Zirconium Dodecaboride-based cutting material

Samples of zirconium dodecaboride are obtained by means of arc and induction melting of a mixture of zirconium and boron powders. A solder for binding the zirconium dodecaboride to the steel holder of the tool is selected. It is established that cutting tools supplied with zirconium dodecaboride may be used in operations of finish turning of adhesive-active titanium alloys.     

碳化锆碱熔制备氧氯化锆的研究

以碳化锆为原料，采用碱熔一水洗一酸浸．结晶工艺制备氧氯化锆，制得的氧氯化锆产品中ZrO2含量达到36．20％。考察了氢氧化钠与碳化锆物料比、碱熔温度、碱熔时间和碳化锆粒度对碱熔过程中锆转化率的影响，以及水与碱熔料比、水洗温度和水洗时间对水洗过程中除硅率的影响。用X射线衍射分析研究了碳化锆在煅烧碱熔过程中的物相变化。结果表明，碱熔过程中碳化锆转化为偏锆酸钠，碱熔的最佳工艺条件为：氢氧化钠与碳化锆的质量比为1.5，煅烧温度800℃，煅烧时间60min，矿样粒度120目。在该工艺条件下碱熔，锆的转化率可达到99％以上。     

大型法兰下料拼焊及外包哈氏合金焊接

贵溪冶炼厂硫酸车间净化工序中动力波溢流堰与烟道过渡段采用了哈氏合金G-30进行贴补防止腐蚀。本文主要介绍了过渡段法兰的数控下料和焊接变形控制措施,通过对外包哈氏合金的化学成分分析,制定合理焊接工艺和方法,保证了焊接质量,满足了生产需要。     

锆的燃烧与防护

核电是我国能源长期发展规划中明确提出的大力发展的行业,它将带动我国核级锆材产业的大发展.介绍了锆是一种高熔点的活性金属,具有引燃能量低,粉尘能自爆,能与氮、二氧化碳反应燃烧,潮湿更易燃烧和能引燃各类物质等特性.综述了锆的燃烧扑灭方法以及预防燃烧和爆炸的具体措施.     

锆合金研究进展及我国核电站用锆材国产化的思考

综合评述了国内外核电站用锆合金材料的研究进展,重点介绍了目前国际上发展成熟的高性能锆合金：法国的M5合金、美国的Zirlo合金、俄罗斯的E635合金、日本的NDA合金及韩国的HANA合金。分析了我国在核电站用锆合金材料研制过程中存在的问题,以及我国核电用锆材国产化的难点。对我国核电用锆材的发展思路提出了几点建议。     

ICP-AES测定金红石中的锆

采用全谱直读电感耦合等离子体发射光谱法测定金红石中锆的含量,方法的检出限为0.02μg/mL,回收率为96.50%~101.00%,相对标准偏差锆为2.62%,测定结果令人满意,方法简捷、快速、可信。     

Zirconium alloys dispersion strengthened with yttria

Abstract

A powder metallurgy process for the manufacture of zirconium alloys dispersion strengthened with yttria particles is described. The resulting alloys con tain a suitable dispersion of stable yttria particles in a fine-grained matrix. Tensile and stress rupture tests over a range of temperature on Zircaloy-2 containing 0, 5 and 10 vol % yttria show the strength of yttria-containing alloys to be significantly improved. The post-irradiation tensile properties of Zircaloy-2 - yttria alloys have been determined with alloys irradiated at 280°C to 9.2 × 10²⁰ n/cm² thermal and 2.3 × 10²⁰ n/cm² fast. The alloys have been subjected to accelerated corrosion tests in steam and exhibit a variable response. Some possible detrimental factors and means of improvemen t of properties are discussed.

The mechanical properties of Zircaloy-2 alloys containing yttria particles are compared to some other zirconium alloys, Zircaloy-2 and zirconium-2.5 wt % Nb and the comparisons show that the dispersion- strengthened alloys arc worthy of further development.

Résumé

La fabrication par frittage des alliages de zirconium renforcés par des particules d'yttria est décrite. Ce procédé donne une dispersion convenable des particules d'yttria dans une matrice à grains fins. Des essais de traction et d'impact, effectués à diverses températures sur du Zircaloy-2 contenant 0,5 et 10 % d'yttria, ont montré que la résistance mécanique des alliages est nettement augmentée. D.autres essais de traction ont été effectués sur des alliages Zircaloy-2-yttria aprés des irradiations de 9.2 × 10²⁰ n/cm² thermique et 2.3 × 10²⁰ n/cm² rapide à 280°C. Les alliages ont été soumis à des essais de corrosion accélérée (vapeur) avec des résultats variables. Dans la discussion on considère les facteurs qui peuvent être miscibles ainsi que déautres améliorations possibles.

La comparaison des propriétés mécaniques des alliages de Zircaloy-2 contenant de l'yttria à celles d'autres alliages de zirconium, Zircaloy-2 et zirconium-2.5,% Nb indique que les alliages à particules dispersées méritent d'être étudiés davantage.     

Features of Production and High-Temperature Oxidation of SHS Ceramics Based on Zirconium Boride and Zirconium Silicide

This article is devoted to the investigation into the combustion kinetics and mechanism of reaction mixtures in Zr–Si–B and Zr–B systems formed according to the forced SHS-pressing of compact ceramic materials, as well as to studying their heat resistance. It is shown that dependences of the combustion temperature and rate on the initial temperature (T₀) for compositions in the Zr–Si–B system are linear; i.e., staging of chemical reactions of formation of zirconium diboride and disilicide remains invariable with an increase in T₀. The values of effective activation energy of SHS process, which evidence the leading role of the reaction interaction of zirconium with boron and silicon in the melt, are calculated. Staging of chemical transformations in the combustion wave of the Zr–Si–B system is investigated: initially the ZrB₂ phase is formed by crystallization from the melt, and then the ZrSi₂ phase appears with a delay of 0.5 s; unreacted Si crystallizes after 1 s. The phase composition of synthesis products, in which the main component is ZrB₂ diboride, and zirconium disilicide, Si, and ZrB₁₂ boride are contained depending on the composition of the reaction charge, is investigated. Compact samples having high hardness and low residual porosity are fabricated according to forced SHS-pressing technology. High-temperature oxidation of SHS samples results in the formation of SiO₂–ZrO₂–B2O₃ oxide films and ZrSiO₄ complex oxide on their surface depending on the composition, which serve the effective diffusion barrier and lower the oxidation rate.     

硫酸锆生产工艺研究

对锆英石生产硫酸锆的工艺进行研究，其主要过程为：碱熔、水洗转型、一次结晶、二次结晶，离心包装。这一独特的工艺方法解决了锆钠分离，锆铁分离和结晶形态等难题，产品质量达到了国内外用户的要求。     

硫酸锆制备工艺研究

介绍了氢氧化钠碱熔分解锆英石，经水洗、酸浸出、结晶等制取硫酸锆的工艺流程、技术条件及试验结果，制得的产品含ＺｒＯ２３４％，杂质含量少。     

Study on Preparation of Zirconium Sulphate

The preparation method of Zr(SO₄)₂*4H₂O was described. It involves following processes zircon fusing with sodium hydroxide, water leaching, sulfuric acid leaching and product crystallized process, etc. The technical factor and the experimental data are given. Among the products, the ZrO₂ content is 34% and impurities are less.     

金属锆制备方法的研究进展

总结了国内外金属锆制备方法.传统方法包括金属热还原法、氢化脱氢法和电解法,但均存在成本高、污染大、操作复杂等问题.指出了直接电脱氧法是一种制备金属单质和合金的新方法,具有成本低,能耗少、污染小、工艺简单的特点,最有希望取代传统的金属锆制备方法.     

The growth of Zirconium single crystals

Abstract

The growth of zirconium single crystals by three different techniques has been studied. For crystals grown by passing samples through a steep temperature gradient in an electron beam furnace, it is shown that there is preferred growth when the 〈111〉 direction in the beta phase which transforms to a 〈12¯10〉 direction in the alpha phase is almost parallel to the longitudinal temperature gradient. Large crystals were also grown by cycling samples through the transformation temperature followed by long annealing just below this temperature and by strain-annealing. For these latter techniques, evidence is presented to show that crystal growth proceeds to reduce the amount of substructure present.

Résumé

On a étudié la croissance de monocristaux de zirconium par trois techniques différentes. Pour des cristaux obtenus en passant des échantillons à travers un fort gradient thermique dans un four à bombardement électronique, on a montré qu'ily a croissance préférentielle lorsque la direction 〈111〉 dans la phase β, qui se transforme en la direction 〈12¯10〉 dans la phase α, est presque paralléle au gradient longitudinal de température. De grands cristaux ont aussi été obtenus par la méthode de l'ecrouissage critique et par la méthode dans laquelle on utilise un cyclage à travers la température de transformation suivi par un long recuit légèrement en dessous de cette température. Pour ces deux derniéres techniques, on a montré que la croissance s'effectue en réduisant la sous-structure dans les grains.     

Compactability of Stabilized Zirconium Dioxide Powder

Features of compacting articles from stabilized zirconium dioxide powder synthesized by the sol-gel method, and also their structure and properties are studied. Compaction parameters are determined. It is shown that the relationship between compact density and extrusion pressure may be described by the Bal'shin equation. It is established that parameters of this equation depend linearly on the duration of zirconium dioxide synthesis.     

氯氧化锆生产中废碱水和锆硅渣回收利用研究进展

锆英砂碱熔法(一酸一碱法)生产氯氧化锆错生大量的废碱水和锆错硅渣,直接排放将对环境造成极大的污染,也是对烧碱和锆资源的巨大浪费.简要介绍了废碱水和废硅渣的来源及性质,重点介绍了废碱水和锆硅渣的回收利用方法及其研究进展.废碱水回收利用方法主要有制备水玻璃、工业用氢氧化钠、偏硅酸钠等,锆硅渣回收利用方法主要有制备复合型聚合硅酸铁铝(PSAF)絮凝剂、白炭黑以及中和处理、锆元素回收等,并对各种回收利用方法的优劣进行了技术和经济分析.相比之下,利用废碱水生产工业用氢氧化钠和锆硅渣中锆元素回收具有流程短、设备简单、投资少等优点,且经济和环境效益显著,将有极好的应用前景.此外,还介绍了废碱水和锆硅渣综合回收利用方法,主要有制备五水偏硅酸钠、层状硅酸钠等.综合回收利用可较为充分的回收废碱水和锆硅渣中有价成分,不产生二次污染,有较好的应用前景.但目前还停留在实验室研究阶段,距离工业化应用尚需进行深人研究和扩大实验验证.     

熔盐电解精炼锆的工艺研究

研究了不同配比的NaCl-K2ZrF6熔盐体系的熔点,K2ZrF6:NaCl=3:7的熔点较低为721℃.在此基础上,研究了熔盐配比、阴极电流密度、电解温度等因素对NaCl-K2ZrF6熔盐体系电解精炼电流效率的影响,结果表明阴极电流密度、电解温度均与电流效率成反比.采用XRD及元素含量分析等方法研究了电解精炼产品质量.较佳的工艺条件为K2ZrF6:NaCl为3:7(%,质量分数),温度800℃,阴极电流密度1 A·cm-2,在此条件下,电流效率可达84%以上.阴极锆为合格的工业级锫产品,产品中Fe,Ni,Cr,Mn等杂质分别由2700×10-6,540×10-6,350×10-6,400×10-6降低到30×10-6,10×10-6,18 ×10-6,100×10-6以下,产品纯度达到99%以上.     

Zirconium alloys produced from far eastern minerals

The zirconium alloy produced from zirconium concentrate by the electroslag method contains 27–35% Si, 19–38% Zr, 0.3–0.5% W, 3–6% Al, 2–5% Mg, and 0.1% Ca; the remainder is iron. This alloy increases the impact strength of steel by 30–70%, reduces the chill blemishing, and improves the strength of iron castings.