Inorganic yellow-red pigments without toxic metals
Inorganic yellow-red pigments without toxic metals
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DOI：
10.1038/35010082
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发表时间：
2000-04-27
期刊：
影响因子：
64.8
通讯作者：
Letschert, HP
中科院分区：
文献类型：
--
作者：
Jansen, M;Letschert, HP
无机颜料自古以来就被人类所利用(1)，在加工或应用过程中，无机颜料仍被广泛用于给高温下的材料着色(2)。事实上，在玻璃、釉料和陶瓷的情况下，没有替代无机颜料着色。然而，大多数无机颜料含有重金属或过渡金属，如果超过临界水平，就会对环境和人体健康产生不利影响。镉基颜料尤其令人担忧(3)：虽然这些颜料由于在水和稀释的无机酸中的溶解度极低而无毒，但镉本身是有毒的，并且可以通过废物处理场和焚烧厂以生物可利用的形式进入环境(4)。这导致了基于预防原则的法规严格限制镉颜料的使用(5)。尽管最近的评估（20,21）已经得出结论，对人类或环境的风险可能没有最初担心的那么大，但对本质上更安全的替代品的强烈需求仍然存在。在这里，我们证明了钙钛矿CaTaO2N和LaTaON2的固溶体构成了这种替代品的有希望的候选者：它们的亮度、着色强度、不透明度、分散性、耐光性和热稳定性可与镉颜料相媲美，而它们的颜色可以通过简单的成分调整来调整到所需的范围，从黄色到橙色再到深红色。由于所有的组成元素都是无害的，这种基于钙钛矿的无机颜料系统似乎是一种很有前途的替代品，可以消除镉排放到环境中的来源之一，并消除对颜料安全性的一些剩余担忧。
Inorganic pigments have been utilized by mankind since ancient times(1), and are still widely used to colour materials exposed to elevated temperatures during processing or application(2). Indeed, in the case of glasses, glazes and ceramics, there is no alternative to inorganic pigments for colouring. However, most inorganic pigments contain heavy metals or transition metals that can adversely effect the environment and human health if critical levels are exceeded. Cadmium-based pigments in particular are a cause of concern(3) : although the pigments are not toxic due to their very low solubility in water and dilute mineral acids, cadmium itself is toxic and can enter the environment in a bioavailable form through waste-disposal sites and incineration plants(4). This has led to regulations, based on the precautionary principle, that strongly restrict the use of cadmium pigments(5). And even though recent assessments(20,21) have concluded that the risk to humans or the environment might be not as significant as originally feared, a strong demand for inherently safer substitutes remains. Here we demonstrate that solid solutions of the perovskites CaTaO2N and LaTaON2 constitute promising candidates for such substitutes: their brilliance, tinting strength, opacity, dispersability, light-fastness and heat stability rival that of the cadmium pigments, while their colour can be tuned through the desired range, from yellow through orange to deep red, by simple composition adjustments. Because all the constituent elements are harmless, this perovskite-based inorganic pigment system seems a promising replacement that could eliminate one of the sources for cadmium emissions to the environment and some of the remaining concerns about pigment safety.