Metal Chips Research Articles

Crystal growth of a new aluminum sodium boride NaAlB 14 and some properties

Single crystals of a new ternary boride NaAlB 14 were obtained from the Na-Al-B system using a high-temperature Al self-flux under an Ar atmosphere. The reagents used to prepare the samples were Na 2B 4O 7 powder, crystalline boron powder and Al metal chips. The optimum conditions to obtained relatively large crystals were found to include soaking temperature 1573 K, soaking time 1 h, cooling rate 50 K/h and the atomic ratios ( n = B/Na = 1.0–4.0) of starting materials. The NaAlB 14 crystal prepared had maximum sizes of approximately 7.3 mm × 3.3 mm × 2.8 mm. The crystals were generally obtained in the form of plate-like crystals with well-developed {0 1 0} faces or trapezoidal-shape crystals enclosed by {1 0 0}, {0 1 0}, {0 1 1} and {0 0 1} faces, and were reddish black with a metallic luster. The values of Vickers microhardness are in the ranges of 23.3 ± 1.0 and 28.4 ± 0.6 GPa for {1 0 0} and {0 1 0} faces, respectively. The susceptibility does not show any particular features, but an increase at low temperatures is indicative of a paramagnetic contribution.

New Method for Evaluating Material Blood Compatibility Using Microchannel Array

Microchannel array chips modified by metal deposition or polymer coating were contacted with blood. Titanium (Ti), chromium (Cr) and gold (Au) films were deposited onto the microchannel array chips. Albumin (Alb) and MPC polymer (MPC) were coated onto other chips. Non-treated Si chips were used as a control. Whole blood was collected with 1000 units/ml heparin solution from young healthy volunteers. The passing time of a 100 µl portion of human whole blood through these channels was measured under a pressure difference of 20 cm H2O. Simultaneously, the flow behavior of blood cells in channel was observed by an optical microscope and recorded by a video recorder. Platelet adhesion was observed on Si, Ti, Cr, and especially on Au. The blood pass-through time (BPT) increased in order of Ti, Si, Cr and Au. On the Alb- and MPC-coated chips, platelets were seldom observed and the BPTs were short in comparison with the metal chips. From these consequences, platelet adhesion depended on the materials. The BPT correlated well to the number of adherent platelets on the materials. Therefore, the blood coagulation reaction originated in platelet activation could be detected using microchannel array. We concluded that this method could be applied to evaluate initial blood compatibility of materials within several minutes in vitro.

Development of Prediction System of Environmental Burden for Machine Tool Operation (1st Report, Proposal of Calculation Method of Environmental Burden)

Recently, some activities for environmental protect have been tried to reduce environmental burdens in a lot of fields. Manufacturing field is also required to reduce them. Hence, prediction system of environmental burden for machining operation is proposed based on LCA (Life Cycle Assessment) policy for future manufacturing system in this research. This system can calculate environmental burden (equivalent CO2 emission) due to electric consumption of a machine tool, cutting tools, coolant, lubricant oil, metal chips and provide the information of accurate environmental burden of machining process by considering some activities related to machine tool. In this paper, the development status of prediction system is described. As a case study, two NC programs that manufacture simple shape are also evaluated to show the feasibility of it.

Ferroelectric properties of PZT films on LaNiO 3 bottom electrode deposited under different oxygen partial pressure

LaNiO 3 (LNO) films were deposited on by RF magnetron sputtering of Ni metal target and La metal chips on top of it under Ar and O 2 atmosphere at different oxygen partial pressures (20, 25, 30, 35, and 40% oxygen). The resistivity of the LNO films increased with the increasing oxygen partial pressure. This is attributed to the reduction of oxygen vacancy concentration. About 150 nm thick Pb(Zr 0.35Ti 0.65)O 3 (PZT) ferroelectric thin films were spin coated on the LNO films with subsequent post annealing. To find out the relationship, the electrical properties of the PZT/LNO thin film capacitors and the oxygen partial pressure, the P– E curve, X-ray diffraction, microstructure, leakage current density, and fatigue property were investigated as a function of oxygen partial pressure. An optimal remanent polarization and lowest leakage current density of the PZT capacitor has been obtained when its LNO thin film bottom electrode was deposited at 30% oxygen partial pressure. The microstructure of the LNO film deposited at 30% oxygen partial pressure had columnar structure, while the ones deposited under other conditions had granular structure. The ferroelectric properties of the PZT/LNO capacitor are critically affected by the structure of LNO bottom electrode, and they are excellent when optimally processed as discussed above.

Analysis of cutting properties with reference to amount of coolant used in an environment-conscious turning process

In the recent years, environmentally conscious design and manufacturing technologies have attracted considerable attention. The coolants, lubricants, solvents, metallic chips and discarded tools from manufacturing operations will harm our environment and the earth’s ecosystem. In the present work, the Tukey method of multiple comparisons is used to select the minimum level of coolant required in a turning process. The amount of coolant is varied in 270 designed experiments and the parameters cutting temperature, surface roughness, and specific cutting energy are carefully evaluated. The effects of coolant mix ratio as well as the amount of coolant on the turning process are studied in the present work. The cutting temperature and surface roughness for different quantity of coolant are investigated by analysis of variance (ANOVA)-test and a multiple comparison method. ANOVA-test results signify that the average tool temperature and surface roughness depend on the amount of coolant. Based on Tukey’s Honestly Significant Difference (HSD) method, one of the multiple comparison methods, the minimum level of coolant is 1.0 L/min with 2% mix ratio in the aspect of controlling tool temperature. F-test concludes that the amount of coolant used does not have any significant effect on specific cutting energy. Finally, Tukey method ascertains that 0.5 L/min with 6% mix ratio is the minimum level of coolant required in turning process without any serious degradation of the surface finish. Considering all aspects of cutting, the minimum coolant required is 1.0 L/min with 6% mix ratio. It is merely half the coolant currently used i.e. 2.0 L/min with 10% mix ratio. Minimal use of coolant not only economically desirable for reducing manufacturing cost but also it imparts fewer hazards to human health. Also, sparing use of coolant will eventually transform the turning process into a more environment-conscious manufacturing process.

工作機械による加工の環境負荷予測システム(G13-2 機械加工および工作機械(2),G13 生産加工・工作機械部門)

Recently, some activities against environmental issues have been tried to reduce environmental burdens in a lot of fields. Manufacturing field is also required to reduce them. Hence, prediction system of environmental burden for machining operation is proposed based on LCA (Life Cycle Assessment) policy for future manufacturing system in this research. This system can calculate environmental burden (equivalent CO2 emission) due to electric consumption of a machine tool, cutting tools, coolant, lubricant oil, metal chips and provide the information of accurate environmental burden of machining process by considering some activities related to machine tool. In this paper, the development status of prediction system is described. As a case study, two NC programs that manufacture simple shape are also evaluated to show the feasibility of it.

Machining of a Zr–Ti–Al–Cu–Ni metallic glass

Zr 52.5Ti 5Cu 17.9Ni 14.6Al 10 metallic glass machining chips were characterized using SEM, X-ray diffraction and nano-indentation. Above a threshold cutting speed, oxidation of the Zr produces high flash temperatures and causes crystallization. The chip morphology was unique and showed the presence of shear bands, void formation and viscous flow.

Failure analysis of a gas pipeline

A 15-km section of a gas pipeline presented leakage during field hydrostatic testing. Preliminary investigation indicated the presence of a cavity, which is roughly composed of a cylindrical surface (region 2) and a plane surface (region 1), both oblique and forming a V-shaped cavity, presenting thickness of 200 μm in the region adjacent to the bore. The surface of the region 1 showed more intense surface plastic deformation (approximately 60 μm deep) than region 2 (approximately 20 μm deep), which presented the formation of metallic chips. The presence of encrusted SiO 2 particles associated with intense superficial plastic deformation lines of the ferritic microstructure—following the orientation of SiO 2 particle/ferrite grains interface and resembling hardness indentation marks—was also observed in the region 1. The results indicated that the formation of the cavity was promoted by the action of an erosion mechanism due to an error during the sand blasting procedure. The local thinning and formation of a stress raiser led to the localised transversal rupture of the tube by a ductile mechanism during the pipeline field hydrostatic testing.

Near infra-red photoluminescence of Nd 3+ in hydrogenated amorphous silicon sub-nitrides a-SiN x:H〈Nd〉

Neodymium-doped hydrogenated amorphous silicon sub-nitrides a-SiN x :H〈Nd〉 thin films were deposited by rf-sputtering using a Si target partially covered by metallic Nd chips and Ar+N 2+H 2 sputtering gas. Characteristic Nd 3+ near infra-red (NIR) photoluminescence (PL) was detected between 10 and 300 K with peaks at ∼935, ∼1090 and ∼1390 nm, corresponding to the intra-4f transitions 4 F 3/2→ 4 I 9/2 , 4 F 3/2→ 4 I 11/2 and 4 F 3/2→ 4 I 13/2 , respectively. Measurements using different excitation wavelengths indicate that the Nd 3+ excitation occurs through the a-SiN x :H matrix. Varying the nitrogen content x from 0 to nearly 1.3 increases the matrix bandgap. The PL efficiency is maximum when the bandgap corresponds to twice the 4 F 3/2→ 4 I 9/2 transition, indicating a defect-related energy transfer mechanism. The temperature quenching can be as low as less than a factor 3 between 10 and 300 K for 2.8 eV gap samples. Thermal annealing can enhance the PL intensity by a factor 10. Neodymium concentrations above ∼3×10 20 atoms/cm 3 slightly reduce the PL intensity probably due to excess of inactive defect centers. Along with erbium-doped amorphous silicon alloys, a-SiN x :H〈Nd〉 can be used in the development of photonic devices in the future.

Magnesium isotope heterogeneity of the isotopic standard SRM980 and new reference materials for magnesium-isotope-ratio measurements

Multicollector ICP-MS has been used for the precise measurement of variations in the isotopic composition of the isotopic standard of magnesium (SRM980) provided by the National Institute of Standards and Technology (Gaithersburg, MD, USA). The SRM980 consists of metal chips weighing between 1 and 50 mg and each unit delivered by the National Institute of Standards and Technology corresponds to a bottle containing about 0.3 g. Height units were analysed. Variations in sample 25Mg/24Mg, and 26Mg/24Mg ratios are expressed as δ25Mg and δ26Mg units, respectively, which are deviations in parts per 103 from the same ratio in a standard solution. The differences in δ25Mg and δ26Mg of the SRM980 are up to 4.20 and 8.19‰, respectively, while the long-term repeatability of δ25Mg and δ26Mg are 0.09 and 0.16‰, respectively, at 95% confidence. However, when plotted in a three-isotope diagram, all the data fall on a single mass fractionation line. Overall limits of error of the SRM980 reported here fall within the previously reported overall limits of error. The isotopic heterogeneity not only corresponds to differences among units but has been found at the chip-size level. This result, due to the precision of the MC-ICP-MS technique, makes the SRM980 inappropriate for the international isotopic standard of magnesium. The SRM980 can still be used to report the excess of 26Mg, which is defined by the deviation from the mass-dependent relationship between 25Mg/24Mg, and 26Mg/24Mg ratios. Two large batches (around 10 g of Mg in each) of pure Mg solutions (in 0.3 M HNO3) have been prepared and characterised. These 2 solutions (DSM3 and Cambridge 1) are suitable reference material because they are immune to heterogeneity. DSM3 and Cambridge 1 are isotopically different (by 1.3‰ per u) and are available upon request from the first author. In addition, DSM3 has an isotopic composition very similar to the Mg-isotopic composition of carbonaceous chondrites (Orgueil and Allende). Because of the lack of heterogeneity and the cosmochemical and geochemical significance of DSM3, we urge the use of DSM3 as the primary isotopic reference material to report Mg-isotopic variations.

Case Study: Color Control in the Automotive Industry

Numerous manufacturers are concerned with ensuring the homogeneity in the colors of different parts that compose their products. This quality objective of primary importance is especially challenging when the parts are sourced by different suppliers. The technical difficulties are accentuated when metallic or pearly paints are used since the presence of metallic chips in the paint causes a variation in the color according to the angle of observation. Also, the development of metametric colors increases these difficulties even more, as these colors are sensitive to different illumination sources. The present study relates to the production of colored car bumpers. By using a spectrocolorimeter and color samples, the process is improved to better respect the customer specifications. To achieve this, critical colors and significant parameters affecting colors are identified, design of experiments is used to optimize the process settings, and a correlation study allows further process improvement. The results achieved are impressive: the quality index used has been improved by 67% in only 6 months. This case study therefore illustrates how simple quality tools can be used in a rigorous search for process improvement toward total color mastering with zero defect objective.

Engine failure caused by erosion–corrosion of fuel manifold

An engine failure caused by erosion–corrosion of a fuel manifold was investigated. The surface of the boost elements (impeller and its cover) of the main fuel pump showed the wear damage by Fe-based particles. This incident reduced the fuel pressure abruptly, and led to engine shut-down. This was confirmed by EDX analysis of the rubbed surface of the boost elements and the metal chips collected form fuel filter. To find the possible source of Fe-based particles the whole fuel system of the aircraft was reviewed. On the basis of this review the fuel manifold attached to the main fuel pump was selected for in-depth analysis. The manifold was cut and its inner surface was examined visually with the aid of a stereoscope revealing internal penetration of the welding metal. This internal welding bead was attacked by erosion–corrosion, partially lifted-off and generated particles. The particles separated from the internal bead and were carried in the fuel. On entering the main fuel pump these particles caused the wear damage. The inner surface of randomly chosen manifolds showed internal welding metal too. Therefore optimization of the welding parameters during the joining process of the manifold was proposed as a remedial action.

Field Dependence of Dielectric Properties of (Pb,Sr)TiO 3 Thin Films

(Pb,Sr)TiO 3 (PST) thin films have been deposited on (111)Ir/SiO 2 /Si and <100>-oriented SrTiO 3 :La substrates by RF magnetron sputtering from a multi-target comprised of a SrTiO 3 ceramics target, 4 PbO pellets and some pure Ti metal chips. The film sputtered on Ir/SiO 2 /Si was polycrystalline film, and showed a slender D-E hysteresis loop. The temperature dependence of dielectric constant showed a very broad peak at 60°C. The dielectric constant was 1250 at 500 kHz and the tunability by DC bias performed a high value of 50% ( E =15kV/mm) at room temperature. The film grown on SrTiO 3 :La substrate was epitaxial film, and drew a small asymmetrical D-E hysteresis loop. The dielectric constant dropped to 140. The tunability was 30% under bias from m 0.8 to 0.8 V (20 kV/mm) at room temperature.

Three-Dimensional Surface Pattern and Chemical Composition of Mucosal Titanium Implant Compartments

Surface topography and chemical composition of mucosal-implant interfaces is thougt to be critical to their clinical success. The aim of our study was to investigate the topography and chemical composition of titanium mucosal-implant interfaces using surface analytical techniques. The mucosal surface compartments of 10 different implant systems were utilized as a test area. The ultramorphological analysis were carried out using Confocal Laser Scanning Microscopy (CLSM), X-ray photoelectron spectroscopy (XPS), Metastable Induced Electron Spectroscopy (MIES), Scanning Electron Microscopy (SEM) and Scanning Force Microscopy (SFM). The surfaces of samples showed different fracturing of metal chips and pitting attack. From the CLSM- and SEM analysis in comparison to the Developed Surface Area (DSA) as ratio of microroughnesses it appears that the diameter of the pits varied in the range of 0,1 to 10 \\micron. MIES showed the presence of Ti, O and C . Several peaks pertaining to titanium and oxygen can be found. The Ti-surface is covered by a 3–5 nm thick TiO2 layer. Only titanium in the oxidic, not in the metallic state is found within the observation depth of 1 nm. We find clear evidence from MIES that saturated hydrocarbon chains form the outermost molecular layer. Virtually no signal from TiO2 is found at the very surface. The results suggest a two-layer structure for the passive film formed on titanium after exposition to the sulcus crevicular fluid. The inner layer has a structure close to TiO2, while the outlayer is dominated by CH2-groups with a few –C=O groups inside the hydrocarbon overlayer. The granular structure observed on mucosal-implant surfaces seems to indicate that the dissolution occurs at localized defects in the passive film influencing the barrier function of implanto-gingival tissues. This was confirmed by the DSA as a hybrid parameter including both spatial and amplitude aspects of the surfaces.

Mist control at a machining center, Part 2: Mist control following installation of air cleaners.

At a machining center used to produce transaxle and transmission parts, aerosol instrumentation was used to quantitatively evaluate size-dependent mist generation of a synthetic metalworking fluid (MWF) consisting primarily of water and triethanolamine (TEA). This information was used to select an air cleaner for controlling the mist. During most machining operations, the MWF was flooded over the part. These machining operations were performed in a nearly complete enclosure that was exhausted to an air cleaner consisting of three sections: a fall-out chamber, a trifilter section to capture metal chips and mist, and a 1.13 m3/sec (2400 ft3/min) blower. The partnering company requested that National Institute for Occupational Safety and Health (NIOSH) researchers perform an evaluation of the effectiveness of a commercially available air cleaner. After NIOSH researchers characterized mist generation at the machining centers and found that performance of a test air cleaner appeared to be suitable, the company installed more than 25 air cleaners on different machining centers in this plant and enclosed the corresponding fluid filtration unit. The facility also has implemented a maintenance program for the air cleaners that involves regularly scheduled filter changes; performance is ensured by monitoring static pressure. A NIOSH-conducted air sampling evaluation showed that area TEA concentrations were reduced from a geometric mean of 0.25 to 0.03 mg/m3. Personal total particulate concentrations were reduced from a geometric mean of 0.22 to 0.06 mg/m3. These results show the effectiveness of this combination of enclosure, ventilation, and filtration to greatly reduce the exposure to MWF mist generated in modern machining centers.

Secondary metals as raw materials for powder metallurgy

The possibility of using new technology based on the disintegrator milling method for utilizing metal chips of cast iron, high-alloy steels, nonferrous alloys (Al−Cu, Zn−Al, Cu−Zn), and used parts of hard metals based on tungsten carbide was investigated. The powders produced were used for corrosion- and wearresistant coatings having properties similar to those of traditional powders.

Repulpable pressure-sensitive adhesive tapes and labels

In recent years, Japan has been witnessing a mounting interest in the recycling of waste paper as a way of protecting the environment. Yet the manufacture of recycled paper has always been subject to the problem of plastic, metal or PE-laminated paper chips mixing in. Especially the contaminants from adhesive tapes and labels (stickies) have posed a difficult problem for the manufacturers of recycled paper. Therefore, the development of repulpable products substituting for them has long been an earnest desire for the industry. To solve this problem, a comprehensive investigation into the pressure-sensitive adhesive, the release agent and the base paper has been carried out, and repulpable PSA packaging tapes and labels that are well suited for the manufacture of recycled paper have been successfully developed. © 1998 John Wiley & Sons, Ltd.

Highly Oriented Nb-Doped Lead Titanate Thin Films by Reactive Sputtering: Fabrication and Structure Analyses

Highly oriented lead titanate thin films have been deposited on bare (100)MgO substrates and on (100)Pt/(100)MgO substrates by reactive sputtering. By adding metallic niobium chips to the target, Nb-doped PbTiO3 films could be obtained as well. The variation in the orientation of PbTiO3 films due to the deposition conditions is described in detail. Due to the highly oriented nature of the films, two types of X-ray diffraction methods were used to evaluate the effect of Nb doping on the tetragonality ratio c/a: one was the conventional θ–2θ Bragg-Brentano X-ray diffraction method (XRD), the other was the in-plane energy-dispersive total reflection X-ray diffraction method (ED-TXRD), which could provide the lattice vectors perpendicular (c axis) and parallel (a axis) to the substrate, respectively. Furthermore, the epitaxy of the deposited PbTiO3 films in relation to the (100)-cut MgO single crystal substrate could be confirmed using ED-TXRD.

Efficient methods of processing metal chips

The development and use of efficient methods of processing chips (particularly alloy chips) is important for solving the problems of conserving resources, improving quality of the metal that is produced, and improving the environmental situation at metallurgical plants.

Crystal growth of vanadium silicides from high-temperature metal solutions and some properties of the crystals

Crystals of vanadium silicides were grown from high-temperature tin and copper solutions in an argon atmosphere using vanadium metal chips and silicon powder as starting materials. The crystals grown were V 3Si, V 5Si 3 and VSi 2. The growth conditions for obtaining single crystals of relatively large size were established. The as-grown V 3Si, V 5Si 3 and VSi 2 crystals were used for chemical analysis and measurements of unit cell dimensions. Densities, microhardness and electrical resistivity were determined on V 5Si 3 crystals, and oxidation at high temperature in air was studied for V 5Si 3 and VSi 2 crystals. The microhardness value on (110) planes of V 5Si 3 is 12.3 (±0.1) GPa. The electrical resistivity determined on V 5Si 3 crystal is 17.6 (± 0.7) μω cm. The oxidation of V 5Si 3 and VSi 2 crystals begins to proceed at a measurable rate in the temperature range of about 355 and 515 °C, respectively. The final oxidation product is V 2O 5. In all cases, non-crystalline SiO 2 seemed to be formed during the oxidation reaction.