Development and Manufacturing of Maltilayr coated Ceramic-Composite Particles.

研究了不同化合物多层包覆的超细复合颗粒。采用了两种方法。(1)将分子结构中含有目标元素的特殊表面活性剂吸附在陶瓷颗粒表面，实现均匀的涂覆和分散。(2)将元件的混合溶液超声雾化形成液体颗粒，用于形成颗粒和涂层，干燥和分解。在反应过程中，形成的颗粒被不同的元素所覆盖。(1)选择钛三异硬脂油异丙醇（TTI）作为模型表面活性剂。将TTI吸附在氧化钇稳定氧化锆（YSZ）颗粒表面，使其表面形成均匀的Ti涂层。带TTI的YSZ作为初级颗粒在癸烷中分散良好。利用离心力制备了钛均匀分布的超细颗粒膜。元素分析表明，其整体组成与吸附等温线预测值吻合较好。(2)选择包覆Ca化合物的Pd细颗粒和SiO_2超细颗粒作为超声雾化方法的模型材料。干燥过程中同时发生水解反应，在控制颗粒大小的条件下，Pd (NO_3)_2是制备致密均匀颗粒的最合适原料。在Pd起始溶液中加入55 ppm-1wt%的Ca (NO_3)_2溶液，形成的Pd金属颗粒表面沉积有Ca化合物。这层涂层保护Pd粒子在加热过程中不被氧化。在起始溶液中加入胶体SiO_2颗粒。在干燥阶段，由于热力学原因，SiO_2颗粒均匀分布在PdO颗粒中。然而，在PdO分解成Pd的过程中，SiO_2颗粒从Pd颗粒内部迁移到表面。Pd粒子表面覆盖了SiO_2。

The ultra-fine composite particles with multilayr coating of different compounds were investigated. Two types of approaches were applied. (1) Special surfactant containing with the target element in the molecular structure was adsorbed on the surface of the ceramic particle to realize the homogeneous coating and dispersion. (2) Liquid particles are formed by the ultrasonic nebulization of mixed solution of the element for forming particle and for the coating, dried and decomposed. During this reaction, formed particle was covered with different element.(1) Titanium tri-iso-stearoil iso-propoxide (TTI) was selected as a model surfactant. TTI was adsorbed on the surface of yttria stabilized zirconia (YSZ) particle to make homogeneous coating of Ti on its surface. YSZ with TTI were well dispersed in decane as a primary particle. Centrifugal force was applied to make ultra-fine particle films with homogeneously distributed Ti. Element analysis revealed the overall composition are well agreed with predicted value from adsorption isotherm.(2) Pd fine particles coated with Ca compound and SiO_2 ultra-fine particle were selected as a model material of the ultrasonic nebulization approach. Pd (NO_3)_2 was most suitable starting material to make dense and homogeneous particle under controlling the particle size by the hydrolysis reaction simultaneously occurred during drying. Adding the 55 ppm-1wt% of Ca (NO_3)_2 solution to the Pd starting solution, Ca compounds deposited on the surface of the formed Pd metal particle. This coating layr protected the Pd particle from oxidation during heating.Colloidal SiO_2 particle was also added into starting solution. At drying stage SiO_2 particles were homogeneously distributed in the particle that is PdO by the thermodynamic reason. However, SiO_2 particles migrated from inside of the Pd particle to the surface during decomposition of the PdO to Pd. Pd particle was covered with SiO_2 on the surface.