共查询到20条相似文献,搜索用时 62 毫秒
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用离子注入、氧化和慢正电子束分析研究了GH903合金的氧化性能的改善与微观作用机理。注入的Cr+.Y+的能量均为60keV,注入的剂量分别由1x1017.cm-2(Cr+)、1x1015Cm-2(Y+)和[1x1015.cm-2(Y+)+1x1017·cm-2(Cr+)]。结束显示,注入样品与未样品相比。氧化增重分别减少4.8%(注Cr+)、24.2%(注Y+)和32.3%(注Y++Cr+)。这表明合金氧化性能改善的作用机理主要是注入离子对样品浅表层内缺陷的填充与退火。同时,注入元素的化学性能和使样品表面更致密也起了重要作用。 相似文献
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沉积在云母片上的纯C60薄膜受20keV的Li+和N+2离子轰击,剂量在0.5×1016/cm2~5.0×1016/cm2之间改变,测量了离子注入后C60薄膜方块电阻随温度的变化,进而推导出C60薄膜电导率随温度和注入离子剂量的变化;分析了非原位测量中氧元素对电导率变化的影响以及能量较高的注入离子对C60薄膜的辐照损伤效应。研究结果表明,Li+注入对C60薄膜电导率的影响明显高于N+2注入的影响,并给出了不同离子注入条件下C60薄膜电导率随温度变化的函数关系式。 相似文献
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离子注入α—Al2O3陶瓷材料的表面改性研究 总被引:5,自引:2,他引:3
研究了α-Al2O3单晶注入N^+后的力学性能变化。结果表明,注入剂量为1×10^17N^+/cm^2时,Al2O3的显微硬度提高了92%,注入剂量为3×10^17N^+/cm^2时,在Al2O3表面形成晶层,导致表面软化,显微硬度只是其50%左右。离子注入在样品表面产生了高达-1150MPa的压应力,材料的断裂韧性的改善与此有关,实验亦发现N^+离子注入后Al2O3的断裂韧性提高了95%左右。 相似文献
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In^+离子注入蓝宝石(α—Al2O3单晶)的表面改性研究 总被引:2,自引:2,他引:0
研究了〈0001〉和〈1^-210〉晶向蓝宝石(α-Al2O3单昌)在注入360keV、1×10^16cm^-2或100keV、6×10^16cm^-1的In^+后产生的损伤、注入层的性能变化和退火行为。实验结果表明,退火过程中损伤的恢复和In的分布与退火气氛有关:在100keV、6×10^16cm^-2的In^+注入时,注入层电阻率降低了10个量级,大小为6.8×10^3Ω·cm,表面损伤层的显 相似文献
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在本征型GaAs中注入2.0MeV(剂量1.0×10^15/cm^2)+2.9MeV(剂量1.1×10^15/cm^2)的^16O,使氧在约1.5-2.5μm之间形成均匀分布。注入样品分别经400-800℃、15min热退火后的电阻率测量表明,经500℃和600℃退火后的样品具有高的电阻率(~10^8Ω·cm);而当退火温度进一步升高时,其电阻率逐渐下降,并具有p型导电行为。沟道RBS分析表明,当 相似文献
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研究了<0001<和<1210>晶向蓝宝石(α-Al2O3单晶)在注入360keV.1×10 ̄16cm ̄-2或100keV、6×10 ̄16cm ̄-2的In ̄+后产生的损伤、注入层的性能变化和退火行为。实验结果表明,退火过程中损伤的恢复和In的分布与退火气氛有关:在100keV、6×10 ̄16cm ̄-2的In ̄+注入时,注入层电阻率降低了10个量级,大小为6.8×10 ̄3·cm,表面损伤层的显微硬度提高了92%;在360keV,1×10 ̄16cm ̄-2的In+注入时,其表面损伤层的显微硬度提高了45%,在空气中不同温度下退火后,其显微硬度的变化和损伤的变化具有相同的规律。 相似文献
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大射野,大深度^60Coγ射线照射条件下组织—空气比的公式计算 总被引:1,自引:0,他引:1
本文利用^60Coγ放射源和72cm×72cm×90cm(长×宽×高)体模,在大射野(10.0cm×10.0cm~50.cm×50.0cm)和大深度d(10.0~70.0cm)照射条件下实测的组织-空气比数据,按Melski计算^60Coγ射线组织-空气比深度函数公式,Ae^Bd+Ce^Dd,利用高斯-牛顿逐次逼近的计算方法,拟合出该公式参数A,B,C和D的最佳估计值,5组数据的残差平方和小于1. 相似文献
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研究了2-羟基-5-烷基苯乙肟(商品代号7804)萃取Am ̄(3+)和镧系元素时,平衡时间、温度、pH值、萃取剂浓度及料液中起始Am ̄(3+)和镧系元素浓度对各元素分配比的影响。研究结果表明,合适的萃取条件为:平衡时间30min、温度20±1°C、萃取剂浓度0.2mol/l、pH4.8—5.1。在此条件下,7804与Am ̄(3+)或镧系元素形成2:1配合物。7804萃取Am ̄(3+)及镧系元素的顺序为:Am>Eu>Sm>Nd>Pr>Ce>La。 相似文献
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R. Mateus A.P. Jesus H. Luís J.P. Ribeiro 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(8):1490-1492
In this work we present an alternative method for PIGE analysis of aluminium in thick samples. This method is based on the ERYA - emitted radiation yield analysis - code, which integrates the nuclear reaction excitation function along the depth of the sample. For this purpose, the excitations functions of the 27Al(p,p′γ1,2)27Al reaction (with gamma-ray energies of 844 and 1014 keV) were employed. Calculated gamma-ray yields were compared, at several proton energy values, with experimental yields for thick samples made of inorganic compounds containing aluminium. The agreement is better than 5%.The 1684 keV resonance of the same reaction, with a natural width of 100 eV, was used to profile samples of Ti implanted with several doses of Al. We show that this resonance, stronger than the 992 keV resonance of the 27Al(p,γ)28Si usually employed for aluminium profiling, leads to similar depth resolution in shorter collection time. 相似文献
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Aluminium alloys containing up to 0.4% silicon and 0.1% indium were irradiated at various doses up to 1021 n/cm2 (E > 0.1 MeV) at pile temperature. Indium was found to enhance and silicon to suppress the nucleation of voids. The reasons for this are discussed in terms of possible nucleation processes. The changes in 0.2% proof stress were correlated with the change in microstructure. 相似文献
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A method is presented for the estimation of the solubility of uranium and plutonium in solvent systems composed of two or more low-melting metals. The method presented for the estimation of the activity coefficient of uranium and plutonium in multi-component solvent systems is applicable to the prediction of solubilities and of distribution coefficients between liquid alloys and molten salts. The theoretical basis for the salt transport separation process used in pyrochemical methods for the recovery of irradiated fast breeder reactor fuels is presented. The methods are illustrated by the computation of the solubility of uranium in liquid Zn-Mg and Zn-Mg-Ca alloys and the distribution of uranium between liquid Zn-Mg alloy and molten MgCl2. 相似文献
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Thin wedge-shaped aluminium specimens were bombarded at 2̃00°C with α-particles to obtain a uniform distribution of He from 0̃.002 to 0.35 at%. The behaviour of the He in the specimens was studied by transmission electron microscopy. It was found that He-bubbles are formed by homogeneous nucleation. They become visible at a diameter of ~10 Å in specimens containing 0̃.007 at% He. With increasing α-dose the bubbles increase both in number and in size until their number becomes constant at ~0.09 at% He. Additional bombardments of such samples lead only to further growth due to He-diffusion. A small zone free of visible bubbles is formed at the specimen surface and its depth depends on the bombardment dose. 相似文献
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S. RundD. Primetzhofer S.N. MarkinD. Goebl P. Bauer 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(11):1171-1174
Charge exchange of 4He+ and 3He+ ions with surfaces of polycrystalline aluminium and Al(1 1 1) was investigated in the low-energy ion scattering (LEIS) regime. Ion spectra were recorded for primary energies ranging from 280 to 4000 eV by using an electrostatic analyzer (ESA). A very low threshold energy Eth for collision induced charge exchange (CI) was deduced from the shape of experimental spectra. Ion fractions P+ were evaluated. No systematic difference in P+ was observed for both, the two surfaces investigated and the two different projectiles. 相似文献
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叙述了热损补偿型铝吸收剂量量热计的结构及测量原理,给出了量热计在10-35℃工作温区的电加热标定因子,得到了60Coγ辐照室中剂量率对距离的分布。 相似文献
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The saturation solubility of aluminium in Pb-17Li has been measured over the temperature range envisaged for a Pb-17Li tritium breeder/coolant blanket for use in a fusion reactor. The solubility is given by the equation log10S(wppm) = 6.249 – 2784.9/T(K) for T = 525 – 813 K.The results are compared to literature values for the solubility of aluminium in pure lead and show good agreement. A value for the enthalpy of solution of + 55.8 kJ mol-1 has been calculated. 相似文献
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Small bubbles in argon-implanted aluminium have been found to contain thin oxide membranes. These membranes lie on {111] planes of the aluminium and are stable to above 500 ° C. It is shown that sufficient oxygen will be knocked-in during argon implantation to precipitate platelets of oxide, on which the bubbles nucleate. This oxygen knock-in mechanism could account for the hitherto surprising stability of helium bubbles in aluminium. 相似文献