稀土在陶瓷材料中的应用

介绍了稀土元素的原子结构和化学特性，较详细地论述了稀土元素SiC、Si3N4、Al2O3、AlN、ZrO2、Y2O3等结构陶瓷以及功能陶瓷和陶瓷色釉料中的应用。     

稀土元素的发色原理及在陶瓷颜料中的应用

根据稀土元素的原子结构特点和光谱特性,分析了稀土元素发色、助色、稳色的原理,以及稀土元素在陶瓷颜料中的应用.     

稀土元素在陶瓷中的应用

从稀土元素的原子结构和化学特性出发,介绍了稀土元素的应用领域,阐述了稀土元素在陶瓷色釉料、各种氧化物陶瓷和非氧化物陶瓷中的应用.     

稀土元素在玻璃陶瓷中的应用

针对我国稀土资源得天独厚的现状，通过对稀土元素电子构型、光谱特征的分析研究，阐述了稀土元素在玻璃陶瓷中的应用以及着色、助色等机理，对陶瓷颜料开发，新型颜料研制，玻璃着色、脱色等具有重要的指导意义。     

几种典型的低介硅酸盐微波陶瓷材料的研究现状

概述了MgO-SiO2,Zn2SiO4,CaSiO3和Re2O3-SiO2(Re=稀土元素)等低介电常数硅酸盐微波陶瓷材料体系的研究进展.讨论了微波介质陶瓷的结构、微波介电性能、降温方法、机理及其存在的问题,指出了微波陶瓷材料今后的研究方向.     

方镁石陶瓷的制备及其结构与性能研究

本文主要介绍方镁石陶瓷制备，以及研究不同稀土元素氧化物添加物对方镁石陶瓷烧结过程及结构和性能影响，从而为实际生产方镁石陶瓷制订工艺参数提供依据。     

稀土氧化物在陶瓷中的应用

针对我国稀土资源得天独厚的现状，从稀土元素的原子结构和化学特性出发，简略介绍了稀土的应用领域，较详细地阐述了稀土在陶瓷色釉料、功能陶瓷、各种氧化物陶瓷和非氧化物陶瓷中的应用。     

钇补强颗粒弥散陶瓷复合材料增韧机制的微观结构表征

在Al2O3/（W,Ti）C陶瓷复合材料中适量添加稀土元素钇能显著提高其断裂韧性。本文运用SEM与TEM技术,从微观结构的角度探讨了其增韧机制。表明,由于稀土钇的添加,使材料内部形成不同程度的强弱界面,它们与扩展中的裂纹相互作用,使得裂纹桥联、裂纹分支、裂纹偏转以及微裂纹增韧机制得到明显增加和加强,从而以多种增韧机制及其协同作用共同提高稀土补强Al2O3/（W,Ti）C陶瓷复合材料的断裂韧性。     

稀土元素的发色特性及其在陶瓷色釉料中的应用

主要介绍了稀土元素的特殊原子结构,发色特性以及其在陶瓷色釉料中作为发色剂、助色剂、稳色剂、变色剂和发光剂的应用。     

请问稀土元素在陶瓷中有哪些应用?

答：稀土元素作为稳定剂、烧结助剂加入到不同的陶瓷中，可以极大地提高和改善某些结构陶瓷的强度、韧性，降低其烧结温度，从而降低生产成本。同时稀土元素在半导体气敏元件、微波介质、压电陶瓷等功能陶瓷中也起到了非常重要的作用。     

稀土氧化物在（Ba,Sr）TiO3基陶瓷材料中的应用

综述了稀土氧化物在各种作用的（Ba,Sr)TiO3基陶瓷中的掺杂改性和应用现状，详细讨论了稀土氧化物掺骠改性作用机理，分析了该领域应用研究的发展方向。为稀土氧化物掺杂改性（Ba,Sr)TiO3基陶瓷提供理论依据。     

添加剂对ZrO_2-MgO系湿敏陶瓷湿阻性能的影响

本文研究了ZrO_2-MgO系湿敏陶瓷Zr/Mg比及添加剂对其湿阻性能的影响,摸索了有关配方和工艺。实验结果表明,提高Zr/Mg比,并引入某些M_2O_3(M为三价金属元素)外加剂对湿阻性能有利,但低温下元件的阻值仍较高。进一步添加外加剂如Li_2CO_3,可使湿阻性能得到改善。     

Preparation and characterization of transparent magneto-optical Ho2O3 ceramics

Transparent magneto-optical Ho₂O₃ ceramics were successfully prepared with an in-line transmittance of ~73% at the wavelength of 1000 nm (~90% of the theoretical transmittance of Ho₂O₃ single crystal) and an average grain size of ~28 μm. The ceramics were fabricated using sulfate-exchanged nitrate-type layered rare-earth hydroxide as the precipitation precursor at a relatively low sintering temperature of 1700°C. The layered compound exhibited nanosheet morphology and fully collapsed into a round oxide powder with an average particle size of ~48 nm by pyrolysis. Calcination temperature for Ho₂O₃ powder significantly affected the optical quality of the sintered body and the optimum calcination temperature was found to be 1050°C. The transparent magneto-optical Ho₂O₃ ceramics displayed wavelength-dependent Verdet constants of −180, −46, and −20 rad/Tm at 632, 1064, and 1550 nm, respectively. Thus, the Ho₂O₃ ceramics show good potential for applications in high-power laser systems.     

纳米陶瓷材料及其制备与应用

由于硬度高、耐高温、耐磨损、质量轻和导热性好，陶瓷材料是现代工业三大基本材料之一，但其脆性大、韧性小而限制了在一些特殊领域的应用。纳米材料及技术运用到陶瓷材料中极大地改善了它的应用性能。本文比较了传统陶瓷与纳米陶瓷的优缺点，介绍了纳米陶瓷材料材料的特性和种类，以及制备方法、应用和国内研究现状。     

Rare-earth high-entropy aluminate-toughened-zirconate dual-phase composite ceramics for advanced thermal barrier coatings

Superb toughening is achieved by incorporating a secondary ferroelastic phase in high-entropy rare-earth zirconate 5RE₂Zr₂O₇ (HZ). Here, we report an enhancement of 64% in fracture toughness through the addition of 30mol% high-entropy rare-earth aluminate 5REAlO₃ (HA) to the HZ matrix (30HA). The aforementioned rare-earth elements RE are La, Sm, Eu, Gd, and Yb. The present dual-phase composite ceramic 30HA has a large fracture toughness of 2.77 ± 0.14 MPa m^1/2, along with excellent high-temperature phase stability, resulting in good usage for potential thermal barrier coating applications. Particularly, the fracture toughness of the dual-phase composite ceramics at first increases to a maximum and then drops suddenly, as the mole fraction of HA increases from 0 to 50%. A clear definition of fitting parameters and their physical significance is provided for a better interpretation of the experimental data. The present toughening mechanism sheds light on microstructure engineering in high-entropy ceramics for excellent mechanical properties.     

Effect of rare-earth oxide additives on transparency and fluorescence of α-SiAlON ceramics

Recently, novel transparent and fluorescent materials are in demand for various optical applications such as lasers, scintillators, and solid-state lighting. α-SiAlON, which has excellent thermal and mechanical properties, also exhibits photoluminescence depending on the stabilized doped rare-earth ions. Its transparency and fluorescence depend on the rare-earth oxide added as a raw material, particularly in conventional powder processing. In this study, we fabricated α-SiAlON ceramics by adding various rare-earth oxides to elucidate their effects on the transparency and fluorescence of these ceramics. High-transparency α-SiAlON ceramics were fabricated by adding rare-earth oxides whose rare-earth ions have small ionic radii: Y₂O₃, Ho₂O₃, Er₂O₃, Tm₂O₃, Yb₂O₃, and Lu₂O₃. Because the fraction of α-SiAlON was high, the relative density was high, and the microstructure was composed of fine grains. In particular, α-SiAlON ceramics prepared by adding Ho₂O₃ showed lower light scattering than the other fabricated α-SiAlON ceramics because of the smaller α-SiAlON grains, resulting in higher in-line transmittance (48% at 600 nm). Furthermore, these transparent α-SiAlON ceramics exhibited fluorescence corresponding to the activated rare-earth ions: Ho³⁺, Er³⁺, Tm³⁺, and Yb³⁺ or Yb²⁺.     

Photochromic effect of transparent lead-free ferroelectric KSr2Nb5O15 ceramics

Transparent KSr₂Nb₅O₁₅ (KSN) lead-free ferroelectric ceramics have been synthesized via modified pressureless sintering method. A significant photochromic effect was observed for the transparent KSN ceramics prepared without rare-earth dopant modification. The piezoelectric properties depend on the grain orientations were investigated. The optical transmittance of the KSN ceramics is greater than 40% in the wavelength range of 530–800 nm. After NUV irradiation, the absorbance was enhanced by more than 40% in a broad visible range (more than 79%). The absorbance returned to the initial value after a thermal bleaching process. The results of the cycling tests and response experiments showed the stability and saturation of the photochromic effect. In addition, the possible photochromic mechanism of the KSN ceramics is discussed and the photochromic centers are identified. This transparent KSN ceramics exhibits an obvious photochromic effect and is a potential candidate materials for optical data storage and information recording applications.     

Distribution of Nd3+ ions in oxyfluoride glass ceramics

It has been an open question whether Nd³⁺ ions are incorporated into the crystalline phase in oxyfluoride glass ceramics or not. Moreover, relative research has indicated that spectra characters display minor differences between before and after heat treatment in oxyfluoride glass compared to similar Er³⁺-, Yb³⁺-, Tm³⁺-, Eu³⁺-, etc.-doped materials. Here, we have studied the distribution of Nd³⁺ ions in oxyfluoride glass ceramics by X-ray diffraction quantitative analysis and found that almost none of the Nd³⁺ ions can be incorporated into the crystalline phase. In order to confirm the rationality of the process, the conventional mathematical calculation and energy-dispersive spectrometry line scanning are employed, which show good consistency. The distribution of Nd³⁺ ions in oxyfluoride glass ceramics reported here is significant for further optical investigations and applications of rare-earth doped oxyfluoride glass ceramics.     

Photoluminescence properties of rare-earth ion-doped Na5YSi4O12-based glass ceramics

We developed herein photoluminescent glass ceramics based on rare-earth ion-doped Na₅YSi₄O₁₂-type materials according to the Na_3+3xY_1?x?yR_ySi₃O₉ (R: Sm³⁺, Eu³⁺, Dy³⁺, Tb³⁺) composition. Glass ceramics generally have the advantages of excellent chemical durability, heat resistance, and moldability over sintered ceramics. Upon irradiation with near-ultraviolet light, Sm³⁺-, Eu³⁺-, Dy³⁺-, and Tb³⁺-doped glass ceramics emit purplish orange, reddish orange, yellow, and green lights, respectively. The photoluminescent emission intensity of glass ceramics is higher than that of the original glasses, and the emission intensity depends on the crystalline phase. The highest emission intensity of various rare-earth ion-doped glass ceramics is obtained when the parameter y is equal to 0.03, 0.16, and 0.02 for the Sm³⁺-, Eu³⁺-, and Dy³⁺-doped glass ceramic samples, respectively. The internal quantum efficiency is 3%, 37%, 7% and 23% for the Sm³⁺-, Eu³⁺-, Dy³⁺-, and Tb³⁺-doped samples, respectively. Thus the Na superionic conducting Na₅YSi₄O₁₂-type glass-ceramics were proved to have potentiality as novel phosphors.     

Oxidation Behavior of Liquid-Phase Sintered Silicon Carbide with Aluminum Nitride and Rare-Earth Oxides (Re2O3, where Re = Y, Er, Yb)

Silicon carbide (SiC) ceramics have been fabricated by hot-pressing and subsequent annealing under pressure with aluminum nitride (AlN) and rare-earth oxides (Y₂O₃, Er₂O₃, and Yb₂O₃) as sintering additives. The oxidation behavior of the SiC ceramics in air was characterized and compared with that of the SiC ceramics with yttrium–aluminum–garnet (YAG) and Al₂O₃–Y₂O₃–CaO (AYC). All SiC ceramics investigated herein showed a parabolic weight gain with oxidation time at 1400°C. The SiC ceramics sintered with AlN and rare-earth oxides showed superior oxidation resistance to those with YAG and Al₂O₃–Y₂O₃–CaO. SiC ceramics with AlN and Yb₂O₃ showed the best oxidation resistance of 0.4748 mg/cm² after oxidation at 1400°C for 192 h. The minimization of aluminum in the sintering additives was postulated as the prime factor contributing to the superior oxidation resistance of the resulting ceramics. A small cationic radius of rare-earth oxides, dissolution of nitrogen to the intergranular glassy film, and formation of disilicate crystalline phase as an oxidation product could also contribute to the superior oxidation resistance.