氧化铝的热释光特性

陶瓷中常含有相当数量的氧化铝成分，研究氧化铝的热释光性特征对进一步提高古物测年的精确度至关重要。实验研究结果表明，氧化铝的热释光性质较为稳定，利用氧化铝的270℃峰测定年龄是切实可行的。     

Recovery of neutron-irradiation-induced defects of Al2O3, Y2O3, and yttrium-aluminum garnet

SiC fiber-reinforced SiC matrix composites (SiC_f/SiC) are considered as one of the candidates for blanket materials in future fusion reactors and as an advanced fuel cladding material for next-generation fission reactors. Generally, the densification of SiC needs sintering additives and oxides such as Al₂O₃, Y₂O₃, and yttrium-aluminum garnet (YAG, Y₃Al₅O₁₂), which are frequently added to SiC. However, the effects of neutron irradiation on sintering additives are still unclear. In this study, we performed the neutron irradiation of Al₂O₃, Y₂O₃, and YAG at fluences up to 2.0–2.5 × 10²⁴ n/m² (E > 0.1 MeV) at 60–90 °C. The isochronal recovery of the macroscopic volume of Al₂O₃ against annealing temperature showed smooth and continuous shrinkage at a temperature of up to 1200 °C, and the volume slightly increased above that temperature. In contrast, the volume of Y₂O₃ showed quick shrinkage at the low temperature range, and slower and smooth recovery was observed up to ～1100 °C. In the case of YAG, the recovery of volume occurred in a step-wise manner at 600–750 °C, and continuous shrinkage occurred at temperatures lower and higher than that temperature range. The activation energies for the macroscopic volume recoveries of three oxides were obtained from the Arrhenius plots of the rate coefficients. Two-stage recovery was observed for Al₂O₃, whereas more complicated recovery processes were suggested for Y₂O₃ and YAG.     

MeV辐射场中Al2O3的剂量学特性

用EGSnrc/DOSRZnrc程序计算水体模中Al2O3剂量计的吸收剂量和剂量计所在处介质的实际吸收剂量,并计算吸收剂量换算因子。剂量计为φ4mm×1 mm的Al2O3薄片,计算深度0.5～8 cm,入射光子能量1～18MeV,入射电子能量1～25 MeV。结果表明：1）吸收剂量换算因子的大小与入射粒子的能量以及剂量计在体模中的深度有关;2）存在一个吸收剂量换算因子变化不敏感的区域,在此区域内吸收剂量换算因子受剂量计深度变化和入射粒子能量变化的影响都很小,可直接用平均值来表示区域内的吸收剂量换算因子。     

离子束辅助沉积制备Al／Al2O3双层膜及其性质

利用离子束辅助沉积的方法在ＣＫ４５号钢和ＡｌＴｉ合金基体上制备了具有不同厚度Ａｌ层或Ａｌ２Ｏ３层的Ａｌ／Ａｌ２Ｏ３双层膜系统，Ａｌ与Ａｌ２Ｏ３层之间是厚度为１００ｎｍ的梯度界面层，利用电化学方法测量了样品在近中性水溶液中耐腐蚀性能，实验中还测量了样品的表面硬度和耐摩擦性能，研究了双层膜系统中Ａｌ或Ａｌ２Ｏ３层厚度变化对样品物理性质和化学性质的影响。     

Al2O3/Y2O3/ZrO2 Ceramic Composite Properties Investigation by Plasma Focus Device

The Al₂O₃–Y₂O₃–ZrO₂ eutectic composition samples were prepared using the Al₂O₃, Y₂O₃, ZrO₂ powder treated at 900 °C for 30 min, pressed at 5 ton for 15 s and sintered at 1500 °C for 2 h. The locally made dense plasma focus (DPF) system with energy 2.8 kJ was used to surface modification of these samples. The samples, mounted at distance about 2 cm from the anode, were exposed to three shots of the DPF in Ar gas at a pressure of 0.8 mbar. The phase and elemental analysis of the untreated and plasma treated samples were conducted by the Raman and EDX spectroscopy. The Raman spectroscopy showed the formation of new phases (α-Al₂O₃ and c-ZrO₂) in the treated samples. The micro-hardness of the plasma treated samples was increased by about 280 % in comparison with the untreated sample.     

Low Temperature Radiation Response of Al2O3 Gate Insulators

The response of Al2O3 MIS capacitors to steady state (Co60) and pulsed high-energy (13-MeV e-) ionizing radiation was measured at 297 and 80 K as a function of applied bias and dose. The radiation sensitivity of the Al2O3 at 80 K was found to be little altered from its room temperature value and was significantly reduced from that of comparable SiO2 gate insulator materials measured under similar conditions. Experimental evidence suggests that the primary mechanism for the superior performance of Al2O3 at 80 K is rapid transport of most of the radiation generated carriers out of the oxide layer. The injection of electrons into the Al2O3 under bias stress was also measured at 297 and 80 K, and was found to be drastically slowed at the lower temperature. As a consequence of its superior performance under irradiation at 80 K, Al2O3 may be an attractive alternative to SiO2 gate insulator materials in critical low temperature applications.     

Simulation of thermal stress in Er2O3 and Al2O3 tritium penetration barriers by finite-element analysis

The physical vapor deposition method is an effective way to deposit Al2O3 and Er2O3 on 316L stainless steel substrates acting as tritium permeation barriers in a fusion reactor.The distribution of residual thermal stress is calculated both in Al2O3 and Er2O3 coating systems with planar and rough substrates using finite element analysis.The parameters influencing the thermal stress in the sputter process are analyzed,such as coating and substrate properties,temperature and Young's modulus.This work shows that the thermal stress in Al2O3 and Er2O3 coating systems exhibit a linear relationship with substrate thickness,temperature and Young's modulus.However,this relationship is inversed with coating thickness.In addition,the rough substrate surface can increase the thermal stress in the process of coating deposition.The adhesive strength between the coating and the substrate is evaluated by the shear stress.Due to the higher compressive shear stress,the Al2O3 coating has a better adhesive strength with a 316L stainless steel substrate than the Er2O3 coating.Furthermore,the analysis shows that it is a useful way to improve adhesive strength with increasing interface roughness.     

Volume change of Al2O3 and MgAl2O4 induced by 14-MeV neutron irradiation

Volume change of Al₂O₃ and MgAl₂O₄ induced by irradiation with 14-MeV neutrons at 50°C has been measured. It is shown that the volume change of A1₂O₃ is anisotropic and is larger than that of MgAl₂O₄ about a factor of five. The result for MgAl₂O₄ is compared with that of fission neutron irradiation.     

Some features of the thermoluminescence of Al2O3 single-crystal powders

Main Science Center of the Russian Federation — Institute of Biophysics. Translated from Atomnaya énergiya, Vol. 79, No. 6, pp. 452–454, December, 1995.     

Permanent Radiation Effects in Hardened Al2O3 MOS Integrated Circuits

Complementary-symmetry metal-oxide semiconductor (COS/MOS) inverter circuits have been fabricated with aluminum oxide as channel insulator. This oxide was formed either by plasma-anodization of Al or by vapor deposition at 450°C using Al-isopropoxide. The RCA CD-4007 circuit configuration was used for these studies. The inverters were subjected to ionizing radiation with the applied gate biases encountered under normal operation (0 and +10 volts). For all units tested, the shifts in the inverter characteristics were due to shifts in the threshold voltages of the individual transistors. No measurable deterioration in gain due to interface state generation was observed. These results confirm the expected radiation hardness measured previously with MOS capacitors. Based on the net voltage shifts in the transfer characteristics of the complementary inverters, plasma-grown A12O3 shows an increase of more than an order of magnitude in hardness over units with SiO2 channel oxide. The hardness of units with deposited A12O3 was found to be intermediate to these. The increased hardness of A12O3 over SiO2 is attributed, at least in part, to the presence of trapping centers for negative charge. This serves to balance the positive trapped oxide charge so that a considerable reduction in the net oxide charge is attained.     

Comparative analysis of the low-energy He+ ions scattering on Al and Al2O3 surfaces

Using the Anderson–Muda–Newns approach, the neutralization rate and the ion survival probability have been calculated for the large angle scattering of low-energy He⁺ ions by Al and by Al₂O₃. The two-band model of the electronic energy spectra is applied for the case of alumina. The electron promotion has been shown to play an important role in the processes of the He⁺ ions scattering by aluminum and alumina. The experimentally observed absence of the matrix effect is discussed on the basis of the obtained results.     

Al2O3:C光致荧光剂量计初步研究

采用液体成膜法制备了Al₂O₃:C光致荧光剂量计（OSLD），开展了剂量学性能的初步研究。退火后本底为0.03 mGy，均匀性优于2%，在0.02 mGy~10 Gy测量范围内具有良好线性响应，线性相关系数R²=0.999 6，对β、γ射线响应系数差异约10%，对中子响应系数约为β、γ射线的4%~7%，剂量计多次测量响应信号无明显衰减，照后两个月响应变化为5%，可用于一定周期内剂量存档、复测。上述结果表明，液体成膜方法制备的OSLD具有良好的剂量学性能，证明该方法可行。     

Al2O3/H2O纳米流体球形下封头表面气泡脱离行为模拟

压力容器内滞留（IVR）策略可在反应堆发生严重事故后,有效地将堆内熔融物滞留在压力容器内,是防止放射性物质外泄的关键技术。纳米流体是将粒径小于100 nm的固体颗粒加入到基液中以提高换热特性的稳定悬浮液,其热物性以及换热特性与传统固液悬浮液相比有较大区别,适宜的纳米流体种类及配比可强化换热。本文采用引入了无网格对流格式的移动粒子半隐法（MPS方法）研究了体积份额为1.0%的Al₂O₃/H₂O纳米流体和纯水中加热面朝下时气泡在加热面上的成长、脱离以及附着形成气膜的过程,探索了气泡脱离的临界角度及其影响因素,为加速纳米流体的工业应用、增强IVR能力提供理论基础。     

Al_2O_3在6MV放疗射线中的吸收剂量比率因子

用EGSnrc/BEAMnrc、DOSXYZnrc、DOSRZnrc模拟计算水体模中Al2O3剂量计的吸收剂量和剂量计对应位置上水的实际吸收剂量,并计算吸收剂量比率因子fmd,讨论Al2O3剂量计的吸收剂量特性.剂量计为φ4mm×1 mm的Al2O3薄片,计算深度0.5-8.0 cm,放疗射线是Varian 600C医用电子直线加速器的6 MV射线和Mohan 6 MV谱线.结果表明:Al2O3剂量计的吸收剂量少于对应位置上水的实际吸收剂量,吸收剂量比率因子fmd与剂量计在体模中的深度有关,在剂量建成区内,fmd对剂量计深度变化敏感;在建成区外fmd受剂量计深度变化的影响很小,用平均值表示不同深度的fmd时偏差不大于1.0%.