| Ceramic decoration technology gets through the screen printing and rotary screen printing times, now enters the era of ink-jet printing. As the third revolution of ceramic decorative technology, ceramic ink-jet printing has incomparable advantages compared with the other printing technology, and has produced huge influence for decoration of ceramic. For ceramic ink-jet printing had attract much attention, in recent years, universities and enterprises had many research papers and patents, many enterprises in the domestic also had their own brands of ceramic ink. The industrial production of ceramic ink which has been most used is the dispersion method, inorganic ceramic pigment and solvent、scattered agent are mixed, they are ultra-fine grinding and dispersing by sand mill, eventually to get a stable suspension. The process is very simple, however, to guarantee the stability of ceramic ink, the inorganic ceramic pigment has to ultra-fine crush to the sub micron level, general speaking, the maximum particle diameter D100 of pigment less than 1μm, and the median D50 is between 200 and 500 nm. At present, praseodymium doped zircon yellow pigment has been mainly used to make yellow ceramic ink, Pr-doped zircon yellow pigment in traditional is mainly used for glaze and blank without superfine pulverization, and the color is also good, after grinding with sand mill, the color is greatly reduced, and can not match the requirement of the color for the people, it is urgent to develop a shining color which has the stronger ability to display, in order to meet the preparation of ceramic ink which has to be crushed hardly.In order to improve the tone of Pr-doped zircon yellow pigments in the ceramic ink, in this paper, the color mechanism of the Pr-doped zircon yellow pigments has been first considered, the content of the Pr element in zircon crystal may be the major factor, and then the production factors have been considered, the amount of Pr6O11、firing system、the amount of mineralizer and the activity of ZrO2 powder are the main production factors, with adjusting the composition of the system and the production process, it can be improving the content of Pr element in zircon crystal, so as to improve the color of Pr-doped zircon yellow pigment. The innovation of this paper is to analyze the influence of various factors on the content of Pr element in ZrSiO4 crystals and its relationship with the tone of Pr-doped zircon pigment, otherwise, the amount of mineralizer and the pretreatment of ZrO2 are the factors that have been discussed in the first time. In this paper, the synthesis of Pr-doped zircon yellow pigment is in solid phase process, solid phase synthesis process is easy to operate and has high efficiency, it is the main method for industrial production.In this paper, the amount of praseodymium oxide(Pr6O11) has been explored in the gradient research, to make clear the influence of the amount of Pr6O11 on the structure of zircon crystals. The experimental results show that: With the amount of Pr6O11 increases, the content of Pr element in zircon crystal also gradually increases, it result the yellow tone of pigment increasing too; When the amount of Pr6O11 reaches a certain value（Pr/Zr=0.06）, the content of Pr element in zircon crystal changes a little, the yellow tone of pigment is not significant affected by the change of the amount of Pr6O11, it indicates that the solid solubility of Pr element in zircon crystal is in the certain extent; When the Pr6O11 concentration is excessive, it will lead the Pr element to enrichment outside the pigment.The firing temperature and holding time were studied by the gradient research, to explore the effects of firing system on the tone of Pr-doped zircon yellow pigment and the crystal structure of zircon, and then optimize the firing system. The experimental results show that: When Pr-doped zircon yellow pigment is fine cooked, 880℃ is closed to the lowest firing temperature, and with the firing temperature raising, the solid solubility of Pr element in zircon crystal and the yellow tone of Pr-doped zircon yellow pigment are decreasing gradually, it indicates that the 880℃is the best firing temperature; The yellowness value of Pr-doped zircon yellow pigment will get to the peak when the holding time reaches 6 hours, when the holding time gets too short or too long, it will decline the content of Pr element in zircon crystal and the tone of pigment, so 6 hours is the best soaking time; High firing temperature and long holding time will result uneven distribution of Pr element.The gradient amount of mineralizer BaF2 and KCl has been investigated. The experimental results show that: The advisable amount of mineralizer will be helpful for the synthesis of zircon crystals, it is conducive to synthetic good quality Pr-doped zircon yellow pigment; When the amount of mineralizer increases, it will inhibit Pr element to getting in zircon crystal, also decrease the yellow value of Pr-doped zircon yellow pigment, and the effect of the amount of mineralizer BaF2 and KCl on inhibiting Pr element to getting in zircon crystal is considerably.After ball milling for ZrO2 powder, the experiments were conducted to explore the effects of ZrO2 powder milling processing on the activity of ZrO2 powder and the yellow tone of Pr-doped zircon yellow pigment. The experimental results show that: With the time of ZrO2 powder milling increases, the activity of ZrO2 powder will be improved, and it is helpful to improve the yellow value of pigment; When the activity of ZrO2 powder improves, it will increase the carrying capacity of zircon crystal for Pr element; When ZrO2 powder milling time is too long, zircon crystal will be abnormal growing, and it will decrease the carrying capacity of zircon crystal.Above all, the discussions show that: When Pr-doped zircon pigment is synthesized in traditional ceramic procedure, the amount of Pr6O11 will be optimal when the molar ratio Pr/Zr gets 0.06, the excess of Pr6O11 will be useless for improving the tone of pigment; Low temperature will be helpful for improving the yellow tone of pigment when the synthesis is complete, and 880℃ can be the optimum firing temperature. Zircon crystal will grow perfectly if holding time is suitable, and the Pr element will dissolve in the crystal mostly without enrichment, and 6 hours may be the optimal holding time. An appropriate amount of mineralizer can ensure the quality of the tone of Pr-doped zircon pigment, when the pigment is fine cooked, the amount of mineralizer should be minimal. The addition of the activity of raw material ZrO2 can increase the content of Pr ions in zircon crystals, and it will be helpful for the tone of pigment too, therefore, it is a effective way to get high-quality Pr-doped zircon pigment by select and pretreat the raw material ZrO2 preferably. |
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