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1.
《Ceramics International》2017,43(16):13127-13132
In this study, we report highly transparent Er:Y2O3 ceramics (0–10 at% Er) fabricated by a vacuum sintering method using compound sintering additives of ZrO2 and La2O3. The transmittance, microstructure, thermal conductivity and mechanical properties of the Er:Y2O3 ceramics were evaluated. The in-line transmittance of all of the Er:Y2O3 ceramics (1.2 mm thick) exceeds 83% at 1100 nm and 81% at 600 nm. With an increase in the Er doping concentration from 0 to 10 at%, the average grain size, microhardness and fracture toughness remain nearly unchanged, while the thermal conductivity decreases slightly from 5.55 to 4.89 W/m K. A nearly homogeneous doping level of the laser activator Er up to 10 at% in macro-and nanoscale was measured along the radial direction from the center to the edge of a disk specimen, which is the prominent advantage of polycrystalline over single-crystal materials. Based on the finding of excellent optical and mechanical properties, the compound sintering additives of ZrO2 and La2O3 are demonstrated to be effective for the fabrication of transparent Y2O3 ceramics. These results may provide a guideline for the application of transparent Er:Y2O3 laser ceramics. 相似文献
2.
Lingling Jin Guohong Zhou Shunzo Shimai Jian Zhang Shiwei Wang 《Journal of the European Ceramic Society》2010,30(10):2139-2143
Commercial Y2O3 powder was used to fabricate highly transparent Y2O3 ceramics with the addition of ZrO2 via slip casting and vacuum sintering. The effects of ZrO2 addition on the transparency, grain size and lattice parameter of Y2O3 ceramics were studied. With addition of ZrO2 the transparency of Y2O3 ceramics increased markedly and the grain size of Y2O3 ceramics decreased markedly by cation diffusivity mechanism and the lattice parameter of Y2O3 ceramics slightly decreased. The highest transmittance (at wavelength 1100 nm) of the 5.0 mol% ZrO2–Y2O3 ceramic (1.0 mm thick) sintered at 1860 °C for 8 h reached 81.7%, very close to the theoretical value of Y2O3. 相似文献
3.
《Ceramics International》2016,42(7):8022-8029
This paper reports on the synthesis of uncoated and Eu2O3-coated spherical Y2O3 ceramic particles using optimized hydrothermal (HM) and microwave-assisted hydrothermal (MWHM) routes. The integration of microwave and hydrothermal processes was shown to enhance the reaction kinetics during the synthesis of uncoated Y2O3. Spherical particles of pure Y2O3 phase with an average particle size of 600 nm and uniform size distribution were obtained via the MWHM process at 180 °C following reaction duration of only 1 h. Y2O3 spherical particles were coated with Eu2O3 via a hydrolysis method at room temperature. The band gap of the resulting phosphors was estimated at 5.7 eV. Eu2O3-coated Y2O3 particles synthesized via the HM and MWHM present bright red PL emission under UV excitations; however, Y2O3 particles obtained via the MWHM method are more efficient than those yielded via the HM technique. Eu2O3-coated Y2O3 particles derived using the optimized MWHM technique present efficient emissions of red light with color purity and down conversion efficiency of approximately 85% and 80%, respectively. The present study demonstrates the suitability of employing coated phosphors in optical display technologies. 相似文献
4.
《Ceramics International》2015,41(7):8755-8760
0–0.7 at% Cr:Y2O3 transparent ceramics were prepared by vacuum sintering. The optimum in-line transmittance in the visible and near infrared region is 78%, and the Vickers hardness of the sintered 0.1 at% Cr:Y2O3 is 10.1 GPa, respectively. The mechanism of Cr-doped and the optical properties has been discussed. The results indicated that the Cr:Y2O3 transparent ceramic is a promising laser material with enhanced mechanical property. 相似文献
5.
V. N. Antsiferov I. G. Sevast'yanova V. I. Ovchinnikova P. P. Tereshina 《Refractories and Industrial Ceramics》1994,35(11):364-366
The influence of heat and laser treatment during the formation of the ultradisperse structure of composite powders of the ZrO2 - Y2O3 - Al2O3 system is investigated. The parameters of short-range order of amorphous powders in the process of heat and laser treatment are determined. The effect of surface modification of ultradisperse powders on the structure formation and phase composition of the ceramics is established.Translated from Ogneupory, No. 11, pp. 12 – 14, November, 1994. 相似文献
6.
Effect of milling ball size on the densification and optical properties of transparent Y2O3 ceramics
Hyeon-Myeong Oh Young-Jo Park Ha-Neul Kim Jae-Woong Ko Hyun-Kwuon Lee 《Ceramics International》2021,47(4):4681-4687
In this study, we report highly transparent Y2O3 ceramics fabricated by hot-pressing only at 1500 °C without a HIP treatment, featuring in-line transmittance levels of 77% and 84% at a wavelength of 400 and 1100 nm, respectively with the grain size suppressed to 710 nm. The effect of the ball size during the grinding of Y2O3 powders on the correlation between the thus-prepared Y2O3 powders and the optical properties of the hot-pressed samples is demonstrated for the first time. With a decrease in the diameter of the ZrO2 balls from 5 mm to 1 mm, the milling efficiency was enhanced and admirable transparency of Y2O3 was attained at a short milling time. However, several micron-sized pores remained in the transparent specimens prepared with 1 mm balls, originating from the inhomogeneously packed region of the green body. Finally, the 2 mm was found to be optimum for obtaining a fine-grained and pore-free microstructure with the best in-line transmittance of Y2O3 ceramics. 相似文献
7.
This paper investigates the effect of nano-size and micron-size Y2O3 powder-coated specimen on high-temperature oxidation resistance of low-alloy Cr–Mo steel (2.25 Cr-1 Mo steel). Both are powder coated by plasma spray coating method. The oxidation rate and reaction kinetics are studied and the post-corroded scales are characterized in Field Emission Scanning Electron Microscope and X-ray Diffraction. The results clearly indicate that nanosize Y2O3-coated (nanostructured) specimen improves the high-temperature oxidation resistance in comparison to the micron-size Y2O3-coated specimen. The detail mechanism of the oxidation of both the coated specimen is discussed in detail in this paper. 相似文献
8.
《Journal of the European Ceramic Society》2019,39(2-3):635-640
5 at.% Yb:Y2O3 transparent ceramics were fabricated using vacuum sintering plus HIP. The ceramics doped with 1 at.% ZrO2 as the sintering additive were densified at 1700 °C in vacuum followed by HIPing at 1775 °C, while those without sintering additives were densified at 1520 °C in vacuum followed by HIPing at 1450 °C. After sintering, both ceramics had relatively high in-line transmittance. However, during laser experiments, the ZrO2-doped Yb:Y2O3 (Zr-YbY) ceramics were photodarkened when irradiated by 940 nm pump light. The discoloration might be attributed to the formation of Zr3+ color centers during lasing. In contrast, no photodarkening effect was detected in the pure Yb:Y2O3 ceramics without sintering additives (P-YbY). The P-YbY ceramics exhibited much higher lasing efficiency (17%) than the Zr-YbY ceramics (9%). To our best knowledge, it is the first time that the photodarkening effect was detected in rare-earth doped sesquioxide laser ceramics. 相似文献
9.
Ultra-highly transparent ZrO2-doped Yb3+: Y2O3 ceramics were prepared by slip casting and vacuum pressureless sintering and the transmittance reached the highest value of 80.9% for the sample doped with 8.0 at% Yb3+. There are three main absorption peaks at 905, 950, and 976 nm, corresponding to the transition from the lowest level of field splitting of 2F7/2 crystal to every splitting energy levels of 2F5/2 crystal field. We analyzed the absorption and emission spectra of transparent Yb3+: Y2O3 from the energy level structure of Yb3+, and the transmission, absorption, and emission spectra were systematically studied. There are three main absorption peaks at 905, 950, and 976 nm and four emission peaks at 1076, 1031, 1013, and 977 nm, respectively. The emission peaks at 977 and 1013 nm broaden and vanish for 8.0 and 10.0 at% Yb3+-doped Y2O3, which may be related to the change of Y2O3 crystal field caused by high concentration. 相似文献
10.
《Ceramics International》2023,49(18):30240-30247
Al2O3/ZrO2(Y2O3) directionally solidified eutectic ceramics (DSECs) with different Y2O3 addition were prepared. Three polymorphs of ZrO2: m-ZrO2, t-ZrO2 and c-ZrO2 appeared and disappeared in order with the increase of Y2O3 addition, the effects of Y2O3 addition amount on the mass fraction of ZrO2 polymorphs were quantitatively analyzed. The gradual decrease of area fraction and average size of colony was attributed to the increase of constitutional undercooling region, the variation of interphase spacing in the colonies was explained via selection mechanism of dendrite tip. The maximum hardness and fracture toughness were 18.35 GPa and 8.55 MPa m1/2 obtained at 9 mol% and 3 mol% Y2O3 addition, respectively. The hardness was determined by the mass fraction of m-ZrO2 phase, the area fraction of intercolony and the residual compressive stress, and the toughening mechanisms were composed of microcrack toughening, t-m transformation toughening and residual stress toughening. 相似文献
11.
《Journal of the European Ceramic Society》2005,25(9):1581-1589
Ceramic laser stereolithography is a manufacturing process suitable candidate for the production of complex shape technical ceramics. The green ceramic is produced layer by layer through laser polymerisation of UV curable ceramic suspensions. A number of critical issues deserve attention: high solid loading and low viscosity of the suspensions, high UV reactivity, prevention of interlayer delamination in the green and in the sintered body, good mechanical performance. In this work, ZrO2 reinforced Al2O3 components have been obtained from an acrylic modified zircon loaded with alumina powders. The zircon compound is effective as organic photoactivated resin and allows the dispersion of a high volume fraction of Al2O3 powder (up to 50 vol.%) while keeping viscosity at reasonable low values. The zircon compound also represents a liquid ceramic precursor that converts to oxide after burning out of the binder. Thanks to the good dispersion of the alumina powder in the zircon acrylate, a uniform dispersion of ZrO2 submicron particles is obtained after pyrolysis. These are located at the grain boundaries between alumina grains. Formation of both monoclinic and tetragonal ZrO2 occurs as evidenced by XRD. No delamination occurs in bending tests as evidenced by SEM fractography, satisfactory modulus and strength values were concurrently found. 相似文献
12.
《Ceramics International》2021,47(20):28859-28865
Highly transparent polycrystalline Tm2O3 ceramics were successfully fabricated by vacuum sintering at temperatures from 1650 to 1850 °C for 8 h using commercial Tm2O3 and ZrO2 (1 at%) powders as starting materials. It is the first time that ZrO2 was reported as a sintering additive to prepare Tm2O3 transparent ceramics. The effects of sintering temperature on the optical transmittance and microstructure of Tm2O3 transparent ceramics were studied. The desired Tm2O3 ceramics with relative density of 99.8% and an average grain size of approximately 9.7 μm were obtained at 1800 °C and the in-line transmittance reached 75% at 880 nm and fluctuated around 80% from 2100 to 2400 nm, respectively. This study demonstrated that Tm2O3 transparent ceramics with higher in-line transmittance and smaller grain size could be prepared by using ZrO2 as sintering additive at a relatively lower vacuum sintering temperature compared to those already reported in open literatures. 相似文献
13.
《Ceramics International》2015,41(7):8481-8487
In this work Sm3+ (0–2.0 at%) and Bi3+ (0–2.0 at%) doped Y2O3 luminescent powders were prepared by a sol–gel method from yttrium acetylacetonate, samarium and bismuth nitrates as metal sources. The as prepared powders (chemical composition is close to stoichiometric Y2O3) present the cubic structure from 700 °C, and at 900 °C are characterized by the presence of rounded particles with heterogeneous size of 42.9 nm. Luminescent effect of ions of Sm3+ and Bi3+ into Y2O3 host as was studied on heat treated powders from 800 to 1100 °C. The combination of the red luminescence from the Sm3+ ions and the bluish from Bi3+, makes the synthesized phosphors candidates to be used in fabrication of phosphor-converted light-emitting diodes (LEDs). 相似文献
14.
《Ceramics International》2023,49(5):7236-7244
A method for preparation of dense Y2O3–MgO composite ceramics by the microwave sintering was developed. The initial powders were obtained by glycine-nitrate self-propagating high-temperature synthesis (SHS) with different oxidant-to-fuel ratio. Density and IR-transmission of microwave sintered Y2O3–MgO ceramics increase with respect to dispersity of the SHS-powders and reach its maximum values for the powder prepared in a 20% fuel excess. The sintering behavior of Y2O3–MgO compacts was investigated by optical dilatometry and measuring an electric conductivity upon heating. Significant microwave radiation power surges at temperatures of 900–1000 °C, caused by the decomposition of magnesium carbonate, have been found. As a result of matching the conditions for the synthesis of powders and sintering modes, a transmission of composite ceramics of 78% at a wavelength of 6 μm was achieved at a maximum processing temperature of 1500 °C. 相似文献
15.
Jian Zhang Liqiong An Min Liu Shunzo Shimai Shiwei Wang 《Journal of the European Ceramic Society》2009,29(2):305-309
Highly transparent Yb3+:Y2O3 ceramics with doping concentration up to 40.0 at.% had been fabricated successfully via hydrogen atmosphere sintering, where the raw powders were synthesized by co-precipitation method. The sintering temperature is about 600 °C lower than its melting temperature. SEM investigation revealed the average grain size of Yb3+:Y2O3 ceramics sintered at 1850 °C for 9 h was about 7 μm. The highest transmittance of as-prepared 1 mm thickness samples around wavelength of 1050 nm reached 80%, which is close to the theoretical value of Y2O3. The optical spectroscopic properties of Yb3+:Y2O3 transparent ceramics have also been investigated, which shows that it is a very good laser material for diode laser pumping and short pulse mode-locked laser. 相似文献
16.
V. S. Glazachev L. B. Borovkova E. S. Lukin 《Refractories and Industrial Ceramics》1978,19(3-4):175-179
Conclusions The degree of translucence of Y2O3 ceramics depends on the amount of additive, the grinding time of the components, and the calcination temperature of the powder. The influence of the technological factors is interrelated; upon them depends the fineness of the powder, the uniformity of the distribution of the additive, and the degree of synthesis of the solid solution.It was established that a poreless high-translucence ceramic can be produced with 6–10 mole % added HfO2 or ZrO2. An x-ray phase analysis was used to determine the lattice constant of the solid solution in the Y2O3-HfO2 and Y2O3-ZrO2 systems and the x-ray density of Y2O3 ceramics containing up to 20 mole % added HfO2 or ZrO2.Translated from Ogneupory, No. 3, pp. 44–48, March, 1978. 相似文献
17.
Min-sung Park Buyoung Kim Taewoo Kim Eunpyo Hong Heesoo Lee 《International Journal of Applied Ceramic Technology》2020,17(3):1224-1230
Lu2O3 and Y2O3 doping of 8, 11, and 18 mol% in ZrO2 were prepared by solid solution reaction, aiming to study the phase stabilization of Lu2O3-doped ZrO2 and Y2O3-doped ZrO2 in terms of phase formation and lattice distortion. The Rietveld refinement results indicated that Lu2O3-doped ZrO2 and Y2O3-doped ZrO2 followed the same trend in terms of cubic phase fraction, increasing from 25%–30% (8 mol%) to 95%–100% (11 and 18 mol%). This phase formation was confirmed by observing the same diffraction ring pattern observed for the Lu2O3-doped ZrO2 and Y2O3-doped ZrO2. The Vickers hardness of the Lu2O3-doped ZrO2 was 4.3% higher than that of Y2O3-doped ZrO2 at 8 mol%, but 9.7% and 14.8% lower at 11 and 18 mol%, respectively. This was likely caused by the lattice distortion effect of Y2O3 doping overpowering the field strength difference between Lu3+ and Y3+. 相似文献
18.
Shuixian Yang Jianmin Li Hao Guo Xiaojian Mao Run Tian Jian Zhang Shiwei Wang 《Journal of the American Ceramic Society》2021,104(9):4304-4308
In this study, highly transparent aluminate oxynitride (AlON) ceramics were prepared via the reactive sintering of Al2O3 and AlN powders using a Y2O3-MgAl2O4-H3BO3 ternary sintering additive. The ternary doping process resulted in the efficient preparation of transparent AlON ceramics with small grains and high transmittance as compared to the binary doping (Y2O3-MgAl2O4) process. The addition of 0.1 wt.% Y2O3-0.4 wt.% MgAl2O4-0.12 wt.% H3BO3 resulted in the formation of a 4-mm-thick AlON ceramic with high transmittance (81% at 600 nm) and low haze (3.46%). This is the best performance in terms of the thickness and transmittance reported for AlON transparent ceramics prepared by the reactive sintering method. 相似文献
19.
Li-Xiang Wu Lin-Lin Zhu Yang You Rui-Lin Lin Qing-Qing Liu Wei-Ming Guo Hua-Tay Lin Kevin Paul Plucknett 《Ceramics International》2021,47(1):935-942
Dense pressure-sintered reaction-bonded Si3N4 (PSRBSN) ceramics were obtained by a hot-press sintering method. Precursor Si powders were prepared with Eu2O3–MgO–Y2O3 sintering additive. The addition of Eu2O3–MgO–Y2O3 was shown to promote full nitridation of the Si powder. The nitrided Si3N4 particles had an equiaxial morphology, without whisker formation, after the Si powders doped with Eu2O3–MgO–Y2O3 were nitrided at 1400 °C for 2 h. After hot pressing, the relative density, Vickers hardness, flexural strength, and fracture toughness of the PSRBSN ceramics, with 5 wt% Eu2O3 doping, were 98.3 ± 0.2%, 17.8 ± 0.8 GPa, 697.0 ± 67.0 MPa, and 7.3 ± 0.3 MPa m1/2, respectively. The thermal conductivity was 73.6 ± 0.2 W m?1 K?1, significantly higher than the counterpart without Eu2O3 doping, or with ZrO2 doping by conventional methods. 相似文献
20.
High transparency Nd: Y2O3 ceramics were prepared by vacuum sintering with La2O3 and ZrO2 sintering additives. The optimum in‐line transmittance of the sintered Nd: Y2O3 is 80.98% at the wavelength of 1100 nm, for which the content of La2O3 and ZrO2 are 10.0 and 3.0 at.%, respectively. This specimen demonstrates homogeneous microstructure with the average grain size of 8.3 μm. The mechanism of sintering with La2O3 and ZrO2 aids and the optical properties was discussed. The absorption, emission cross section, and fluorescence lifetime have been estimated as 1.62 × 10?20 cm2, 5.13 × 10?20 cm2, and 232 μs, respectively. Vickers hardness and the fracture toughness were measured of 9.18 GPa and 1.03 Mpa·m1/2, respectively. All the results indicate that Nd: Y2O3 transparent ceramic is a promising candidate for laser material. 相似文献