我国钛容器易发生塑性开裂的原因和对策

根据固体与分子经验电子理论，对Ｗ２Ｃ相的价电子结构进行了定量分析，通过键距差方法计算了Ｗ２Ｃ晶体中各键上的共价电子数。结果表明，近似平行于ｃ轴最近邻的Ｗ－Ｃ原子键最强，其共价电子数ｎＡ＝０．６９９２５，键能ＥＡ＝１４１．２ｋＪ／ｍｏｌ；近似平行于ｃ轴的Ｗ－Ｗ原子间结合力次之，其共价电子数ｎＧ＝０．２０８３４，键能ＥＧ＝４６．２４ｋＪ／ｍｏｌ；位于（０００１）面上的Ｗ－Ｗ原子键也较强，该键上共价电子     

Nd2Fe14B／α—Fe纳米晶双相复合永磁合金

采用快淬火及热处理工艺,通过复合添加Ｄｙ和Ｇａ,制备了高磁性能的Ｎｄ２Ｆｅ１４Ｂ／α－Ｆｅ纳米晶双相复合永磁合金,合金最佳磁性能为,Ｊｆ＝１．１６１Ｔ（１１．６ｋＧｓ）,Ｈｃｉ＝５８０．５０ｋＡ／ｍ（７．３０ｋＯｅ）和（ＢＨ）ｍａｘ＝１６２．７ｋＪ／ｍ＾３（２０．５ＭＧｓ．Ｏｅ）。该合金成分为Ｎｄ７．５Ｄｙ１Ｆｅ８５Ｂ４．５Ｇａ２,其显微组织由晶粒尺寸约为３２ｎｍ的硬磁相Ｎｄ２Ｆｅ１４Ｂ和１６ｎｍ     

快速凝固（Sm1—xBx）Fe2合金的结构和磁性

采用真空单辊快淬法（铜辊,线速度达２０～２３ｍ／ｓ）将成分为（Ｓｍ１－ｘＢｘ）Ｆｅ２（ｘ＝０,０．０１５,０．０３,０．０４５,０．０６）合金锭,制成快速凝固的鳞片状合金,再经粉碎在３０ＭＰａ压力下,模压成φ１０ｍｍ圆片,然后进行ＸＲＤ分析,比磁化强度和磁致伸缩（λ″－λ┴）的测量。实验结果表明各样品只有少量非晶相,主要是ＳｍＦｅ２及少量的ＳｍＦｅ５和ＳｍＦｅ７化合物。样品（Ｓｍ０．９８５Ｂ０．０１５）Ｆｅ２和（Ｓｍ０．９４Ｂ０．０６）Ｆｅ２,在７２０ｋＡ／ｍ磁场下,比磁化强度分别为：５９．５,５２．３Ａｍ２ｋｇ－１,在８８５ｋＡ／ｍ磁场下（λ″－λ┴）分别为：－５１０×１０－６和－３１０×１０－６。     

纳米日Fe74.7—xCu1NbxV1.8Si13.5B9合金的磁性

本文报道Ｆｅ７４．７－ｘＣｕ１ＮｂｘＶ１．８Ｓｉ１３．５Ｂ９（ｘ＝１，１．５，２）纳米晶软磁合金的综合磁性，Ｘ＝２的合金高频铁损水平为：Ｐ３／１００ｋ＝４６８ｋＷ／ｍ＾３；Ｐ２／２００ｋ＝７０６ｋＷ／ｍ＾３；Ｐ２／５００ｋ＝３６２０ｋＷ／ｍ＾３和Ｐ０．５／１０００ｋ－８１０ｋＷ／ｍ＾３，优于Ｆｅ－Ｃｕ－Ｎｂ－ＳＩ－Ｂ类纳米晶合金的水平，所考察的三种合金铁损水平者大大优于功率优良的Ｍｎ－Ｚｎ铁氧体Ｈ     

用热分析技术研究氟碳铈精矿碳酸钠焙烧反应动力学

利用山东微山氟碳铈精矿添加２０％Ｎａ２ＣＯ３的ＴＧＤＴＡ曲线,采用ＦｒｅｅｍａｎＣａｒｏｌ法和差减微分法热分析技术,研究其焙烧反应动力学,取得了令人满意的结果。利用ＴＧ曲线计算得到的反应表观活化能Ｅ＝１８８．６ｋＪ／ｍｏｌ,反应级数ｎ＝０．８９;利用ＤＴＡ曲线计算得到的反应表观活化能Ｅ＝１８１．４ｋＪ／ｍｏｌ,反应级数ｎ＝０．７３。两种方法计算的结果吻合较好。同单纯氟碳铈精矿的焙烧反应动力学计算结果相比较,加入Ｎａ２ＣＯ３使氟碳铈精矿的焙烧分解反应变得复杂,但可以使反应的活化能降低,有利于精矿的分解。     

Fe—28Al—5Cr与Fe—28Al—5Cr—0.5Nb—0.1C合金的超塑性变形能力与特征

研究了 Ｆｅ－２８Ａｌ－５Ｃｒ（原子分数）与 Ｆｅ－２８Ａｌ－５Ｃｒ－０．５Ｎｂ－０．１Ｃ合金的高温变形行为,结果表明,在 ８５０ ℃左右,应变速率为 ８．３×１０－４ ｓ－１时,呈现一定的超塑性变形能力,延伸率分别达到 １４５％和 ２５４％;应变速率敏感指数 ｍ分别为 ０．４与 ０．３５;激活能分别为： ２４３ ｋＪ／ｍｏｌ与 ２１８ ｋＪ／ｍｏｌ．在变形过程中,位错堆积形成小角度晶界,并逐渐转变成大角度晶界,使粗大的原始晶粒细化．     

Fe73.5Cu1Nb3Si13.5B9非晶合金的晶化动力学

用差热分析（ＤＴＡ）结合Ｘ射线衍射（ＸＲＤ）,研究了Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９非晶合金的晶化动力学。结果表明：温度在０～７００℃范围内,该合金的晶化相为α－Ｆｅ和Ｆｅ２Ｂ;α－Ｆｅ相晶化表观激活能为４５２．３９ＫＪ／ｍｏｌ,Ｆｅ２Ｂ相的晶化表观激活能３９５．２３ＫＪ／ｍｏｌ;两相在晶化初期激活能最小,随晶化量Ｘｃ的增加而迅速境大,在α－Ｆｅ的体积分类为３０％～８０％,Ｆｅ２Ｂ的体积分     

TiB2和ZrB2晶体结构与性能的电子理论研究

根据固体与分子经验电子理论,对ＴｉＢ２和ＺｒＢ２相进行了价电子结构分析,采用键距差（ＢＬＤ）方法,计算了ＴｉＢ２和ＺｒＢ２晶体中各键上的共价电子数。结果表明：ＴｉＢ２和ＺｒＢ２相是靠键距为√３α／３的Ｂ－Ｂ最强键连接的,该键上的共价电子数影响化合物的硬度。化合物的强度可由η＝ｎ√ｎＴ来衡量。     

La_1－zRz（Fe_1－x－yCoxAly）_（13）金属间化合物磁熵变特性研究

本文对用Ｆｅ、Ａｌ替代Ｃｏ的Ｌａ（Ｆｅ（０．７３）－ｘＣｏｘＡｌ（０．２７））（１３）系和用Ｒ（Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｄｙ，Ｇｄ）替代Ｌａ的Ｌａ１－ｚＲｚ（Ｆｅ（０．７１）Ｃｏ（０．０２）Ａｌ（０．２７））（１３）系的结构、磁性及磁熵变特性进行了研究。实验发现，Ｌａ（Ｆｅ（０．７８）－ｘＣｏｘＡｌ（０．２７））（１３）系的晶体结构均保持ＬａＣｏ（１３）的立方结构，每３ｄ原子的饱和磁矩与其电子数ｎｄ的关系在富Ｃｏ侧符合刚性能带模型，而在富Ｆｅ侧则与该模型不符。当ｘ＝０．０２时该化合物的居里温度在室温并有较高的磁熵变△ＳＭ，在１．１１ＭＡ／ｍ（１．４Ｔ）磁场下的（△ＳＭ）ｍａｘ为１３ｋＪ／ｍ３·Ｋ。对于Ｌａ１－ｚＲｚ（Ｆｅ（０．７１）Ｃｏ（０．０２）Ａｌ（０．２７））（１３）系，实验发现除Ｃｅ外，其它稀土元素均不能与Ｌａ、Ｆｅ、Ｃｏ、Ａｌ形成１：１３相，而是形成了２：１７相。     

Fe—5Ni合金奥氏体高温变形行为

在温度９７３－１３７３Ｋ，形变速率２×１０＾－５－１．５×１０＾－２ｓ＾－１的试验条件下，研究了Ｆｅ－５Ｎｉ合金奥氏体的高温拉伸变形行为。结果表明：高温变形时峰值应力σｐ与温度Ｔ和形变ε之间符合五式关系：Ｚ＝εｅｘｐ（Ｑ／ＲＴ）＝Ａ（ｓｉｎｈ（ασｐ））＾ｍ。高应变速率区的激活能Ｑ为３１４ｋＪ／ｍｏｌ，与Ｆｅ的自扩散激活能Ｑｓｄ相当，变形由空位扩散所控制；而低应变速率区的Ｑ为２０２ｋＪ／ｍｏｌ，约     

MoSi2和WSi2的价电子结构及性能分析

根据固体与分子经验电子理论，对MoSi2和wSi2的价电子结构进行了定量的分析，通过键距差方法计算了MoSi2和WSi2晶体中各键上的共价电子数．结果表明：在MoSi2和WSi2晶体中，沿（331）位向分布的Mo-Si和W-Si原子键最强，这些键上的共价电子数和键能分别影响化合物的硬度和熔点．晶体中晶格电子数影响其导电性和塑性，MoSi2晶体中含有较高密度的晶格电子，因此MoSi2的导电性和塑性比WSi2好．并从键络分布的不均匀性解释了MoSi2和WSi2脆性产生的原因．     

Al-Cu合金GP区形成过程的价电子结构演变

基于EET理论和Gerold的Al-Cu合金GP区终态原子结构模型,建立GP区价电子结构计算模型,研究GP区价电子结构的演变过程,提出形成过程中GP区点阵常数的计算方法,计算GP区的价电子结构,分析了Cu含量对其价电子结构的影响。结果表明,Al-Cu合金时效过程中GP区是渐进形成的。在形成初期,Spinodal分解机制占主导作用;在形成后期,正常的形核-长大机制占主导作用。随着Cu原子的富集,GP区最强共价A键的共价电子对数nA逐渐增加,B、C、D键的共价电子对数nB、nC、nD逐渐减少。GP区A键变强的原因在于B、C、D键上的共价电子逐渐向A键转移。     

Enthalpies of formation of solid Sm---Al alloys

A direct isoperibolic differential calorimeter was used to measure the formation heats of the Sm---Al intermetallic compounds. X-ray powder diffraction, optical and scanning electron microscopy and electron probe microanalysis were used to check the composition of the samples. The following values of Δ_fH⁰ for the different compounds were obtained in the solid state at 300 K: Sm₂Al, = −38.0 ± 2 kJ (mol atoms)⁻¹; SmAl, −49.0 ± 2 kJ (mol atoms)⁻¹; SmAl₂, −55.0 ± 2 kJ (mol atoms)⁻¹; SmAl₃, −48.0 ± 2 kJ (mol atoms)⁻¹. The results are discussed and compared with earlier experimental data.     

Mo(Si0.95,Al0.05)2价电子结构计算及其性能分析

根据固体与分子经验电子理论（EET）,采用键距差法（BLD）,分析并计算了C11b型金属间化合物MoSi2的价电子结构与理论键能;采用合金元素Al部分取代MoSi2晶格中的Si原子,依据固体与分子经验电子理论在代位式固溶体中的平均原子模型,分析并计算了C11b型Mo(Si0.95,Al0.05)2的价电子结构与理论键能。结果表明：Al微合金化改变了Mo原子和Si原子的杂化状态,从而使相应的价电子结构参数发生变化。与MoSi2相比,Mo(Si0.95,Al0.05)2固溶体中共价电子数在总价电子数中所占的比例（h）由65.87%降至64.28%,因而Al微合金化不利于MoSi2强度的提高;但是晶格电子数由4.7141增至4.9202,所以Al微合金化有利于MoSi2塑性的改善。     

LiB化合物X射线衍射强度计算与晶胞中电子密度分布

讨论了LiB化合物X射线衍射的实验方法及衍射强度计算模型,并对该物相的电子密度函数进行了分析,结果表明,在经过对X射线的透射效应和Debye因子各向异性的简化修正后,X射线衍射强度理论值与实验结果吻合很好,电子密度函数分析表明,在LiB单胞中沿[001]方向B与B之间存在高密度电子分布,Li原子的电子向B原子发生了转移,进一步支持了LiB化合物中B在[001]方向以供价健相连及元素Li以Li^ 状态存在的观点。     

R dependence of electronic structure in perovskite type structure compounds, RBRh3 (R: Sc, Y and La)

The electronic structures of perovskite type structure, RBRh₃ (R: Sc, Y and La) were studied by X-ray photoelectron spectroscopy and calculation with full potential linearized augmented plane wave (FLAPW) method. As the lattice constant of the crystals increases with the atomic number of R, it can be discussed how the bond length between boron and rhodium atoms effect on the bonding character. The valence band XPS profiles of the samples are well coincided with the calculated profiles. The calculated electron density maps of the valence bands indicate the following. The charge transfer directions are from R to rhodium atoms and from boron to rhodium atoms. The bonds of RRh and BRh atoms have also covalent character. The covalency of RRh bond increases with the order of the atomic number of R atoms. On the other hand, the covalent bond of BRh decreases with the order atomic number.     

高温下金与石英的相互作用及其对浸金过程的影响

金在高温下可能与石英及硅酸盐类矿物相互作用，导致焙烧后矿石中金回收难度增大。于不同温度(600℃~750℃)和时间(1~4 h)条件下对石英-硫化矿-金粉混合物进行焙烧，考察焙烧渣中金的氰化浸出率。结果表明，高温会活化石英并与金相互作用，导致焙烧渣中的金难以被氰化物浸出。第一性原理计算表明，金原子在石英(101)表面的吸附能为-300.01 kJ/mol，Au-1与石英表面的Si-12距离为0.2264 nm，石英表面Si-12的电子转换到Au-1原子上，布居值和键长数据显示金原子与石英(101)表面的硅原子存在键合作用，印证了焙烧试验结果。     

Structural features of compounds with tetrahedral structures or tetrahedral anion partial structures derived from two valence electron concentration rules

The total and the partial valence electron concentrations(VEC), two variables which can be easily calculated from the composition of the compound and the valence electron numbers of the participating atoms, serve as useful parameters to predict probable structural features of compounds with a tetrahedral structure or a tetrahedral anion partial structure such as an anionic tetrahedron complex. The structural features to be predicted are the average number of nonbonding orbitals, the number of atoms in molecular structures, the average number of anion-anion bonds per anion or the average number of electrons which remain with the cation to be used either for cation-cation bonds or nonbonding orbitals.     

HOT DEFORMATION OF CAST Pr-Fe-B MAGNETS

The hot deformation process of cast Pr_(19)Fe_(74.5)B_5Cu_(1.5) magnets were studied.It isfound that the easy-axes are aligned parallel to the compressive strain direction in vari-ous hot deformation process.During hot deformation,the crushing of Pr_2Fe_(14)B matrixgrains and the relative slip and rotation between the grains take place and the Pr-richmelt is squeezed out of the magnet,leading to a fine,dense and well-aligned microstruc-ture in the fully-deformed magnets.Magnetic properties of B_r=990 mT,_iH_c=880kA/m and(BH)_m=191 kJ/m~3are obtained.The increase of coercivity is attributed tothe fine Pr_2Fe_(14)B grains and the thin Pr-rich phase layer continuously distributed atthe grain boundaries.The increasing remanence is resulted primarily from the develop-ment of the easy-axis alignment as well as from the densification of the Pr_2Fe_(14)B matrix.The easy-axis alignment is developed by the relative slip and rotation of the crushedPr_2Fe_(14)B grains.A full and slow hot deformation is necessary for the good easy-axisalighnment and high magnetic properties.     

Structural features of compounds with tetrahedral structures or tetrahedral anion partial structures derived from two valence electron concentration rules

The total and the partial valence electron concentrations(VEC), two variables which can be easily calculated from the composition of the compound and the valence electron numbers of the participating atoms, serve as useful parameters to predict probable structural features of compounds with a tetrahedral structure or a tetrahedral anion partial structure such as an anionic tetrahedron complex. The structural features to be predicted are the average number of nonbonding orbitals, the number of atoms in molecular structures, the average number of anion-anion bonds per anion or the average number of electrons which remain with the cation to be used either for cation-cation bonds or nonbonding orbitals.