Crystallographic Changes Research Articles

Magnetism in four-layered Aurivillius Bi[formula omitted]FeTi[formula omitted]O15 at high pressures

We report the structural and magnetic properties of four-layer Aurivillius compound Bi5FeTi3O15 (BFTO) at high hydrostatic pressure conditions. The high-pressure x-ray diffraction (XRD) data does not explicitly show structural phase transitions with pressure, however the observed changes in lattice parameters indicate structural modifications at different pressure values. In the initial pressure region values (up to 2.2 GPa), the lattice parameters a- and b- are nearly equal implying a quasi-tetragonal structure, however as the pressure increases a- and b- diverges apart and exhibits complete orthorhombic phase at pressure values of about ≥8 GPa. Principal component analysis (PCA) of high pressure Raman measurements point out an evident change in the local structure at about 5.5 GPa indicating that the evolution of the local structure under applied pressure seems to not follow crystallographic changes (long range order). Nuclear forward scattering (NFS) measurements reveal the development of magnetic ordering in BFTO at 5K with high pressures. A progressive increase in magnetic order is observed with increase in pressure at 5 K. Further, NFS measurements carried out at constant pressure (6.4 GPa) and different temperatures indicate that the developed magnetism disappears at higher temperatures (20 K). It is attempted to explain these observations in terms of the observed structural parameter variation with pressure.

Surface evolution of crystalline SrTiO3, LaAlO3 and Y3Al5O12 targets during pulsed laser ablation

Pulsed laser ablation and deposition find applications in various technological and scientific fields, where precise control of the laser target interaction is crucial for achieving reproducible results. In this work, we investigated pulsed laser ablation of single crystalline (001), (011) and (111) oriented SrTiO3 (STO), (102) LaAlO3 (LAO) and (001) Y3Al5O12 (YAG) targets. The morphology, oxygen loss, and crack formation on the target surfaces after irradiation with a series of KrF excimer laser pulses will be discussed. The target surface morphology was imaged by atomic force, scanning electron microscopy and confocal laser scanning microscopy. Electron backscatter diffraction analysis and energy-dispersive X-ray spectroscopy were used to analyze the crystallographic changes of the surface and the elemental composition. The target material STO shows a significant crack formation and layer separation increasing with surface crystal orientation from (001) through (011) to (111) and laser pulse fluence. In contrast, the laser-ablated surfaces of LAO show only thin hairline cracks and YAG stays free of cracks in the whole laser fluence range investigated but presents large chipped areas.

Durability of the FeNi3@Ni Material Designed for Water Electrolysis Enhanced by High Frequency Alternating Magnetic Field

This work aims to mimic in “model” conditions the influence of an electrochemical environment associated with an alternating magnetic field (AMF) exposure on FeNi3@Ni nanoparticles. These have been designed to perform alkaline water electrolysis (AWE) enhanced by AMF, the latter allowing to heat locally the catalyst by hysteresis and eddy current losses. The (electro)chemical effect of the aggressive alkaline environment (reducing/oxidizing potential and atmosphere) and of the temperature (mimicking the AMF-induced heating) are addressed by using dedicated (in situ) techniques. First, durability tests carried out in a rotating disk electrode setup without AMF are presented; they show the poor hydrogen evolution reaction durability but an acceptable oxygen evolution reaction durability of this material. Complementary identical location (IL) transmission electron microscopy enables us to track the associated morphology/composition changes experienced by the catalysts in these conditions. Second, IL scanning electron microscopy unveils the fate of electrodes having operated in AMF-enhanced AWE. Third, the influence of a reductive/oxidant atmosphere, combined with a high temperature exposition (up to 600 °C), indicates that this material undergoes crystallographic changes, which may alter the electrochemical activity in long-term experiments with repetitive AMF exposures. The combination of these tests provides insights into the possible long-term durability of this catalytic material in AMF-enhanced AWE.

Unraveling the Structural Instability of Li(Ni0.80Co0.15Al0.05)O2 as a Cathode Material Due to Operating a Li‐ion Battery

The change of the crystal structure for Li(Ni0.80 Co0.15 Al0.05 )O2 as a cathode material in a Li-ion battery is traced. During charging and discharging, the crystallographic change of Lix (Ni0.80 Co0.15 Al0.05 )O2 (x≈ 1.0-0.25) is confirmed with in situ X-ray diffraction, an electrochemical measurement, and the density functional theory calculation. Li atoms after cycling do not completely return to the initial state and defects in the Li-layer generate about 5%. The effect of defects in the Li-layer reveals the transformation of crystal structure and the change of lattice constants. Upon increasing the temperature, the instability of Li0.95 (Ni0.80 Co0.15 Al0.05 )O2 is clearly shown as the movement of transition metals using X-ray and neutron diffraction. The crystallographic values dramatically change upon increasing from 373 to 423 K, but linearly vary upon decreasing temperature. Furthermore, the result of the calculation demonstrates that the possible atom for mixing is Ni. The evolution of magnetic properties explicitly certifies the atomic movement that gives rise to a spin-glass state through the induction of ferromagnetism. In conclusion, defects are created in crystal structure during operation of the Li-ion battery and generate structural instability. The results provide the cause and mechanism of the degradation of cathode material in a Li-ion battery.

Resolving the Role of Configurational Entropy in Improving Cycling Performance of Multicomponent Hexacyanoferrate Cathodes for Sodium‐Ion Batteries

AbstractMn‐based hexacyanoferrate (Mn‐HCF) cathodes for Na‐ion batteries usually suffer from poor reversibility and capacity decay resulting from unfavorable phase transitions and structural degradation during cycling. To address this issue, the high‐entropy concept is here applied to Mn‐HCF materials, significantly improving the sodium storage capabilities of this system via a solid‐solution mechanism with minor crystallographic changes upon de‐/sodiation. Complementary structural, electrochemical, and computational characterization methods are used to compare the behavior of high‐, medium‐, and low‐entropy multicomponent Mn‐HCFs resolving, to our knowledge for the first time, the link between configurational entropy/compositional disorder (entropy‐mediated suppression of phase transitions, etc.) and cycling performance/stability in this promising class of next‐generation cathode materials.

Biodiesel production over sodium carbonate and bicarbonate catalysts

Biodiesel, a mixture of alkyl esters (FAME), is viewed as a feasible renewable fuel to substitute fossil diesel. The first-generation biodiesel raises several sustainability issues and new production processes using low-grade fats and heterogeneous catalysts are envisaged. Biodiesel from alimentary grade oil and waste frying oil was produced by methanolysis (oil/methanol = 12 M ratio), at 67 °C, using anhydrous sodium carbonate and bicarbonate, commercial materials as catalysts (5% by oil weight) in a batch reactor at atmospheric pressure. Sodium carbonate had a higher catalytic activity for the methanolysis of the fresh oil (97% of FAME after 90 min) than for the frying oil (12% of FAME after 90 min), which can be attributed to the greater acidity of the fried oil, which promotes the partial neutralization of the catalyst. Sodium bicarbonate, less active than sodium carbonate, showed similar catalytic activities for both fats (84–85% of FAME after 180 min), appearing to be less sensitive to the acidity of the raw material, which may derive from its lower basicity. Both catalysts suffer crystallographic changes during reaction being both converted into similar mixtures of hydrated carbonate/bicarbonate slats, like trona. The methanol solubility of sodium carbonate seems to have a null homogeneous contribution to the catalytic process since the co-produced glycerin presented a pale-yellow color which is characteristic of heterogeneous catalyzed methanolysis processes. Such result was corroborated by thermogravimetric analysis of glycerin which showed small residual masses due to minor solubilization of catalyst. FTIR spectra of glycerin showed low contamination with MONG (Matter Organic Non-Glycerin), thus the contribution of homogeneous catalysis was not meaningful.

Femtosecond laser microstructuring of monolithic zirconia: Effects of laser parameters on resin bond strength

This study aimed to investigate the effects of different femtosecond (fs) laser treatment protocols on the surface roughness (Ra) and shear bond strength (SBS) of resin cement to zirconia. A total of 110 zirconia specimens were divided into 11 subgroups according to the surface treatment: Control (C), airborne-particle abrasion (APA), laser irradiation applying 400 mW, 600 mW, and 800 mW of 90 fs laser pulses with 1, 5, and 10 repetitions (Fs(400/1), Fs(400/5), Fs(400/10), Fs(600/1), Fs(600/5), Fs(600/10), Fs(800/1), Fs(800/5), and Fs(800/10) ), respectively). Ra values were measured using a profilometer, and topographical changes were evaluated under a scanning electron microscope. X-ray diffraction analyses were performed to determine the crystallographic changes. Self-adhesive resin cement was bonded to zirconia specimens, and SBS tests were conducted. C and Fs(800/10) groups exhibited the lowest and the highest Ra and SBS values, respectively. Regardless of the fs laser power, application of five and 10 repetitions resulted in higher Ra values than air-abrasion. Fs(400/10), Fs(600/5), Fs(600/10), Fs(800/5), and Fs(800/10) groups showed higher SBS values than the APA group (p < .05), while SBS of other laser groups did not differ from the APA group (p > .05). Fs laser treatment protocols used in this study may be promising for zirconia-resin bonding. However, the effects of these treatments on the mechanical properties of zirconia need evaluation.

Photoacoustic Enhancement of Ferricyanide-Treated Silver Chalcogenide-Coated Gold Nanorods.

Plasmonic gold nanorods (AuNRs) are often employed as photoacoustic (PA) contrast agents due to their ease of synthesis, functionalization, and biocompatibility. These materials can produce activatable signals in response to a change in optical absorbance intensity or absorbance wavelength. Here, we report a surprising finding: Ag2S/Se-coated AuNRs have a ~40-fold PA enhancement upon addition of an oxidant but with no change in absorption spectra. We then study the mechanism underlying this enhancement. Electron micrographs and absorption spectra show good colloidal stability and retention of the core-shell structure after potassium hexacyanoferrate(III) (HCF) addition, ruling out aggregation and morphology-induced PA enhancement. X-ray diffraction data showed no changes, ruling out crystallographic phase changes upon HCF addition, thus leading to induced PA enhancement. Attenuated total reflectance-Fourier transform infrared spectroscopy and zeta potential analysis suggest that PA enhancement is driven by the irreversible displacement of hexadecyltrimethylammonium bromide with HCF. This is further confirmed using elemental mapping with energy-dispersive X-ray analysis. PA characterization after HCF addition showed a four-fold increase in the Grüneisen parameter (Γ), thus resulting in PA enhancement. The PA enhancement is not seen in uncoated AuNRs or spherical particles. Two possible mechanisms for PA enhancement are proposed: first, the photo-induced redox heating at the Ag2S/Se shell-HCF interface, resulting in an increase in temperature-dependent Γ, and second, an enhanced electrostriction response due to HCF adsorption on a layered plasmonic nanoparticle surface, resulting in a high thermal expansion coefficient (β) that is directly proportional to Γ.

Effect of femtosecond laser and sllica-coating on zirconia framework-veneering ceramic bonding, surface chemistry and crystallographic changes

The aim of this study was the assessment of various surface conditioning methods upon zirconia framework veneering ceramic bonding, crystallographic changes, and surface chemistry. 91 prepared zirconia specimens were randomly assigned to 4 groups (n = 18) according to conditioning method: Group SB: Air-borne-particle abrasion with 50 µm Al2O3; Group R: Tribochemical silica coating; Group FL: Femtosecond-laser application; Group Si25: argon/oxygen plasma (8:1 in flux) film deposition on the zirconia surface for 25 min and Group Si49: as in Si25 but only 49 min. The veneering ceramic was fired upon the zirconia surface and the interface of the framework-veneer assemblies were subjected to shear force using a Universal Testing Machine (1 mm/min). Three specimens from every group were analyzed with profilometry and SEM. Data were statistically analyzed using a One-way ANOVA and Tukey’s test for multiple comparisons (α = 0.05). Failure modes were obtained and SEM-EDX was used to identify tetragonal to monoclinic transformation phase change. Group Si49 (32 ± 3) presented the highest mean bond strength values (MPa) followed by Group Si25 (28 ± 6) being not significant from one another (p > 0.05). Groups SB (15 ± 5) and R (16 ± 5) did not show significant difference (p > 0.05), being significantly less than that of Group FL (22 ± 6) (p < 0.05). All groups presented predominantly mixed failures. Silica-based coating was most effective in terms of bond strength, minimal flaws and transformation in the zirconia tested.

Investigation of crystallographic changes across the Cr/a-Si interface by X-ray absorption spectroscopy

X-ray Absorption Fine Structure spectroscopy (XAFS) has been employed to investigate the crystallographic changes that evolved across the Cr/a-Si interface as a function of annealing temperature. A stack of 400nm a-Si and50nm metallic Cr film is deposited onto a fused silica substrate by electron beam evaporation. Thesestacks are subjected to annealing temperature from 200°C to 700°C in nitrogen-rich atmosphere to facilitate the metal diffusion and subsequent phase formation across the interface. XAFS investigations were carried out in twoconfigurations to study the change in local chemistry of Cr indepth andtop layers of the stack simultaneously. XAFS analysis confirmed thatthe FSC stack annealed at 200°C has a dominant metallic Cr concentration along with a minority content of Cr2O3 andCr3Si. On increasing the annealing temperature, metallic Cr converted into Cr2O3 andCr3Si up to an intermediate temperature of 500°C and finally at 700°C it transformed to CrSi2. It is also confirmed from total reflection XAFSthatCr diffusion intoa-Si is the preferred phenomenon that takes place acrossthe Cr/a-Si interface. The diffusion of Cr and subsequent thermodynamic conditions required for the formation of different Cr phases are discussed to understand the factors that affect the Schottky properties of the Cr/a-Si interface.

Effect of Fiber Orientation on Microstructure and Texture Evolution During the Cold‐Rolling of Al–Mg–Si Alloy

A material with a strong double fibrous texture is subjected to rolling with various deformation paths—unidirectionally and with 90° rotations about the normal direction (cross‐rolling). Additionally, the orientation of the initial fiber is manipulated to force unlikely grain rotations. The purpose of these procedures is to study the dependence between crystallographic and morphological texture changes caused by the rolling. Microstructure observations show that deformation mechanism responsible for the final microstructure depends on the initial fiber orientation. The crystallographic texture is related to the deformation mode and leads toward expected orientations; however, the initial grain boundaries alignment has a strong impact on the final microstructure. Unidirectional rolling results in typical orientations along the β‐fiber in all investigated cases. The texture created during the more complex deformation path with inset rotations follows the geometrical constraints for fourfold symmetry, even if this required unlikely rotations toward the α‐fiber.

Wavelength dependence of picosecond-pulsed laser ablation of hot-dip galvanized steel

Laser ablation of galvanized steel at a wavelength of 343, 515 and 1030 nm was compared for single as well as multiple picosecond laser pulses. The characteristics of ablated craters, such as ablation rate, crater shape and chemical composition, in relation to the processing parameters were studied. Surface morphology of the laser ablated craters were characterized with the help of confocal laser scanning microscopy and scanning electron microscopy. Chemical compositional and crystallographic changes were analyzed by energy-dispersive X-ray spectroscopy and electron backscatter diffraction respectively. Three ablation regimes were identified in the ablation process of galvanized steel. For equal amount of fluence, ablation rates are found to increase with decreasing laser wavelength. Analyzing the crater shape and the cross-sectional chemical composition, three possible applications are identified for three different wavelengths when processing galvanized steel with picosecond pulsed lasers, namely coating removal, surface texturing and micro-drilling.

Iron(II) Complexes of 4-(Alkyldisulfanyl)-2,6-di(pyrazolyl)pyridine Derivatives. Correlation of Spin-Crossover Cooperativity with Molecular Structure Following Single-Crystal-to-Single-Crystal Desolvation.

The complex salts [Fe(L1)2]X2 (1X2; L1 = 4-(isopropyldisulfanyl)-2,6-bis(pyrazolyl)pyridine; X– = BF4–, ClO4–) form solvated crystals from common organic solvents. Crystals of 1X2·Me2CO show abrupt spin transitions near 160 K, with up to 22 K thermal hysteresis. 1X2·Me2CO cocrystallizes with other, less cooperative acetone solvates, which all transform into the same solvent-free materials 1X2·sf upon exposure to air, or mild heating. Conversion of 1X2·Me2CO to 1X2·sf proceeds in a single-crystal to single-crystal fashion. 1X2·sf are not isomorphous with the acetone solvates, and exhibit abrupt spin transitions at low temperature with hysteresis loops of 30–38 K (X– = BF4–) and 10–20 K (X– = ClO4–), depending on the measurement method. Interestingly, the desolvation has an opposite effect on the SCO temperature and hysteresis in the two salts. The hysteretic spin transitions in 1X2·Me2CO and 1X2·sf do not involve a crystallographic phase change but are accompanied by a significant rearrangement of the metal coordination sphere. Other solvates 1X2·MeNO2, 1X2·MeCN, and 1X2·H2O are mostly isomorphous with each other and show more gradual spin-crossover equilibria near room temperature. All three of these lattice types have similar unit cell dimensions and contain cations associated into chains through pairwise, intermolecular S···π interactions. Polycrystalline [Fe(L2)2][BF4]2·MeNO2 (2[BF4]2·MeNO2; L2 = 4-(methyldisulfanyl)-2,6-bis(pyrazolyl)pyridine) shows an abrupt spin transition just above room temperature, with an unsymmetrical and structured hysteresis loop, whose main features are reversible upon repeated thermal scanning.

Phase Field Modeling of Crystallographic Corrosion Pits

The modeling of corrosion to understand and predict corrosion behavior is a topical issue. Here, a 3D phase field model is developed to simulate the pit morphology, primarily focusing on crystallographic pits. A crystallographic function is employed to incorporate different corrosion rates for different crystallographic planes. The model is benchmarked and validated against an analytical solution for a simple case. 3D crystallographic pits in a single crystal are simulated and the effect of substrate orientation on the pit morphology is studied. The crystallographic pit morphology changes significantly with the substrate orientation and these morphologies have a symmetry consistent with the substrate orientation. This first 3D phase field model of crystallographic pits will help in predicting the intricate shapes of pits, thereby, pushing the frontiers of pitting corrosion modeling.

Effect of dislocation pattern on the magnetic domain structure of pure polycrystalline Ni

We investigated the influence of discrete dislocation, dislocation cell, and cell block on the magnetic domain structure in deformed polycrystalline Ni. Discrete dislocation and dislocation cell structure manifested a short-range effect on the local domain structure. By contrast, dislocation cell block structure significantly changed the magnetic domain by generating 180° domain walls. Our observations indicated that the change of magnetic property as a function of plastic deformation should be discontinuous. However, in macroscale, the coercivity and hysteresis loss monotonically increased as increasing flow stress increases. The discrepancy between the phenomena at different scales is attributed to the crystallographic orientation change in plastic deformation.

Unraveling the State of Charge-Dependent Electronic and Ionic Structure–Property Relationships in NCM622 Cells by Multiscale Characterization

LiNi0.6Co0.2Mn0.2O2 (NCM622) undergoes crystallographic and electronic changes when charging and discharging, which drive the cathode material close to or even beyond its stability window. To unravel the charge compensation mechanism of NCM622, spatially resolved atomic force microscopy (AFM) measurements in electrochemical strain microscopy (ESM) and conductive AFM (C-AFM) modes are obtained, and the spectroscopic information and crystallographic information are compared. All experiments are performed with two sets of samples: state-of-the-art samples that are composed of a binder, a conductive additive, and an active material and polished samples for single-particle analysis. Near-edge X-ray absorption fine structure spectroscopy shows that ionic Ni2+ reacts to give Ni3+ when charging and forms covalent bonds with its oxygen neighbors. A Ni2+/Ni3+ gradient across the particles balances out with the increasing state of charge, as verified by ESM. Therefore, the results also provide an important view that improves the mechanistic understanding of ESM in electrode materials. Finally, the interplay between the electronic and ionic conductivities and the crystallinities of NCM622 cathodes is elaborated and discussed.

PCA-Assisted Raman Analysis of Osteonecrotic Human Femoral Heads.

Osteonecrosis of the femoral head (ONFH) occurs frequently in adolescents and young adults and causes progressive deformation and destruction of the hip joint and impairs standing and walking, resulting in a significant decrease in the quality of life of patients. In addition, studies have shown that a history of corticosteroid administration and heavy alcohol consumption are closely related to the occurrence of ONFH. However, the detailed mechanism by which steroid administration and alcohol consumption are associated with the development of the disease is still unknown. With many researches still ongoing and without a clear biological pathway for osteonecrosis, effective preventive measures cannot be taken. Therefore, the current focus of ONFH treatment is to establish an early diagnosis and treatment strategy. We obtained the femoral heads of four patients with steroidal ONFH and three patients with alcoholic ONFH. We then compared the femoral heads of steroidal and alcoholic osteonecrosis by analyzing them at the molecular level by Raman spectroscopy. Crystallographic changes (deformations) in the mineral phase and fraction of organic material respect to the total mass were then plotted as a function. We found that changes in bone composition in ONFH were different in steroidal and alcoholic ONFH. We conclude that this suggests that the developmental mechanisms of steroidal and alcoholic ONFH may follow different paths. We also noticed that while steroid seem to lead to a more marked degradation of the tissue, alcohol seem to affect also the quality of the healthy tissue.

Insights into the sodium storage mechanism of Bi2Te3 nanosheets as superior anodes for sodium-ion batteries.

Although bismuth-based anode materials for sodium-ion batteries (SIBs) have attracted wide attention, their large volume variation hinders their actual applications, especially in Bi2Te3 systems. In this study, Bi2Te3 nanosheets (BT-Ns) are fabricated by a novel strategy via a solvent reductive reaction. The elements Bi and Te are spontaneously grown into ultrathin nanosheets because the hexagonal crystal of Bi2Te3 has a strong tendency to grow horizontally. The crystal structure of the BT-Ns is well developed and the thickness is about 1.42 nm, which can not only offer more active sites but also promote electrical conductivity and the diffusion of Na ions and electrons. It exhibits excellent rate and long-term cyclic performance, delivering 364.0 mA h g-1 at 5 A g-1 after 1200 cycles. The high rate and long-term cyclic performance of the Bi2Te3 anodes is attributed to the facile design of the 2D nanosheet structure, presenting an effective strategy to construct anodes for SIBs. The sodium storage mechanism of Bi2Te3 follows a three-step crystallographic phase change of Bi2Te3, discovered by an in situ X-ray diffraction analysis. The applicability of BT-N anodes in full cells via pairing with Na3V2(PO4)3 cathodes delivers excellent performance (energy density of 107.2 W h kg-1) and satisfactory practical applied prospects.

Impact of Substrate Biasing During AlN Growth by PEALD on Al2O3/AlN/GaN MOS Capacitors

AbstractIn this article, the role of the substrate biasing during the passivation of GaN with AlN deposited by plasma enhanced atomic layer deposition (PEALD) is investigated. In addition to a commonly used remote inductively‐coupled plasma source, the PEALD reactor is equipped with another power supply allowing the substrate to be biased and to adjust the ion energy impinging on the substrate surface. The presence is reported of a narrow bias window where the GaN passivation is significantly improved compared to a standard AlN film deposited without bias. It is found that the AlN film quality is enhanced and the crystallographic structure changes from a well‐ordered epitaxial relationship with the GaN substrate to textured films when applying a bias. Finally, the capacitance–voltage characteristics (C–V) of Al2O3/n‐GaN and Al2O3/AlN/n‐GaN metal‐oxide‐semiconductor (MOS) capacitors are also studied. It is shown that the addition of an AlN interlayer deposited with the appropriate bias is essential to positively shift the flatband voltage of the C–V characteristics while preserving high AlN/n‐GaN interface quality. Therefore, the GaN passivation with AlN deposited using substrate biasing provides a promising pathway towards the manufacturing of normally‐off MOS‐channel high electron mobility transistors.

Impact of spark plasma sintering process on tribo surface of Al/CNT composites

Spark Plasma Sintered Aluminium (SPSed Al) composites are widely used in various micro components of the engineering applications. This paper deals with the evaluation of tribological behavior of the SPSed Al composites with respect to the SPS process parameters. The multi-walled Carbon Nano Tubes (CNTs) are added to the SPSed Al composites to improve its wear resistance by a solid lubrication effect. The presence and distribution of CNT over the Al matrix are confirmed through the FESEM analysis and the crystallographic changes of the SPSed Al/CNT composites are examined using the XRD analysis. The hardness of the SPSed Al/CNT composite has been improved by the re-crystallization at the optimal SPS condition. It also influences the frictional wear behavior of the Al/CNT composites and it resulted in overcome of ploughing on the Al surface. The frictional wear behavior of the SPSed Al/CNT composites is optimized using the taguchi methodology and the minimum wear rate of 24.7 × 10–6 g m−1 and the CoF of 0.192 are obtained for the Al/CNT1 wt% composite sintered at 500 °C and ball milled at 300 rpm for 480 min. The worn surface of the Al/CNT1 wt% composite reveals that the mild abrasive wear is occurred at the optimal tribo condition.