稀土硫化物包覆云母珠光颜料的制备及光谱性能研究

发布时间：2018-08-21 10:28

【摘要】：稀土硫化物材料由于其独特的光、电、磁等优良特性,已经被广泛应用于无机颜料、光学材料和热电材料等领域,但目前对其近红外反射性能的相关研究还较少。本文在云母片上包覆硫化铈制备珠光颜料,结合了云母特殊的层状结构和硫化铈高的反射指数,既可以获得较高红外反射率的反射隔热颜料,又可以提高硫化铈颜料的亮度。另一方面,传统的硫化铈纳米粒子制备温度较高,造成纳米粒子极易团聚等缺点严重影响了颜料的着色性能,利用颗粒包覆技术将纳米材料包覆在云母基体表面能够有效的防止纳米颗粒团聚。本文采用溶胶凝胶法结合硫化法制备mica/Ce_2S_3材料,并用Y~(3+)、La~(3+)分别进行掺杂得到mica/Ce_(2-x）Y_xS_3、mica/Ce_(2-x）La_xS_3系列样品,采用X射线衍射仪(XRD)、热分析仪(TG-DSC)、扫描电镜(SEM)、分光光度计(UV-vis-NIR photometer)、色差仪等对珠光颜料进行晶体结构、表面形貌、颜色性能、耐光性能、紫外吸收以及红外反射性能等测试表征。实验结果表明:mica/Ce_2S_3材料的最佳硫化温度为850℃,当Na+/Ce~(3+)摩尔比为0.2时,该条件下制备的mica/Ce_2S_3复合珠光颜料的紫外吸收性能、颜色性能以及γ-Ce_2S_3晶型最好;掺杂M~(3+)(M=Y~(3+),La~(3+))离子并没有改变硫化铈的立方晶体结构。Ce_(2-x）Y_xS_3包覆量小于10wt%时,此时云母表面未形成完整包覆层,当包覆量过高时,纳米粒子出现少量的团聚,增加了材料表面形貌粗糙度,因此选择包覆率为15wt%为最优方案。包覆率为15wt%时,包覆在云母表面的Ce_(2-x）Y_xS_3纳米粒子分布较为均匀,存在少量的大颗粒,形貌大致呈近球形。对于合成的mica/Ce_(2-x）Y_xS_3珠光颜料,抗氧化性能提高至500℃,拓宽其颜料的应用领域;包覆云母后,提高了硫化铈颜色的亮度,从而具有较好的颜色性能。随着M~(3+)(M=Y~(3+),La~(3+))离子掺杂浓度的增加,样品逐渐由暗红色变为亮红色再逐渐变为橙红色。纯的硫化铈的近红外太阳反射率值为77%,当包覆率为15wt.%,该复合粉体的近红外太阳反射率值达到93%左右,说明片状云母可以提高硫化铈的红外反射性能。对于合成的mica/Ce_(2-x）M_xS_3(M=Y~(3+),La~(3+))复合珠光颜料,具有较好的紫外吸收以及红外反射性能。因此,在防晒及隔热保温的冷颜料领域具有广阔的应用前景。研制的mica/Ce_(2-x）M_xS_3(M=Y~(3+),La~(3+))复合珠光颜料在紫外光的照耀测试下几乎无色差,说明具有较好的耐光性,可应用于室外建筑涂料中。
[Abstract]:Rare earth sulphide materials have been widely used in inorganic pigments, optical materials and thermoelectric materials due to their unique optical, electrical and magnetic properties. However, there are few studies on their near-infrared reflectivity. In this paper, pearlescent pigments were prepared by coating cerium sulphide on mica sheets, combining the special layered structure of mica and sulfur. The high reflective index of cerium sulfide can not only obtain high reflective and heat-insulating pigments with high infrared reflectivity, but also improve the brightness of cerium sulfide pigments. On the other hand, the high preparation temperature of traditional cerium sulfide nanoparticles has seriously affected the pigments'coloring properties, such as easy agglomeration of nanoparticles, and so on. Mica/Ce_2S_3 composites were prepared by sol-gel method combined with vulcanization method. Mica/Ce_ (2-x) Y_xS_3, Mica/Ce_ (2-x) La_xS_3 and Mica/Ce_ (2-x) La_xS_3 were doped with Y_ (3+) and La_ (3+) respectively. The samples were prepared by X-ray diffraction (XRD), thermal analysis (TG-DSC), scanning electron microscopy (SEM). The results show that the optimum curing temperature of mica/Ce_2S_3 is 850 C and the molar ratio of Na +/Ce~ (3 +) is 0.2. Mica/Ce_2S_3 composite pearlescent pigment has the best ultraviolet absorption property, color property and crystal form of gamma-Ce_2S_3; doping M~ (3+) (M=Y~ (3+), La~ (3+)) does not change the cubic crystal structure of cerium sulfide. When the coating content of Ce_ (2-x) Y_xS_3 is less than 10wt%, the mica surface does not form a complete coating, and when the coating amount is too high, nanoparticles appear. A small amount of agglomeration increases the surface roughness of the material, so the coating rate of 15wt% is the best scheme. When the coating rate is 15wt%, the Ce_ (2-x) Y_xS_3 nanoparticles coated on the mica surface distribute uniformly, there are a small number of large particles, and the morphology is approximately spherical. For the mica/Ce_ (2-x) Y_xS_3 pearlescent pigment, the oxidation resistance is good. With the increase of M ~ (3 +) (M = Y ~ (3 +), La ~ (3 +)) ion doping concentration, the samples gradually change from dark red to bright red and then to orange red. The results show that the flake mica can improve the infrared reflectivity of cerium sulfide. For mica/Ce_ (2-x) M_xS_3 (M=Y_ (3+), La_ (3+)) composite pearlescent pigments, it has better ultraviolet absorption and infrared reflectivity. The mica/Ce_ (2-x) M_xS_3 (M=Y_ (3+), La_ (3+)) composite pearlescent pigment has almost no chromatic aberration under ultraviolet irradiation test, indicating that it has good light resistance and can be used in outdoor architectural coatings.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ628.2

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