Fine Granular Structure Research Articles

Structural, mechanical and tribological properties of WS2-Ti composite coating with and without hard under layer of TiN

The present work reports on the structural, mechanical and tribological properties of WS2 and WS2-Ti composite coating with and without hard under layer of TiN. Pulsed DC closed field unbalanced magnetron sputtering was employed for deposition of the films. The films were characterised with energy dispersive X-ray microanalysis (EDX), grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scratch adhesion test, nanoindentation test and pin-on-disc tribological test. The GIXRD spectrum for WS2 film showed prominent orientation of (002) basal plane parallel to the substrate which was also supported by its morphology showing a fine granular structure. Addition of around 13at.% Ti to the WS2 matrix induced turbostratic stacking of the 10 L (L=0, 1, 2,…) planes, however, the (002) orientation was retained. The film’s hardness, adhesion to the substrate, as well as the tribological properties improved with Ti addition. Addition of a hard under layer of TiN resulted in a denser top WS2-Ti layer because of enhanced nucleation promoted by structural defects of the hard under layer. The tribological performance of the top WS2-Ti layer also improved on TiN under layer addition because of the enhanced load bearing capacity of the top layer.

Antimicrobial and decorative ion-plated copper-containing ceramic coatings

New-generation decorative ceramic coatings have frequently been requested to be diverse in color and scratch resistant, and demonstrate antimicrobial functions. Because long-established silver-containing decorative hard coatings have involved using noble silver metal, incorporating copper into the deposited hard coatings should exhibit antimicrobial functions as well. Such coatings may fulfill the multiple surface functions of decoration, wear resistance, and antimicrobial properties. This study used arc ion plating (AIP) to prepare TiN coating while using magnetron sputtering (MS) to incorporate copper to obtain copper-containing titanium nitride coatings (Cu-containing TiN) on Ni/Cr pre-electroplated Cu–35Zn substrates, a common material for sanitary wares. Experimental results show that the coatings are well crystalline TiN up to a Cu content of 14.35at.%, over which the coatings present fine granular structure and is undetectable by XRD. The surface hardness, wear resistance, and corrosion resistance of the Cu-containing TiN coatings were higher than those of the pre-electroplated Cu–35Zn substrate. Antimicrobial efficacy of the Cu-containing TiN coatings against Escherichia coli (E. coli) was satisfied, according to the JIS Z2801:2000 standard, when the copper content in the deposited films achieved 21.65at.%.

On the Effects of Hot Forging and Hot Rolling on the Microstructural Development and Mechanical Response of a Biocompatible Ti Alloy

Zr, Nb, and Ta as alloying elements for Ti alloys are important for attaining superior corrosion resistance and biocompatibility in the long term. However, note that the addition of excess Nb and Ta to Ti alloys leads to higher manufacturing cost. To develop low-cost manufacturing processes, the effects of hot-forging and continuous-hot-rolling conditions on the microstructure, mechanical properties, hot forgeability, and fatigue strength of Ti-15Zr-4Nb-4Ta alloy were investigated. The temperature dependences with a temperature difference (ΔT) from β-transus temperature (Tβ) for the volume fraction of the α- and β-phases were almost the same for both Ti-15Zr-4Nb-4Ta and Ti-6Al-4V alloys. In the α-β-forged Ti-15Zr-4Nb-4Ta alloy, a fine granular α-phase structure containing a fine granular β-phase at grain boundaries of an equiaxed α-phase was observed. The Ti-15Zr-4Nb-4Ta alloy billet forged at Tβ-(30 to 50) °C exhibited high strength and excellent ductility. The effects of forging ratio on mechanical strength and ductility were small at a forging ratio of more than 3. The maximum strength (σmax) markedly increased with decreasing testing temperature below Tβ. The reduction in area (R.A.) value slowly decreased with decreasing testing temperature below Tβ. The temperature dependences of σmax for the Ti-15Zr-4Nb-4Ta and Ti-6Al-4V alloys show the same tendency and might be caused by the temperature difference (ΔT) from Tβ. It was clarified that Ti-15Zr-4Nb-4Ta alloy could be manufactured using the same manufacturing process as for previously approved Ti-6Al-4V alloy, taking into account the difference (ΔT) between Tβ and heat treatment temperature. Also, the manufacturing equivalency of Ti-15Zr-4Nb-4Ta alloy to obtain marketing approval of implants was established. Thus, it was concluded that continuous hot rolling is useful for manufacturing α-β-type Ti alloy.

Improved properties of Mn series ultralow carbon steel with ultrafine bainitic structure

In order to reduce the cost of alloying elements, Mn series ultralow carbon bainitic (ULCB) steels have been developed. The different cooling conditions have been used to improve the mechanical properties of Mn series ULCB steels in the present study. The hot rolled ULCB steel plates with 26 mm thickness were water quenched to different finishing quenching temperatures (550, 450 and 350°C) followed by air cooling. Results show that the as rolled ULCB steel plates exhibit high yield strength of 775 MPa and low energy transition temperature of −55°C when the finishing quenching temperature is chosen at 450°C. Low temperature impact toughness was improved through control of the finishing quenching temperature. Microstructure observations show that a fine granular bainite structure is obtained, and the granular bainite structure exhibited shorter crack propagation path than both granular ferrite and lath martensite structures, which contributed to the improved combination of strength and toughness. Furthermore, the formation process of fine granular bainite structure was investigated.

The Features of the Structure and Magnetic Properties of Co-SiO2, Co-Al2O3 Composite Films with Tunneling Magnetoresistance Effect

In the present work, we have studied the structural, magnetic and magnetoresistive properties of Cox(SiO2)100-x and Cox(Al2O3)100-x composite thin films, obtained by magnetron co-sputtering of metallic and insulator targets. It was shown by transmission electron microscopy and by temperature and field dependences of the magnetization that the films have a fine granular structure. For a wide range of compositions an adequate description was possible in frame of the model of homogeneous non-interacting superparamagnetic hexagonal lattice Co particles. Magnetoresistive sensor prototypes were designed on the base of an optimized magnetoresistive Co50(Al2O3)50 composite films

Effect of Deposition Polymerization Technique of Pyrrole on Properties of UHMWPE Fiber

The two deposition polymerization techniques, i.e. vapor phase and liquid phase pyrrole deposition polymerization were applied to Ultra-high-molecular-weight polyethylene (UHMWPE) fiber in this paper. The effect of deposition technique on the surface morphology, mechanical properties, electrical stability and surface roughness of fibers were discussed. The result showed that deposition technique has a strong effect on the properties of UHMWPE fibers. Fibers treated by vapor phase deposition polymerization has much fine and small granular structure, lower resistance, better mechanical property and higher surface roughness value.

Analysis of an illustrative interaction between structural features and earthworm populations in Brazilian ferralsols

Ferralsols are characterized by poorly-defined horizons, weak macrostructure and strong development of a fine granular structure comprising subangular micro-aggregates. In this study, the morphological and physical modifications caused by earthworm activity in a clayey ferralsol were analysed. After describing soil structures, undisturbed samples were taken for evaluating aggregates and determining clod bulk density and particle density. Soil water retention properties were measured and an inventory of soil invertebrate macrofauna was created. The structural and porous transformations were due to aggregates created by earthworm activity. Changes in bulk density can be associated with pore modifications caused by a change in the proportions of aggregate types, and a notable reduction of total porosity was measured, tending to increase soil volume with dense aggregates. Structural modifications affected the topsoil down to 0.5m and water retention between −1 and −33kPa, the principal water compartment of these soils.

Enhanced magnetic softness and high-frequency characteristics of Fe 51.1Co 48.9B–Al 2O 3 nanogranular films

The effect of simultaneous introduction of Al2O3 and B on the structure, soft magnetic, electrical and high-frequency characteristics of Fe51.1Co48.9B–Al2O3 nanogranular films was studied. The Al2O3 and B addition leads to the formation of a fine granular structure. The magnetic softness and high-frequency characteristics can be enhanced by simultaneously introducing a small amount of Al2O3 and B into the Fe51.1Co48.9 films. Compared with Fe65Co35B–Al2O3 films, the high-frequency properties are improved in the Fe51.1Co48.9B–Al2O3 films by increasing Co/(Fe + Co) ratio.

Self-restoration of post-agrogenic chernozems of Russia: Soil development, carbon stocks, and dynamics of carbon pools

This chronosequential study focuses on the vegetation succession, pedogenesis, carbon stocks, and functionally different carbon pools of post-agrogenic chernozems under self-restoration in the forest steppe zone of the European part of Russia. The sites investigated were comparable in terms of climate, soil texture, and land-use history, but differed in their duration of agricultural abandonment, covering 8, 19, 37, and 59 years of self-restoration. During self-restoration, the vegetation showed development towards virgin steppe and the soils towards natural chernozem. Pedogenesis resulted in the formation of a fine granular structure and loss of ploughing features. Organic carbon (OC) content increased from 38.9 g kg − 1 to 54.5 g kg − 1 in the upper 10 cm of topsoil. Increasing C contents did not reach the OC level of the natural chernozem, showing 78.9 g kg − 1 . Nitrogen contents and cation exchange capacity (CEC) values increased, showing significant positive correlations with soil organic carbon (SOC) content and resulting in chronosequential constant Corg/N ratios. The SOC accumulation rate for the 59 years of self-restoration was about 52 g m − 2 y − 1 for the mean of the upper 0.2 m and 103 g m − 2 y − 1 in the upper 0.5 m. Thus, carbon stocks increased to 91% of the natural chernozem. Functionally different SOC pools showed their quantitative alterations during self-restoration. The OC of the clay fraction (% of soil) increased in line with the recovery of total SOC at soil depths 0–0.5 m from 1.49% to 2.17% on average. The OC of the density fraction < 1.8 g cm − 3 (free particulate organic matter (POM) and occluded POM) and OC from sand and coarse silt fractions increased only in the upper 10 cm of topsoil. After 59 years of self-restoration, the rate of occluded POM (19.8% of SOC) still did not match the level of the natural chernozem (26.3% of SOC). The results of the study show an increasing SOC sink during the self-restoration of chernozems but no full restoration within the investigated time scale of 59 years.

Granule Structure and Distribution of Allomorphs in C-Type High-Amylose Rice Starch Granule Modified by Antisense RNA Inhibition of Starch Branching Enzyme

C-type starch, which is a combination of both A-type and B-type crystal starch, is usually found in legumes and rhizomes. We have developed a high-amylose transgenic line of rice (TRS) by antisense RNA inhibition of starch branching enzymes. The starch in the endosperm of this TRS was identified as typical C-type crystalline starch, but its fine granular structure and allomorph distribution remained unclear. In this study, we conducted morphological and spectroscopic studies on this TRS starch during acid hydrolysis to determine the distribution of A- and B-type allomorphs. The morphology of starch granules after various durations of acid hydrolysis was compared by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that amorphous regions were located at the center part of TRS starch subgranules. During acid hydrolysis, starch was degraded from the interior of the subgranule to the outer surface, while the peripheral part of the subgranules and the surrounding band of the starch granule were highly resistant to acid hydrolysis. The spectroscopic changes detected by X-ray powder diffraction, 13C cross-polarization magic-angle spinning NMR, and attenuated total reflectance Fourier transform infrared showed that the A-type allomorph was hydrolyzed more rapidly than the B-type, and that the X-ray diffraction profile gradually changed from a native C-type to a CB-type with increasing hydrolysis time. Our results showed that, in TRS starch, the A-type allomorph was located around the amorphous region, and was surrounded by the B-type allomorph located in the peripheral region of the subgranules and the surrounding band of the starch granule. Thus, the positions of A- and B-type allomorphs in the TRS C-type starch granule differ markedly from those in C-type legume and rhizome starch.

Microstructure and Mechanical Properties of Sn-Bi Alloy Treated in the Semi-Solid State by Mechanical Stirring Process

In this work, the effect of stirring time on the solidifed microstructures and mechanical properties of semi-solid Sn-Bi slurry was investigated by the mechanical stirring method. The results indicated that a fine round granular solidifed structure of Sn-Bi semi-solid slurry was obtained at 142 and stirred for 8 min. Compared with the Sn-Bi alloy prepared conventional die casting, the mechamical properties of semi-solid Sn-Bi alloy was improved prominently. The percentage elongation of semi-solid Sn-Bi alloy was increased 67 % compared with that of the Sn-Bi alloy prepared conventional die casting.

Synthesis and characterization of [4-(2,4-dichlorophenoxybutyrate)-zinc layered hydroxide] nanohybrid

A new layered organic–inorganic nanohybrid material in which an agrochemical, 4-(2,4-dichlorophenoxy)butyrate (DPBA) is intercalated into inorganic interlayers of zinc layered hydroxide (ZLH) was synthesized by direct reaction of aqueous DPBA solution with zinc oxide. The resulting nanohybrid is composed of the organic moieties, DPBA sandwiched between ZLH inorganic interlayers. The nanohybrid afforded well ordered crystalline layered structure, a basal spacing of 29.6 Å, 23.5% carbon (w/w) and 47.9% (w/w) loading of DPBA. FTIR study shows that the absorption bands of the resulting nanohybrid composed the FTIR characteristics of both the DPBA and ZLH which further confirmed the intercalation episode. The intercalated organic moiety in the form of nanohybrid is thermally more stable than its sodium salt. Scanning electron micrograph shows the ZnO precursor has very fine granular structure and transformed into a flake-like when the nanohybrid is formed. This work shows that the nanohybrid of DPBA-ZLH can be synthesized using simple, direct reaction of ZnO and DPBA under aqueous environment for the formation of a new generation of agrochemical.

Analysis and Comparison of Vapor and Liquid Deposition of Pyrrole on Wool Fiber

Polypyrrole/wool composite fiber was prepared by in situ oxidative polymerization from vapor phase and liquid phase pyrrole at room temperature, by using FeCl3 as catalyst. The effect of deposition technique on the surface morphology, mechanical properties and the electrical stability of fibers were discussed. The result showed that deposition technique has a strong effect and fiber prepared by vapor phase deposition has much fine and small granular structure, lower resistance, better mechanical property and electrical stability.

Reduction of magnetic grain size of perpendicular recording media with CoCrW seed layer

We report the use of CoCrW seed layer (SL) for making the fine grain granular structure and high crystalline orientation of CoCrPt-oxide magnetic recording layer. It is found that CoCrW SL should be of amorphouslike structure to make fine grain of CoCrPt-oxide magnetic layer. Moreover, the smooth surface of CoCrW SL provides high crystalline orientation of the CoCrPt-oxide magnetic layer.

Tube structure and ultrastructure of serpulids from the Jurassic of France and Switzerland, its evolutionary implications

Four different tube ultrastructures were identified in the eight studied Jurassic serpulid species. The simple prismatic structure of single layered Serpula aff. convoluta and Tetraserpula planorbiformis, and the spherulitic prismatic structure of outer tube layer in S. aff. trigona are interpreted as the original tube ultrastructures. The fine homogeneous granular structure in Mucroserpula quinquangularis, Serpula conformis, S. limata, S. aff. subcrispa, S. aff. trigona and coarse angular crystal homogeneous structure in Filogranula tricristata are interpreted as diagenetically altered structures. The diagenetically altered tube ultrastructure is common in the Jurassic serpulids, which can be explained by their original aragonitic or dominantly aragonitic composition. There is no evidence of complex oriented tube ultrastructures in the Jurassic, such as calcitic lamello-fibrillar structure, which may have evolved later in the Cretaceous or early Cenozoic.

Ceramic from nanopowders and its properties

The possibilities for obtaining ceramic from nanodispersed silicon dioxide and hydroxyapatite powders are examined. Ceramic with fine-granular (3 – 10 µm) structure has been obtained. Transmission and scanning electron microscopy and x-ray phase analysis are used to study the properties of the initial nanopowder and ceramic. The glassy materials obtained from Tarkosil (silicon dioxide) powder are transparent in the ultraviolet range. Strong ceramic samples of hydroxyapatite with grains and pores smaller than 1 µm or less and with open porosity uniformly distributed throughout the volume have been obtained. The results of the investigation could be useful for developing medical implants based on hydroxyapatite and ceramic membranes with controllable porosity.

Relationship between methylene blue values of concrete aggregate fines and some concrete properties

The fine granular structure and surface activity of clay minerals increase the amount of mixing water needed to provide workability in concrete. Even when the microfine material percentage in fine aggregate is low, the methylene blue value of the fine aggregate increases when materials of clay origin are present. In this study, methylene blue values were determined in fine aggregate samples used to produce ready-mixed concrete. Samples were taken from four different aggregate quarries, and relationships between methylene blue values of the concrete samples produced with these aggregates and some of their properties were investigated. Tests were done to determine the quality of microfine material (i.e., passing 0.063 mm sieve). Slump, ultrasonic pulse velocity, compressive strength, and surface abrasion resistance tests were performed on concretes made with these aggregate fines. It is shown that clay content, as indicated by the methylene blue value test, affects the concrete properties, but the microfine material percentage does not give any hint about clay content.

Differences in the immunolocalization of surfactant protein (SP)‐A, SP‐D, and KL‐6 in pulmonary alveolar proteinosis

Idiopathic pulmonary alveolar proteinosis (PAP) is a rare lung disorder characterized by excessive accumulation of surfactant lipoprotein in alveoli, which is caused by autoantibody against granulocyte-macrophage colony-stimulating factor. The case of a 42-year-old man with idiopathic PAP, who had worked in steel and cement plants for the past 10 years, is presented. His serum anti-GM-CSF antibody level was markedly increased. Lung specimens obtained during video-assisted thoracoscopic surgery were examined on immunohistochemistry using mAb for localization of surfactant proteins A and D (SP-A and SP-D) and a mucin-like protein, KL-6. Furthermore, western blot analysis of his bronchoalveolar lavage fluid (BALF) was performed using anti-SP-A and anti-SP-D mAb. As well as KL-6, SP-A was localized in the intra-alveolar fine granular substances. But on HE staining the SP-D was localized in SP-A-negative foci corresponding to eosinophilic large globules that were surrounded by an SP-A-positive fine granular structure. On western blot the specificity of mAb was shown. In conclusion, this is the first report demonstrating the striking difference in the distribution of SP-A and SP-D in the intra-alveolar substance of a patient with idiopathic PAP.

Microstructure and magnetic properties of FePt-SiO2 granular films with Ag addition

Perpendicularly anisotropic L10-ordered FePt-SiO2 granular films with an average grain size of 15 nm and a relatively narrow size distribution were prepared by cosputtering Fe, Pt, and SiO2 on MgO (001) substrates at 700 °C. By reducing the substrate temperature to 500 °C, the average grain size was further refined to 6.2 nm with a standard deviation of 1.7 nm; however, the FePt particles remained as an A1 disordered phase. Alloying Ag to the FePt particles and increasing the Ar gas pressure in the sputtering chamber were found to be both beneficial for enhancing the L10 ordering while keeping the fine granular structure.

Microstructure and Martensitic Transformation Behaviors of Explosively Welded NiTi/NiTi Laminates

The study is a first attempt to prepare bulk NiTi/NiTi shape memory alloy (SMA) laminates with a macroscopic heterogeneous composition by explosive welding and investigate their microstructures and martensitic transformation behaviors. After explosive welding, a perfect interfacial bonding between the two components and a reversible martensitic transformation are realized in the tandem. Results show achievement of a fine granular structure and the maximum value of microhardness near the welding interface because of the excessive cold plastic deformation and the high impact velocity during the explosive welding. Meanwhile, the effects of aging on the transformation of the welded tandem are investigated by differential scanning calorimeter (DSC) and subject to discussion. The transformation temperatures of NiTi/NiTi SMAs increase with the rise of the aging temperature. The experimental results indicate the shape memory properties of NiTi/NiTi SMA fabricated by explosive welding can be improved by optimizing the aging technology.