Effect Of Annealing Treatment Research Articles

Effect of annealing treatment on the tribological performance of hydrogenated amorphous diamond coatings doped with nitrogen

Pure a-C:H and some nitrogenated coatings (a-C:N:H) with 0.12–2.95 at%N were deposited onto 316 L and Si wafer via the plasma-enhanced chemical deposition (PECVD) technology. Pin-on-ball sliding tests against Al2O3 balls were carried out for as-deposited and annealed coated specimens. The micro-morphology and chemical bonding structure of these coatings with different treatments were characterized using FE-SEM, FTIR, Raman, and XPS. The OH group can be incorporated into the coating bulk, and becomes the active site that reacts with the dangling Al on the counter-body surface to increase the coefficient of friction (CoF), thus gradually increasing the abnormal transition stage occurring in the CoF-sliding time curve. N doping transforms the OH group into NO and CO bonds, and enhances the O/C ratio in the coating to increase the wear rate. Either as as-deposited or an-annealed, the CoF of the pure a-C:H coating always raised with sliding distance, and it was larger than the N-doped coatings. However, the N doped coatings presented higher wear rate. The a-C:N:H coating with 0.12 at% N exhibited the best anti-wear performance, which was with almost the same wear rate as a pure a-C:H coating.

Effect of solvents and annealing treatment on the properties of the methylammonium lead tribromide perovskite thin films

Solution-processed hybrid organic–inorganic perovskites from organoammonium halide and lead halide precursors form effective active layers for optoelectronics devices. The solvent plays a decisive factor on the preparation of active layer for perovskite application. In this report, the properties of methylammonium lead tribromide (MAPbBr3) thin films were studied using various solvents. The solvents used were dimethylformamide (DMF), dimethyl sulfoxide (DMSO), a mixture of DMF + IPA (Isopropanol). The photoluminescence and absorption spectra show a good solubility of the perovskite content in the mixed solvent than that with DMF or DMSO which is attributed to the good crystallization of content in the film. Furthermore, the effect of annealing treatment on the structural and optical properties of MAPbBr3 thin films prepared with DMF + IPA was investigated. The MAPbB3 film annealed at 100 °C has considerably improved the dissociation of the charges resulting from the good interaction of the solvent with the perovskite material and the good perovskite film quality.

Modeling and Experimental Studies on Adsorption and Photocatalytic Performance of Nitrogen-Doped TiO2 Prepared via the Sol–Gel Method

Nitrogen-doped TiO2 has a great potential as a photocatalyst under visible light irradiation with applications in the removal of air and water pollutants, and the treatment of bacterial contaminations. In this study, nitrogen-doped TiO2 nanoparticles were synthesized via the sol–gel method and a post-annealing heat treatment approach. The effects of annealing treatment on the photocatalyst crystalline size and degree of crystallinity were analyzed. Methylene blue dye was used as the model water contaminant for the evaluation of the photoactivity of the synthesized nitrogen-doped TiO2 nanoparticles. The degradation of methylene blue was attributed to three mechanisms, i.e., adsorption, photocatalysis, and direct light photolysis. A kinetic model was developed to distinguish the impact of these three different mechanisms on the removal of contaminants. Adsorption and photocatalysis are heterogeneous processes for removing water organic contaminants. The characterization analysis demonstrates that they are relevant to the microstructures and surface chemical compositions of nitrogen-doped TiO2 photocatalysts. The processing–structure–performance relationship helped to determine the optimal processing parameters for nitrogen-doped TiO2 photocatalyst to achieve the best performance. While we used methylene blue as the model contaminant, the generalized quantitative model framework developed in this study can be extended to other types of contaminants after proper calibration.

Electron beam welding of a novel near α high temperature titanium alloy powder compact: effect of post-welding heat treatment on tensile properties

A novel near α high temperature titanium alloy (Ti55) was produced from powder compact through hot isostatic pressing. Electron beam welding (EBW) was used to join the Ti55 alloy powder compact and effects of annealing treatment on the microstructure and mechanical properties of EBW joints were investigated. The residual stress distribution of as-welded joint was calculated using finite element method (FEM). The results show that the microstructure and microhardness profiles are non-uniform across the EBW joints. The tensile residual stresses are confirmed across the as-welded joints based on FEM analysis. All of tensile specimens failed at the base metal, indicating that the mechanical properties of EBW joints are equal to those of base metal, or better. The tensile strength of as-welded and as-annealed joints increases slightly compared with base metal. An obvious reduction on the reduction of area of EBW joints was obtained after annealing at 500 °C. Related mechanisms were discussed based on the residual stress, tensile deformation and the strain rate sensitivity.

Effect of Annealing on Heavy-Load Wear Performance of Wear Resisting Steel–Carbon Steel–Cladded Plate

The effect of annealing treatment on the wear performance of hot-rolled wear-resistant steel–carbon steel–cladded plates was investigated. A novel cladding procedure that can provide high wear resistance, a strong structure, and low cost is typically employed for metallurgical mining equipment, agricultural machinery, coal mining, and other industries. The cladded plates were first annealed at different temperatures and sampled for friction and wear experiments on an RETC MFT-5000 friction–wear tester and then an online 3D optical profiler was used to observe the wear tracks. Finally, the microstructure near the wear track was analyzed by using electron backscatter diffraction. The results show that the wear resistance of the BTW1/Q345R plate becomes weaker with an increase in temperature. Due to the properties of the plate, fluctuations still occur in the stable stage. At the annealing temperature of 860 °C, the cladded plate has the best wear resistance, which is proved with a maximum scratch width of 1.419 mm and a maximum scratch depth of 43.2 μm.

Microstructure and thermal conductivity of Cu-Cu2AlNiZnAg/diamond coatings on pure copper substrate via high-energy mechanical alloying method

In the present work, a novel system of Cu2AlNiZnAg high entropy alloys (HEAs) powder was successfully synthesized and Cu-Cu2AlNiZnAg/diamond coatings were fabricated on T2 pure Cu substrate via mechanical alloying method. Characterization of the Cu2AlNiZnAg HEA powder indicated that a single FCC solid solution phase was formed and no indication of any amorphous phase or intermetallic compound was found in the microstructure. The FCC phase was Cu-rich phase. The coatings exhibit a microstructure composed of black particles of diamonds and gray areas of Cu2AlNiZnAg HEA reinforced Cu matrix composites. The effects of Cu-Cu2AlNiZnAg/diamond ratio and milling time on the fabrication of coatings were investigated. The effect of annealing treatment on the microstructure of coatings was discussed. The microhardness of the coating was far higher than that of copper substrate whether it was annealed or not. The thermal conductivity of the fully coated sample was improved greatly after annealing, reaching 358.53W•m−1•K−1, which was superior to the T2 pure copper with the same annealing treatment.

Effect of annealing treatment at 550 °C on ferrite of thermally aged cast austenitic stainless steels and ageing kinetics of reverted cast austenitic stainless steels

Ageing of Cast Austenitic Stainless Steels (CASS) was attributed to the decomposition of the ferrite by spinodal decomposition and precipitation of G-phase particles. This leads to an increase in hardness and a decrease in Charpy-impact energy. It is possible to restore the mechanical properties of these steels by annealing treatment above the Fe-Cr miscibility gap in order to dissolve α’ phase. In this work, an annealing treatment for 2 h at 550 °C followed by water quenching was applied to various Mo-free and Mo-bearing steels. This treatment allowed to restore almost completely the mechanical properties of Mo-free steels and partly Mo-bearing steels regardless of the initial ageing time. The mechanical property changes were attributed to the complete dissolution of spinodal decomposition and complete or partial dissolution of G-phase particles. After annealing, a re-ageing kinetics was studied. The preexisting G-phase particles have minor influence on the kinetic of spinodal decomposition until 2,400 h at 400 °C.

Cuboid-like nanostructure strengthened equiatomic Ti–Zr–Nb–Ta medium entropy alloy

This study investigates the effect of annealing treatment on the phase transformation and mechanical properties of the equiatomic TiZrNbTa MEA from room temperature to 1200 °C. After annealing at 1200 °C for 24h, the single solid-solution body-centred cubic (BCC) phase in the as-cast Ta25Zr25Nb25Ti25 transformed into an extremely high number density (~103/μm2) of Ta–Nb-rich BCC nanocuboidal phase (28 ± 10 nm square, BCC1) and a nanostrip-like Zr-rich BCC phase (3 ± 2 nm thick, BCC2). The phase separation from BCC to BCC1 and BCC2 arises from two primary reasons: (i) the high positive mixing enthalpy of both Ta–Zr and Nb–Zr (strong tendency to separation between each pair), and (ii) the 3–4 orders of magnitude higher mobility of Zr than Ta, Nb and Ti in these MEAs (kinetically driven). Detailed CALPHAD simulations of phase formation in this MEA agreed with experiments and provided insightful phase transformation details. The calculated diffusion distance of Zr (~4.1 nm) from the CALPHAD data corresponds to the measured Zr-rich nanostrip thickness (3 ± 2 nm). The nanocuboidal BCC1-BCC2 structure exhibited 112<111>-type of twinning deformation under compression at room temperature. The Ta25Zr25Nb25Ti25 MEA retained yield strength of ~410 MPa at 1000 °C and ~210 MPa at 1200 °C. The phase transformation during cooling after annealing and the microstructural evolution during compression at temperatures from 600 °C to 1200 °C were characterized and discussed in detail.

Effect of europium on the blue–green emission of ZnS thin films by polyol and dip-coating technique

This work reports the effect of annealing treatment (550, 650, and 750 °C) and europium concentration (1-7 at.%) on the structural, morphological, and optical properties of ZnS:Eu3+ thin films synthesized by the polyol method and dip-coating technique. The films were indexed to the zinc-blende phase of ZnS with crystallite size ranging from 2-7 nm and exhibited preferential orientation at the (111) plane according to the XRD analyses. The SEM and AFM images indicate homogeneous, flat, crack-free, compacted films, with pyramidal grain shape and particle size distribution about ∼25 nm. High transmittance in the visible region (above 80 %) and band gap (3.75-3.9 eV) computed by the Tauc model were obtained by UV–VIS spectroscopy. The PL spectra show the emission bands related to radiative recombination involving defect states, particularly, zinc and sulfur vacancies. The PL spectra also indicate that the higher the europium concentration, the higher the emission light intensity in the blue–green regions. At the same time, the typical 5D0→7F2 transition from Eu3+ is barely noticeable due to a poor energy transfer from the ZnS host to the Eu ions. On the other hand, by increasing the annealing temperature from 550 to 750 °C, a 2.5-fold decrease in the emission intensity is recorded.

Thermally Stimulated Current Study and Relaxation Behaviour of Annealed Copolymer P(VDF-TrFE) Films for Potential Pyroelectric Energy Harvesting

The effects of annealing treatment on the polarization of copolymer P(VDF-TrFE) free-standing films were thoroughly studied by the thermally stimulated current (TSC) method using decomposition analysis and first-order kinetic theory. The TSC measurement mainly revealed three depolarization peaks, which are known as the β, α and Curie mode (ρ) peaks in P(VDF-TrFE). The origin of the TSC peaks and their relaxation behaviour were correlated with structural, morphological and electrical properties such as ferroelectricity, dielectricity and pyroelectricity. Spin-coated copolymer thin films with thicknesses of 300 nm were also prepared from 5 wt.% solutions. Both free-standing and thin films were initially annealed in the range of their Curie temperature up to the melting point [80–140°C] to increase their crystallinity. A remnant polarization current of 76.7 mC m−2, which gives a pyroelectric coefficient of 31 μC m−2K−1 and a figure of merit FD of 86 μC m−2K−1 (1 kHz), was obtained from the sample annealed at 100°C, where the percentage of crystallinity was maximum and the phase was about to transition from ferroelectric to paraelectric.

Effect of annealing treatment on magnetic texture of cold rolled ULC steel

Anisotropic behaviors of cold rolled and annealed ULC steels are evaluated by orientation imaging microscopy (OIM) and magnetic Barkhausen emission (MBE) techniques. The MBE voltage is found higher along RD than TD, indicating the presence of favorable magnetic easy axis along RD for both 50 and 80% cold rolled steels. The recovery occurred at low temperature (T < 500 °C) annealing causes a higher anisotropy coefficient (‘k’) for 50% than 80% CR steel, while at high temperature (T > 500 °C) annealing leads to an abrupt drop of ‘k’ value for both cold rolled steels. Furthermore, the kernel average misorientation map, obtained from OIM, decreases with increasing annealing temperatures.

Effect of Annealing Treatment on Microstructure, Mechanical Properties and Oxidation Resistance of SiCp/Al Coating Synthesized on Ti–6Al–4 V Alloy Substrate by Mechanical Alloying Method

An Al–SiC coating was synthesized on Ti–6Al–4 V alloy substrate using the mechanical alloying method. The effects of annealing treatment on the microstructure, the microhardness, the friction and wear resistance and the high-temperature oxidation resistance of the coating were investigated. The results showed that the coating had a composite structure in which the reinforcing SiC particles were evenly dispersed in the Al matrix. Both the surface microhardness and the wear resistance of the substrate improved because of the as-synthesized coating. The oxidation resistance was enhanced because of the formation of an Al3Ti layer and a Ti5Si3-rich layer in the coating during oxidation. Specifically, the coating formed a tri-layer structure during thermal exposure due to the reaction in the coating and interdiffusion between the coating and the substrate. The outer layer had a complex structure, which was comprised of the Al–Si alloy as the matrix and the unevenly distributed SiC and Al4C3. This layer had low microhardness and tended to flake in both friction and oxidation processes. The inner layer was an Al3Ti layer, which had high microhardness and favorable wear resistance, and could protect the substrate from severe oxidation at elevated temperature. A Ti5Si3-rich interlayer between the inner layer and the substrate formed in the initial annealing process and could further retard the inward diffusion of oxygen during oxidation.

Effects of Annealing Treatment on the Anisotropy Behavior of Cold-Rolled High-Manganese Austenite Stainless Steels

High-Mn (over 24 wt%) austenitic steels recently have been developed with excellent mechanical properties such as high strength and ductility at very low temperatures for cryogenic application. Especially, cold-rolling process is and effective method to increased yield and tensile strength of high-Mn steel when making products. In our previous work, we have investigated the correlation between microstructure and mechanical properties due to recrystallization without considering the characteristics of the cold-rolling direction of high-Mn steels. In this study, we evaluated the effects of anisotropic behaviors on the heat treatment of cold-rolling high-Mn steels. Despite the heat treatment, differences between transverse and longitudinal direction in the cold-rolled conditions generally affected the recrystallized microstructure. Such anisotropic behaviors caused changes in mechanical properties such as tensile and Charpy impact test, as microstructure along cold-rolling direction.

The Properties of Cd1−xZnxTe Films Prepared by RF Magnetron Sputtering

Cd1−xZnxTe films were prepared on borosilicate glass substrate using RF magnetron sputtering in this work. The effects of sputtering power, sputtering pressure and substrate temperature on the properties of the films were investigated in detail. The films were annealed in CdCl2 atmosphere for 2 h at 200 °C, 300 °C, and 400 °C, respectively. The effects of annealing treatment on the properties of the films were also investigated. The properties of the films were investigated by x-ray diffraction, atomic force microscopy, and current–voltage (I–V) characterization. The results indicate that crystalline quality and the average grain size of the films increases with the increases of sputtering power. The grain size of the films becomes larger as the substrate temperature increases. The Zn concentration of the films rises as the sputtering pressure increases. After annealing, the grain size of the films becomes larger, furthermore, the resistivity decreases.

Microstructural and chemical analysis of polycrystalline LiNbO3 films obtained by room-temperature RF sputtering after various annealing durations

The development of materials for industrial applications is in constant evolution. Regarding environmental or health laws, the use of some materials is restricted (lead-based). In this context, lithium niobate (LiNbO3) is studied in order to develop the performances of the RF (radio frequency) applications (for instance, filters using the bulk acoustic wave or surface acoustic wave technology). The deposition of LiNbO3 is mainly performed by chemical or physical vapor deposition and solgel techniques, resulting in polycrystalline films with or without a preferred orientation. For RF applications, LiNbO3 films need to be highly textured with a preferred orientation among the (006) plane in order to maximize the electrical response. In the present work, 150 nm thick LiNbO3 films were grown by RF sputtering at room temperature on Si substrates with native SiO2. The films were annealed at 950 °C, with an original process, for various durations. Polycrystalline yet (006) preferentially oriented LiNbO3 films were obtained on silicon. The properties of the as-deposited and annealed films were analyzed by x-ray diffraction (XRD), Raman spectroscopy, secondary ion mass spectrometry (SIMS), and scanning electron microscopy (SEM). The annealing treatment effect was highlighted by symmetric XRD analysis. The adhesion of the films is confirmed by SEM analysis. The diffusion profile of Li was characterized by SIMS and XPS analyses. This process, mainly based on a specific annealing treatment, leads to the synthesis of nearly stoichiometric LiNbO3 on silicon, and the effect of the thermal treatment on the texture of the film is highlighted.

Effect of annealing treatment on multilayer TiO2 films on the performance of dye-sensitized solar cells

In this work, four layers of TiO2 films have been prepared and applied as photoanode of dye-sensitized solar cell (DSSC). The multilayer TiO2 underwent annealing treatment at various temperatures, in the range 300−550 °C at 50 °C interval. The influence of annealing temperature on the properties of multilayer TiO2 and the performance of the device has been investigated. The samples possess higher optical absorption in UV region than in visible region. The morphology of the sample is active nanoparticle and scatter nanoparticle with its size is bigger than active nanoparticle. The highest η of 2.51 % was obtained from the device utilizing the sample annealed at 500 °C due to the lowest charge transfer resistance at the interface of Pt/electrolyte and electrolyte/N719 dye/TiO2.

Effect of annealing treatment on microstructures, mechanical properties and cavitation erosion performance of high velocity oxy-fuel sprayed NiCoCrAlYTa coating

The mechanical parts serving in the marine environment are up against the dual damage of corrosion and cavitation erosion, so the NiCoCrAlYTa coating with excellent corrosion resistance is successfully prepared by high velocity oxy-fuel (HVOF) sprayed technology to protect the equipment from deterioration. The chemical composition and mechanical properties as well as the microstructure evolution of the coating before and after annealing treatment are studied. At the same time, the influence of annealing treatment on the corrosion and cavitation erosion behaviors of the coating is investigated, as well. The NiCoCrAlYTa coating mainly contains γ-Ni, β-NiAl, and γ’-Ni3Al phases. During the deposition, the microcrystals or incomplete crystals generate in the interior of the coating because of the large temperature difference and impact force. Meanwhile, there is twin crystal structure in the as-spayed coating. After annealing treatment, the growth of grains and the segregation of reactive elements improve interface strength and inhibit the formation of micro-defects in the coating. The annealing temperature is of significance to the microstructure, mechanical properties, anti-corrosion and cavitation erosion resistance of the coating. This study provides a combined approach toward improving the corrosion and cavitation erosion resistance of NiCoCrAlYTa coatings.

Thermal conductivity enhancement of PLA/TPU/BN composites by controlling BN distribution and annealing treatment

ABSTRACTPolylactic acid (PLA)/thermoplastic urethane (TPU)/boron nitride (BN) composites were successfully prepared, the effect of microstructure evolution along with the compositional change and annealing treatment on the thermal conductivity of composite was investigated. Owing to the selective distribution of BN in low-viscosity TPU phase, the compactness of thermally conductive networks in PLA/TPU/BN composites was reinforced. Thereby, the thermal conductivity of PLA/TPU/BN composites was obviously improved by 21.6% at 25 wt-% BN than that of PLA/BN composites. Moreover, research on the effect of annealing treatment on the thermal conductivity of composites found that the crystallinity of PLA had been improved by the recrystallisation and the thermal conductivities of composites were enhanced. Finally, due to the possible hydrogen bonding between PLA and TPU, PLA/TPU/BN composites showed no serious deterioration in mechanical properties. This work endows new enlightenment to fabricate composites with great thermal conductivity without causing serious damage to mechanical properties.

Effects of annealing treatment on microstructure, electrical and magnetodielectric properties of BiFe0.98Co0.02O3/Al–doped ZnO layered thin films prepared by chemical solution deposition

Multiferroic thin films of BiFe0.98Co0.02O3 (BFCO) were grown on Al2O3 (ALO) substrates having a buffer layer of Al (2%) doped ZnO (ZAO) prepared by using chemical solution deposition (CSD) method. Effect of annealing temperature and annealing atmosphere on the structural, microstructural, dielectric, leakage, transport, magnetic and magnetodielectric (MD) properties of films have been investigated. BFCO/ZAO/ALO films grown under oxygen atmosphere show better crystallinity, smooth surface and slightly larger grain size than that of the films annealed in air. Lower leakage current, higher dielectric constant, lower dielectric loss, lower a.c. conductivity and larger MD and magnetoimpedance (MI) effects have been observed for the film annealed at 550 °C under oxygen atmosphere. In order to verify the state of oxygen vacancies, photoluminescence spectra have been studied. Room temperature magnetic behavior of the BFCO/ZAO/ALO films has been studied by performing magnetization measurements. The effect of magnetic field on the dielectric constant and impedance (MD & MI) have been discussed on the basis of magnetostriction effect and mobility of interfacial charges at grain boundaries and bilayer interface.

Solvothermal growth of aligned SnxZn1-xS thin films for tunable and highly response self-powered UV detectors

In this study, well-aligned SnxZn1-xS (0 ≤ x ≤ 0.12 mol) nanostructured thin films were successfully grown on the glass substrate by a solvothermal method for ultraviolet detector applications. XRD results revealed a hexagonal wurtzite structure for all the SnxZn1-xS thin films. Through structural and morphological studies, as the Sn-content increases, the c-axis orientation became stronger. A comprehensive investigation of the morphological evolution also confirmed a considerable influence of Sn2+ incorporation on the growth mechanism and shape of the SnxZn1-xS nanostructures. The optical measurements indicated that as the Sn-content increases, a linear relationship between the band gap and Urbach energy was found, in which the band gap energy experienced a significant decrease from 4.20 to 3.83 eV; whereas the Urbach energy was dramatically broadened. A gradual increase was observed in the intensity of photoluminescence spectra, in which three prominent emission peaks were found, indicating a successful formation of the SnxZn1-xS nanostructures. The photosensing performance of the samples was studied for the first time. The ultraviolet detectors based on the Au/SnxZn1-xS thin film junctions featured an excellent rectification behavior and attractive photovoltaic effect under UVB exposure. The enhancing effects of annealing treatment on the photoelectric behavior of the samples were also noted. The photoresponse characteristics of the self-powered ultraviolet detectors exhibited a high Ion/Ioff ratio > 103 and a fast photoswitching speed with superior stability and reproducibility at zero voltage. Additionally, notable photosensitivity and detectivity of more than ∼20 times are achieved at the self-powered mode.