Influence Of Crystalline Structure Research Articles

Influence of crystalline structure on creep resistance capability in semi-crystalline Polymers: A coarse-grained molecular dynamics study

In this study, we investigated the intrinsic correlation between the crystal configuration and persistent mechanical stability of semi-crystalline polymers. The creep resistances of microstructures with different grain sizes and the same crystallinity were evaluated using coarse-grained molecular dynamics simulations. It was demonstrated that under tensile loading at constant pressure, microstructures with larger grains have more pronounced resistance to molecular rearrangement and significantly delay creep deformation. The improved creep resistance can be attributed to two factors. First, larger crystal sizes result in an increased moment of inertia, reducing the angular velocity required for the rotational rearrangement of the crystalline phase. Second, the elongated crystalline stems enhance the resistance to intermolecular slippage, elevating the strain energy necessary to disrupt the crystalline structure. These findings reveal the molecular basis of creep resistance at the nanoscale and highlight the pivotal role of crystal morphology in enhancing the long-term mechanical integrity of polymers.

Novel process for facile preparation of mesoporous silica-based materials with controllable pore structure from coal fly ash

Extraction of silica from fly ash to produce mesoporous silica materials is one of the most important utilization approaches. Mesoporous silica could not be synthesized on a large-scale by conventional sol-gel method. In this paper, facile preparation of mesoporous silica with controllable pore structure from fly ash by the template-free process via two steps of mineral phase transformation and selective acid etching was proposed. The influence of crystalline structure and acid etching degree on structure of as-synthesized mesoporous silica materials was revealed, as well as mechanism of crystalline structure transformation and pore structure formation. The results show that mullite and quartz could be transformed into acid-soluble kaliophilite when fly ash reacted with K2CO3 at temperature of 800–1100 °C. The hexagonal kaliophilite would be transformed into orthorhombic KAlSiO4–O1 phase when the temperature is controlled at 1100 °C. Mesoporous silica with specific surface area of 475.93 m2/g and 642.57 m2/g could be synthesized from activated fly ash with kaliophilite and KAlSiO4–O1 phase crystalline structure. By controlling the degree of acid etching, mesoporous silica materials with different pore structures can be obtained. This paper provides a cost-effective and large-scale process for the preparation of mesoporous silica materials with controllable pore structure from solid waste fly ash.

The correlation between structural factors and Stokes shifts in zero-dimensional Antimony(III) halides

Zero-dimensional (0D) hybrid metal halides (HMHs) have recently garnered significant attention as promising light emitters due to their distinctively Stokes-shifted broadband emissions resulting from self-trapped excitons (STEs). However, the influence of crystalline structures on the Stokes shift remains inadequately understood. Herein, we design and synthesize a series of 0D (Ph4P)2SbCl5-xBrx (Ph4P = tetraphenylphosphonium, x = 0–5) compounds to elucidate the intrinsic relationship between structural factors and the Stokes shift in 0D Sb(III) halides. Our comprehensive investigations into their crystalline structures and photoluminescence (PL) properties unveil that the Stokes shift correlates with intra- and inter-pyramidal [SbCl5-xBrx]2- units. Specifically, a shorter vertical Sb–Cl bond within the square pyramid, coupled with a greater Sb⋯Sb distance between the pyramidal units, facilitates significant structural relaxation in excited states, resulting in a larger Stokes shift, and vice versa. Notably, this principle applies not only within identical space groups but also across different crystal systems. Furthermore, our findings are supported by analyses of the structures and PL properties of other reported 0D Sb(III) halides with square pyramidal coordination. This study elucidates the structure-dependent nature of the Stokes shift in 0D Sb(III) halides, offering a novel avenue for the design of functional 0D metal halide materials.

Competition of shearing and cavitation effects on the deformation behavior of isotactic polypropylene during stretching

Owing to the unique cross-hatched structure of α crystal, the deformation behavior of isotactic polypropylene (iPP) differs considerably with the traditional polymers. The influence of crystalline structures on the cavitation and shearing effects of α-iPP under tensile loading is still not well established. In this work, various iPP samples were prepared via crystallizing from 0 °C to 130 °C, after which the crystalline structures were characterized via differential scanning calorimetry, polarized optical microscopy and scanning electron microscopy. The lamellar thickness and crystallinity of α-iPP precursor films change slightly, while the content of tangential lamellae in α-spherulite and the spherulite size increase significantly with the decreasing supercooling. On the other hand, the morphological evolution of α-iPP during stretching was tracked by in-situ two-dimensional small angle X-ray scattering. It is found that cavitation effect become dominant instead of shearing effect when the size of α-spherulite exceeds 25 μm. Furthermore, we disclose four typical deformation behaviors of α-iPP resulting from the competition between intra-spherulitic deformation and inter-spherulitic deformation, namely the shearing without cavitation, shearing then localized cavitation, homogeneous cavitation with concomitant shearing, and cavitation with absence of shearing. Accordingly, we construct a route for the structural evolution of α-iPP with different crystalline structures during stretching, which provides an effective guidance to produce diverse iPP films with desired structures and tunable functionalities.

Historical Perspectives on Evolution from Elctrodeposition to Electrochemistry

Among numerous findings by human beings, electrodeposition is of great importance in the whole invention and is getting to be a core technology to date. The applications of electroplating used in electronics devices, magnetic recording heads and media, chemical biosensors, and batteries are some typical examples surrounding our present world. Looking back on the history of electrodeposition, the first trial was carried out in the Mesopotamian-era in 1500 BC, which was a Sn plating on iron wares. For Japan, the beginning of plating was performed back in the 6th century for a Au amalgam plating on the Buddha statue at Asuka-era Temple. Hence, the technology of electrodeposition has been developed and evolved for a long period of time along with humankind.While electrodeposition is known to be a traditional way to form metal or non-metal ions on various substrates, it is still kept being one of the cutting edge technologies to date. Because desired thin films, such as CoFeNi for hard disk and Cu wiring for silicon devices, can be easily obtained by the fine control of the chemistry on the interface between the electrode and electrolyte. The sequential high-throughput with outstanding cost effectiveness also push forward this technology to practical applications in various industrial fields. An example of the fine control of deposited films popped up in our mind is the idea of UPD (underpotential deposition) by ad-atom in 1978. Such an idea of ppm or ppt content of metal ions in the plating bath resulted in the practical realization of electroless plating disk for PATTY HDD device (1981 NEC,NTT). Electrodeposition is also known to be a game-changer in the scientific history as well. For the fabrication of soft magnetic materials, the electrodeposited thin film of Co65Ni23Ni12 achieved low-Hc with high-Bs for the first time, which was breaking the common sense that high-Bs is incompatible with low-Hc in soft magnetic materials. [1, 2] Such an electroplating technology is on going to the next stage for 3D memories. Ever since electrodeposition was conducted in earnest by Jacobi et al in 1837, its practical use in sub-micron scale was established in 1997 as damascene process to ULSI internal wiring technology and is now available to handle atomic-scale of fabrication in various fields.This year marks the 100th anniversary of the establishment of the ECS Electrodeposition Division. There is no doubt that ECS has contributed significantly to the development of the Electrodeposition field since 1922. In today's lecture, we will introduce our research concept on electrodeposition in the various fields based on electrochemistry, such as magnetism, sensors, and electronics on the basis of our achievements of their practical use for future industrial usage including battery devices. [3][1] T. Osaka et al., “A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity”, Nature, 392, 796 (1998).[2] T. Osaka et al., “Influence of crystalline structure and sulfur inclusion on corrosion properties of electrodeposited CoNiFe soft magnetic films”, Journal of the Electrochemical Society, 146, 2092 (1999).[3] T. Osaka, “Spotlight on Japanese Battery Technologies”, Nature jobs, 2015. Figure 1

Influence of crystalline structure on diffusion barrier property of electroless Ni–Fe–P coatings in Zn–Al solder interconnects

The rapid growth of interfacial Cu–Zn intermetallic compounds (IMCs) at Zn–Al/Cu solder interfaces significantly deteriorates their integrity due to the physical mismatch of interface materials. Thus, a robust interlayer to inhibit the interactions between solder and substrate at elevated temperature is urgently required. In this work, ternary Ni–Fe–P coatings with various crystalline structure were electroless plated on Cu substrates to investigate their interfacial reactions and diffusion barrier properties in Zn–Al solder interconnects. It was found that Ni–Fe–P coatings can significantly suppress the growth of interfacial IMCs in Zn–Al solder interconnects during liquid-solid reaction. Moreover, crystalline structure of Ni–Fe–P coatings played a vital role in the interfacial reactions and microstructural evolutions at the Zn–Al/Ni–Fe–P interfaces. The Ni–Fe–P coating with mixed structure (amorphous + crystalline) exhibited the best diffusion barrier properties among three types of the coatings for the thinnest and void-free Al3Ni2 layer, while crystalline Ni–Fe–P coating is the worst due to not only the rapidly growth of Al3Ni2 and Fe2Al5 phases but also the spalling phenomenon of Al3Ni2 particles.

Influence of crystalline structure on rf dissipation in superconducting niobium

Bulk niobium is the most common material used in the fabrication of rf superconducting cavities for accelerators. Predicting and reducing the rf surface dissipation in these cavity structures is mandatory, since it has a tremendous cost impact on the large accelerator projects. In this paper the author hopes to demonstrate that sources of dissipation usually attributed to external causes (mainly flux trapping during cooldown and hydrides precipitates) are related to the same type of crystalline defects that affect the local superconducting properties and can be at the source of early vortex penetration at the surface. We also want to show how these types of defects can explain some of the discrepancies observed from other laboratories in niobium cavity doping experiments. Understanding the origin and the role of these defects could provide direction for improving material specifications as well as improving fabrication control from sheet material to completed cavity. In particular, we will demonstrate that dislocation entanglements, due to the fabrication damage layer, have the strongest impact for the pinning behavior of trapped flux, as well as hydrogen segregation in cavity niobium. The author wishes to present to the superconducting radio frequency (SRF) accelerator community the synthesis of experimental results scattered in the literature, completed with some personal results. The results of this effort provide a new perspective on recently published work in the domain of SRF cavity doping and sensitivity to trapped flux during cooldown. I will also try to draw whenever possible, some conclusions about other types of superconductors used for SRF applications including $\mathrm{Nb}/\mathrm{Cu}$ thin films and to discuss their possible change of behavior with field or frequency. I will concentrate on surface and material science aspects since the experimental results on rf cavities have already been treated elsewhere.

The role of structural properties on magnetic characteristics of glass-coated microwires

We report on the influence of crystalline structure on the magnetic properties of glass-coated microwires with CoFe-based metallic core realised as an amorphous matrix with nanocrystals. Using X-ray diffraction analysis and transmission electron microscopy, we have examined the structural features of the core, and demonstrated a possibility to tailor magnetic response of microwires by changing their crystalline structure. Finally, we present the first attempt to “visualise” stress distribution in the core of microwires, using crystal orientation imaging obtained by transmission electron microscopy.

Effect of Compositions, Crystal Structures and Morphologies on Photo-Luminescent Property of LaPO<sub>4</sub>:Gd<sup>3+</sup>

Various LaPO4:Gd3+ samples were synthesized by the hydrothermal method under different conditions to investigate the influence of crystalline structures, compositions and morphologies on the photo-luminescence. The compositions, crystal structures and morphologies were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photo-luminescence emission spectrum (PL). The results revealed that the emission intensity of LaPO4:Gd3+ reached the maximum value as the mass percentage concentration of Gd3+ ions ascended to 3%. Monoclinic LaPO4:Gd3+ had stronger emission intensity than hexagonal sample which had more zeolitic water, higher symmetry and lower crystallinity. The nanospheres which dispersed better and had higher uniformity and surface atom fraction had the stronger PL intensity than the nanorods. It has been found that the La0.97Gd0.03PO4, which was prepared under the condition of pH=1, T=20 °C and excess PO43-, performed the best PL property after heat treatment at 900 °C for 4h.

The formation of stable hydrogen impermeable TiN-based coatings on zirconium alloy Zr1%Nb

TiN coatings were deposited by DC reactive magnetron sputtering (dcMS) method on Zr1%Nb substrates with different film thickness. The influence of crystalline structure and thickness of the coatings on hydrogen permeation was investigated. The results revealed that the increase in thickness of the film reduced hydrogen permeability. 1.54 μm TiN deposited in N2/Ar gas mixture with a ratio of 3/1 reduces hydrogen permeation in more than two orders of magnitude at 350 °C. Adhesion strength decreased with increasing film thickness (0.55 to 2.04 μm) from 7.92 to 6.65 N, respectively. The Ti underlayer applied by arc ion plating (AIP) leads to the formation of stable Ti/TiN coatings on Zr1%Nb under thermocycling conditions up to 800 °C. Meanwhile, hydrogen permeation rate of Ti/TiN deposited by combination of AIP and dcMS remains at the same level with TiN deposited by dcMS.

Structure and properties of vacuum ion-plasma coatings

The influence of crystalline structure on the tribotechnical properties of Mo and W dichalcogenide coatings deposited via vacuum ion-plasma methods is investigated. The antifrictional properties and durability of the coatings are verified by means of tribotechnical tests, and electron diffraction and electron microscopy studies of the structures thereof are performed. It is established that the deposition of a wear-resistant sublayer and coating doping provide a positive influence, substantially enhancing the coating durability and leading to extremely low friction.

Effect of crystalline structure on the mechanical response of polypropylene under cyclic deformation

Abstract To evaluate the influence of crystalline structure on the mechanical behavior of polypropylene (PP), uniaxial tensile cyclic tests with a mixed program (oscillations between fixed maximum strains and the zero minimum stress) were performed on isotactic PP (iPP) manufactured by the Ziegler-Natta catalysis method, metallocene catalyzed PP (mPP), and annealed mPP. Although the stress-strain diagrams of iPP and mPP under tension are quite similar, their responses under unloading differ markedly. The residual strain (measured as the strain under retraction down to the zero stress) of iPP strongly exceeds that of non-annealed mPP, and annealing of mPP increases this difference. To rationalize these findings, constitutive equations are developed in cyclic viscoelasticity and viscoplasticity of semicrystalline polymers, and adjustable parameters in the stress-strain relations are found by fitting the observations. The ability of the model to describe the observed phenomenon and to predict the mechanical response in multi-cycle tensile tests, with various deformation programs, is demonstrated by numerical simulation.

Influence of crystalline structure on triboengineering properties of vacuum ion-plasma coatings

The influence of the crystalline structure on the triboengineering properties of coatings is studied whey they are applied with vacuum ion-plasma methods. The coatings were subjected to triboengineering tests for antifriction properties and durability. The crystalline structure and properties were subjected to electronography and electron microscopy. It is established that the wear-resistant sublayer and the alloying of the antifriction dichalcogenide with additional elements produces a positive effect.

Influence of crystalline structure and surface treatment of TiO2particles on their interaction with polar organic molecules

Influence of crystalline structure and surface treatment of TiO₂particles on their interaction with polar organic molecules

Influence of crystalline structures on the domain configurations in controlled mesoscopic ferromagnetic wire junctions

A role of crystalline structures on domain wall formation is investigated by magnetic force microscopy (MFM) using mesoscopic wire junctions of both epitaxial bcc Fe and polycrystalline permalloy. Three sets of structures were fabricated with ferromagnetic wires (30 nm thick, 0.2⩽w⩽50 μm wide and 200 μm long); straight wires, two wires connected at the ends (L shapes), and crosses. Fe samples show complicated domain configurations due to magnetocrystalline anisotropy, while permalloy samples show simple domain with shape anisotropy. These results show that spin configurations at the junction can be precisely tuned by varying not only the shape and the size but also the crystalline structures of the sample.

Influence of crystalline structure and amorphous materials in the depth resolution of sputter etching

AbstractThe dependence of depth resolution Δz/z on the sputtering angle θ is investigated for three sputter‐deposited films: Cr (bee), SiNx (amorphous) and FeCoTb (amorphous). The depth resolution for the Cr system exhibits two maxima at θ = 35° and 45°. These are characteristic for bee textured material but different from fee textured material. The amorphous films show a very weak dependence, if any, owing to the absence of crystallites and crystalline texture. These results are in accordance with channeling theory.

Second-harmonic generation in reflection from crystalline metals: the influence of structure disordering

We report theoretical and experimental studies of the influence of crystalline structure on the nonlinear-optical response of monocrystalline metals. We show that the lattice disordering leads to a decrease of both the anisotropy and the absolute value of the quadrupole second-order nonlinear susceptibility, in agreement with experiments on optical second-harmonic generation in reflection from the surfaces of various Al samples.

Influence of semi-external molecular motions on35Cl NQR frequencies and relaxation in solid benzenesulphonyl chloride

Measurements of the temperature dependence of the 35Cl nuclear quadrupole resonance frequency, nu Q(T), in the gamma phase of benzenesulphonyl chloride and the spin-lattice relaxation time, T1(T), for the three crystalline phases of the same compound were used to study the influence of different crystalline structures on the triggering of semiexternal molecular modes. From a comparative analysis of the effects that the semi-external modes (SEM) have upon nu Q(T) and T1(T) it is possible to deduce that there is a weak influence of the crystalline structure on the triggering temperature of SEMs. Furthermore, some properties of molecular torsional and semi-external modes, for each crystalline structure of benzenesulphonyl chloride, are deduced.

Cyclopolymerization. IX. Radiation-Induced Solid-State Polymerization of N-Octadecyldimethacrylainide

Solid-state cyclopolymerization of N-octadecyldimethacrylamide(ODMA) has been investigated in an attempt to clarify the effect of its long-chain substituent on the polymerization, as compared with the reported polymerization of N-substituted dimethacrylamides(RDMA) which have small substituents. The polymerizability of ODMA has been found to be higher than that of RDMA in the solid state, especially in the postirradiation polymerization, though the former is comparable with the latter in the solution polymerization. X-Ray diffraction studies have revealed that poly(ODMA) is a partially crystalline polymer, in contrast to the poly(RDMA) which is amorphous. However, the other results are similar to those obtained in the polymerization of RDMA, viz., the sigmoid time–conversion curve, higher polymerizability in the liquid state than in the solid state, structural characteristics of the polymer, and the fact that the rate-determining step of the solid-state polymerization of ODMA is an intramolecular cyclization reaction. Consequently, it has been suggested that the polymerization of ODMA proceeds under the influence of crystalline structure, probably due to the ordered arrangement originating from its long octadecyl group, but some destruction of the structure is necessary for the polymerization.