Tetragonal zirconia (T-ZrO2) ceramic nanopowders stabilized with 3 mol% Y2O3 were synthesized via polyacrylamide gel method, using ZrOCl2?8H2O and Y(NO3)3?6H2O as raw materials. The effect of temperature on phase comp...Tetragonal zirconia (T-ZrO2) ceramic nanopowders stabilized with 3 mol% Y2O3 were synthesized via polyacrylamide gel method, using ZrOCl2?8H2O and Y(NO3)3?6H2O as raw materials. The effect of temperature on phase composition and morphology of YSZ nanopowders and sintering behavior of YSZ ceramics was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers hardness tester. The aging-resistance of YSZ ceramics was measured by means of aging experiments. The results demonstrated that the phase composition of YSZ ceramic nanopowders had no obvious change and it was composed of T-ZrO2. Particle size of well-dispersed YSZ ceramic nanopowders increased from 17 to 35 nm with increasing calcining temperature from 600 to 800 ℃. There was noticeable negative correlation between calcining temperature and the relative density of YSZ ceramic at the same sintering temperature. The aging experiments showed that water vapor facilitated tetragonal to monoclinic phase transformation, and the sample that had smaller grain size exhibited better aging-resistance. It can be concluded that when the calcining temperature is 600 ℃ and sintering temperature is 1550 ℃, the relative density and hardness of YSZ ceramic arrive at the peak of 96.64% and 11.135 GPa respectively, and it has less microcracks and excellent aging-resistance.展开更多
The harm of organic polluted wastewater to the environment has been paid more and more attention by the major scientific and technological countries in the world. The development of semiconductor green technology driv...The harm of organic polluted wastewater to the environment has been paid more and more attention by the major scientific and technological countries in the world. The development of semiconductor green technology driven by light energy can effectively control the pollution of organic wastewater to the environment. In order to overcome the disadvantages of aluminate based photocatalyst as a new type of semiconductor photocatalyst for the low efficiency of charge carrier separation and low utilization of sunlight caused by its high energy band value, researchers have carried out in-depth research on it based on the theory of energy band arrangement. In this paper, a variety of methods to enhance the photocatalytic activity of aluminate based photocatalysts were reviewed, and the effects of different processes on the photocatalytic activity of aluminate based photocatalysts were compared. Through the advanced preparation technology, special heterojunction aluminate based photocatalyst can effectively enhance the photocatalytic activity of single component aluminate photocatalyst. The development trend and corresponding photocatalytic mechanism of spinel M (M=Mg, Sr, Ba) aluminate and aluminate based photocatalysts synthesized by polyacrylamide gel method are emphasized, it will provide reference for the industrial application and development of aluminate based photocatalysts in the future.展开更多
基金Funded by the National Natural Science Foundation of China(No.51964035)the Natural Science Foundation of Inner Mongolia Autonomous Region(No.2019MS0520)。
文摘Tetragonal zirconia (T-ZrO2) ceramic nanopowders stabilized with 3 mol% Y2O3 were synthesized via polyacrylamide gel method, using ZrOCl2?8H2O and Y(NO3)3?6H2O as raw materials. The effect of temperature on phase composition and morphology of YSZ nanopowders and sintering behavior of YSZ ceramics was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers hardness tester. The aging-resistance of YSZ ceramics was measured by means of aging experiments. The results demonstrated that the phase composition of YSZ ceramic nanopowders had no obvious change and it was composed of T-ZrO2. Particle size of well-dispersed YSZ ceramic nanopowders increased from 17 to 35 nm with increasing calcining temperature from 600 to 800 ℃. There was noticeable negative correlation between calcining temperature and the relative density of YSZ ceramic at the same sintering temperature. The aging experiments showed that water vapor facilitated tetragonal to monoclinic phase transformation, and the sample that had smaller grain size exhibited better aging-resistance. It can be concluded that when the calcining temperature is 600 ℃ and sintering temperature is 1550 ℃, the relative density and hardness of YSZ ceramic arrive at the peak of 96.64% and 11.135 GPa respectively, and it has less microcracks and excellent aging-resistance.
文摘The harm of organic polluted wastewater to the environment has been paid more and more attention by the major scientific and technological countries in the world. The development of semiconductor green technology driven by light energy can effectively control the pollution of organic wastewater to the environment. In order to overcome the disadvantages of aluminate based photocatalyst as a new type of semiconductor photocatalyst for the low efficiency of charge carrier separation and low utilization of sunlight caused by its high energy band value, researchers have carried out in-depth research on it based on the theory of energy band arrangement. In this paper, a variety of methods to enhance the photocatalytic activity of aluminate based photocatalysts were reviewed, and the effects of different processes on the photocatalytic activity of aluminate based photocatalysts were compared. Through the advanced preparation technology, special heterojunction aluminate based photocatalyst can effectively enhance the photocatalytic activity of single component aluminate photocatalyst. The development trend and corresponding photocatalytic mechanism of spinel M (M=Mg, Sr, Ba) aluminate and aluminate based photocatalysts synthesized by polyacrylamide gel method are emphasized, it will provide reference for the industrial application and development of aluminate based photocatalysts in the future.
