低成本燃烧合成氮化铝粉体

从降低燃烧合成氮化铝成本的角度出发，研究了在不使用惰性稀释剂氮化铝的条件下，氮气压力等因素对于燃烧合成过程及燃烧产物相组成及其微观形貌的影响。实验结果表明：在不添加氮化铝作为惰性稀释剂的情况下也可以成功制备出纯度高、氧含量低、粒度细小的单相氮化铝粉体。此外，氮气压力对于原料铝粉的氮化程度及燃烧产物的微观形貌有着较大的影响。     

稀释剂对燃烧合成的ZrN的影响

探讨了一种新型的燃烧合成ＺｒＮ的工艺，该工艺的特点是用ＺｒＨ２作原料，在低压氮气下进行ＺｒＮ的燃烧合成。并讨论了其脱氮化机理，探索了产物相稀释剂对合成过程、产物相及产物形貌的影响。结果表明：在低压氮气下，用ＺｒＨ２燃烧合成ＺｒＮ的艺是可行的。当产物相稀释剂的添加量为２０％－２５％。粒度与原料粒度接近时，其转化率最高，且颗粒的形貌合成前后没有改变，仍为片层状结构。     

稀释剂对燃烧合成ZrN的影响

探讨了一种新型的燃烧合成ＺｒＮ的工艺，该工艺的特点是用ＺｒＨ２作原料，在低压氮气下进行ＺｒＮ的燃烧合成。并讨论了其脱氢氮化机理，探索了产物相稀释剂对合成过程、产物相及产物形貌的影响。结果表明：在低压氮气下，用ＺｒＨ２燃烧合成ＺｒＮ的工艺是可行的。当产物相稀释剂的添加量为２０％～２５％，粒度与原料粒度接近时，其转化率最高，且颗粒的形貌合成前后没有改变，仍为片层状结构     

CaWO4-NaCl-CaCl2体系熔盐电解制备钨粉的表征与电化学分析

通过熔盐电解法从CaWO4-NaCl-CaCl2体系制备出金属钨粉,采用X射线衍射仪(XRD)、电子扫描显微镜(SEM)和能谱分析仪(EDS)对钨粉的形貌和相组成进行表征。在试验数据的基础上计算电流效率,通过分析电解过程中形成的中间产物,讨论电解过程中的电极反应,采用循环伏安法和方波伏安法分析体系的基本热力学性质。结果表明:在750℃、槽电压2.5 V下经5 h以上电解可制备出纯度达到99%、平均粒度低于2μm的金属钨粉,实验中的电流效率可达到80%;电解过程的电极反应不可逆,浓差极化是体系电解速率的主要阻力。     

NaCl含量对盐助燃烧合成超细硼化钨粉体相组成和粒度的影响及其作用机制

在W-B_2O_3-Mg体系中引入不同含量的稀释剂NaCl,盐助燃烧合成了超细硼化钨粉体,利用XRD、SEM和EDS对合成粉体的相组成及粒度进行了分析。结果表明未加入NaCl时,燃烧合成产物浸出前主要是W_2B_5和MgO的混合团聚物,颗粒形貌接近于椭球形;加入NaCl后,除了W_2B_5和MgO外,还出现了新相WB,颗粒形貌不规则且有微弱团聚现象;浸出后产物主要由大量的小尺寸硼化钨颗粒组成,粉体组成由W_2B_5转变为W_2B_5+WB+B的复合物。浸出产物W与B元素的总含量均达到了98%以上,当NaCl含量k=5时达到了最大值98.51%;其平均粒度随NaCl含量的增加而减小,当k=20时达到粒度的最小值0.85μm。     

电场作用下压坯密度对W—C—Co体系燃烧合成的影响

采用Gleeble-3500D热模拟机,在电场和大热流密度作用下,研究压坯密度对88(W+C)-12Co(质量分数)粉末压坯燃烧合成的影响.结果表明:当压坯相对密度为71%～75%,体系的点火温度为727～753℃;随压坯密度提高,体系点火温度降低,点火延迟时间有所缩短,但变化幅度不大.同时,合成产物的XRD和SEM结果表明:压坯密度对燃烧合成产物的相组成影响不大,均由WC和W2C组成;但随压坯密度增大,产物中碳化钨颗粒逐渐减小.     

电场诱导下压坯密度对Fe-V-C体系燃烧合成的影响

采用Gleeble热模拟机，在电场和大热流密度作用下，研究压坯密度对Fe—V-C三元系粉末压坯燃烧合成的影响。结果表明，当压坯相对密度为73％～83％时，体系的点火温度范围为753-771℃；随压坯密度增大，体系点火温度提高，点火延迟时间增加，所达到的最高温度也有所提高；压坯密度对燃烧合成产物的相组成影响不大，均由FeC、V8C7，和V6C5组成；但随压坯密度增大，产物颗粒有所长大。     

成型压力对盐助燃烧合成超细CeB6粉体粒度和纯度的影响及其作用机制

在B_2O_3-CeO_2-Mg体系中引入发热剂KClO_3,利用盐助燃烧法制备超细高纯度CeB_6粉体,研究成型压力对盐助燃烧合成超细CeB_6粉体粒度和纯度的影响。借用SEM、EDS、TEM和XRD探讨了盐助燃烧合成法制备CeB_6粉体的形成机理。结果表明,燃烧合成的主要产物为CeB_6,且随着成型压力的增大,浸出后产物的平均颗粒尺寸略微有增加,平均尺寸为0.830～0.930μm,整体粒度分布较为均匀;浸出产物的纯度随着成型压力的增加呈现出先增加后减小的趋势,当压力为20 MPa时,纯度达到最大值99.0%,但不同压力下各试样纯度均在98.0%以上。     

燃烧合成Mg2Ni的影响因素

用XRD和SEM对Mg-Ni体系燃烧合成产物进行了研究。结果表明：Mg—Ni压坯预热至440℃以上均可热爆合成Mg2Ni，且预热速度越大产物越致密；过大的压坯密度，降低了体系的燃烧温度，影响Mg，Ni间的反应程度；而对于细小的Mg粒，由于较高的燃烧温度，导致合成产物出现严重的烧结现象；此外热爆合成产物在一定温度下适当的保温，有助于提高Mg2Ni的纯度。     

铝热剂反应燃烧合成Al2O3—TiC陶瓷的径向显微组织变化

研究了压坯直径对燃烧合成Al2O3－TiC陶瓷的燃烧速度和温度的影响以及圆柱试样的径向微观组织变化。燃烧合成的圆柱试样轴心区直径1．5μm～5.5μm的圆形颗粒为TiC,具有熔化特征的边长10μm～20μm的多边形为含有少量TiC的刚玉;在二分之一半径处,TiC颗粒和刚玉块的尺寸分别减小为0．1μm～3μm和5μm～15μm;但在靠近合成试样圆周及其圆柱表面,刚玉变成为了晶须,TiC则是0．1μm－0．5μm的微小颗粒组成的团聚体。这是因为试样在燃烧合成过程中沿周向和径向均有热量传递,燃烧过程中径向不同位置温度的显著变化导致了微观组织的变化。     

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。     

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.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.