How to improve Zr-Pr yellow
In the early years, zirconium - praseodymium pigments often have a brown tone. To the late 50s, people finally developed a bright yellow zircon color, namely zirconium praseodymium yellow (Pr-Si-Zr).
In 1952, a Japanese scholars developed a lemon yellow zirconite base color under high temperature synthesis by adding rare earth mixture with praseodymium to zirconium dioxide and silicon dioxide.Four years later, we finally developed the zirconite yellow color which was synthesized by adding NaCl and Na2MoO4 as the chemical agent in the above components.This study also showed that the rare earth metal praseodymium oxide could be used to synthesize bright lemon yellow zirconium base color.Lanthanum oxide and cerium oxide darken the color, while rubidium oxide has an absorption peak at 580nm, which changes the yellow color.Adding a certain amount of alkali metal oxide, fluoride or bromide as oxidant can reduce the synthesis temperature and greatly enhance the colorimetry.
Like the vanadium zirconium blue material, the main crystalline phase after the color is fired is zirconite.Zircon - praseodymium yellow has a bright yellow color, and its tone is not sensitive to the ratio of ZrO2 and SiO2. And the addition amount of praseodymium oxide is limited, not more than 5%.
Compared with other high temperature ceramic yellow color, zirconium praseodymium yellow color is more clear and bright.They have neither the reddish gray of tin vanadium yellow nor the yellowish brown of zirconium yellow.The spectral reflectance curve of the colouring material indicates that the maximum reflectance is at 560nm.And the change of reflectance of color in the red and green wavelength range is much smaller than that in the long yellow wavelength region.At the same time, zirconium praseodymium yellow has a very wide application temperature.Zirconium praseodymium yellow has been widely used as glaze color. The operating temperature range is SK06 cone to SK12 cone (980~1350℃).
Zircon series of color has very good mutual miscibility.It can be widely used to match harmonic color.If the vanadium zirconium blue and zirconium praseodymium yellow are mixed in a certain proportion to made green color, it appears very bright green in the glaze.The colored ions in zirconite pigments enter the ZrSiO4 lattice during the formation of ZrSiO4 between Zr02 and SiO2 under the action of mineralizer.
