两种快速测定锆铪的光度法

研究了锆和铪的二甲酚橙络合物在高氯酸介质中、硫酸钠下存在的吸收光谱,结果表明:在高氯酸介质中,Zr(Ⅳ)-XO,λmax为555~558 nm;Hf(Ⅳ)-XO,λmax为535 nm。在常温下,Hf(Ⅳ)-XO在558 nm和500 nm处的吸光度比值稳定。对锆铪混样可用双波长K系数法测出锆的含量,用差减法求出铪的量,此法适用范围为锆(铪)0~25μg/25 mL;在低温(0~5℃)时,有硫酸钠存在的条件下,铪被有效隐蔽,测出锆的含量,再结合EDTA滴定法可求出铪的含量,该法适用范围为锆0~30μg/25 mL,铪0~40μg/25 mL。两种测定分析方法的相对误差均在10%以下。     

直流电弧空气等离子体炬阴极材料的烧蚀研究

空气等离子发生器中阴极材料的烧蚀行为直接影响阴极寿命,阴极材料和工作环境不同是影响阴极烧蚀的重要因素.通过直流电弧空气等离子体炬切割实验,研究了两种切割电极用阴极材料(Hf和Ag)烧蚀行为,采用扫描电镜(SEM)深入分析了阴极烧蚀机制.发现在同等条件下,Hf阴极的烧蚀量和烧蚀率远低于Ag阴极,Hf阴极的抗烧蚀性能较好.随着工作时间间隔的延长,Hf阴极和Ag阴极的烧蚀率都会降低,并且在连续工作时间大于60 s后,两种阴极材料的阴极烧蚀率都逐渐趋于一定值.分析表明,阴极烧蚀量的大小主要取决于阴极液化区域的大小以及液体或气体溅射量的大小,在工作环境下,阴极的导热性和电子逸出功对阴极的烧蚀量都有着至关重要的影响.在影响阴极烧蚀性能诸因素中,阴极材料的电子逸出功占据主导地位,为主要因素;阴极材料的导热性和熔点占据次等地位,为次要因素.     

Investigation into the occurrence forms of oxygen in hafnium nanopowders

The synthesis modes are studied with the purpose of developing hafnium powders with the lowest oxygen content. The results of investigations into the influence of preparation conditions on the occurrence forms of oxygen in hafnium nanopowders are considered. The studies were performed using the methods of analytical chemistry, X-ray diffractometry, and electron microscopy. The data of the phase and structural analyses, the results of microscopic investigations, the chemical analysis for oxygen, and the investigation of the samples for the presence of dissolved gases are presented.     

Generalization of information on phase diagrams of binary hafnium systems

Prospects of applying the analogy principle when investigating binary hafnium compounds are considered. The classification of binary hafnium compounds by the main distinctive features of their phase diagrams is developed using a taxonomic approach. Seven uniform groups of compounds under consideration are distinguished and distinctive features of phase diagrams of each group are determined. The rationality of a two-dimensional metric, the application of which ensures obtaining qualitative evaluations of similarity of various diagrams and reveals the analog compounds, is substantiated. The results of classification can be used when substantiating the compositions of certain basic hafnium alloys and master alloys.     

Al-rich portion of the Al-Hf phase diagram

Electrical resistivity measurements, differential thermal analysis, optical microscopy, and the deposition of hafnium compound particles from a melt are used to study the Al-rich portion of the Al-Hf phase diagram. Prominence is given to the hafnium solubility in solid and liquid aluminum. The studies show a peritectic character of the invariant reaction during the solidification of alloys with sufficiently high hafnium contents and a slight difference between the peritectic and melting temperatures of pure aluminum. The hafnium solubility in solid and liquid aluminum is shown to increase with the temperature. The hafnium solubility in solid aluminum at the peritectic temperature (maximum solubility) is 1.00 wt % (0.153 at %); the hafnium solubility in liquid aluminum at this temperature is 0.43 wt % (0.065 at %).     

惰气熔融-红外法测定铪中氢含量

使用LECO-NH836氮氢分析仪，采用惰性气氛熔融试样，红外法检测铪中氢含量.选择1.00 g镍篮作为铪中氢释放的助熔剂，研究不同分析功率对氢含量分析值的影响，选择分析功率为5 000 W，最短分析时间为60 s，试样质量为0.10 g，验证了钛标准物质的适用性.对2组试样11次平行测定结果的RSD分别为5.64 %和1.52 %，精密度良好.加标回收率为95.18 %~105.26 %.研究结果对准确测定铪中氢含量具有指导意义.      

DIBK-P204体系萃取锆和铪的动力学

研究了DIBK-P204体系萃取锆和铪的动力学,采用恒界面池法考察搅拌速度、界面积和温度对锆和铪萃取速率的影响。结果表明,DIBK-P204体系对锆和铪萃取速率符合准一级反应,萃取反应的控制类型分别为相内反应控制和混合控制,对锆和铪萃取的表观活化能分别为-32.193kJ/mol和-18.984kJ/mol,升高温度不利于萃取反应的进行。     

铪在粉末冶金高温合金中的作用研究概况

结合铪在铸造高温合金以及变形高温合金中的作用,简要说明了在粉末冶金高温合金中添加铪的重要性,并重点概述了铪在粉末冶金高温合金中的作用及应用,最后探讨了加铪以提高粉末冶金高温合金性能的研究方向.     

DIBK溶剂萃取法分离锆铪

以二异丁基甲酮(DIBK)作萃取剂,以TBP或P204作改质剂,从不同酸性介质中萃取分离锆铪。考察酸性介质、TBP加入量、P204加入量和盐析剂(NH4)2SO4等对萃取分离锆铪效果的影响。结果表明:DIBK只有在HSCN介质中优先萃取铪,改质剂TBP或P204的加入能显著增加铪的萃取率和锆铪的分离系数。锆铪的分离系数可达到9,与MIBK萃取分离锆铪的性能相似。     

溴邻苯三酚红—氯化十六烷基三甲铵光度法同时测定锆和铪

本文对Zr(Hf)—BPR—CTMAC体系的多元配合物进行了研究.发现在锆、铪共存时,可利用试剂加入顺序的不同,其锆、铪配合物之吸光度直有极大差异,则可分别测出锆、铪的含量,适用范围为锆(铪)0～37μg/25ml.     

Synthesis of hafnium carbide by mechanochemistry and irradiation

The interaction in the Hf–C system during mechanical activation performed in a high-energy planetary ball mill and the irradiation-assisted fabrication of hafnium carbide from an Hf/C mechanocomposite are studied by synchrotron X-ray diffraction (at a quantum energy of 33.7 keV) and high-resolution scanning electron microscopy. The mechanochemical interaction results in the formation of an Hf/C mechanocomposite at the first stage and mechanical activation for ≥8 min forms hafnium carbide. The irradiation of the Hf/C mechanocomposite with a high-energy electron beam (~150 W/mm²) causes melting and spreading of hafnium over the carbon particle surface and the crystallization of hafnium carbide.     

Activated sintering of W-HfC composite materials

The features of consolidation of the particles during the activated sintering of tungsten powders with different values of dispersity (d _av = 2–3 and 0.8–1.0 μm) are investigated. Sintering was activated by introducing nickel additives (up to 0.5 wt %), tungsten nanoparticles (up to 30 wt %), and finely dispersed hafnium carbide (5–30 vol %) with subsequent milling in a vibrating mill. The uniaxial compaction of the samples has been performed under pressures from 50 to 1000 MPa, and sintering was performed in vacuum at 1850°C with holding for 1 h. It is shown that the additives of tungsten carbide increase the density of sintered billets and, in combination with dispersed hafnium carbide, tungsten-based composite materials with a grain size up to 2 μm can be obtained.     

DIBK-TBP萃取分离锆铪的热力学研究

对二异丁基甲酮(DIBK)和TBP从HSCN介质中协同萃取锆铪的性能及热力学进行研究,采用对数函数外推法求得DIBK-TBP体系萃取反应的热力学平衡常数分别为log(K12,Zr)=4.73和log(K12,Hf)=-5.09,锆铪与SCN-形成配合物Zr(SCN)3+和Hf(SCN)3+的稳定性常数分别为1×109.86和1×10-0.80,而铪的分配比在硫氰酸盐存在时要大于锆的分配比,说明过渡金属离子锆和铪在硫氰酸盐存在时与一般金属离子与配位体形成的配合物的稳定性常数愈大,金属离子的分配比愈大的规律相矛盾,并计算出萃取反应的焓变分别为ΔHZr=-11.43 kJ.mol-1和ΔHHf=-7.80 kJ.mol-1,说明对锆铪的萃取反应为放热反应,升高温度不利于萃取反应的进行,常温下自由能变分别为ΔGZr=-26.54 kJ.mol-1和ΔGHf=28.57 kJ.mol-1,熵变分别为ΔSZr=51.54 J.(K.mol)-1和ΔSHf=-124.07 J.(K.mol)-1,说明铪离子比锆离子更易与SCN-形成配位键,从而生成中性分子Hf(SCN)4与有机相发生溶剂化作用而进入有机相中。     

合金渣中铪的MIBK萃取分离试验

采用MIBK作为萃取剂,在盐酸体系下,对含铪合金渣中的铪进行萃取分离试验,主要考察合金渣中含量较高的锆、钛、铬和铪在萃前液不同氢离子浓度、NH4SCN浓度、有机相HSCN浓度及相比下的分离性能。结果表明,铪和锆钛分离难度较大、和铬分离较易,铪的最优分离条件为:萃前液氢离子浓度0.96mol/L、萃前液NH4SCN浓度2.56mol/L、有机相HSCN浓度2.73 mol/L、相比1。在最优条件下,铪和锆的相对分离系数为6.63,铪的分配比为1.79,对于锆含量较低的合金渣,可以有效提升锆铪分离效率,钛最好于萃取分离前进行分离。     

合金渣中钛铪的离子交换分离研究

在酸性体系下,采用阳离子交换法对铪钛的分离进行了研究。结果表明,001*7阳离子交换树脂可以有效实现铪的吸附,通过控制淋洗液pH可有效实现铪钛的分离,所得解吸液中Ti/Hf小于0.003 5。     

不同种类岩石的光声光谱定性解析研究

采用光声光谱技术对不同成分的岩石样品进行了分析。根据一维简化模型,从理论上讨论了圆柱形光声盒内岩石样品产生的光声信号的大小,得出岩石的光声信号正比于其光吸收系数,同时也依赖于岩石的热学性质,与岩石的热扩散长度、热导率等有关。通过用光源为氙灯的光声光谱仪得到了样品的分辨率为1 nm的近红外光声光谱,实验所用样品为白砂岩、泥晶灰岩、页岩、细砾岩、花岗岩等岩石。结果表明不同岩石产生的光声信号的强弱不同,光声光谱的吸收峰个数及吸收峰波长也与岩石的种类相关。实验结果为光声光谱技术定性分析岩石的可行性提供了依据。     

DIBK-TBP体系萃取铪和锆的动力学研究

在恒界面池中研究DIBK-TBP协同萃取体系萃取铪、锆的动力学,考察了温度、界面积和搅拌强度等对萃取速率的影响。结果显示,DIBK-TBP体系萃取铪和锆的过程符合一级动力学反应;对铪的萃取为相内反应和扩散共同影响的混合控制类型,表观活化能-43.106kJ/mol;对锆的萃取与搅拌强度、比界面积无关,为相内反应控制类型,表观活化能-16.024kJ/mol。     

硼化铪粉末制备研究

硼化铪(HfB_2)具有优异的抗氧化性能,作为超高温材料在耐磨涂层、航空领域具有极高的应用价值,而纯度是影响其应用的关键因素。本文采用烧结工艺制备HfB_2粉末,利用X射线衍射仪、扫描电子显微镜、X射线能谱仪等表征了粉末的结晶性能、形貌、元素分布等。研究了硼源、混料方式对HfB_2粉末结构的影响,测定C、O等杂质含量,通过差减法计算得HfB_2纯度。结果表明,碳化硼(B4C)作为硼源、混料采用机械混合的HfB_2性能最佳,X射线衍射中仅有HfB_2结晶峰,扫描电镜中均为HfB_2紧密团聚形貌,通过化学分析测定杂质含量,差减法计算HfB_2纯度可达到98.19%。     

The extraction of hafnium (IV) by some organophosphorus reagents in the presence of two mineral acids

Extraction of hafnium (IV) was studied from solutions of mixtures of perchloric and nitric acids and of perchloric and hydrochloric acids of constant total acidity 2, 4, 6 and 8 M and c_Hf ? 4 × 10^?4mol l^?1. The organic phase consisted of solutions of various acidic or neutral organophosphorus reagents including di-n-butylphosphoric acid, di-n-amylphosphoric acid, di-n-octylphosphoric acid, n-decylphenylphosphonic acid, tri-n-butylphosphine oxide, tri-n-octylphosphine acid (TOPO), tri-n-phenylphosphine oxide, and tri-n-butylphosphate (TBP); or of 2-thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, or N-benzoyl-N-phenylhydroxylamine in benzene, chloroform, or n-octane. Pronounced synergic extraction of hafnium occurs only with organophosphorus reagents from aqueous phases whose acidity is not lower than 3 M (HClO₄ + HNO₃) or 5 M (HClO₄ + HCl). The synergic effect was not affected markedly by variation of the initial concentration of hafnium in the range 1 × 10^?8 ?4 × 10^?4 mol l^?1, but it decreased with increasing initial concentration of the organophosphorus reagent and decreasing concentration of the H⁺ ions. No synergism was observed for the extraction of hafnium from mixtures of perchloric and sulphuric acids. It is suggested that the hafnium passes into the organic phase in the form of mixed complexes, the salting-out effect of perchloric acid playing an appreciable part.