的钛酸镁钾片晶。以Mg(OH)_2、K_2CO_3和TiO_2为原料,加入KCl为熔盐,采用熔盐法合成钛酸钾镁片晶(KMTO)。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)技术手段研究了煅烧工艺(升温速率、煅烧温度、保温时间)对钛酸钾镁片晶组成及形貌的影响,并对其反应机理进行了初步的探讨。结果表明,不同的煅烧工艺对熔盐法合成钛酸镁钾片晶的组成及形貌产生了显著的影响,以200℃/h升温至800℃后,再以100℃/h升温至1000℃,保温2 h,通过水洗干燥,即可得到结晶度较高、形貌比较均匀的K_(0.8)Mg_(0.4)Ti_(1.6)O_4片晶。

Effect of Calcination Process on Platy Potassium Magnesium Titanate by Molten Salt Method

Potassium magnesium titanate with excellent mechanical properties is widely used as friction materials of various advanced brake pads. The influence of composition and morphology on braking effect is very large, but the traditional synthesis method can not effectively control it. In this paper, we successfully obtained the potassium magnesium titanate with excellent crystallinity and morphology by controlling the calcination process. Platy potassium magnesium titanate(KMTO) was synthesized by molten salt method with KCl as the molten salt and Mg(OH)₂, K₂CO₃ and TiO₂ as raw materials. The effect of calcination process(heating rate, calcination temperature and holding time) on phase composition and morphology of obtained KMTO were analyzed by X-ray diffraction and scanning electron microscopy. The mechanism of this reaction was explored preliminarily. Calcination process was found to significantly affect the composition and morphology of KMTO synthesized by molten salt method. When raw materials are calcined at 1000 ℃ for 2 h by heating rate at 200 ℃/h(>800℃) and 100 ℃/h(>800 ℃), platy K_0.8Mg_0.4Ti_1.6O₄ with high crystallinity and uniform morphology is obtained after washing and drying.