Search

Abstract B 4 C/TiB 2 ceramic composites were fabricated by reinforcing carbon and silicon (10 wt.% total mass) with the help of pressureless sintering at 2150 °C. The influence of C and Si additives on the phase composition, microstructures and mechanical properties of B 4 C/TiB 2 ceramic composites were investigated through the characterizations of XRD, SEM, BSEM and EDS. Compared to B 4 C/TiB 2 ceramic composites without C-Si additives, coarsely plate-like SiC grains were formed in composites at a C: Si mass ratio ∼0:10. By increasing the C:Si mass ratio, the size of the plate-like SiC grains decreases, while the amount of plate-like SiC grains increases. When the C:Si mass ratio was 7:3, multilamellar graphite appeared on the B 4 C grain boundary. Moreover a large number of lamellar graphite grains appeared at a mass ratio of C:Si ∼10:0. Graphite reacted with B 2 O 3 on the B 4 C grain boundary, and the sintered body shrank quickly. Due to the presence of lamellar graphite, the relative density of the sintered body significantly increased from 89.2% to 98.9%. The mechanical properties such as flexural strength ∼336 MPa (∼26.79% increment) and fracture toughness ∼ 5.11 MPam1/2 (∼21.19% increment) were significantly improved compared with the B 4 C/TiB 2 ceramic composite. Graphical abstract Image 1 Highlights • High-performance B 4 C/TiB 2 composites were prepared by pressureless sintering. • The size of plate-like SiC grains decreases with mass ratio of C:Si increasing. • Fracture toughness of sample C10S0 improve owing to crack deflection and bridging. [ABSTRACT FROM AUTHOR]

Copper (Cu) gained its importance in several applications due to its attractive thermal characteristics. However, its applications are limited, wherever high strength and high thermal conductivity are desirable. Thus, an attempt was made to develop Cu/CNT composites having the improved mechanical and thermal properties. Initially, Cu/CNT composite powder was synthesized through molecular level mixing technique, where the functionalized 20–40 nm and 40–60 nm diameter CNT with varying concentrations from 0.25 to 1.0 wt.% with an increment of 0.25 wt.% were used. The powder was uniaxially compacted at 800 MPa and sintered in the range of 2–8 hr at 900 °C. The best characteristics of Cu/CNT composites obtained from the present study are as follows: Relative density (RD) – 89.1%, Hardness – 61.2 ± 0.58 VHN, Thermal conductivity – 343 W/mK and these characteristics obtained their maximum value at 0.25 wt.% CNT concentration and started to decrease irrespective of CNT diameter. [ABSTRACT FROM AUTHOR]

In this study, copper/few-layered graphene (Cu/FLG) composite powder is prepared using two different approaches, chemical synthesis and mechanical milling, and the effect of the processing routes on the mechanical and thermal behaviors of hot-pressed pallets is examined. With both processing routes, the strength of the matrix is increased ∼3.90 and ∼2.82 times by grain refinement, and is further increased 1.14 times by incorporating 0.5 vol.% FLG. In addition, for both processing routes, the coefficient of thermal expansion is reduced from ∼17.07 to ∼15.15 (ppm/K) by incorporating 0.5 vol.% of FLG in both composites. Considering its cost-effectiveness, simplicity, and potential for mass-production, the mechanical process demonstrates the ability to produce Cu/FLG composites with a high mechanical and thermal performance that is comparable to solution-based chemical synthesis routes. [ABSTRACT FROM AUTHOR]

The optically good quality single crystals of triphenylphosphine oxide 4-nitrophenol (TP4N) with maximum dimension of 15 × 10 × 5 mm 3 were grown by slow evaporation solution technique (SEST) at room temperature. The cell dimensions of the grown TP4N crystal were confirmed by single crystal X-ray diffraction (SXRD) and the crystalline purity was confirmed and planes were indexed by powder X-ray diffraction (PXRD) analysis. Functional groups of TP4N crystal were confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance of the grown crystal was determined by the UV–Vis NIR spectral analysis and it has good optical transparency in the entire visible region. The band tail (Urbach ) energy of the grown crystal was analyzed and it appears to be minimum, which indicates that the TP4N has good crystallinity. The position of valence band (E v ) and conduction band (E c ) of the TP4N have been determined from the electron affinity energy (E A ) and the ionization energy (E I ) of its elements and using the optical band gap. The thermal behaviour of the grown crystal was investigated by thermogravimetric and differential thermal analysis (TG-DTA). Vickers microhardness analysis was carried out to identify the mechanical stability of the grown crystal and their indentation size effect (ISE) was explained by the Meyer’s law (ML), Hays-Kendall’s (HK) approach, proportional specimen resistance (PSR) model, modified PSR model (MPSR), elastic/plastic deformation (EPD) model and indentation induced cracking (IIC) model. Chemical etching study was carried out to find the etch pit density (EPD) of the grown crystal. Laser damage threshold (LDT) value was measured by using Nd:YAG laser (1064 nm). The dielectric permittivity (ε՛) and dielectric loss ( tan δ) as a function of frequency was measured. The electronic polarizability (α) of the TP4N crystal was calculated. It is well matched to the value which was calculated from Clausius-Mossotti relation, Lorentz-Lorentz equation, optical band gap and coupled dipole method (CDM). The Z-scan technique was carried out using solid state laser (640 nm) to analyze the nonlinear optical properties of the TP4N crystal. It exhibits the self-defocusing and saturable absorbance effect during analysis of closed and open aperture respectively. The nonlinear optical parameters such as refractive index (n 2 ), absorption coefficient (β) and the third order nonlinear optical susceptibility (χ (3) ) were analyzed. [ABSTRACT FROM AUTHOR]

Conventional polyimide nanocomposites reinforced with graphene-based nanofillers usually possess excellent properties, such as high thermal decomposition temperature, enhanced tensile strength, tensile modulus, etc. However, the elongation at break of the nanocomposites is reduced. Here, we prepared N-doped graphene quantum dots/colorless polyimide nanocomposite (N-GQDs/CPI) films for the first time by in-situ polymerization, whose elongation at break is about 2 times that of the pure film. Meanwhile, the thermal properties and other mechanical properties of the films are improved. Through analyzing FT-IR, XPS, XRD, TAG SEM, etc. of N-GQDs and the films, we consider that the strengthening mechanism of matrix performance is attributed to N-GQDs' well dispersion, its small size effects and strong interface interaction with the matrix. Furthermore, at the indicative wavelength of 550 nm, the optical transmittance of the film with 1 wt% N-GQDs still maintains 79%, indicating the resulting films have excellent optical transmittance. The hydrophilic properties of the prepared films' surface is reduced, their water surface contact angle are increased from 63 ± 2.7° to 92 ± 1.7° with the content of N-GQDs increasing. This research shows that N-GQDs can enhance the various properties of polyimide and provides a high performance nanocomposite films for potential flexible substrates. [ABSTRACT FROM AUTHOR]

Eutectic Sn-Zn alloy is considered as one of the best lead free solder alloys in microelectronic industry. That motivates our group to select different weight percentage of Antimony (Sb) (0.5, 1.0, and 1.5 wt%) as an alloying to Sn-9.0Zn-0.5 Al solder alloy. The thermal behavior, microstructure modification as well as tensile properties of the new developed solder alloys were investigated. A slight increment of the melting temperature (∼ 1 °C) was recorded using differential scanning calorimetry (DSC) after additions of Sb. For 1.5 wt% of Sb, two endothermic peaks at 200.8 °C and 201.5 °C were observed, which are assigned as hypoeutectic Sn-Zn composition. X-ray diffraction (XRD) measurements confirm the existence of β-Sn phase, α-Zn phase, and Sb-Sn intermetallic compounds (IMCs). Scanning electron microscope (SEM) images indicate that the Sb additives refine the microstructure and form a uniform distribution of IMCs in the matrix of solder. The road-like α-Zn phase, Al 6 Zn 3 Sn and SbSn IMCs were clearly appeared in β-Sn matrix, which are responsible of the enhancement in tensile strength. Moreover, α-Zn phases in the Sn-9Zn-0.5Al-1.5Sb alloy were modified as needle-like, broken enormously, depleted, and circle shapes. Generally, The Sb-containing alloys have higher ultimate tensile strength (UTS) and lower elongation than Sb-free solder alloy due to the solid solution and second phase dispersion strengthening effect. The relationship between UTS and temperature follow the Arrhenius law. The average activation energies (Q) were found to be 44.4 ± 1.0 kJ/mol, and the average stress exponents (n) were usually around 5.3 ± 0.45, which are close to pipe diffusion controlled creep in β-Sn matrix. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) composites reinforced with two types of graphite nanoplatelets varying in lateral size - small (GNP-S) and large (GNP-L) - were produced via melt compounding. Morphological, thermal, mechanical, and electrical properties were investigated to reveal the influence of particle size. Electron microscopy and X-ray diffraction showed well dispersed small GNP-S particles up to 10 wt.% loading, while large GNP-L particles started to agglomerate at loadings ⩾7 wt.%. Addition of GNPs improved the Young’s modulus of the composites by 10% and 24% for small and large nanoplatelets, respectively, the latter being among the highest reported for PLA/GNP systems. For GNP-L this larger increase could be partly explained by an increase in crystallinity while no such effect was observed for GNP-S. Conversely, GNP-L systems showed embrittlement while polymer yield was preserved for GNP-S. GNP-L resulted in a lower electrical percolation threshold. However, systems based on smaller GNP-S particles showed significantly enhanced conductivity and a reduction in percolation threshold after annealing. Heat distortion temperature (HDT) increased by up to 13 °C, with large GNP-L showing the slightly larger increase. [ABSTRACT FROM AUTHOR]

Boron compounds such as colemanite, tincal and ulexite are of interest in many application areas due to their great properties. Colemanite and ulexite was used individually as fillers to prepare epoxy composites in this study. The influences of amount of filler, type of hardener and plasticizer addition on the properties of the novel composites were investigated with instrumental analyses and tests. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses showed good dispersion of filler in the epoxy matrix. Improvement in tensile properties was obtained up to 5 wt% filler content in the composites. Water sorption reduced dramatically with increasing amount of filler compared to neat epoxy. Excellent corrosion resistance and strong adhesion properties were observed in all composites. Thermogravimetric analyses (TGA) and vicat softening temperature (VST) tests indicated that colemanite had better synergistic effect on the thermal properties of the neat epoxy than ulexite. Resistance to cold environment of the composites was quite high. It was thought that the composites can be evaluated successfully with the mentioned advantages in many industrial fields such as construction, coating, flooring, and so on. [ABSTRACT FROM AUTHOR]

In this work, in order to investigate the reinforcement effects of organic montmorillonite (OMMT) modified epoxy mortar binders (EMBs), a series of OMMT/EMB composites with different OMMT loadings were prepared. The structure and thermal stability of OMMT were studied by X-ray diffraction (XRD), Fourier transform infrared spectrum, and thermogravimetric analysis (TGA). The effects of OMMT on the structure, glass transition, damping properties, thermal stability, mechanical properties and morphology of EMB were characterized by XRD, dynamic mechanical analysis, TGA, tensile test, and scanning electron microscopy. XRD results indicated that epoxy chains intercalated into the OMMT layers and led to the expansion of OMMT layer spacing. The presence of OMMT increased the glass transformation temperature, crosslink density of the neat EMB. Furthermore, the incorporation of OMMT improved the thermal stability of the EMB. The OMMT/EMB composites showed higher tensile strength and Young’s modulus than the neat EMB. Homogenous dispersion of OMMT in EMB matrix was observed. [ABSTRACT FROM AUTHOR]

Palygorskite (Pal) and modified Pal (OPal) by a silane coupling agent are used to improve the mechanical and thermal properties of poly(butylene succinate) (PBS) and the nanocomposites are prepared by melt blending. The synthesized palygorskite PBS nanocomposites are characterized by thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The mechanical properties and dynamic mechanical and crystallization behavior have been studied. Surface modification improves the dispersion of Pal in the PBS matrix and 16% improvement in the tensile strength is observed from palygorskite PBS nanocomposites with 3 wt.% of OPal compared to pure PBS. The flexural properties and thermal stability of the palygorskite PBS nanocomposites are also enhanced significantly in the presence of OPal. Incorporation of OPal increases the storage modulus and decreases tan δ demonstrating the reinforcing effects of clay on the PBS matrix. Thermal analysis reveals that the Pal nanoparticles are effective nucleating agents accelerating crystallization. The glass transition temperature increases slightly in the presence of palygorskite except the sample with 2 wt.% clay. [ABSTRACT FROM AUTHOR]

X-ray diffraction analysis of as-received desert sand from a Middle East country showed the presence of quartz (SiO 2 ), calcite (CaCO 3 ), gypsum (CaSO 4 .2H 2 O), NaAlSi 3 O 8, Mg 2 (Al 3.9 Si 5.1 O 18 ) and Mg 3 Al 2 (SiO 4 ) 3 phases. A batch of as-received desert sand was melted into calcium magnesium aluminosilicate (CMAS) glass at ~1500 °C. From inductively coupled plasma-atomic emission spectrometry, chemical composition of the CMAS glass was analyzed to be 27.8CaO-4MgO-5Al 2 O 3 -61.6SiO 2 -0.6Fe 2 O 3 -1K 2 O (mole %). Various physical, thermal, and mechanical properties of the glass have been evaluated. Bulk density of CMAS glass was 2.69 g/cm 3 , Young׳s modulus 92 GPa, Shear modulus 36 GPa, Poisson׳s ratio 0.28, dilatometric glass transition temperature (T g ) 706 °C, softening point (T d ) 764 °C, Vickers microhardness 6.3±0.4 GPa, indentation fracture toughness 0.75±0.15 MPa.m 1/2 , and coefficient of thermal expansion (CTE) 9.8×10 −6 /°C in the temperature range 25 to 700 °C. Temperature dependence of viscosity has also been estimated from various reference points of the CMAS glass using the Vogel-Fulcher-Tamman (VFT) equation as well as from the glass composition. The glass remained amorphous after heat treating at 850 °C for 10 h but crystallized into CaSiO 3 and Ca 2 Mg 0.5 AlSi 1.5 O 7 phases at 900 °C or higher temperatures. Crystallization kinetics of the CMAS glass has also been investigated by differential thermal analysis (DTA). [ABSTRACT FROM AUTHOR]

An efficient nonlinear optical single crystal of 2-phenylethylammonium p-hydroxybenzoate (2PPHB) was grown from aqueous solution by slow evaporation solution growth method. Single crystal X-ray diffraction studies confirmed that 2PPHB crystallizes in orthorhombic crystal system with non-centrosymmetric space group of Pna21. The presence of functional groups in the synthesized compound was identified by FTIR spectral analysis. The grown crystals were thermally stable up to 155°C. UV-vis absorption, photoluminescence and birefringence optical properties of grown crystal were explored. The laser induced surface damage threshold and relative second harmonic generation properties of the grown crystal were studied using Q-switched Nd:YAG laser. The variation of dielectric properties of the grown crystal with frequency was investigated for different temperatures. The mechanical response of the crystal was studied by Vicker's microhardness technique. [ABSTRACT FROM AUTHOR]

Ethylene-vinyl acetate (EVA)/sepiolite nanocomposites were prepared by melt blending in a twin screw extruder. The structural, morphological, thermal, flammability and mechanical properties of the EVA/sepiolite nanocomposites were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), thermal analysis, tensile properties and limiting oxygen index (LOI) measurements. X-ray diffraction analysis and FESEM revealed good dispersion of sepiolite in EVA matrix. The tensile strength of EVA/sepiolite increased by 21% and Young's modulus increased by 47% at 5 wt% and 7 wt% sepiolite content, respectively. The thermal stability and fire retardancy of the nanocomposites improved with sepiolite incorporation. [ABSTRACT FROM AUTHOR]

Structure and mechanical properties of the novel casting AJ62 (Mg–6Al–2Sr) alloy developed for elevated temperature applications were studied. The AJ62 alloy was compared to commercial casting AZ91 (Mg–9Al–1Zn) and WE43 (Mg–4Y–3RE) alloys. The structure was examined by scanning electron microscopy, x-ray diffraction and energy dispersive spectrometry. Mechanical properties were characterized by Viskers hardness measurements in the as-cast state and after a long-term heat treatment at 250°C/150hours. Compressive mechanical tests were also carried out both at room and elevated temperatures. Compressive creep tests were conducted at a temperature of 250°C and compressive stresses of 60, 100 and 140MPa. The structure of the AJ62 alloy consisted of primary α-Mg dendrites and interdendritic nework of the Al4Sr and massive Al3Mg13Sr phases. By increasing the cooling rate during solidification from 10 and 120K/s the average dendrite arm thickness decreased from 18 to 5μm and the total volume fraction of the interdendritic phases from 20% to 30%. Both factors slightly increased hardness and compressive strength. The room temperature compressive strength and hardness of the alloy solidified at 30K/s were 298MPa and 50 HV 5, i.e. similar to those of the as-cast WE43 alloy and lower than those of the AZ91 alloy. At 250°C the compressive strength of the AJ62 alloy decreased by 50MPa, whereas those of the AZ91 and WE43 alloys by 100 and 20MPa, respectively. The creep rate of the AJ62 alloy was higher than that of the WE43 alloy, but significantly lower in comparison with the AZ91 alloy. Different thermal stabilities of the alloys were discussed and related to structural changes during elevated temperature expositions. [ABSTRACT FROM AUTHOR]

Abstract: Ethylene-vinyl acetate copolymer (EVA) flame retarded by a combination of intumescent flame retardants (IFR) and organically modified montmorillonite (OMMT) have been crosslinked by high-energy electron beam irradiation. The structure was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of electron beam irradiation on the thermal, mechanical and dynamic mechanical properties of the irradiated EVA nanocomposites were investigated. The XRD and TEM results demonstrated that the OMMT was well dispersed in the EVA nanocomposites. The LOI and UL-94 results showed that a synergistic effect on the flame retardancy of EVA nanocomposite existed between the IFR and OMMT. With the addition of 1wt% OMMT and 24wt% IFR, the LOI value of EVA/IFR/OMMT nanocomposite increased from 30.5 % to 33.5 %. The mechanical properties of the irradiated EVA nanocomposite were evidently improved at 160kGy dosage with the increase in the tensile strength to 18.5MPa. Thermal oxidative degradation of the flame-retardant EVA/IFR/OMMT nanocomposites was characterized by thermogravimetric analysis/infrared spectrometry (TG–IR) and real-time Fourier transformed infrared spectroscopy (RT-FTIR). [Copyright &y& Elsevier]

Abstract: A simple method based on the combination of the intercalation from solution and melt-processing preparation methods was used to prepare highly exfoliated and compatible thermoplastic starch (TPS) and montmorillonite clay (MMT) nanocomposites. The effects of the MMT content on the thermal, structural, and mechanical properties of the nanocomposites were investigated. XRD diffraction was used to investigate the MMT exfoliation/intercalation degrees in the TPS matrix. Data from thermogravimetric analysis and differential scanning calorimetry revealed that the addition of MMT increased the thermal stabilities of TPS nanocomposites. Young''s modulus and tensile strength increased from 8.0 to 23.8MPa and 1.5 to 2.8MPa with an increasing MMT content from 0 to 5wt% without diminishing their flexibility. The improvement in such properties can be attributed to the good dispersion/exfoliation of MMT in the TPS matrix. Combining both methods, it was possible to obtain homogenous and transparent nanocomposites with excellent thermal and mechanical properties for application as packaging materials. [Copyright &y& Elsevier]

Abstract: Natural cellulose fabrics were newly identified from the branches of the Cordia dichotoma. The structure of the fabrics was analysed by FTIR and X-ray diffraction. The net-like morphologies of the untreated, bleached and 5% NaOH (alkali) treated lignocellulose fabrics were observed by SEM and POM. The increase in thermal stability of alkali treated fabrics when compared to the untreated and bleached fabrics was confirmed by the TGA analyses. The effect of bleaching and alkali treatment on the properties of the fabrics was also studied. The alkali treated fabrics exhibited the highest tensile strength of 36.2MPa, elongation at break of 2% and Young''s modulus of 3699.2MPa when compared to the untreated and bleached fabrics. The structure and properties of the fabrics indicated that they could be suitable for blending and processing with biodegradable polymers to make green composites for various types of applications. [Copyright &y& Elsevier]

Abstract: Talc-loaded isotactic polypropylene (iPP) composites with various contents of talc were fabricated by compression molding, following slow- and fast-cooling processes, to obtain slow-cooled samples (SCS) and fast-cooled samples (FCS), respectively. Lamellar thickness of the α-crystal of iPP in the SCS is observed to be larger than that in the FCS by X-ray diffraction study. Rolled fast-cooled samples (RFCS) were also prepared at 25 °C in order to examine the crystal growth of iPP. An epitaxial growth mechanism of the α-crystal of iPP from the talc crystal is proposed. Surface of talc-loaded FCS appears with a smaller particle size than that of talc-loaded SCS and RFCS as observed by a scanning electron microscope. Young’s modulus and tangent modulus of FCS are found lower than those of SCS with the addition of talc up to 20 wt% and higher above this concentration, except microhardness which is higher in SCS at all contents of talc. From thermal studies, talc-loaded SCS and FCS are found to show higher melting temperature than the neat samples. Effect of cooling and rolling on the structures and properties of the fabricated composites are elaborately discussed. [ABSTRACT FROM AUTHOR]

Abstract: Layer-aligned poly(vinyl alcohol)/graphene nanocomposites in the form of films are prepared by reducing graphite oxide in the polymer matrix in a simple solution processing. X-ray diffractions, scanning electron microscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis are used to study the structure and properties of these nanocomposites. The results indicate that graphene is dispersed on a molecular scale and aligned in the poly(vinyl alcohol) (PVA) matrix and there exists strong interfacial interactions between both components mainly by hydrogen bonding, which are responsible for the change of the structures and properties of the PVA/graphene nanocomposites such as the increase in Tg and the decrease in the level of crystallization. [Copyright &y& Elsevier]

Abstract: The new natural fabric Grewia tiliflia was extracted from its tree. This uniaxial fabric was analyzed by chemical, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and polarized optical micro-scopic techniques. The effect of alkali treatment on the mechanical, morphological, and thermal properties of the fabric was examined. The tensile strength, modulus, and the thermal stability of the fabric were found to improve on alkali treatment. From the mechanical and thermal degradation studies of this fabric, it was concluded that the fabric can be used as reinforcement in the preparation of green composites and for other high-value fabric applications. [Copyright &y& Elsevier]

Abstract: New type of aromatic–aliphatic polyamide/montmorillonite nanocomposites were produced using solution intercalation technique in dimethylacetamide. The modification of clay was carried out with ammonium salt of long chain alkyl amine. The nanocomposites were probed for organoclay dispersion, mechanical, thermal and water absorption measurements. Formation of delaminated and intercalated nanostructures was confirmed by X-ray diffraction and TEM studies. Improvement in tensile strength and modulus was observed for nanocomposites with optimum organoclay content (8-wt.%). Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. Differential scanning calorimetric results revealed increase in glass transition temperatures (T g ) with augmenting organoclay in the nanocomposites. Water uptake of the nanocomposites reduced than the neat polyamide rendering decreased permeability. [Copyright &y& Elsevier]

Abstract: This paper presents the results of detailed studies carried out on the densification of TiB2 with CrB2 as sinter additive by hot pressing. The dense compacts were characterized by measurement of hardness, indentation fracture toughness, flexural strength, coefficient of thermal expansion and electrical resistivity. Oxidation characteristics were investigated between 600°C and 1000°C and isothermal oxidation kinetics at 850°C. Phase identification and surface morphology analysis of hot pressed and oxidized samples were done using XRD and SEM. A high density of 96.61% Τ.D was obtained with the addition of 2.5% CrB2 by hot pressing at 1750°C under 35MPa pressure. Hardness values of composites with 2.5–10% CrB2 were close to 24GPa and fracture toughness in the range of 3–5MPam1/2. Coefficient of thermal expansion of the composite with 10% CrB2 was measured in the range of 6.21–7.43×10−6/K from room temperature to 1000°C. Electrical resistivity of TiB2 +10%CrB2 was measured as 32.83, 75.97 and 120μΩcm at 25°C, 500°C and 900°C, respectively. Observed nature of oxidation was parabolic for all composites. Formation of continuous and thick glassy film was observed with increased CrB2 content in the composite. TiO2 and CrBO3 phases were identified on the oxidized surface which are responsible for the improved oxidation resistance of this composite. [Copyright &y& Elsevier]

Abstract: The melt-spinning processes of binary Sn–10wt.% Sb and ternary Sn–10wt.% Sb–In were analyzed using X-ray diffractometer and differential thermal analysis (DTA). The results showed that supersaturated solid solution and new intermetallic compound In3Sn were produced during melt-spinning technique not found under equilibrium conditions. It is also found that a small amount of In addition significantly lowers the melting point of the Sn–10wt.% Sb alloy and reduce the crystal size to ≈60nm. Also, tin–antimony solder doped with In exhibits good mechanical properties, Vickers hardness and mechanical strength due to refined microstructure. This work was performed to study the influence of rapid solidification and indium addition on structure and properties of tin–antimony based alloys. [Copyright &y& Elsevier]

Abstract: Curaua fibres have specific mechanical properties similar to inorganic fibres and are an important renewable raw material. Milled curaua fibres, submitted to different treatments, were characterized by mechanical and thermal properties, moisture content, water absorption, surface morphology, FTIR spectroscopy, density and X-ray diffraction. Except for moisture content and mechanical properties, no other significant changes were observed after the treatments. The treated fibres also show an increase of surface roughness. [Copyright &y& Elsevier]

Abstract: Nonlinear optical single crystals of ammonium pentaborate (APB) were grown by the slow cooling method from aqueous solution. Grown crystal was characterized by powder X-ray diffraction (PXRD) and FT-IR spectral analysis. Perfection of the grown crystal was evaluated by high-resolution X-ray diffractometry (HRXRD). The effect of nylon threading on the perfection of the grown bigger crystal was also studied by HRXRD. The range and percentage of optical transmission was ascertained by recording UV–vis–NIR spectrum. Thermal properties were investigated by TG–DTA and DSC analyses. Its mechanical hardness was estimated by Vickers microhardness tester. [Copyright &y& Elsevier]

Nanocomposites were prepared from organoclay and aramid obtained from 4-aminophenylsulfone and isophthaloyl chloride in dimethylacetamide. Thin hybrid films were characterized by transmission electron microscopy, X-ray diffraction, tensile testing, thermogravimetric analysis, differential scanning calorimetry and water absorption measurements. Improvements in tensile modulus (122%), mechanical strength (46%), and glass transition temperatures (43%) relative to pristine aramid were observed. These nanocomposites were thermally stable in the range 225–450°C. Water uptake and permeability of the nanocomposites was reduced at higher loadings of organoclay. [Copyright &y& Elsevier]

Abstract: Renal stone containing calcium oxalate monohydrate as a major component was subjected to microhardness and acoustic studies in order to understand its mechanical properties in vitro and use them to help in the treatment procedures for more effective stone fragmentation. The chemical composition and the crystalline nature of the stone were verified using Fourier Transform Infrared spectroscopy, X-ray diffraction and the stone was also analyzed using thermo gravimetric analysis and by differential thermal analysis. The microhardness values were almost constant around 1000 MNm−2 in the load range of 1.96 N–9.8 N. The values of fracture toughness and brittleness index for the stone in this load range was varying from 1.12 (0.307) MNm−3/2 to 1.48 (0.296) MNm−3/2 and 674.25 m−1/2 to 878.07 m−1/2 respectively. The density of the stone and the ultrasonic longitudinal wave velocity in the stone were found to be 1880 kgm−3 and 3399 ms−1 respectively indicating that the urinary stone under study was a compact one. The acoustic impedance and the dynamic modulus values were calculated as 6.39×106 kgm−2 s−1and 21.72 GNm−2 respectively. [Copyright &y& Elsevier]

With respect to the fact that persimmon leaves having better effects on medical area applications, a persimmon leaves/cellulose blend fiber was prepared by wet spinning from a DMSO/polyoxymethylene solvent under different spinning conditions, e.g. the temperature of coagulation bath, amount of persimmon leaves added and concentration of spinning solution. Based on mechanical measurement, X-ray diffraction and DSC characterization, it was found that this blend fiber had similar mechanical and thermal properties as referenced cellulose fiber obtained using the same method. [Copyright &y& Elsevier]

Melt blends of syndiotactic polystyrene (sPS) and poly(p-phenylene sulfide) (PPS) have been prepared by using an internal mixer at 300 °C. The thermal, mechanical and morphological properties of binary blends of sPS with PPS have been investigated in this paper. The thermal and morphological properties show the immiscible binary blend evidences, which have a clear phase separation between the components at all compositions and a lack of adhesion at the interface. According to the X-ray diffraction patterns of blends, the crystalline structure of sPS in the blend is not altered from α form to β form. Indeed, the results for tensile test reveal that there is no synergism of the modulus of elasticity for sPS/PPS blend system. [Copyright &y& Elsevier]

The influence of heat treatments on the structure and the mechanical properties of a Zr55Cu30Al10Ni5 bulk metallic glass is studied. Cyclic treatments above 480 °C lead to quite unchanged elastic moduli and hardness, while the thermal expansion coefficient keeps decreasing with rising annealing temperature above 460 °C, whereas a monotonous treatment rises respectively the elastic moduli and the hardness by 30% and 13%. [Copyright &y& Elsevier]

X-ray single-crystal study on the slow evaporation technique grown 2-amino-6-methylpyridinium succinate (2A6MS) exposes its crystal system which belongs to triclinic with centrosymmetric space group P 1 ¯ . A crystal having a dimension of 20 × 8 × 4 mm3 was achieved. 1H NMR spectrum was recorded to investigate the chemical surroundings of various hydrogens in the grown 2A6MS complex and to compliment the X-ray single crystal analysis. FTIR and Raman spectral analyses supported the presence of identified functional groups in the chemical structure. The optical studies by UV–Vis and PL have shown the cut-off wavelength at 348 nm and an occurrence of a high optical emission band at 380 nm under an excitation with 342 nm. The thermal/chemical stability up to 104.3 °C and the absence of phase transformation were confirmed by the TG-DSC study. Vicker's micro hardness test at room temperature and Chemical etching perceived the mechanical property and the grown-in features of the 2A6MS crystal. SHG study confirmed that the grown 2A6MS crystal has SHG which is very well compared with the standard KDP crystal. Density functional theory (DFT) computation was used on B3LYP/6–311++G (d, P) basis set to optimize molecular geometry, HOMO-LUMO energies, Mulliken population analyses, molecular electrostatic potential, NBO, and first order hyperpolarizability. Image 1 • Organic new single crystal of 2-Amino-6-methylpyridinium succinate (2A6MS) belongs to triclinic crystal system with space group P 1 ¯ . • The various quantum mechanical parameters were calculated by density functional theory. • The lower cut-off wavelength (348 nm) and good transmission percentage (81%) of grown crystal was obtained. • 2A6MS crystal belongs to soft category material (n = 2.5). • SHG efficiency of 2A6MS crystal higher than that of KDP crystal. [ABSTRACT FROM AUTHOR]