Use of various MgO resources for high-purity Mg metal production through molten salt electrolysis and vacuum distillation

A green and effective electrolytic process was developed to produce high-purity Mg metal using primary and secondary resources containing Mg O as a feedstock. The electrolysis of various Mg O resources was conducted using a Cu cathode in MgF2– LiF – KCl molten salt at 1043 K by applying an average current of 1.44 A for 12.5 h. The electrolysis of calcined North Korean magnesite and seawater Mg O clinker yielded Mg alloys of MgCu2and(Cu) phases with current efficiencies of 89.6–92.4%. The electrolysis of oxidized Mg O-C refractory brick, aged ferronickel slag, and ferronickel slag yielded Mg alloys of MgCu2and(Cu) phases with current efficiencies of 59.3–92.3%. The vacuum distillation of Mg alloys obtained was conducted at 1300 K for 10 h to produce high-purity Mg metal. After vacuum distillation, Mg metal with a purity of above 99.994% was obtained. Therefore, this study demonstrates the feasibility of the production of high-purity Mg metal from various Mg O resources using a novel electrolytic process with a Cu cathode, followed by vacuum distillation.

Production of high-purity Mg metal from dolomite through novel molten salt electrolysis and vacuum distillation

In this study,a novel Mg production process for producing high-purity Mg metal from dolomite was developed.When the electrolysis of calcined dolomite was conducted using Cu cathode and C anode in MgF_(2)–LiF molten salt at 1083–1173 K by applying an average current of 1.42–1.46 A for 9.50–21.0 h,the current efficiency of 66.4–88.6%was obtained.The produced Mg alloys consisted of MgCu_(2)and Cu(Mg)or MgCu_(2)and CuMg_(2)phases,depending on the Mg concentration in the Mg alloy.When the electrolysis of calcined dolomite was conducted in MgF_(2)–LiF–CaF_(2)molten salt at 1083 K,the current efficiency was 40.9–71.4%,owing to undesired reactions such as electroreduction of Ca^(2+)or/and CO_(3)^(2−)ions.Meanwhile,the current efficiency increased from 40.9%to 63.2%by utilizing a Pt anode,because the occurrence of CO_(3)^(2−)ions in the molten salt was prevented.After vacuum distillation of the obtained Mg alloys at 1300 K for 10 h,Mg metal with a purity of 99.9996–99.9998%was produced.Therefore,the feasibility of this novel process for the production of high-purity Mg metal from dolomite was demonstrated.

Source and hazard identification of heavy metals in soils of Changsha based on TIN model and direct exposure method

A total of 153 soil samples were collected from Changsha City, China, to analyze the contents of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn. A combination of sampling data, multivariate statistical method, geostatistical analysis, direct exposure method and triangulated irregular network （TIN） model was successfully employed to discriminate sources, simulate spatial distributions and evaluate children＇s health risks of heavy metals in soils. The results show that not all sites in Changsha city may be suitable for living without remediation. About 9.0% of the study area provided a hazard index （HI）1.0, and 1.9% had an HI2.0. Most high HIs were located in the southern and western areas. The element of arsenic and the pathway of soil ingestion were the largest contribution to potential health risks for children. This study indicates that we should attach great importance to the direct soil heavy metals exposure for children＇s health.

A High Performance Sub-100nm Nitride/Oxynitride Stack Gate Dielectric CMOS Device with Refractory W/TiN Metal Gates

By complementing the equivalent oxide thickness （EOT） of a 1.7nm nitride/oxynitride （N/O） stack gate dielectric （EOT- 1.7nm） with a W/TiN metal gate electrode,metal gate CMOS devices with sub-100nm gate length are fabricated in China for the first time. The key technologies adopted to restrain SCE and to improve drive ability include a 1.7nm N/O stack gate dielectric, non-CMP planarization technology, a T-type refractory W/TiN metal stack gate electrode, and a novel super steep retrograde channel doping using heavy ion implantation and a double sidewall scheme. Using these optimized key technologies, high performance 95nm metal gate CMOS devices with excellent SCE and good driving ability are fabricated. Under power supply voltages of VDS ± 1.5V and VGS± 1.8V,drive currents of 679μA/μm for nMOS and - 327μA/μm for pMOS are obtained. A subthreshold slope of 84.46mV/dec, DIBL of 34.76mV/V, and Vth of 0.26V for nMOS, and a subthreshold slope of 107.4mV/dec,DIBL of 54.46mV/V, and Vth of 0.27V for pMOS are achieved. These results show that the combined technology has indeed thoroughly eliminated the boron penetration phenomenon and polysilicon depletion effect ,effectively reduced gate tunneling leakage, and improved device reliability.

Cu Diffusion in Co/Cu/TiN Films for Cu Metallization

Some information on how to use in-situ determined diffusion coefficient of Cu to make barrier layer of Cu metallization in ultra large scale integrations （ULSIs） was provided. Diffusion coefficients of Cu in Co at low temperature were determined to analyze Cu migration to Co surface layer. The diffusion depths were analyzed using X-ray photoelectron spectroscopy （XPS） depth profile to investigate the diffusion effect of Cu in Co at different temperatures. The possible pretreatment temperature and time of barrier layer can be predicted according to the diffusion coefficients of Cu in Co.

Study on influences of TiN capping layer on time-dependent dielectric breakdown characteristic of ultra-thin EOT high-k metal gate NMOSFET with kMC TDDB simulations

The thickness effect of the TiN capping layer on the time dependent dielectric breakdown（TDDB） characteristic of ultra-thin EOT high-k metal gate NMOSFET is investigated in this paper.Based on experimental results,it is found that the device with a thicker TiN layer has a more promising reliability characteristic than that with a thinner TiN layer.From the charge pumping measurement and secondary ion mass spectroscopy（SIMS） analysis,it is indicated that the sample with the thicker TiN layer introduces more Cl passivation at the IL/Si interface and exhibits a lower interface trap density.In addition,the influences of interface and bulk trap density ratio Nit/Not are studied by TDDB simulations through combining percolation theory and the kinetic Monte Carlo（kMC） method.The lifetime reduction and Weibull slope lowering are explained by interface trap effects for TiN capping layers with different thicknesses.

Behavior of Non-metallic Inclusions in Centrifugal Induction Electroslag Castings

In order to know the behavior of non-metallic inclusions in centrifugal induction electroslag castings (CIESC), non-metallic inclusions in 5CrMnMo and 4Cr5MoSiV1 were qualitatively and quantitatively analyzed. The largest size of inclusions in the casting and the thermodynamic possibility of TiN precipitation in steel were also calculated. The results show that sulfide inclusions are evenly distributed and the content is low. The amount of oxide inclusions in CIESC: 4Cr5MoSiV1 steel is close to the ESR steel and lower than that in the EAF steel, and there are some differences along radial direction. Nitride inclusions are fine and the diameter of the largest one is 3-1 mum. With the increase of the centrifugal machine's rotational speed, the ratio of round inclusions increases and the ratio of sharp inclusions decreases. According to the experiment and the calculation results, it is pointed out that the largest diameter of non-metallic inclusions in the CIESC 4Cr5MoSiV1 casting is only 6.6 mum, and [N%][Ti%] in 4Cr5MoSiV1 steel should be controlled less than 4.4x 10(-5) in order to further reduce the amount and size of TiN inclusions.

Synthesis of α-Selenoesters By Reactions of α-Bromoesters With Diselenides Promoted By Metallic Tin

α-Bromoesters can react with diselenides by metallic tin in THF to give α-selenoesters in moderate to good yields.

REGIOSELECTIVE ALLYLATION OF THE TERMINAL EPOXIDES BY ALLYL BROMIDE AND METALLIC ZINC OR TIN

Allylation of terminal epoxides(1)to give the homoallylic alcohols(2)and bishomoallylic alcohols(3)can be carried out successfully by allyl bromide and metallic zinc or tin.The effect of substituents on epoxides was studied.

STUDIES ON THE PROPERTIES OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS Ⅲ TRANSMETALLATION REACTION OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS WITH METALLIC TIN

The transmetallation reaction of 4 Schiff base type arylmercury compounds with metallic tin has been carried out in refluxing xylene.It was found that the reaction proceeds in the same manner as that of chloro[2-(phenylazo)phenyl]mercury(Ⅱ) to give dichlorobisaryltin(Ⅳ).The ~1H NMR spectra of the products provide evidence for the presence of N→Sn intramolecular coordination.The formation of dichlorobisaryltin(Ⅳ)as a unique product probably arises from the N→Sn intramolecular coordination which results in the increasing of the stability of the molecule.

电火花沉积反应合成TiN增强Fe基金属陶瓷涂层

利用自制的电火花沉积充气密闭式保护装置和DZ-1400型电火花沉积/堆焊机,以工业纯钛TA2为电极,以工业纯氮为保护气和反应气,在45#钢基体试样表面制备出了厚度为60～80μm的TiN增强金属基陶瓷涂层。采用扫描电镜(SEM)观测了涂层微观结构和界面行为,分析了涂层形成机理,利用X射线仪(XRD)测定了涂层的物相组成,利用显微硬度仪测试了涂层的显微硬度,利用自制磨损试验机对比了涂层与淬火W18Cr4V高速钢的耐磨性。结果表明:涂层主要由TiN和FeTi两相组成,涂层组织致密、均匀、较连续,涂层与基体形成良好的冶金结合,涂层显微硬度HV高达15.88GPa,约是基体硬度的5倍,涂层具有较好的耐磨性。

SiO_2层晶化对TiN/SiO_2纳米多层膜结构和性能的影响

采用多靶磁控溅射法制备了一系列具有不同SiO2调制层厚的TiN/SiO2纳米多层膜.利用X射线衍射,X射线能量色散谱、扫描电子显微镜、高分辨电子显微镜和微力学探针表征和研究了多层膜的生长结构和力学性能.结果表明,具有适当厚度(0.45-0.9nm)的SiO2调制层,在溅射条件下通常为非晶态,在TiN层的模板作用下晶化并与TiN层共格外延生长,形成具有强烈(111)织构的超晶格柱状晶多层膜;与此相应,纳米多层膜产生了硬度和弹性模量异常增高的超硬效应(最高硬度达45GPa).随着SiO2层厚度的继续增加,SiO2层转变为非晶态,阻断了多层膜的共格外延生长,使纳米多层膜形成非晶SiO2层和纳米晶TiN层的多层结构,多层膜的硬度和弹性模量逐渐下降.

TC4合金表面激光熔覆NiCrBSiC+TiN粉末涂层的微观组织研究

采用CO2激光在TC4合金表面进行了NiCrBSiC+TiN粉末的熔覆试验,获得了连续均匀、无气孔和裂纹的熔覆层,利用EPMA、SEM和TEM分析了激光熔覆层的微观组织。结果表明,熔覆层的组织为在Ni基合金基体上均匀分布着TiN颗粒和针状的M23(CB)6相,TiN颗粒与Ni60合金结合紧密,界面干净光滑。熔覆层与TC4合金呈冶金结合,结合区的组织由柱状晶和树枝晶组成,基底热影响区为马氏体组织。

TiC/TiN复合陶瓷刀具材料的力学性能研究

以微米TiC和TiN为主要原料,以微米Cr、Ni以及Co为添加剂,采用真空热压烧结工艺制备了TiC/TiN复合陶瓷刀具材料。测试和分析了烧结样品的相对密度、弯曲强度、断裂韧性以及硬度性能。结果表明,当微米TiC添加量(质量百分数)为48%,TiN为16%、Cr为7.2%、Ni为21.6%以及Co为7.2%时,所制备的复合陶瓷刀具材料性能最佳,相对密度值为95.2%,弯曲强度575 MPa,断裂韧性为9.32 MPa·m1/2,硬度值为1288 kgf/mm2。

0Cr18Ni10Ti钢中TiN夹杂物的危害及应对措施

浅述了Ti N给0Cr18Ni10Ti等含Ti奥氏体不锈钢使用带来的影响,并对如何降低0Cr18Ni10Ti钢中Ti N数量及评级的措施进行了分析讨论。选择适宜的原辅料、冶炼工艺流程及工艺参数,可有效降低钢中Ti N;推广应用00Cr19Ni10N是解决Ti N危害的最有效手段。

辐照对聚酰亚胺基板铜薄膜金属化TiN阻挡层的影响

采用物理气相沉积方法在聚酰亚胺基板上沉积Cu薄膜,利用TiN阻挡Cu元素向聚酰亚胺基板内部扩散。研究了在60Co-g射线辐照条件下,TiN阻挡层的阻挡效果,扫描俄歇微探针谱图分析表明:TiN层可以有效地阻挡Cu元素向聚酰亚胺基板内的扩散。当照射剂量大于2105 Gy后,TiN失去阻挡Cu元素扩散的效果。

反应电火花沉积合成TiN金属基复合涂层

利用自制的反应电火花沉积合成系统,以TA_2为电极,以工业纯氮为保护气,在45#钢基体试件表面上原位反应合成了TiN金属基陶瓷复合涂层。利用X射线仪测定了涂层的物相组成,利用显微镜观察分析了涂层断面形貌及组织,利用硬度仪测试了涂层的显微硬度,利用磨损试验机对比了涂层与淬火W18Cr4V高速钢的耐磨性能。结果表明:涂层的平均维氏硬度为13230 MPa,涂层中TiN物相的平均晶粒大小为50 nm,涂层具有较好的耐磨性。

Co-Mo-N/TiN催化剂的制备及其氧还原性能研究

以改进的溶胶凝胶法将Co、Mo混合氧化物负载在纳米氮化钛上,经程序升温氨还原得到催化剂CoMo-N/Ti N,并使用XRD、EDS、CV、RDE等方法对催化剂的结构及氧还原性能进行测试.结果显示,热处理温度为650℃时制得的催化剂Co-Mo-N-650的氧还原催化活性最好,其氧还原起始电位为0.372 V(vs.SCE),在转速为2 000 rpm时极化电流密度达2.21 m A·cm-2,并得到了该催化剂上氧还原反应的转移电子数为2.6,说明Co-Mo-N-650催化的氧还原反应主要按二电子路径进行.

带有TiN阻挡层的新型Au金属化系统在硅微波器件中的应用

将带有ＴｉＮ、Ｗ和Ｍｏ阻挡层的Ａｕ金属化系统用在高频大功率三极管上，对其ＥＢ结进行了高温大电流应力和高温存储试验。结果表明采用ＴｉＮ作阻挡层的管子的寿命比用Ｗ作阻挡层的管子提高了两倍多：用ＴｉＮ作阻挡层的管子和用Ｗ作阻挡层的管子具有较好的耐高温特性，与Ｍｏ作阻挡层的管子相比它们承受的温度更高。

TiN薄膜的循环制备和电学性质

用金属有机物化学气相淀积(Metal Organic Chemical Vapor Deposition,MOCVD)制备了 TiN 薄膜,通过不同循环制备的、厚度相同的平面薄膜电阻率的比较研究了 TiN 薄膜的电学性质．结果表明,多次循环会引入界面而增大电阻率, 与薄膜成分和微结构分析的结果一致．得到了单循环的最优厚度以使样品电阻率最低．通过相同循环、不同厚度样品在真实器件中电学性能的比较,发现介窗(Via)直径越小,TiN 薄膜对介窗电阻的影响越大．