二氧化硅包裹铋基黄色料的制备及其稳定性

采用沉淀法合成了主要成分为Bi_0.82V_0.45Mo_0.55O₄和Na_0.5Bi_0.5(MoO₄)的铋基黄色料,再用水解法对色料进行SiO₂包裹,制得了一系列耐酸性和耐温性均有较大幅度提高的包裹型色料。 采用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线荧光光谱(XRF)、傅里叶变换红外光谱(FT-IR)等技术对色料进行了表征。 研究结果表明,在V(H₂O):V(TEOS)=1:18、摩尔比n(Si)/n(Bi)=4、反应温度T_b为45 ℃、滴加水的速度v_d≤0.3 mL/min的条件下,可获得厚度为100 nm左右、均匀致密的二氧化硅包裹层,且包裹色料呈鲜艳明亮的绿相黄,其色度参数L^*、a^*和b^*值分别为78.85、-6.85和71.63;该条件下所得包裹色料的耐酸性和耐温性最佳,色料浸泡于1 mol/L的盐酸中30 min损失量由未包裹色料的100%降至28.25%,耐温性由未包裹色料的600 ℃提升到860 ℃。

Preparation and Stability of Silica Coated Bismuth-Based Yellow Pigments

Silica coated bismuth-based yellow pigments with better acid resistance and temperature stability were successfully prepared by hydrolysis method using Bi_0.82V_0.45Mo_0.55O₄ and Na_0.5Bi_0.5(MoO₄) prepared by precipitation method. The as-obtained pigments were characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), X-ray fluorescence spectrometer(XRF) and Fourier transform infrared spectroscopy(FT-IR). The results showed that compact and uniform amorphous SiO₂·xH₂O coating layers with the thickness of around 100 nm were obtained under the volume ratio of H₂O to TEOS was 18, the ratio of n(Si)/n(Bi) was 4, T_b was 45 ℃, and v_d≤0.3 mL/min. The coated pigments showed the nature of bright yellow, and the values of L^*, a^* and b^* were 78.85, -6.85 and 71.63, respectively. Compared with the uncoated pigments, the acid mass loss of coated pigments under the most optimized condition, after half an hour immersion in 1 mol/L hydrochloric acid, declined from 100% to 28.25% and the tolerable temperature was improved from 600 ℃ to 860 ℃.