铁离子掺杂对铜铬黑颜料呈色性能的影响

Effect of Fe^(3+) Doping on the Color Performance of CuCr_(2)O_(4) Black Pigment

为改善CuCr_(2)O_(4)黑色颜料呈色性能,将Fe^(3+)掺杂进入CuCr_(2)O_(4)晶体中,采用共沉淀法制备CuCr_(2-x)Fe_(x)O_(4)(x=0,0.04,0.05,0.06,0.07),并对所制备样品进行TG-DTA、XRD、SEM、Raman、XPS、UV-Vis吸收光谱和色度值的测试与表征。结果表明,Fe以三价态固溶进入Cr3+位置,未出现杂质相,得到的CuCr_(2-x)Fe_(x)O_(4)晶粒细小、分散均匀。Fe^(3+)掺杂可减小CuCr_(2)O_(4)的禁带宽度,从1.25 eV减小到1.08 eV,禁带宽度的减小是由于2p(O^(2-))→3d(Fe^(3+))和Fe^(3+)的d-d(^(6)A_(1g)→^(4)T_(1g)和^(6)A_(1g)→^(4)T_(2g))电荷跃迁引起的。禁带宽度的减小使得黑色颜料对可见光(380~780 nm)的吸收率提高,L^(*)值减小,呈现出良好的黑度。得到的最佳黑色颜料为CuCr_(1.95)Fe_(0.05)O_(4),L^(*)=17.63,a^(*)=-0.77,b^(*)=-1.61。

In order to improve the color performance of CuCr_(2)O_(4) black pigment,CuCr_(2-x)Fe_(x)O_(4)(x=0,0.04,0.05,0.06,0.07)were prepared by co-precipitation method.The samples were characterized by TG-DTA,XRD,SEM,Raman,XPS,UV-Vis and chromaticity values.The results show that the substitution of Fe^(3+)for Cr3+in CuCr_(2)O_(4),and the valence state of Fe is trivalent.There are no impurity phases.The CuCr_(2-x)Fe_(x)O_(4) has well-defined spinel structure,fine grain and good dispersion.The Fe^(3+)substitution decreases the band gap of pigments from 1.25 eV to 1.08 eV,attributes to 2 p(O^(2-))→3 d(Fe^(3+))charge transform and d-d(^(6)A_(1g)→^(4)T_(1g),^(6)A_(1g)→^(4)T_(2g))charge transform in Fe^(3+),which increases absorption in visible light(380 nm to 780 nm),decrease L^(*)value and shows good blackness.The CuCr_(1.95)Fe_(0.05)O_(4) has the optimal chromaticity values which are L^(*)=17.63,a^(*)=-0.77,b^(*)=-1.61.