Chevrel-phase sulfides Cu_xMo₆S₈, where 2.0≤x≤4.0, were prepared by reacting appropriate amounts of Cu, Mo, and MoS₂ powders at 1273–1523 K for 8 h in vacuum. The samples were then densified by pressure-assisted sintering at 1223–1473 K for 1 h at a pressure of 30 MPa in vacuum. The density of all the sintered samples was greater than 95% of the theoretical density. X-ray analysis showed that all the sintered samples consisted entirely of the hexagonal Chevrel phase. The value of the lattice parameters a and c increased with the Cu content. Measurement of the Seebeck coefficient, electrical resistivity, and thermal conductivity was carried out on single-phase sintered Cu_xMo₆S₈ samples in the temperature range of 300–950 K. All the sintered samples had a positive Seebeck coefficient. Further, the thermoelectric properties improved when the Cu content was increased. With an increase in the Cu content, the Seebeck coefficient and electrical resistivity increased, while the thermal conductivity decreased. The highest dimensionless thermoelectric figure of merit ZT (0.4) was observed in Cu_4.0Mo₆S₈ at 950 K.

We investigated the magnetic and electrical properties of a heavy-ion irradiated single crystalline iron film. A high quality Fe (001) film on MgO (001) was fabricated using the molecular beam epitaxy technique. The iron film was treated by 3.2 MeV Ni ion irradiation at room temperature using a tandem accelerator. Although the residual electrical resistivity increased by 0.9×10⁻⁸ Ωm after ion irradiation, the M-H curves did not change significantly. These results indicate that the formation of small irradiation defects such as sub-nanometer size vacancy clusters has little influence on magnetocrystalline anisotropy and the magnetization process of iron.

The Nd-rich phase of Nd-Fe-B sintered magnets, which contains some amount of oxygen, plays an important role for generating coercivity. However, the influence of interfacial microstructure between Nd₂Fe₁₄B and Nd-rich phases has not been clear. In this study, Nd₂Fe₁₄B/Nd(-O) interface was prepared by thin film technique and the influence of oxidation state of Nd-rich phase on the coercivity was investigated. A Nd-Fe-B layer was deposited by ultra high vacuum (UHV) magnetron sputtering, and the film was oxidized under low vacuum condition (low oxidation state) or Ar atmosphere (high oxidation state). A Nd layer was deposited on the oxidized Nd-Fe-B layer, and the film was annealed at 250–650°C for 60 min. The coercivity of films oxidized in low oxidation state was recovered by annealing at 250–650°C, and an amorphous phase was observed at the interface between Nd₂Fe₁₄B and hcp Nd₂O₃ (+ fcc NdO_x) phases in the film annealed at 350°C. On the other hand, the coercivity of films oxidized in high oxidation state was lower than that of films oxidized in low oxidation state, and it decreased more about 20% by annealing at 250–350°C. However, an amorphous phase was not observed at the interface of these films. After annealing above 550°C, the coercivity of films oxidized in both low and high oxidation state recovered drastically to the almost same value of as-deposited film. From the SAD patterns of TEM observation, a metastable C-Nd₂O₃ phase was present in the Nd-rich phase of these films. In addition, it is known that the wettability of Nd-rich phase improves at temperatures around 550°C. Therefore, it is considered that the increase of coercivity is related to the improvement of fluidity of Nd-rich phase or the existence of C-Nd₂O₃ phase.

Characterization of the internal friction properties of 2.25Cr-1Mo steel was investigated with the forced flexural oscillation by a dynamic mechanical analyzer (DMA). Over the range of variables (temperature, frequency, and vibration strain amplitude) normally encountered in service applications, the results show that the internal friction and modulus of 2.25Cr-1Mo steel at elevated temperatures were dependent not only on the temperature, but also on the frequency. Meanwhile, the internal friction was independent of strain amplitude in the present range below 2×10⁻⁴. According to analysis of above results, it indicated that the internal friction consists of two components. Both components are due to relaxation mechanisms: the first is a thermoelastic relaxation and the second is a broad diffusion-controlled relaxation.

The synthesis of bioinert oxide films on pure Ti surfaces by chemical-hydrothermal treatment was investigated. Some pure Ti substrates were chemically treated with H₂O₂/HNO₃ to form a TiO₂ gel layer prior to hydrothermal treatment. Two types of solutions in the hydrothermal treatment were prepared: Zr(OH)₄ gel dispersed NH₃/CH₃CH(OH)COOH solution and Zr dissolved NH₃/CH₃CH(OH)COOH solution. A uniform layer of very fine crystals were formed on the surfaces of the specimens subjected to the hydrothermal treatment. Sharp peaks attributed to TiO₂ and/or ZrO₂ appeared after the hydrothermal treatment. ZrO₂-TiO₂ composite films were successfully produced on the Ti surface by hydrothermal treatment with the Zr(OH)₄ gel dispersed NH₃/CH₃CH(OH)COOH solution at 453 K for 12 h, following the chemical treatment. The proliferation of osteoblast-like MC3T3-E1 cells was also investigated. The cells were observed to have spread their pseudopodiums. The cell density increased monotonically with incubation period for all specimens. The proliferation of cells was strongly influenced by the surface roughness; the cell densities increased with decreasing roughness in the range of Ra=20–80 nm. Furthermore, the surface products with TiO₂ showed a relatively low rate of proliferation. The strong attachment of cells to the surface may hinder cell migration.

Porous aluminum is expected to be used as a multifunctional material because of its light weight, high energy absorption and high sound-insulating properties. Recently, a precursor method based on FSP has been developed to improve the cost-effectiveness and productivity of fabricating porous aluminum. Aluminum alloy die castings have the advantages of high productivity, low cost and high recyclability. Thus, it is expected that, by using aluminum alloy die castings in the FSP route, the improved cost-effectiveness and productivity of porous aluminum can be realized. In this paper, the most important parameters of the precursor method, i.e., the holding temperature, holding time and the amount of alumina powder added to the precursor as a stabilization agent, were considered. Experiments under two sets of conditions were carried out to fabricate porous aluminum with high porosity and high quality (a uniform pore size distribution with highly spherical pores). It was shown that closed-cell porous aluminum with a porosity of about 65% was successfully fabricated using ADC12 aluminum alloy die castings. When the holding time during foaming was fixed at 12 min, high-porosity and high-quality porous aluminum was obtained by adding 10 mass% alumina at holding temperatures of 933 K and 963 K (slightly higher than the melting point of ADC12 aluminum alloy). When the amount of alumina added was restricted to 5 mass% and the holding temperature was fixed at 933 K or 963 K, it was demonstrated that high-porosity and high-quality porous aluminum can be obtained with a holding time of 10 min and a holding temperature of 933 K.

Vapor grown carbon fiber (VGCF) reinforced aluminum matrix composites were fabricated by spark sintering processes. VGCFs in composites became to be dispersed uniformly in the aluminum matrix by decreasing a diameter of aluminum powder. The electrical conductivity of composites was reduced remarkably compared with monolithic aluminum block. On the other hand, the electrical conductivity of the composites was slightly reduced with increasing a diameter of aluminum particle. Meanwhile, the experimental electrical conductivity of VGCF/Al composites was lower than the theoretical one calculated by Chang’s and Fan’s models, which is caused by the strain fields containing larger residual stress in aluminum matrix around VGCF.

Total materials requirement (TMR) for the recycling of elements and materials (Urban Ore TMR) from end-of-life electric home appliances (cathode ray tube TV, liquid crystal display TV, refrigerator, washing machine, air conditioner and microwave oven) have been estimated and evaluated. The estimation were carried out using scenario analyses, in which the number of recycled elements and/or materials was changed considering additional energy for advanced recycling. As the results of the estimation, the urban ore TMR of gold, silver, copper and stainless steel were lower than TMR when they are smelted from natural ore (natural ore TMR) for all the scenarios. The urban ore TMR for iron (steel), aluminum and die-casting aluminum were mainly affected by the dilution ratio using pure element for the recycling. The recyclability of the elements and materials are discussed from the view point of TMR.

First-principles calculations of the thermodynamic properties of Ti₂AlC and Ti₂SC were carried out. The temperature dependence of bulk modulus, the pressure dependence of normalized volume V⁄V₀, thermal expansion coefficient, specific heats, and Debye temperature were successfully obtained through the quasi-harmonic Debye model in the temperature range from 0 to 1000 K and the pressure range from 0 to 50 GPa. The calculated results were compared with available experimental data. The effects of the bonding strength of Ti-S and Ti-Al on the thermodynamic properties were discussed.

The brittle-to-ductile transition (BDT) in arsenic doped (001) CZ silicon single crystals has been experimentally studied. The temperature dependence of apparent fracture toughness was measured by three-point bending tests at various strain rates. The BDT temperature in arsenic doped silicon was found to be lower than that in non-doped. The activation energy was obtained from the strain rate dependence of the BDT temperature. It was found that the value of the activation energy in the arsenic doped silicon is lower than that in non-doped, suggesting that the dislocation velocity in the silicon single crystal was increased by arsenic doping. The effect of increasing in dislocation velocity on the BDT temperature was also investigated by two-dimensional discrete dislocation dynamics simulations, indicating that the BDT temperature is decreased by increasing in dislocation velocity.

Titanium dioxide (TiO₂) photocatalyst was fabricated by anodic oxidation on pure titanium in an electrolyte of a sulfuric acid, and effect of ultrasonic irradiation during anodic oxidation was explored. It was found that ultrasonic irradiation increased crystallinity of the anodic oxide. The hydrophilicity of the as-anodized oxide was improved by applying ultrasonic irradiation, and it is similar to that of the annealed oxide without applying ultrasonic irradiation. In contrast, the photoactivity of the as-anodized oxide was not altered by applying ultrasonic irradiation.

In order to analyze the magnetic behaviors of iron complexes biologically synthesized in magnetic bacteria MS-1, we performed FMR (Ferromagnetic Resonance) measurements for each fraction of the cell. We observed FMR spectra from the ferric iron (Fe³⁺) compounds distributed in each fraction of the MS-1 cell. In particular, the magnetosome fraction yielded an anisotropic FMR signal, whereas other fractions were simple FMR spectra of a Gaussian type.
Upon counting the numbers of spins in various cell fractions, we compared them with the iron population as determined by the 1.10-phenanthroline method. We found a good correlation between the number of spins and the iron population in several cell fractions. We concluded that the cell fractions, other than those fractions containing magnetite, consist mostly of ferric irons rather than ferrous irons.

Crystal orientations after cold rolling to a 50% thickness reduction were measured at mid-thickness parallel to the rolling plane for two aluminum single crystals: one having a {100} ⟨001⟩ orientation and the other having an orientation deviated 5° about the rolling direction axis from ideal {100} ⟨001⟩. The crystal rotation axis orientations calculated from electron backscatter diffraction were compared with ⟨112⟩ lattice rotation axis orientations geometrically assigned to individual slip systems. The crystal rotation axis orientations were explained by the resultant lattice rotation axis orientation consisting of the four active slip systems having high Schmid factors. The microstructure in the single crystal having {100} ⟨001⟩ was subdivided by primary active slip systems, whereas the microstructure in the single crystal with deviated orientation was subdivided by secondary active slip systems, which developed band structure parallel to the rolling direction. The crystal rotation axis orientation method is useful for determination of the type and slip amplitude of active slip systems.

Hydrogen permeation behavior in carbon steel exposed to gaseous hydrogen was visualized using a hydrogen microprint technique (HMT). Effects of hydrogen gas pressure and charging time on the hydrogen permeation were particularly examined. The amount of permeated hydrogen was dependent on the charging time during the exposure to gaseous hydrogen. It was found that silver particles, which represented the evolution site of hydrogen atoms, were distributed almost uniformly in the matrix after hydrogen gas charging. These particles were arranged at the periphery of the second phase particles such as Al₂O₃. Area density of the silver particles clearly increased when the time for hydrogen gas charging was increased. Preferential accumulation of silver particles around Al₂O₃ particles was clearly identified; however, no silver particles were observed directly on the Al₂O₃ particles. This indicated that hydrogen atoms were diffused not through the inside of the second phase particles but through the interface between the second phase particles and the matrix phase.

We have investigated the effects of subzero treatment on microstructures and mechanical properties of austempered ductile cast irons. The retained austenite microstructure was transformed to martensite microstructure by subzero treatment and strain. The ratio of the transformation to martensite increased with decreasing the subzero treatment temperature. By decreasing the subzero treatment temperature and increasing the strain, the retained austenite of the specimens with more Cu contents was transformed more to martensite. While the values of strength and hardness increased by decreasing the subzero treatment temperature, the values of elongation and impact decreased. Moreover, the strength and hardness of the specimens with more Cu contents increases, whereas the values of elongation and impact decreased. As a result, it was found that an addition of Cu in subzero treatment of the specimens had a little effect on the strength and hardness, but had a significant effect on the impact values.

The morphology of the compounds formed by the reactive diffusion between solid Fe and liquid Al was experimentally observed using Fe/Al diffusion couples. The diffusion couples were prepared by an isothermal bonding technique and then immediately annealed at temperatures of T=973, 1023 and 1073 K for various times up to t=2.4×10³ s. At these temperatures, Fe is solid, but Al is liquid. During annealing, a compound region consisting of Fe₂Al₅ and FeAl₃ is formed at the Fe/Al interface in the diffusion couple and grows towards the Fe solid specimen. However, FeAl₂ and FeAl were not detected clearly. The thickness is much smaller for FeAl₃ than for Fe₂Al₅, and thus the compound region is mainly composed of Fe₂Al₅. At T=973–1073 K, FeAl₃ is produced as a rather uniform thin layer. On the other hand, the Fe₂Al₅ region shows the irregular tongue-like morphology at T=973–1023 K but the uniform layer morphology at T=1073 K. The irregularity of the Fe₂Al₅ region is attributed to the anisotropy for the interdiffusion coefficient of Fe₂Al₅. The temperature dependence of the irregularity implies that the anisotropy is large at T=973–1023 K but small at T=1073 K. The mean thickness of the compound region is proportional to a power function of the annealing time. Although the activation enthalpy of the proportionality coefficient is evaluated with an Arrhenius equation, the morphology of the Fe₂Al₅ region varies depending on the annealing temperature. In such a case, the rate-controlling process for the growth of the compound region cannot be readily estimated from the activation enthalpy.

Consolidation of cordierite disc specimens was undertaken under concentrated solar beam in a solar furnace at PSA (Plataforma Solar de Almería). Satisfactory extent of densification was achieved by the present solar-sintering experiment. The mechanical properties measured for the solar-sintered cordierite test pieces were; density ρ=2.45±0.02 g/cm³, Vickers microhardness HV=7.31±0.29 GPa, Young’s modulus E=97±5 GPa, shear modulus G=38±2 GPa, Poisson ratio ν=0.27±0.01, fracture toughness K_IC=1.50±0.15 MPa·m^1⁄2 and modulus of rupture evaluated by ring-on-ring test MOR_ROR=57.8±13.7 MPa which were comparable to those of the counterparts sintered by conventional industrial gas furnace.

The strengthening effect of nanosized Cu precipitates in bcc Fe has been studied by performing molecular dynamics simulations of the interaction between a screw dislocation and a coherent bcc Cu precipitate of 1–4 nm diameter in bcc Fe. The dislocation detachment mechanism changes from shear at a precipitate diameter of 4 and 2.5 nm in the twinning and anti-twinning directions, respectively, due to the coherency loss caused by the screw dislocation assisted martensitic transformation of the precipitate. The screw dislocation detachment mechanism with the larger, transformed precipitates involves annihilation-and-renucleation, or Orowan looping in the twinning vs. anti-twinning direction, respectively. The critical resolved shear stress (CRSS) of the screw dislocation-precipitate interaction increases with increasing precipitate size, and is strongly dependent on the precipitate structure and detachment mechanism. The CRSS is much larger in the anti-twinning direction.

It is well known that the adhesion of the electroless Ni-P coating on aluminum alloy substrate can be remarkably improved by introducing the double zincate treatment as a pretreatment process. This study investigated the effects of the alloying element and zincate treatment on adhesion of electroless Ni-P coating on various aluminum alloy substrates using peeling test, FE-SEM and XPS. Surface morphology of zinc deposit from the 1st zincate treatment and its adhesive strength were changed, depending on the alloying element. The zinc deposit from the 2nd zincate treatment became uniformly thin, and the adhesive strength was improved irrespective of the alloying element. By dipping the zinc deposit obtained at the 1st zincate in 5% HNO₃ solution, most of the zinc deposit on aluminum substrate was dissolved, but XPS analysis revealed that the existence of zinc, whose state was metal, at the surface of aluminum alloy substrate after this dipping. This zinc at the surface should be an important factor influencing morphology of zinc deposit at the 2nd zincate treatment, so that zinc deposit became highly uniform and thin. This zinc at the surface can be attributed to the diffusion of zinc and aluminum between the zinc deposit from the 1st zincate and the aluminum alloy substrate.

The mechanical properties of oxide scales at high-temperature were studied in order to improve the surface quality of commercial Si-containing high strength steels. Specific oxides of Fe₂O₃, Fe₃O₄, FeO and Fe₂SiO₄ were synthesized by powder metallurgy. The Vickers hardness, thermal expansion coefficient and thermal conductivity were measured at high-temperatures. A series of measurements confirmed that the physical properties of the synthesized oxides were different each other. From the Vickers hardness measurements, it was verified that the hardness of each synthesized oxide was identical with the naturally-formed iron oxide, as observed in the cross-section of oxide scales on steels. The influence of the Fe₂SiO₄ formed on Si-containing steels on the scale adhesion at high temperature and the surface property is discussed on the basis of the physical properties of the oxides.

In order to suppress generation and growth of whiskers, the effect of laser irradiation on tin-electroplated film on copper was studied by scanning electron microscopy and X-ray diffraction method. In the case of as-plated film, whiskers were generated on the electroplated tin film of 1 μm thickness within 432 ks. Residual stress of this film and the number of whiskers increased with the amount of copper-tin intermetallic compounds (Cu₆Sn₅) which developed between the plated film and the copper substrate. On the other hand, in electroplated tin film subjected to diode laser of 300 W for 100 to 1000 ms, no whiskers were formed even after 10 Ms. Residual stress of tin after laser irradiation was tensional at first, then, the stress did not change appreciably after 2.6 Ms. Uniform layer of Cu₆Sn₅ was formed immediately after laser irradiation, and the morphology showed no meaningful change even after 10 Ms. Whiskers are thought to be suppressed by covering the interface between tin and copper with layer of Cu₆Sn₅ and by reducing nonuniformity of stress field.

In (Fe, Ni)-Cr-C alloys, with Fe replaced by 25 mass%Ni–70 mass%Ni in high-chromium cast irons, the effects of Ni content on the solidification structure, solidification sequence, and liquidus surface diagram were investigated.
The microstructures of alloys consist of matrix and M₇C₃ carbides precipitated as primary and/or eutectic crystals. They resemble general high-chromium cast iron except for mostly austenitic matrix. According to EDS analyses of alloy contents in each phase of specimens, the Cr content in M₇C₃ carbide increases concomitantly with increasing Ni content, but that in γ exhibits almost no change.
Solidification begins by crystallization of primary austenite (γ) in hypoeutectic alloy and that of primary M₇C₃ carbide in hypereutectic alloy. Either case is followed by precipitation of (γ+M₇C₃) eutectic. However, graphite precipitates from melt in the alloys with high-C or high-Ni content and its precipitation region shifts to the low-C–high-Cr side as the Ni content increases. The (γ-M₇C₃) eutectic line on the liquidus surface diagram moves strongly to the low-C side with increased Ni content, but it returns to the high-C side when Ni contents become greater than 50 mass%. The diagrams produced using thermo-Calc software resemble those constructed based on experimental results.

In this study, an aging treatment was performed to investigate the microstructures and mechanical properties of Mg-10Li-0.5Zn (LZ101) alloy. Experimental results show that the LZ101 Mg-Li alloy exhibits a dual-phase microstructure of α (HCP) and β (BCC) phases, and has a good ductility. The 723 K solid-solution treated LZ101 Mg-Li alloy exhibits a single β structure and produces α precipitates after natural and artificial aging. The solid-solution treated specimen has lower mechanical strength and higher elongation than the as-extruded one. The aged specimens exhibit a typical behaviour of precipitation hardening. The maximum tensile strength can reach 188 MPa, 180 MPa and 173 MPa, corresponding to the natural aging of 345.6 ks, 423 K aging of 21.6 ks and 523 K aging of 10.8 ks.

Metallic glasses have been reported to exhibit excellent properties, such as high strength, high corrosion resistance, high wear resistance, which result from their amorphous structure. Because of a drastic reduction in their viscosities in supercooled liquid region, metallic glasses have an excellent workability through viscous deformation for the production of various industrial parts.
Recently, much attention has been paid to Fe-based metallic glasses because of their rich resources in addition to their excellent mechanical and magnetic properties. However, due to their poor glass-forming ability, the size of the Fe-based bulk metallic glass by conventional casting techniques is limited. In the present investigation, nearly fully densified disk-shaped compacts of [(Fe_0.5Co_0.5)_0.75Si_0.05B_0.2]₉₆Nb₄ metallic glass were produced from a gas-atomized amorphous powder by spark plasma sintering (SPS). The processing temperature and the time that assure the supercooled liquid state of the compacts were determined from the Time-Temperature-Transformation (TTT) diagram that was constructed by isothermal differential scanning calorimetry. The mechanical properties of the consolidated samples were evaluated by compression test. Comparatively low values of the fracture stress, Young’s modulus and yielding stress of SPSed sample compared to the casted samples were observed, which is discussed on the basis of the integrity of the interparticle bonding.

The reduction kinetics of Fe₂O₃ nanopowder was investigated by monitoring the reduction behavior in real-time and measuring the amount of outflowing water vapor using in-situ hygrometry study. The kinetics of hydrogen reduction of Fe₂O₃ was also studied on the basis of phase transformation, structure modification and outflowing diffusion of water vapor of the Fe₂O₃ powder during reaction. Activation energy for the hydrogen reduction of Fe₂O₃ nanopowder was calculated at various heating rate conditions and conversion fraction of reaction. The activation energies for reduction of Fe₂O₃ nanopowder obtained in this study existed in the range of 20–46 kJ/mol. The activation energy for reduction of Fe₂O₃ nanopowder obtained in this study decreased from 46 kJ/mol to 20 kJ/mol during the entire reduction process. Therefore, the hygrometry study is a powerful tool for in-situ kinetic study of hydrogen reduction of metal oxide for mass production.

In this study, hot forging process of Co-Ni-Cr-Mo superalloy was carried out at temperatures ranging from 950 to 1200°C and strain rates ranging from 0.01 to 30 s⁻¹. In order to obtain an optimum forging condition, various processing maps were constructed, such as a power efficiency map and an instability map, at different strain levels on the basis of a dynamic material model. At a strain of 0.5, temperatures 1050–1200°C and strain rates of 10–30 s⁻¹, dynamic recrystallization was observed with power efficiency values ranging from 35 to 44%. Flow localization due to dynamic strain aging and/or deformation twinning at temperatures 950–1000°C and at low strain rates were observed to be in good agreement with those observed in the instability map.

Synchrotron X-ray microtomography was used to observe hydrogen micropores. Competitive growth between pre-existing high-density micropores and voids originating from damage during loading was observed in an aluminum alloy during a tensile test. Extensive and premature growth of pre-existing hydrogen micropores has been observed during tension, while the ordinary damage initiation increased rapidly more later. According to the estimation on the areal fraction of dimple patterns originating from the pre-existing hydrogen micropores, it has been concluded that the hydrogen micropores more or less make contributions to ordinary ductile fracture.

The undercooling, microstructures and hardness of Sn-rich Pb-free solders changed by a reaction with Cu-xZn alloy under bump metallurgy (UBM) were investigated and compared to those of solders with Cu UBM. The investigation was based on four types of Sn-rich solders (pure Sn, Sn-0.7Cu, Sn-3.5Ag and Sn-3.8Ag-0.7Cu, where the numbers are all in mass percent unless specified otherwise) and three types of UBMs (pure Cu, Cu-10Zn and Cu-20Zn). The undercooling of the Sn-rich solders was reduced significantly by the reaction with the Cu-xZn UBMs. A decrease of 21–27°C in the undercooling was obtained, whereas a decrease of only 10–16°C was obtained by the reaction with Cu UBMs. In the Sn-rich solders after the reactions with the Cu-xZn UBMs, there was a barely perceptible large growth of primary intermetallic compound phases, such as Cu₆Sn₅ and Ag₃Sn; moreover, there were a large increase in the volume fraction of the eutectic phases and a coarsening of β-Sn dendrites. In addition, the Sn-rich solders with Cu-xZn UBMs showed a large increase in hardness. These changes in the undercooling, microstructures and hardness are discussed in terms of the compositions of Sn-rich solders changed by the interfacial reactions with Cu-xZn UBMs.

A quantitative analysis of calcium phosphate (CP) layers deposited on metallic titanium substrates was carried out by X-ray fluorescence spectrometry (XRF) in order to evaluate the osteogenic capability of metallic biomaterials. The titanium substrates were prepared by NaOH and heat treatments, and then, they were soaked in Hanks’ balanced saline solution (HBSS) at 310 K, leading to the deposition of a CP layer on the sample surface. The resulting samples were analyzed by XRF, and the amount of Ca and P in the CP layers was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). As a result, calibration curves were obtained for determining the amounts of Ca, P and the CP deposition; the XRF quantification of the CP layers was carried out with good accuracy.

Changes in the phase composition and crystallite size of a rapid quenched Nd_4.5Fe₇₇B_18.5 alloy, caused by thermomagnetic measurements (TM) have been studied using XRD methods of phase analysis, crystallite size and lattice microstrain determination. Structural changes in regard to optimal magnetic state were additionally analyzed by TEM. Magnetic properties in optimal magnetic state and after TM were observed using room temperature SQUID measurements. The obtained experimental results suggest the Fe₃B/Nd₂Fe₁₄B and partly α-Fe nanocomposite structure of the alloy in the optimized magnetic state, with mean crystallite size (<30 nm). After TM, an increased amount of α-Fe phase, presence of different oxide and Fe-B phases as well as growth of crystallites are found to be the main reasons for the observed quality loss of hard magnetic properties.

Pores form readily in aluminum alloy castings. The percentage of porosity is often used to quantitatively evaluate the quality of aluminum alloy castings. In this study, the relative porosity, as represented by the percentage of porosity in Al and Al-XSi alloys is evaluated. Nondestructive ultrasonic techniques are adopted to investigate the relative porosity of Al and Al-XSi alloys. The relationship between the relative porosity and ultrasonic characteristics, including the ultrasonic velocity and the attenuation coefficient, are determined and compared, and the pore formation in the alloys is also discussed.

This study evaluates the characteristics of welds resulting from joining dissimilar alloys, steel SPRC440 and aluminum alloy 6K21. The joint was obtained by means of AC pulse MIG welding, which alternates between direct current electrode positive (DCEP) and direct current electrode negative (DCEN), based on the EN ratio.
In order to evaluate the AC pulse MIG welding for the dissimilar joining of steel SPRC440 to Aluminum alloy 6K21, the arc characteristics in relation with varying EN ratios were analyzed. The AC pulse MIG welding process showed good gap bridging ability. The joining quality of the dissimilar alloys was evaluated by the analyzing the intermetallic compound layer.

Bacterial leaching was applied to recover metal values from complex sulfide concentrates. The leaching kinetics were observed to depend on various leaching parameters, including Fe(II) concentration, pH and pulp density. The rate of leaching decreased with increase of iron precipitation rate. The leaching results indicated good bacterial activity. A Principle Component Analysis showed all the variables can be classified into four groups which account for more than 79.7% of the variance. The four groups were described as factors like leaching kinetics, bacterial activity, leaching parameters and bacterial metabolites.

Platelet-like natural crystalline graphite with nano-scale thickness was fabricated through low expansion and exfoliation processes. Graphite, as a starting material, had an average particle size of 10 μm. A graphite intercalation compound (GIC) was prepared by mixing sulfuric acid and hydrogen peroxide with the graphite. It was treated at various temperatures and retention times in the furnace to control the expansion ratio, and then ground for size reduction in the attrition mill. The size reduction efficiency increased as the expansion ratio increased to 25 vol%, after which the efficiency decreased again by over 25 vol%. Since the process of size reduction involves repeated exfoliation and expansion of graphite, it revealed a stage-by-stage decrease pattern as the grinding time increased. In this research, the exfoliation rate of platelet-like natural graphite was improved via the low expansion method. Nano-platelet-type graphite with an average particle size of 3 μm was fabricated, but its layer was 20–50 nanometers thick.

TiO₂ thin films were deposited on rutile SnO₂ films by reactive radio frequency magnetron sputtering. The effect of thickness of TiO₂ layer, on the microstructure and chemical states of the TiO₂/SnO₂ thin films, was investigated in detail. With the increase of TiO₂ film thickness deposited on SnO₂ film, the crystallization of TiO₂ film becomes more perfect, and more Ti atoms are bonding in forms of stoichiometric TiO₂. There is a thickness of TiO₂ film (150 nm) deposited on SnO₂ substrate that yields the best photo-induced superhydrophilicity and surface wettability.

The relationship between the microstructures and mechanical properties in the ternary Zr-Co-Ni alloys has been investigated. X-ray diffraction measurements at room temperature show that Zr₅₀Co_50−xNi_x alloys undergo martensitic transformation from the B2 to B33 structures by the substitution amounts of Ni above 14% for Co. The tensile strength and elongation increase remarkably by substituting Ni up to 13%. Especially, the Zr₅₀Co₃₉Ni₁₁ alloy has the extremely high total elongation of 23%. There are many {021}_B33 deformation twins in addition to the dislocations with the ⟨100⟩-type Burgers vector just near the fractured area. These twins are considered to be an internal defect of the deformation induced martensite which has high hardness about 430 Hv. Therefore, it is concluded that the remarkable enhancement of the ductility of Zr-Co-Ni alloys is due to the transformation induced plasticity.

Positron emission particle tracking with positron annihilation spectroscopy was used in order to visualize particulate motion within a high shear mixer. As a result, it was possible to visualize the high-speed behavior of particulates within a fluid bed in a mixer, which is an important basic operation in materials processing. It was demonstrated that this method can be useful in improving process design or in improving the quality of the resultant product.

We previously proposed a new method to synthesize nano-sized powders of various alloys and intermetallic compounds. The method consisted of electrical wire explosion of electrodeposted metal wires. In this study, the method was applied for Ti-Cr alloy. The overall composition of the Cr-coated Ti wire was about Ti-25 at% Cr. The explosion products consisted of equilibrium phases of α-Ti and TiCr₂ phases along with meta-stable Ti-rich β phase. The composition of β phase estimated from its lattice parameter was Ti-13 at% Cr. The β phase decomposed completely to α-Ti and TiCr₂ phases during isothermal aging at 600°C for one day.