160kVA钟罩式钽铌高真空垂熔炉的研制

国内最早烧结钽铌条的真空垂熔炉是由国外引进的。当时烧结尺寸为西10mm×400mm的细条。随着钽铌生产任务的增加，现有设备不能满足生产需求，采用国外设备其价格也很昂贵，所以在参照国外设备的基础上，重新设计并研制成功了160kVA钽铌高真空垂熔炉，可烧结西28mm×900mm的钽条，每根条重5～6．5k。     

真空高温垂熔炉自动升温控制的设计改进及实践

针对高熔点金属钽、铌提纯致密化的常用设备真空高温垂熔炉的工艺温度精确控制的问题,通过智能仪表的恒功率控制的方法,以加在炉内钽、铌坯料上的加热功率为控制对象,实现钽、铌坯料在炉内烧结温度及升温速率的自动控制,使钽、铌坯料的烧结产品的纯度、晶粒组织及密度都大大提高.     

钽丝精密绕线机设计

介绍了钽丝精密绕线机的设计思路、工作原理,利用现有闲置粗绕机的机械装置,重新设计电气控制系统,通过HMI、PLC控制变频主电机、伺服排线电机,实现钽丝的高速精密排线绕线.能够做到钽丝均匀的密排,丝间没有缝隙、没有摞丝,达到"镜面"效果.     

真空钽烧结炉

钽、铌是国防和科学研究等领域中的重要金属。钽、铌粉的烧结工艺要求在高温高真空电炉里进行。某些压制品的烧结法质量与炉子的真空度有密切的关系,往往真空度提高一个数量级,烧结温度大约能降低100～120℃左右,而制品的烧结质量则有显著的提高,对钽、铌粉原料的     

钽条高温真空烧结炉的研制

介绍了高温真空烧结炉技术性能、设备结构及特点。该设备的研制成功对钽工业的进步和发展具有重要的现实意义。     

高温热电偶

一、性能: 1.量程上限达4200°F(2315℃),可以扩展至115000°F(2760℃)。 2.有3种铂——铑和3种钨——铼热电偶。 3.保护套管(以下简称套管)的材料为钽、钼、氧化锆、石英或氧化铝。     

抓工业炉节能技术改造促企业节能降耗工作

１企业产品与生大规模宝鸡有色金属加工厂是我国最大的稀有金属加工企业，主要产品有钛、钨、钼、钽、铌、锆、铪及其合金等稀有金属材料的锭、板、管、棒、丝、带、箔、型材、锻件、铸件等。产品已达９５个牌号、２８０个品种、５０００多种规格，生产规模为年产各种稀有金属加工材２７５０ｔ，并保留有６０００ｔ的发展余地，主导产品“宝鸡钛”名扬海内外，工厂被誉为“中国钛城”。２工业炉使用及管理概况我厂目前在用的各种工业炉有１００余台，其中真空熔炼炉１３台，真空退火炉９台，　工频炉和中频炉１３台，箱式电阻加热炉４４台，…     

中圣集团

江苏中圣高科技产业有限公司是在新加坡上市的中圣集团的控股子公司,公司是以节能环保工程设计为龙头。特种材料设备制造为基础。提供工程化一条龙服务的高新技术企业。公司提供钛、镍、锆、钽、铜、蒙乃尔合金等有色金属及其复合材料的标准、非标准设备的咨询、开发、设计、制造业务,     

电炉新产品简介

该炉炉体为密封结构,通氢气以保护被加热工件和发热体。本设备主要用于高熔点钨、钼、钽等稀有金属再加热及退火等用。产品主要技术规格及参数:工作室尺寸(长×宽×高)2300×800×120毫米额定功率110瓩最高工作温度1400℃     

巴西政府提议在土著民居住地进行石油勘探

正Energy Daily,2020-01-111月11日据报道,提交国会的法案草案称,巴西政府将提议法律上认为在土著民居住地进行油气勘探和建水电站合法。开放受保护的本国领土是总统Jair Bolsonaro的竞选承诺,但激进分子指责经济活动加剧了暴力并扩大森林砍伐。巴西许多土著部落居住的亚马逊雨林富含矿产(金、铜、钽、铁矿石、镍和锰)。巴西环球报称,该草案也允许土著民在其土地上"进行经济活     

Effects of tungsten oxide addition on the electrochemical performance of nanoscale tantalum oxide-based electrocatalysts for proton exchange membrane (PEM) fuel cells

In the present study, the properties of non-platinum based nanoscale tantalum oxide/tungsten oxide-carbon composite catalysts were investigated for potential use in catalyzing the oxygen reduction reaction on the cathode side of a PEM fuel cell. All of the tantalum oxide-based catalysts exhibit high ORR on-set potentials, comparable with the commercial Pt/C catalyst even though oxygen reduction current was limited. The tungsten oxide doping to tantalum oxide improved catalytic performance. The performance enhancement was due to a decrease in resistance polarization with increasing tungsten content mainly due to the decrease in resistance polarization. XPS results indicate that the oxidation state of tungsten is +6 and that of the tantalum is +5, suggesting that excess oxygen is generated in the resulting oxide structure. This compositional effect seems to reduce resistance polarization by altering the surface chemistry of the tantalum oxide and enhancing the reaction steps such as surface diffusion. Maximum performance was achieved with a catalyst containing 32 mol% of tungsten oxide, reaching a mass specific current density of ∼7% that of the commercial Pt/C catalyst at 0.6 V vs. NHE and ∼35% at 0.2 V vs. NHE. In term of area-specific current density, five-fold increase in loading of the doped catalyst leads to a 4-4.5 fold increase in area specific current density at 0.6 V vs. NHE, reaching 66% that of the Pt/C catalyst at 100 rpm and 35% at 2400 rpm.     

A novel non-platinum group electrocatalyst for PEM fuel cell application

Precious-metal catalysts (predominantly Pt or Pt-based alloys supported on carbon) have traditionally been used to catalyze the electrode reactions in polymer electrolyte membrane (PEM) fuel cells. However as PEM fuel systems begin to approach commercial reality, there is an impending need to replace Pt with a lower cost alternative. The present study investigates the performance of a carbon-supported tantalum oxide material as a potential oxygen reduction reaction (ORR) catalyst for use on the cathode side of the PEM fuel cell membrane electrode assembly. Although bulk tantalum oxide tends to exhibit poor electrochemical performance due to limited electrical conductivity, it displays a high oxygen reduction potential; one that is comparable to Pt. Analysis of the Pourbaix electrochemical equilibrium database also indicates that tantalum oxide (Ta₂O₅) is chemically stable under the pH and applied potential conditions to which the cathode catalyst is typically exposed during stack operation. Nanoscale tantalum oxide catalysts were fabricated using two approaches, by reactive oxidation sputtering and by direct chemical synthesis, each carried out on a carbon support material. Nanoscale tantalum oxide particles measuring approximately 6 nm in size that were sputtered onto carbon paper exhibited a mass-specific current density as high as one-third that of Pt when measured at 0.6 V vs. NHE. However, because of the two-dimensional nature of this particle-on-paper structure, which limits the overall length of the triple-phase boundary junctions where the oxide, carbon paper, and aqueous electrolyte meet, the corresponding area-specific current density was quite low. The second synthesis approach yielded a more extended, three-dimensional structure via chemical deposition of nanoscale tantalum oxide particles on carbon powder. These catalysts exhibited a high ORR onset potential, comparable to that of Pt, and displayed a significant improvement in the area-specific current density. Overall, the highest mass-specific current density of the carbon-powder supported catalyst was ˜9% of that of Pt.     

Electrochemical and optical properties of sputter deposited Ir–Ta and Ir oxide thin films

Addition of tantalum oxide has been investigated in order to improve the electrochromic properties of iridium oxide. Films of iridium–tantalum oxide and iridium oxide have been prepared and studied with regard to their optical and electrochemical properties. It can be seen that the addition of tantalum decreases the optical absorption coefficient and increases the ion diffusion coefficient. The change of properties is thought to be a result of the dilution of colouring iridium oxide with the better ion conducting tantalum oxide.     

Effect of nickel addition on the solubility of hydrogen in tantalum

A study of isothermal as well as isobaric P–C–T equilibrium measurements has been investigated for the solubility of hydrogen in tantalum and its alloys with nickel (1.7 and 4.9 atom % Ni) in the temperature range of 673–873 K and hydrogen pressure range of 0.60–1.20 atmospheres. The alloys were prepared by arc melting in an inert atmosphere. The dissolved hydrogen was within the solid solubility range corresponding to the temperature and followed the Sievert's law. The hydrogen solubility in tantalum decreased on the addition of nickel as an alloying element. The change in enthalpy and the change in entropy of solution for hydrogen in the tantalum metal and its alloys were calculated. The heat of reaction for hydrogen solution in all the samples was exothermic. The enthalpy of solution for hydrogen in the tantalum matrix increases on the addition of Ni as an alloying element.     

Corrosion behavior analyses of metallic membranes in hydrogen iodide environment for iodine-sulfur thermochemical cycle of hydrogen production

HI decomposition in Iodine-Sulfur (IS) thermochemical process for hydrogen production is one of the critical steps, which suffers from low equilibrium conversion as well as highly corrosive environment. Corrosion-resistant metal membrane reactor is proposed to be a process intensification tool, which can enable efficient HI decomposition by enhancing the equilibrium conversion value. Here we report corrosion resistance studies on tantalum, niobium and palladium membranes, along with their comparative evaluation. Thin layer each of tantalum, palladium and niobium was coated on tubular alumina support of length 250 mm and 10 mm OD using DC sputter deposition technique. Small pieces of the coated tubes were subject to immersion coupon tests in HI-water environment (57 wt% HI in water) at a temperature of 125–130 °C under reflux environment, and simulated HI decomposition environment at 450 °C. The unexposed and exposed cut pieces were analyzed using scanning electron microscope (SEM), energy dispersive X-ray (EDX) and secondary ion mass spectrometer (SIMS). The extent of leaching of metal into liquid HI was quantified using inductively coupled plasma-mass spectrometer (ICP-MS). Findings confirmed that tantalum is the most resistant membrane material in HI environment (liquid and gas) followed by niobium and palladium.     

Iridium-based oxides: Recent advances in coloration mechanism, structural and morphological characterization

Films of iridium–tantalum oxide and iridium oxide have been prepared by sputtering and studied regarding their structure and electrochemical properties. X-ray diffraction and transmission electron microscopy showed an average grain size of 3–4 nm for both films. Point energy dispersive X-ray spectrometry showed an inhomogeneous distribution of iridium and tantalum indicating that the iridium–tantalum oxide may be a mixture of small IrO₂ and Ta₂O₅ grains, which is consistent with the determined composition IrTa_1.4O_5.6. X-ray photoelectron spectroscopy gave valuable information on the stabilization process of the as-deposited films involving an uptake of oxygen, and on a coloration mechanism only including protons.     

Synthesis and interlayer modification of RbLaTa2O7

A layered semiconductor, lanthanum tantalum oxide was prepared by solid reaction at high temperature, and the processes for the modification of the interlayers by protonation, intercalation and pillaring were investigated. n-Butylamine could easily be intercalated into the interlayers of HLaTa₂O₇ to significantly enhance the interlayer distance, which facilitated the exchange of cation with n-butylamine. Finally, CdO pillars in the interlayer of lanthanum tantalum oxide were formed via calcinating at 500°C in air.     

Low-temperature combustion waves in low-energy K2TaF7–Si-additive systems

This work presents the use of a thermocouple technique for measuring temperature profiles in a condensed K₂TaF₇–Si system blended with a small amount of Teflon [(C₂F₄)_n] or potassium chlorate (KClO₃). A base experiment is described in detail to demonstrate the ability of the system to react under a low-rate self-sustaining mode at ambient temperature. The ignition temperatures, temperature–time profiles, combustion parameters, and final products are presented with respect to the additive concentration. The combustion processes begin at 340 and 450 °C for the KClO₃ and (C₂F₄)_n-containing mixtures, respectively. The maximum temperatures of both KClO₃ and (C₂F₄)_n-containing mixtures range from 470 to 960 °C and the combustion self-propagates along the sample at a speed of 0.01–0.08 cm/s. The solid combustion products produced under the optimized conditions include fine powders of tantalum, tantalum carbide, and tantalum silicides. The chemical mechanism of the combustion process and reaction parameters responsible for low-speed wave propagation are presented and discussed.     

Investigations of the thermophysical properties of monocrystalline tungsten

Monocrystalline tungsten and its alloys are of interest in the design and manufacture of high temperature facilities operating at high (up to 2500 °C) temperatures in vacuum under mechanical loads. This paper demonstrates advantages of using monocrystalline tungsten as a structural material in high-tech industry in comparison with polycrystalline materials. The results of comparative studies of the thermophysical properties of polycrystalline and monocrystalline tungsten 4% tantalum alloy are presented. It is shown that monocrystalline tungsten based materials are more suitable for use under high temperatures and high mechanical stresses than polycrystalline. Use of monocrystalline tungsten as a structural material makes it possible to prolong the service life of modern technical facilities.