In掺杂促进AuCuNi合金表面氧化膜形成的第一性原理计算

目的 采用第一性原理计算In掺杂促进AuCuNi合金表面氧化膜的形成机制,以为在金基合金中掺杂元素,促进表面氧化膜生成提供理论依据。方法 基于构建适用于第一性原理计算、原子比Au:Cu:Ni=9:5:2的晶体结构模型,对In掺杂AuCuNi体系模型的稳定性、偏析特性以及吸附特性进行计算。结果 In原子替代掺杂AuCuNi合金(111)面中各元素后形成新的AuCuNiIn表面,掺杂形成能均为负值,这说明In替位AuCuNi合金(111)面中任何一个原子都会促进AuCuNi表面的稳定性。当In替位掺杂AuCuNi表面第一层的Ni原子时,稳定性提升最大,掺杂形成能为–1.326 eV;当In替位掺杂AuCuNi表面第三层的Ni原子时,掺杂形成能最大为?0.503 eV,这表明当In原子掺杂到该位置时,体系稳定性的提升最小。通过偏析能的计算发现,掺杂后的In有向其他位点偏析的趋势,最易向偏析能最小的位点偏析,即向表层Ni原子偏析,偏析能为?0.739 eV。因此,使In原子替位掺杂第一层的Ni原子,形成最稳定的AuCuNiIn表面结构。此外,通过在AuCuNiIn表面吸附氧原子和计算吸附能发现,当原子顶位吸附时吸附能都比较高,这说明Au、Cu、Ni原子都不易在顶位吸附氧原子,其中T3(Au)位点的吸附能为0.034 eV,其值大于0,说明Au原子的顶位不会自发地吸附氧原子。表层原子中吸附能最低的几个位点H3(?3.571 eV)、H1(?3.462 eV)、B2(?3.021 eV)的氧原子均与In原子成键,这说明In原子附近更易吸附氧原子。最后,通过电荷差分密度图和布居分析,发现O原子与周围其他原子有明显的电荷转移,并与In原子、Cu原子和Ni原子形成键。这进一步表明O原子与周围原子发生化学反应,提高了材料表面的稳定性,证实了吸附能计算的准确性。结论 基于以上计算分析得出In原子的掺杂可以有效促进AuCuNi表面氧化膜的形成。通过第一性原理计算预测了元素掺杂对材料表面性能的影响,为掺杂促进材料表面氧化膜的形成提供了一定的理论参考。     

CO与CO_2在铂表面吸附模式或可能性研究

用第一性原理密度泛函理论研究了CO在Pt(111)、Pt(100)面上的吸附行为,并对吸附体系的吸附热、C-O键和C-Pt键的键长、布居数分析、电子态密度进行了研究。经比较吸附能、化学键参数和CO布居数,发现在CO主要以C朝下的方式吸附在Pt位,C原子与Pt原子间发生了强烈的杂化作用。为防止铂CO中毒,一般可采用在燃料气中充入一定量的氧气,这些氧气与CO反应生成CO2。计算表明,CO2不会在Pt(111)与(100)上面吸附,从而表明生成的CO2不会阻挡CO与Pt的作用,不会降低Pt的催化效应。     

钙钛矿催化材料La1-xCexCoO3+δ的制备、表征及甲烷燃烧催化性质

采用柠檬酸发泡法制备了钙钛矿LaCoO3催化材料;研究了Ce对La进行掺杂替代对催化材料性能的影响;通过BET、XRD、SEM等手段对催化材料进行了物性表征;以甲烷完全燃烧为目标反应,研究了钙钛矿La1-xCexCoO3 δ的催化性能.结果表明:铈掺杂对材料晶相有较大影响,当掺杂量x小于0.3时,粉体晶型基本不变,而当掺杂量达到0.5时,有明显CO3O4晶相出现,LaCoO3钙钛矿晶相完整性遭到破坏,当掺杂量大于0.7时,钙钛矿晶相大大弱化甚至消失;LaCoO3是一种性能优良的甲烷燃烧催化材料,Ce的掺杂替代对催化材料活性有明显影响,并增强了催化材料的高温稳定性能,铈最佳掺杂量为0.3;前驱体经700℃焙烧形成了较为完整的钙钛矿晶型,经800℃焙烧后,催化材料最高活性为:t10%=390℃,t90%=603℃.     

Co掺杂ZnO薄膜的制备及其红外反射性能研究

目的 提高真空保温管道中红外反射层的红外反射性能。方法 以四水合醋酸钴和二水合乙酸锌为金属离子源,利用溶胶-凝胶法制备了不同Co掺杂量的ZnO溶胶(Zn1–xCoxO,x=0, 0.02, 0.04, 0.06, 0.08, 0.10)。进一步采用提拉法在镜面316L不锈钢表面制备薄膜,经450 ℃退火处理3 h后得到所需样品。利用热重-差示扫描量热法(TG-DSC)表征Zn1–xCoxO凝胶在热处理时发生的干燥、晶化过程。利用X射线衍射仪(XRD)分析表征不同Co掺杂量的薄膜中的物相组成。利用场发射扫描电子显微镜(FE-SEM)观察薄膜表面的微观形貌。利用能谱仪分析(EDS)热处理后薄膜表面的元素分布情况。利用UV-Vis-NIR分光光度计测试涂层的红外反射性能。结果 所得的Zn1–xCoxO溶胶在基体表面铺展良好,经热处理后晶粒分布均匀,表面致密无明显缺陷;涂敷Zn1–xCoxO薄膜后,样品红外反射性能得到明显改善,由纯基体的0.6355提升至最佳值0.8131(其中,x=0.06)。同时,XRD结果表明掺杂并未导致样品物相的改变,薄膜材料仍然保持稳定的六角纤锌矿结构,但随着Co掺杂量的提高,样品在(101)晶面发生择优取向。经28 d 400 ℃有氧热处理后,试样仍能保持0.8018的较高反射率。结论 通过在红外反射层表面涂敷Zn1–xCoxO薄膜,不但可有效提高其红外反射率,还可对内部金属基体起到良好的保护作用,从而提高热力管道的隔热性能和使用寿命。     

Ir/SiC界面结合力、稳定性和电子结构的第一性原理研究

基于密度泛函理论（DFT）第一性原理研究了Ir(111)/SiC(111)界面。在考虑不同堆垛位置和表面封端的基础上,共研究了6种不同的界面构型。结果表明：具有9层原子层的Ir(111)表面构型表现体相材料的特征,而12层原子层的SiC(111)表面构型能体现体相SiC的性能。粘附功和界面能结果表明,C封端顶位堆垛（C-TS）和Si封端中心位堆垛（Si-CS）界面构型具有最大的粘附功,分别为6.35和6.23 J/m²,是最稳定的构型;弛豫后的界面能分别为0.07和0.10 J/m²。电子结构分析表明：C-TS界面处具有离子特性,而Si-CS界面处具有共价键特性。C-TS和Si-CS界面的结合强度和稳定性归因于Ir-d与C-p,Si-p轨道之间的杂化。与C-TS界面相比,Si-CS界面第2层原子与界面Ir原子的相互作用更大。     

PtPb/ C 催化剂的制备及其对甲酸电氧化的催化性能

目的通过Pb元素的添加来提高Pt/C催化剂电催化氧化甲酸的性能。方法通过乙二醇协助硼氢化钠还原法,以氯铂酸为Pt源和硝酸铅为Pb源制备不同原子比的PtxPb/C催化剂。采用X射线衍射光谱法(XRD)和透射电子显微镜技术(TEM)表征样品的晶体结构和颗粒形貌;采用循环伏安法表征样品催化氧化甲酸的性能。结果利用乙二醇协助硼氢化钠还原法成功制得了Pt和Pb原子比不同的PtxPb/C催化剂,XRD和TEM测试结果表明这些样品均为Pt的面心立方结构,且颗粒大小均一、分散均匀,其平均粒径为4 nm左右。循环伏安测试结果表明PtxPb/C催化剂催化氧化甲酸的性能优于商业Pt/C催化剂的催化性能,且受Pt和Pb原子比的影响,当原子比为5∶1时,其对氧化甲酸的催化性能最好,峰电位对应的Pt的比质量活性达到2000 m A/(mg Pt),远远高于商业Pt/C,同时计时电流曲线表明其具备良好的稳定性。结论 Pb原子的加入影响了Pt原子的电子结构,与Pb对Pt的协同作用共同促进了CO等中间产物在Pt表面的快速氧化,降低了催化氧化甲酸的初始电位,促使甲酸在低电位直接氧化为CO2和H2O,提高了其催化氧化甲酸的峰电流,有效减轻了Pt中毒,提高了其催化活性。     

碳酸二羟基·四氨合铂(Ⅳ)二水合物的合成、表征及性质

合成了一种用作前驱体的,具有八面体结构新型水溶性的金属复合离子型化合物碳酸二羟基.四氨合铂(IV)二水合物([Pt(NH3)4(OH)2]CO3.2H2O),用元素分析和X射线单晶衍射仪(XRD)对其结构进行了表征,用热重-差热(TG-TDA)测试其热分解特性,并对比评价制备DOC催化剂的性能。结果表明,化合物为单斜晶系、P21/c空间群,晶胞参数为:a=0.88191(14) nm,b=1.17817(18) nm,c=1.01533(16) nm,V=0.9978(3) nm³,Z=4,R1=0.0403,wR2=0.1235,R1=0.0466,wR2=0.1353。其晶体结构为以Pt(IV)为中心与4个NH3和2个羟基配位形成八面体的二价阳离子;TG-DTA测试显示化合物分解峰出现在223.8℃;制备得到的DOC催化剂催化活性和起燃温度优于传统前驱体化合物。     

溶胶-凝胶法制备Pt2+掺杂Bi2O3及光催化性能研究

用溶胶-凝胶法制备了Pt2+掺杂的Bi2O3光催化剂(Pt/Bi原子比分别为1/100、2/100、3/100和4/100),以甲基橙为模拟有机污染对催化剂的光催化性能进行了考察。光催化剂用BET、XRD、XPS和紫外-可见漫反射进行了表征,结果表明Pt/Bi原子比为3/100时催化剂的比表面最高;经500℃焙烧后光催化剂晶型为α-Bi2O3;掺杂Pt2+后Bi2O3在可见光区的吸收增强;掺杂Pt2+后Bi 4f7/2和O 1s结合能均向低能端偏移,催化性能测试结果表明Pt/Bi原子比为3/100时的催化剂活性最高。增加的比表面、对可见光响应增强和结合能向低能端偏移均有利于提高Bi2O3光催化活性。     

Photocatalytic Activity of Pt2 +-doped Bi2O2 Prepared by Sol-gel Method

用溶胶-凝胶法制备了Pt2+掺杂的Bi2O3光催化剂(Pt/Bi原子比分别为1/100、2/100、3/100和4/100),以甲基橙为模拟有机污染对催化剂的光催化性能进行了考察.光催化剂用BET、XRD、XPS和紫外-可见漫反射进行了表征,结果表明Pt/Bi原子比为3/100时催化剂的比表面最高;经500℃焙烧后光催化剂晶型为α- Bi2O3;掺杂Pt2+后Bi2O3在可见光区的吸收增强;掺杂Pt2后Bi4f7/2和O1s结合能均向低能端偏移,催化性能测试结果表明Pt/Bi原子比为3/100时的催化剂活性最高.增加的比表面、对可见光响应增强和结合能向低能端偏移均有利于提高Bi2O3光催化活性.     

氧化铝掺杂对Ba0.6Sr0.4(Zr0.2Ti0.8)O3陶瓷介电性能的影响

Zr4+取代Ti4+的Ba0.6Sr0.4(Zr0.2Ti0.8)O3固溶体在降低介电常数的同时,保持了BST固溶体优异的可调性。为降低BST材料的介电损耗和介电常数,以氧化铝为改性剂对Ba0.6Sr0.4(Zr0.2Ti0.8)O3材料(BSZT材料)进行了掺杂。随着氧化铝掺杂质量分数从1%到10%增加,BSZT材料的介电常数从5000降低到了1550(100kHz),介电损耗降低到0.001(100kHz)以下,而材料的介电可调性保持在35%左右(1.5kV/mm)。X射线衍射图谱表明,烧结后得到的BSZT材料具有典型的钙钛矿结构。扫描电子显微镜观察表明,氧化铝的掺杂使得陶瓷致密度较高,晶粒均匀。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.