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Structural and electrochromic property control of WO3 films through fine-tuning of film-forming parameters

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High Temperature Materials and Processes
From the journal High Temperature Materials and Processes Volume 43 Issue 1

Abstract

Tungsten trioxide (WO3) films, extensively investigated for their remarkable electrochromic properties, have proven to be highly versatile in numerous applications. However, the challenge of achieving large-scale WO3 films with substantial dimensions and volumes remains a critical obstacle for industrial-scale production. Among the available techniques, magnetron sputtering stands out as the most efficient and straightforward method for the industrial preparation of WO3 films. In this comprehensive study, we meticulously explored the impact of various process parameters in magnetron sputtering on the film formation properties. By employing a controlled variable approach, we systematically investigated the influence of gas flow (Ar), sputtering pressure, power, and time. Our meticulous observations revealed that each parameter exerted distinct effects on the intricate film formation process. Careful analysis of the final dataset unequivocally demonstrated that when the sputtering conditions were meticulously optimized, the resulting films exhibited an extraordinary maximum transmittance change of 85% at a specific wavelength of 0.6 μm. Furthermore, these films showcased rapid coloring and bleaching response times, clocking in at an impressive 15 and 20 s, respectively, without any significant degradation even after undergoing 5,000 cycles. These groundbreaking findings provide invaluable insights into the intricate film formation process associated with magnetron-sputtered WO3.

Keywords: tungsten trioxide films; WO3 ; magnetron sputtering; process parameters; film-forming properties

1 Introduction

The concept of electrochromism finds its roots in Deb’s seminal proposal in 1969, which first demonstrated the intriguing color-switching phenomenon of Tungsten trioxide (WO3) from transparent to blue states when subjected to an applied voltage [1]. This groundbreaking discovery sparked a widespread interest among researchers, triggering extensive investigations into various aspects of electrochromic materials and technologies [2–5]. Despite the emergence of numerous diverse electrochromic materials over the years, WO3 continues to reign supreme owing to its exceptional optical modulation capabilities and robust stability. As a result, considerable efforts have been devoted to the development of WO3-based electrochromic devices, with the ultimate goal of expanding their applications across a wide range of fields [6–8]. While the precise mechanism underlying WO3 color change remains a topic of ongoing debate, it is widely accepted that the simultaneous migration and extraction of electrons and metal cations (or protons) play pivotal roles in this intricate process [9–11]. Furthermore, the morphology and overall structure of WO3 films exert a profound influence on the dynamics of color change. The choice of preparation method directly impacts the structural characteristics and surface morphology of WO3 films [12,13].

Among the various techniques available for depositing metal oxides, physical and chemical methods are the most prevalent [14–18]. In the case of WO3 films, sol–gel and electrochemical deposition methods are commonly employed in laboratory settings for film preparation [19–21]. The sol–gel method involves the growth of crystalline WO3 on a substrate by heating a reactor containing raw materials such as tungsten powder [22–24]. This method offers precise control over the composition and structure of the material, and its properties can be further enhanced through the incorporation of dopants. Notably, Shen et al. have reported that doping WO3 with rare earth elements imparts not only its inherent electrochromic characteristics but also additional electrofluorescent properties [25,26]. However, the optical modulation of crystalline WO3 is less than ideal [27]. In contrast, the electrochemical deposition method entails depositing peroxytungstic acid from a precursor solution onto a substrate, followed by oxidation through baking to form WO3 films. This technique enables rapid deposition rates, resulting in amorphous structures that exhibit excellent electrochromic performance and physical robustness. Moreover, it offers precise control over film thickness and uniformity. However, the challenge lies in preparing large-size films using this method, which poses obstacles to industrialization due to its high cost, complexity, and potential environmental impact. Both sol–gel and electrochemical deposition methods face limitations in terms of their suitability for the preparation of large-size WO3 films, thereby impeding the commercialization of this material.

Magnetron sputtering, a technique within the physical vapor deposition family, has emerged as a dominant method for film deposition in industrial settings, thanks to its robust equipment stability, ease of control, extensive coating area capabilities, and strong adhesion properties [28,29]. Therefore, the industrial significance of researching the preparation of WO3 films through magnetron sputtering is substantial [30,31]. In this study, WO3 films with diverse parameters were synthesized using magnetron sputtering, and the impact of deposition factors including sputtering pressure, power, duration, and gas flow rate on the structure and properties of the WO3 films was rigorously investigated and analyzed. Additionally, the preparation conditions associated with optimal performance of WO3 films were identified, which exhibit a positive influence on the industrial-scale preparation of WO3 films for large-area applications.

2 Experimental section

2.1 Materials

The chemical materials such as lithium perchlorate (LiClO4, 99%), ethanol (PC, 99%), acetone (PC, 99%), and propylene carbonate (PC, 99.7%) were obtained from Sinopharm Chemical Regent Co., Ltd. The relevant sputtering targets (WO3) were purchased from Xinnuo New Material. All the commercially obtained reagents were implemented without any purification.

2.2 Preparation of WO3 films

All WO3 films in this work were synthesized by using magnetron sputtering. Prior to deposition, the interior of the magnetron sputtering chamber was meticulously cleaned to eliminate any contaminants, such as dust or debris. The target was positioned on the cathode, and the glass substrates were ultrasonically cleaned in a solution of equal parts DI water, acetone, and ethanol for 5 min. The substrates were then fixed in place within the deposition chamber, with their position adjusted to align directly with the target. The chamber was evacuated to a base pressure ranging from 4 × 10−4 to 1 × 10−4 Pa, after which argon (Ar) gas was introduced to maintain the pressure between 0 and 6 Pa. The power density of the sputtering power supply was controlled within the range of 10–100 kW·m−2, and the sputtering time was set from 50 to 200 min. Once the specified time had elapsed, the power supply and associated gas valves were turned off, and the deposited film was removed from the chamber.

2.3 Characterizations

All electrochemical behaviors in this work were studied with the aid of an electrochemical workstation (CHI 660D, Shanghai Chenhua, China), including chronocoulometry, cyclic voltammetry, and multi-potential steps. The crystalline structure of the films was characterized by X-ray diffraction (XRD) mapping (X’Pert PRO, PANalytical B.V., New Zealand). Surface morphology and thickness of films were carried out by using scanning electron microscopy (SEM, SU8200, Hitachi, Japan). In addition, the optical properties (transmittance, absorption, reflectance, and response speed) of the films were measured by UV–Vis–NIR spectrophotometers (V670, JASCO, Japan), with in situ tests in solution as reference and non-in situ tests in air as reference.

3 Results and discussion

This study aimed to examine the influence of various magnetron sputtering parameters on the ultimate characteristics of the films. Among the numerous parameters considered, four key parameters, namely Ar gas flow, chamber pressure, applied power, and deposition time, were selected for a thorough investigation. A comprehensive summary of 10 films, each deposited under different parameter settings, is provided in Table 1. Subsequent sections will delve into a detailed analysis of the individual effects associated with each of these parameters.

Table 1

List of samples prepared with different parameters

Sample number Gas (Ar) flow (sccm) Pressure (Pa) Power (W) Time (min)
1# 30 3 80 120
2# 60 3 80 120
3# 90 3 80 120
4# 40 3 60 160
5# 40 3 100 96
6# 40 3 120 80
7# 40 0.6 80 120
8# 40 1.5 80 120
9# 40 5.5 80 120
10# 40 3 80 120

3.1 Influence of gas (Ar) flow

During the magnetron sputtering process, Ar gas is employed to facilitate collisions with electrons, leading to the generation of ions that impinge upon the cathode. Consequently, target atoms are sputtered and subsequently deposited onto the substrate. Moreover, the magnetron sputtering chamber operates under vacuum conditions, with the concentration of Ar gas defining the gaseous environment within the chamber. As a result, the flow rate of Ar gas exerts a significant influence on the final quality of the film. To examine this effect, samples 1#, 10#, 2#, and 3# were carefully selected for comparative analysis, with increasing trends in Ar flow rates while maintaining other conditions constant.

The surface morphology and the precise thickness of the prepared WO3 films were assessed using SEM. As depicted in Figure 1a, c, e, and g, the film surfaces exhibit a smooth and uniform appearance, devoid of discernible grain structures. The inset of Figure 1 reveals that the thickness of the WO3 film is approximately 0.7 μm. Furthermore, XRD analysis was conducted on the films, as depicted in Figure 1i. The XRD patterns of the four films exhibit no additional diffraction peaks compared to those of the bare ITO substrate beneath. These findings are consistent with previous reports, which suggest that the WO3 films possess an amorphous structure [32].

Figure 1 (a, c, e, and g) Surface, (b, d, f, and h) cross-section SEM graphs, and (i) XRD patterns of samples 1#, 10#, 2#, and 3#.
Figure 1

(a, c, e, and g) Surface, (b, d, f, and h) cross-section SEM graphs, and (i) XRD patterns of samples 1#, 10#, 2#, and 3#.

Moreover, the exact thickness measurements of the four samples were ascertained through SEM cross-sectional analyses of the films (see Figure 1b, d, f and h). The film thickness values are recorded as 0.47, 0.48, 1.20, and 1.50 μm, respectively, indicating a progressive increase in WO3 film thickness corresponding to a significant elevation in the Ar flow rate while all other conditions remain constant. The underlying mechanism driving this observation stems from the fact that within a specific range of Ar flow rates (30–40 sccm), the film thickness remains relatively consistent. However, as the Ar flow rate experiences a substantial surge within the same range (from 30 to 60 to 90 sccm), there is a simultaneous increase in the concentration of Ar ions. This heightened concentration results in an intensified release of energy during collisions with the target surface, thereby augmenting sputtering efficiency (resulting in an increased deposition of WO3 atoms through sputtering bombardment) and subsequently leading to the thickening of the WO3 film.

Figure 2 illustrates the electrochromic properties of the four samples. As depicted in Figure 2a–d, the transmittance of the films in the bleached state remains relatively consistent. Conversely, upon coloring, the overall transmittance of samples 1#, 10#, and 2# approaches 0 (particularly noticeable is the gradual disappearance of the peak at 1.0 μm), indicating a deepening of the coloration. However, the overall transmittance of sample 3# increases by approximately 5%. This outcome can be attributed to the excessive thickness of the 3# sample, which hinders the migration of lithium ions, thereby leading to an incomplete coloring process. Apart from this, the response time and coloring efficiency (CE) at the maximum transmittance difference (0.6 μm) for the four films were evaluated (Figure 2c–f). The results show that the coloring time for all four samples is approximately 20 s, while the bleaching time is around 15 s. The coloring efficiencies of the four films are 40.1, 41.5, 41.0, and 43.2 cm2·C−1, respectively. Based on these findings, samples 1#, 10#, 2#, and 3# exhibit comparable electrochromic performance, with sample 10# demonstrating the best overall characteristics. The flow rate of Ar gas during the fabrication process exerts a profound influence on both the microstructure and performance of electrochromic films. Maintaining a moderate and suitable Ar flow rate proves advantageous in achieving effective film densification, thereby facilitating enhanced ion diffusion and improved electrochromic properties. Detailed analysis of the cross-sectional morphology unequivocally reveals that sample 10#, produced by employing an appropriate and moderate Ar flow rate, showcases a dense morphology. Consequently, it manifests the most desirable overall characteristics, encompassing heightened coloration depth and superior coloration efficiency.

Figure 2 (a) Transmittance spectra, (b) response curves, coloration efficiency of samples (c) 1#, (d) 10#, (e) 2#, and (f) 3#.
Figure 2

(a) Transmittance spectra, (b) response curves, coloration efficiency of samples (c) 1#, (d) 10#, (e) 2#, and (f) 3#.

The cyclic operational life of the diverse samples was meticulously evaluated. Specifically, the transmittance spectra of the samples were meticulously scrutinized following 5,000 cycles and juxtaposed with the initial state data. The pertinent outcomes are visually depicted in Figure 3. Noteworthy observations reveal that samples 1#, 10#, and 2# exhibit a decline in transmittance in the bleached state, with sample 10# demonstrating the most modest attenuation. Conversely, these samples maintain relatively consistent transmittance levels in the colored state. Sample 3# manifests a transmittance difference of less than 5% between the colored and bleached states after 5,000 cycles, underscoring a substantial diminishment in its color-altering capacity. In summation, sample 10# emerges as the epitome of superior performance.

Figure 3 Cycle stability of samples (a) 1#, (b) 10#, (c) 2#, and (d) 3#.
Figure 3

Cycle stability of samples (a) 1#, (b) 10#, (c) 2#, and (d) 3#.

3.2 Influence of pressure

During the magnetron sputtering process, the chamber’s internal pressure can be finely controlled by adjusting the pumping speed of the molecular pump. As previously mentioned, Ar gas acts as the excitation source, with its overall composition playing a pivotal role in the film deposition process. Therefore, it is imperative to explore cavity pressure as a variable. Based on the parameters outlined in Table 1, samples 7#, 8#, 10#, and 9# were sequentially selected for comparative analysis based on increasing pressure.

Initially, the surface morphology and thickness of these four films were meticulously examined using SEM (refer to Figure 4a–h). Observations from Figure 4a, c, e, and g indicate that all four samples exhibit an amorphous structure, albeit with noticeable surface cracks on samples 10# and 9#. Similarly, the XRD patterns of the four film samples alongside the blank ITO glass in Figure 4i validate their amorphous nature as WO3 films (no additional peaks are observed relative to the blank ITO glass). To delve into the thickness variations of these samples, the outcomes from cross-sectional scanning and imaging of the four films are illustrated in Figure 4b, d, f, and i. Notably, the thickness of samples 7# and 8# is approximately 1.08 μm, while samples 10# and 9# exhibit reduced thicknesses of 0.48 and 0.42 μm, respectively. This reduction can be attributed to a diminishing pressure within the chamber despite maintaining a constant influx of Ar. The decrease in pressure, indicated by a lower molecular pump pumping speed, leads to an excess of Ar participating in the sputtering process within the chamber. This surplus Ar results in heightened energy losses during material deposition collisions, consequently diminishing the energy, migration ability, bonding capacity, and orientation of the WO3 material upon substrate contact. These combined factors contribute to the reduced thickness of the WO3 film.

Figure 4 (a, c, e, and g) Surface, (b, d, f, and h) cross-section SEM graphs, and (i) XRD patterns of samples 7#, 8#, 20#, and 9#.
Figure 4

(a, c, e, and g) Surface, (b, d, f, and h) cross-section SEM graphs, and (i) XRD patterns of samples 7#, 8#, 20#, and 9#.

The same electrochromic performance test was conducted on the aforementioned four samples (Figure 5). From Figure 5a and b, it is observed that samples 7# and 8# exhibit no significant change in transmittance between the bleached and colored states, indicating their lack of color-changing capability. This can be attributed to the low Ar pressure during fabrication. When the Ar pressure is low (and the molecular pump pumping speed is high), the excitation deposition of WO3 is efficient, resulting in a thicker film. However, this thicker film lacks channels that can facilitate ion migration in and out, rendering it incapable of undergoing color changes. Additionally, a comparison of sample 10# with sample 9# reveals that the bleached state transmittance spectrum of sample 9# has decreased by approximately 10%, and its response speed and CE value are also lower than those of sample 10#. Overall, sample 10#, with a maximum transmittance difference of 85%, a coloring response time of 23 s, a bleaching response time of 17 s, and a CE value of 41.5 cm2·C−1, exhibits the best performance.

Figure 5 (a–d) Transmittance spectra, (e–h) response curves, and (i–l) coloration efficiency of samples 7#, 8#, 10#, and 9#.
Figure 5

(a–d) Transmittance spectra, (e–h) response curves, and (i–l) coloration efficiency of samples 7#, 8#, 10#, and 9#.

These observations can be attributed to the excessively high Ar pressure during fabrication. As the pressure increases, the film thickness decreases, and the color-changing ability deteriorates. This can be explained by the fact that the thinning of the thickness decreases the amount of insertion ions. The reduced film thickness also results in insufficient interaction between the ions and the electronic structure of the material, leading to decreased coloration efficiency. In summary, the Ar pressure during the fabrication process plays a crucial role in determining the electrochromic performance of the WO3 films. Moderate pressure optimizes film properties for efficient ion migration and electronic interaction, leading to superior color-changing capabilities. Conversely, excessively low or high pressure results in films that lack channels for ion migration or have compromised color-changing ability, respectively.

Similarly, a life test was conducted on this group of samples (notice: samples 7# and 8# were not included due to their inability to change color). The results, as shown in Figure 6, indicate that compared to sample 10#, sample 9# exhibits a more pronounced decline, with a significant decrease in the transmittance spectrum of the bleached state and an increase of approximately 5% in the transmittance spectrum of the colored state. Consequently, sample 10# demonstrates the best performance in this group.

Figure 6 Cycle stability of samples (a) 10# and (b) 9#.
Figure 6

Cycle stability of samples (a) 10# and (b) 9#.

3.3 Influence of power and time

The two primary factors influencing the magnetron sputtering process are power and time. In this section, these two factors were specifically analyzed and compared. Given their interdependence, the product of power and time was maintained constant during the comparative test to better assess their individual effects. As shown in Table 1, the power gradually increases while the time decreases for the four parameters of samples 4#, 10#, 5#, and 6#, with the product of power and time being constant at 9,600.

SEM and XRD characterization were also performed on this group of samples (Figure 7). Figure 7a, c, e, and g reveals an irregular amorphous structure across all four samples, a characteristic further affirmed by the XRD pattern in Figure 7i. Notably, the thickness of these samples does not adhere to a uniform trend: at 80 W power and 120 min time, the film thickness is minimized at 0.48 μm. The film thickness undergoes fluctuations as power increases from 60 to 80 W, 100, and 120 W, coupled with time reductions from 160 to 120, 96, and 80 min. Initially decreasing from 0.61 to 0.48 μm, the thickness subsequently rises to 0.88 and 1.10 μm. This variance can be attributed to the divergent regulatory impacts of power and time. For subsequent discourse, the ratio of power to time is denoted as power density. Beyond 80 W, as power continues to climb, the kinetic energy in the sputtering process intensifies, elevating the power density and consequently augmenting the total film thickness. Conversely, when power falls below 80 W, the film density decreases due to lower power and power density. With extended sputtering time, the volume of accumulated film expands, resulting in increased film thickness. This underscores that the influence of time on film sputtering efficiency surpasses that of power when power is below a specific threshold (80 W), whereas power assumes greater significance when surpassing this value.

Figure 7 (a, c, e, and g) Surface, (b, d, f, and h) cross-section SEM graphs, and (i) XRD patterns of samples 4#, 10#, 5#, and 6#.
Figure 7

(a, c, e, and g) Surface, (b, d, f, and h) cross-section SEM graphs, and (i) XRD patterns of samples 4#, 10#, 5#, and 6#.

The electrochromic properties of the four samples were evaluated and found to be comparable across all parameters (Figure 8). The transmittance spectra of the four samples are essentially identical, with a maximum optical modulation of approximately 80% achieved at 0.6 μm. The coloring and bleaching times are also consistent, at approximately 15 and 20 s, respectively. As observed in Figure 8i–l, the CE for these four samples is maintained at around 40%. The above results illustrate the small effect of a certain ratio or different power and time on the EC properties of the films.

Figure 8 (a) Transmittance spectra, (b) response curves, coloration efficiency of samples (c) 4#, (d) 10#, (e) 5#, and (f) 6#.
Figure 8

(a) Transmittance spectra, (b) response curves, coloration efficiency of samples (c) 4#, (d) 10#, (e) 5#, and (f) 6#.

Figure 9 presents the cycle stability data for this set of samples. It reveals that after 5,000 cycles of operation, both the bleached and colored transmittances of sample 4# have experienced significant decay. In contrast, samples 10# and 5# exhibit a decrease in only the bleached transmittance (with a more pronounced decrease in sample 5#), while sample 6# has lost its color-changing capability. Among this group of samples, sample 10# continues to perform the best.

Figure 9 Cycle stability of samples (a) 4#, (b) 10#, (c) 5#, and (d) 6#.
Figure 9

Cycle stability of samples (a) 4#, (b) 10#, (c) 5#, and (d) 6#.

4 Conclusion

In this research, the process parameters governing the magnetron sputtering of WO3 films were meticulously scrutinized, delving into the distinct impacts of gas (Ar) flow, chamber pressure, sputtering power, and time on the ultimate film formation. The gas (Ar) flow and chamber pressure, instrumental in regulating the Ar content within the chamber, play a pivotal role in determining the sputtering efficiency of the target, consequently influencing the thickness of the final film. Moreover, the power density, a function of power and time interaction, exerts a profound influence on the microstructure of the film, dictating whether it manifests as sparse or dense. The comparative analysis indicates that the optimal performance across the resultant films was attained when the gas (Ar) flow stood at 40 sccm, chamber pressure at 3 Pa, and power and time settings at 80 W and 120 min, respectively (sample 10#). This exploration not only establishes a theoretical groundwork but also furnishes a technical framework for the industrial-scale fabrication of large-scale, high-capacity inorganic electrochromic WO3 films.

Acknowledgments

This research was also supported by the Changzhou Science and Technology Plan Project (CJ20220050), the City Key Laboratory of Changzhou for Low Carbon Building Materials and Urban-Rural Ecology (CM20223004), and Jiangsu Province construction system technology project (2022ZD052).

  1. Funding information: This research was supported by the Engineering Research Center Program of Development & Reform Commission of Jiangsu Province (Grant No. [2021] 1368) and Higher Education Technological Innovation Team Program of Education Department of Jiangsu Province (Grant No. [2021] 1).

  2. Author contributions: Gai Lin conceived and designed the study. Gai Lin, Xiaobo Li, and Dexi Liu performed the experiments. Gai Lin wrote the paper. Gai Lin, Xiaobo Li, Dexi Liu, Peijiang Liu, and Zibao Jiao reviewed and edited the manuscript. All authors read and approved the manuscript.

  3. Conflict of interest: Authors state no conflict of interest.

  4. Data availability statement: Research data are not shared due to commercial sensitivities.

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Received: 2024-05-24
Revised: 2024-08-12
Accepted: 2024-08-13
Published Online: 2024-09-02

© 2024 the author(s), published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

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https://doi.org/10.1515/htmp-2024-0047
Keywords for this article
tungsten trioxide films; WO3; magnetron sputtering; process parameters; film-forming properties
Creative Commons
BY 4.0

Articles in the same Issue

  1. Research Articles
  2. De-chlorination of poly(vinyl) chloride using Fe2O3 and the improvement of chlorine fixing ratio in FeCl2 by SiO2 addition
  3. Reductive behavior of nickel and iron metallization in magnesian siliceous nickel laterite ores under the action of sulfur-bearing natural gas
  4. Study on properties of CaF2–CaO–Al2O3–MgO–B2O3 electroslag remelting slag for rack plate steel
  5. The origin of {113}<361> grains and their impact on secondary recrystallization in producing ultra-thin grain-oriented electrical steel
  6. Channel parameter optimization of one-strand slab induction heating tundish with double channels
  7. Effect of rare-earth Ce on the texture of non-oriented silicon steels
  8. Performance optimization of PERC solar cells based on laser ablation forming local contact on the rear
  9. Effect of ladle-lining materials on inclusion evolution in Al-killed steel during LF refining
  10. Analysis of metallurgical defects in enamel steel castings
  11. Effect of cooling rate and Nb synergistic strengthening on microstructure and mechanical properties of high-strength rebar
  12. Effect of grain size on fatigue strength of 304 stainless steel
  13. Analysis and control of surface cracks in a B-bearing continuous casting blooms
  14. Application of laser surface detection technology in blast furnace gas flow control and optimization
  15. Preparation of MoO3 powder by hydrothermal method
  16. The comparative study of Ti-bearing oxides introduced by different methods
  17. Application of MgO/ZrO2 coating on 309 stainless steel to increase resistance to corrosion at high temperatures and oxidation by an electrochemical method
  18. Effect of applying a full oxygen blast furnace on carbon emissions based on a carbon metabolism calculation model
  19. Characterization of low-damage cutting of alfalfa stalks by self-sharpening cutters made of gradient materials
  20. Thermo-mechanical effects and microstructural evolution-coupled numerical simulation on the hot forming processes of superalloy turbine disk
  21. Endpoint prediction of BOF steelmaking based on state-of-the-art machine learning and deep learning algorithms
  22. Effect of calcium treatment on inclusions in 38CrMoAl high aluminum steel
  23. Effect of isothermal transformation temperature on the microstructure, precipitation behavior, and mechanical properties of anti-seismic rebar
  24. Evolution of residual stress and microstructure of 2205 duplex stainless steel welded joints during different post-weld heat treatment
  25. Effect of heating process on the corrosion resistance of zinc iron alloy coatings
  26. BOF steelmaking endpoint carbon content and temperature soft sensor model based on supervised weighted local structure preserving projection
  27. Innovative approaches to enhancing crack repair: Performance optimization of biopolymer-infused CXT
  28. Structural and electrochromic property control of WO3 films through fine-tuning of film-forming parameters
  29. Influence of non-linear thermal radiation on the dynamics of homogeneous and heterogeneous chemical reactions between the cone and the disk
  30. Thermodynamic modeling of stacking fault energy in Fe–Mn–C austenitic steels
  31. Research on the influence of cemented carbide micro-textured structure on tribological properties
  32. Performance evaluation of fly ash-lime-gypsum-quarry dust (FALGQ) bricks for sustainable construction
  33. First-principles study on the interfacial interactions between h-BN and Si3N4
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  35. Just-in-time updated DBN BOF steel-making soft sensor model based on dense connectivity of key features
  36. Effect of tempering temperature on the microstructure and mechanical properties of Q125 shale gas casing steel
  37. Review Articles
  38. A review of emerging trends in Laves phase research: Bibliometric analysis and visualization
  39. Effect of bottom stirring on bath mixing and transfer behavior during scrap melting in BOF steelmaking: A review
  40. High-temperature antioxidant silicate coating of low-density Nb–Ti–Al alloy: A review
  41. Communications
  42. Experimental investigation on the deterioration of the physical and mechanical properties of autoclaved aerated concrete at elevated temperatures
  43. Damage evaluation of the austenitic heat-resistance steel subjected to creep by using Kikuchi pattern parameters
  44. Topical Issue on Focus of Hot Deformation of Metaland High Entropy Alloys - Part II
  45. Synthesis of aluminium (Al) and alumina (Al2O3)-based graded material by gravity casting
  46. Experimental investigation into machining performance of magnesium alloy AZ91D under dry, minimum quantity lubrication, and nano minimum quantity lubrication environments
  47. Numerical simulation of temperature distribution and residual stress in TIG welding of stainless-steel single-pass flange butt joint using finite element analysis
  48. Special Issue on A Deep Dive into Machining and Welding Advancements - Part I
  49. Electro-thermal performance evaluation of a prismatic battery pack for an electric vehicle
  50. Experimental analysis and optimization of machining parameters for Nitinol alloy: A Taguchi and multi-attribute decision-making approach
  51. Experimental and numerical analysis of temperature distributions in SA 387 pressure vessel steel during submerged arc welding
  52. Optimization of process parameters in plasma arc cutting of commercial-grade aluminium plate
  53. Multi-response optimization of friction stir welding using fuzzy-grey system
  54. Mechanical and micro-structural studies of pulsed and constant current TIG weldments of super duplex stainless steels and Austenitic stainless steels
  55. Stretch-forming characteristics of austenitic material stainless steel 304 at hot working temperatures
  56. Work hardening and X-ray diffraction studies on ASS 304 at high temperatures
  57. Study of phase equilibrium of refractory high-entropy alloys using the atomic size difference concept for turbine blade applications
  58. A novel intelligent tool wear monitoring system in ball end milling of Ti6Al4V alloy using artificial neural network
  59. A hybrid approach for the machinability analysis of Incoloy 825 using the entropy-MOORA method
  60. Special Issue on Recent Developments in 3D Printed Carbon Materials - Part II
  61. Innovations for sustainable chemical manufacturing and waste minimization through green production practices
  62. Topical Issue on Conference on Materials, Manufacturing Processes and Devices - Part I
  63. Characterization of Co–Ni–TiO2 coatings prepared by combined sol-enhanced and pulse current electrodeposition methods
  64. Hot deformation behaviors and microstructure characteristics of Cr–Mo–Ni–V steel with a banded structure
  65. Effects of normalizing and tempering temperature on the bainite microstructure and properties of low alloy fire-resistant steel bars
  66. Dynamic evolution of residual stress upon manufacturing Al-based diesel engine diaphragm
  67. Study on impact resistance of steel fiber reinforced concrete after exposure to fire
  68. Bonding behaviour between steel fibre and concrete matrix after experiencing elevated temperature at various loading rates
  69. Diffusion law of sulfate ions in coral aggregate seawater concrete in the marine environment
  70. Microstructure evolution and grain refinement mechanism of 316LN steel
  71. Investigation of the interface and physical properties of a Kovar alloy/Cu composite wire processed by multi-pass drawing
  72. The investigation of peritectic solidification of high nitrogen stainless steels by in-situ observation
  73. Microstructure and mechanical properties of submerged arc welded medium-thickness Q690qE high-strength steel plate joints
  74. Experimental study on the effect of the riveting process on the bending resistance of beams composed of galvanized Q235 steel
  75. Density functional theory study of Mg–Ho intermetallic phases
  76. Investigation of electrical properties and PTCR effect in double-donor doping BaTiO3 lead-free ceramics
  77. Special Issue on Thermal Management and Heat Transfer
  78. On the thermal performance of a three-dimensional cross-ternary hybrid nanofluid over a wedge using a Bayesian regularization neural network approach
  79. Time dependent model to analyze the magnetic refrigeration performance of gadolinium near the room temperature
  80. Heat transfer characteristics in a non-Newtonian (Williamson) hybrid nanofluid with Hall and convective boundary effects
  81. Computational role of homogeneous–heterogeneous chemical reactions and a mixed convective ternary hybrid nanofluid in a vertical porous microchannel
  82. Thermal conductivity evaluation of magnetized non-Newtonian nanofluid and dusty particles with thermal radiation
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