Volume and Surface Properties of Antimony-Containing Nickel Melts

A decrease in the detrimental effect of an antimony impurity in nickel is considered using structure-sensitive parameters, namely, density and surface tension. Samples of experimental heats containing 0.01–0.05 wt % Sb are prepared from a preliminarily cast master alloy. Antimony additions are found to increase the density of the nickel melt substantially. A negative density hysteresis appears in the temperature dependences recorded upon cooling. Antimony in the nickel melt is found to have a high surface activity and to decrease its surface tension strongly. When the melt is heated, its surface tension increases, which is accompanied by the passage of antimony into the volume and by changes in the volume and surface solution compositions.     

镍添加量对W-Ni-Sr电极材料组织和性能的影响

采用粉末冶金工艺制备W-Ni-Sr电极材料,采用光学显微镜和扫描电镜/能谱分析研究了W-Ni-Sr电极材料组织形貌和晶粒大小的变化,测试了材料的密度、硬度、电导率和热导率。研究了镍添加量（0～5%）对W-Ni-Sr电极材料组织性能的影响。结果表明,Ni对电极材料起到活化烧结的作用,添加1%镍即可使材料相对密度达97%以上;然而镍添加量增多,会增大材料的逸出功,对电极材料的电子发射不利,同时降低材料的熔点、电导率、热导率,对抗烧蚀性能不利。综合分析认为,镍的最佳添加量为1%。     

Thermodynamic Properties of Fe-C-N and Fe-C-B-N Melts

The saturated solubility of carbon and nitrogen in Fe-C-N and Fe-C-B-N melts was measured experimentally at 1 485℃ to obtain the activity interaction coefficients between components in these melts. A new method was used to treat experimental results. Using thermodynamic derivation and calculation, some important interac- tion coefficients between components in these melts were obtained.     

Thermodynamic Properties of Cu-Ce-O and Cu-RE-O Melts

ＴｈｅｒｍｏｄｙｎａｍｉｃＰｒｏｐｅｒｔｉｅｓｏｆＣｕ－Ｃｅ－ＯａｎｄＣｕ－ＲＥ－ＯＭｅｌｔｓ￥ＨｏｎｇＬａｎ；ＳｕｉＺｈｉ－Ｔｏｎｇ；ＷａｎｇＣｈａｎｇ－Ｚｈｅｎ（ＤｉｖｉｓｉｏｎｏｆＭｅｔａｌｌｕｒｇｉｃａｌＰｈｙｓｉｃｏｃｈｅｍｉｓｔｒｙ，Ｎｏ...     

Effect of Vacuum Carburizing on the Structure and the Properties of Aluminide Coatings on Nickel Superalloys

The processes that occur during vacuum carburizing of turbine blades made of carbon-free nickel superalloys are considered. Disperse alloying-element carbide particles are found to form in the surface layer of the VZhM5 alloy. These particles increase the fatigue life of the alloy during high-temperature oxidation. The disperse carbide particles are shown to hinder the formation of coarse γ′-Ni₃Al grains and topologically close-packed phases under a coating; hence, they prevent premature fracture of the alloy.     

高镍锌白铜的性能研究

采用水平连铸－拉拔－轧制生产工艺锌白铜异材，对高镍锌白铜的金相组织，机械性能及退火工艺进行了研究。研究表明α单相高镍锌白铜具有优良的机械性能，适宜冷热加工，退火温度为７００－７５０℃，颜色为银白色。该材料完全能满足高档眼镜用异形材料的要求。     

镍对Cr-Ni-Si系铸造不锈钢性能的影响

研究了Ｃｒ－Ｎｉ－Ｓｉ系耐浓硝酸铸造不锈钢的化学成分,耐蚀性、冲击韧性。试验结果表明,含７％Ｎｉ的铁素体－奥氏体双相钢,具有良好的冲击韧性和耐腐蚀性能。     

钴对钼丝加工及组织性能的影响

研究了钴对钼丝的拉伸性能及其加工硬化的影响。对加工态和退火态纯钼丝及掺杂结构钼丝的金相组织、力学性能进行观察和分析,发现钼中加钴提高了钼丝的加工硬化率,降低了再结晶温度,并且明显改善了退火钼丝的室温延性。因此,掺钴钼丝是一种性能优良的丝材。     

Effect of Secondary Melt Refining on the Properties of an EP602 Nickel Superalloy

The influence of argon blowing of the EP602 alloy melt in a ladle is considered. Ladle treatment during the manufacture of nickel superalloys is shown to form a more equilibrium and homogeneous structure of a melt, which leads to changes in the structure and properties of the solid metal.     

The Electrochemical Formation of Ni-Tb Intermetallic Compounds on a Nickel Electrode in the LiCl-KCl Eutectic Melts

The work presents an electrochemical study on the formation of Ni-Tb intermetallic compounds in the LiCl-KCl-TbCl₃ melts on tungsten and nickel electrodes at 773 K (500 °C) by electrochemical techniques. For a tungsten electrode, cyclic voltammetry and square-wave voltammetry showed that the electrochemical reduction of Tb(III) proceeded in a one-step process involving three electrons at ?2.06 V (vs Ag/AgCl). For a nickel electrode, the reduction potential of Tb(III)/Tb was observed at more positive values than those on W electrode by cyclic voltammetry, due to the formation of Ni-Tb intermetallic compounds. Square-wave voltammetry and open-circuit chronopotentiometry put into evidence the formation of intermetallic compounds at around ?1.27, ?1.63, and ?1.88 V, respectively. Three alloy samples were obtained by potentiostatic electrolysis on a Ni electrode at various potentials and analyzed by X-ray diffraction, scanning electron micrograph, and energy-dispersive spectrometry. The analysis results confirmed the formation of Ni₁₇Tb₂, Ni₅Tb, and Ni₂Tb alloy compounds.     

锰铁熔体中磷和锰的热力学性质

通过１４００℃下Ｆｅ－Ｍｎ－Ｃ－Ｐ系中碳的溶解平衡实验，测定了该熔体中碳的溶解度，应用热力学理论计算出，，，并提出了适用于锰铁熔体中磷和锰的活度系数计算式     

Effect of Annealing on the Interfacial and Structural Properties of Amorphous Silicon-Hafnia Films

Chemical and physical properties of the interface formed between amorphous silicon (a-Si) and hafnium oxide (HfO₂) were investigated using X-ray reflectivity (XRR) and X-ray photoelectron spectroscopy (XPS). XRR showed that the interface layer formed between the a-Si and HfO₂ layer had a thickness of 0.7 ± 0.3 nm and a density of 4.4 ± 0.2 g/cm³. Based on the XPS results, the interface comprised HfO₂, silicon oxide, and hafnium silicate phases. High-temperature annealing led to the conversion of elemental silicon and nonstoichiometric silicate into silicon dioxide phases. This reaction was also accompanied by the chemical reduction of the HfO₂ phase. Annealed films crystallized into the monoclinic phase of HfO₂ with a preferred orientation along the (111) axis.     

Effect of Pulsed Laser Radiation on the Properties of Resistive Thick Films Based on Nickel and Barium Borides

We have used atomic force microscopy to study the surface morphology of resistive thick films based on powders of nickel and barium borides and a glass binder, treated with laser radiation. We used x-ray phase analysis to study the phase composition of these films. We have observed a change in the surface morphology, the phase composition, and the electrical resistance of the studied films as a function of the laser radiation energy.     

In Situ Observation of Collision between Exogenous and Endogenous Inclusions on Steel Melts for Active Steel Filtration

In a confocal scanning laser microscope, interactions between exogenous and endogenous inclusions on steel melts have been investigated. Higher capillary long-range attraction forces as well as higher acting lengths of the capillary forces between exogenous and endogenous particle pairs have been observed in comparison to endogenous inclusions pairs. The contribution of the roughness of the exogenous inclusions to the capillary attraction forces has been discussed and a surface filter design for a higher filtration efficiency of steel melts has been proposed.     

Study of Effect of Non-Metallic Inclusions on Structural State and Properties of Low-Carbon Microalloyed Structural Steels

Metallurgist - The effect of silicate glassy inclusions, formed in the final stages of ladle treatment and during continuous casting, on the structural state of cast billets and the properties of...     

Characterization of Nickel Diffusion and its Effect on the Microstructure of Nickel PM Steels

Admixing pure elements to powder mixes can cause the formation of heterogeneous microstructures in sintered parts. For instance, nickel is renowned for forming nickel-rich areas (NRA) in powder metallurgy (PM) nickel steels due to its poor diffusivity in iron matrix (or lattice). The present work is aimed at characterizing the principal diffusion mechanisms of nickel and their influence on microstructures and properties of PM nickel steels. A new wavelength dispersive X-ray spectrometry (WDS) approach linking line scans and X-ray maps to concentration maps is proposed. Grain boundary and volume diffusion coefficients of admixed nickel have been determined in PM nickel steels using Suzuoka’s equation. Results also show that nickel distributes itself in the iron matrix mainly by surface and grain boundary diffusion.     

Influence of Atomic and Molecular Hydrogen in Silumins Melts on Their Mechanical Properties

Metallurgist - We study the influence of gas porosity caused by the presence of dissolved hydrogen on the mechanical properties of Al–Si alloys. The results are obtained by testing cast...     

Thermodynamic Properties of Carbon and Manganese in Mn-C and Mn-Fe-C Melts

Carbon solubility in Mn Fe melts （xMn =0. 083-0. 706, XFe =0. 034-0. 715） was measured experimentally at various temperatures. By thermodynamic derivation and calculation, the relationship between activity coefficient of carbon in infinite dilute solution of manganese in Mn-C system and temperature was obtained. Using Gibbs-Duhem relationship, the experimental results of this study, and experimental data obtained by strict thermodynamic derivation and calculation in references, the relationships between other thermodynamic properties （εCC, εCCC, εCFe, εCCFe, and εCFeFe） in Mn-Fe-C system and temperature were obtained.     

高Cr镍基铸造高温合金中的沉淀相及其对性能的影响

对一种高Cr镍基铸造高温合金的铸态、固溶态和标准热处理态的组织进行了光学和电子显微镜观察,并进行了相分析.测定了不同时效时间,即沉淀相析出过程对合金力学性能的影响.结果表明,合金中沉淀相有α-Cr相、γ'相和少量的M12C6及M6C相.存在含量为10%左右的α-Cr相是本合金的显著特点.随着沉淀相析出过程的延长,合金的硬度、拉伸和持久性能不断提高.但是各性能提高的速度不同,由快到慢的顺序依次为硬度、拉伸强度和持久寿命.