Argon Oxygen Research Articles

Studying the Constitutive Model of Damage for a Stainless Steel Argon–Oxygen Decarburization Slag Mixture

The purpose of this study was to fully explore the mechanical properties of five different doses of an Argon–Oxygen Decarburization slag mixture in an unconfined compressive strength test. The peak stress, elastic modulus, and stress–strain curve of the mixture were studied for 90 days. Based on the experimental data and according to the theory of damage mechanics, the concept of damage threshold (t) was introduced to construct a damage constitutive model. Referring to the damage threshold of concrete, that of the mixture was determined to be 0.7 times higher than the peak strain, and the correlation coefficient between the established model and the test curve was above 0.85. These results indicate that the addition of AOD slag and fly ash can cause hydration reactions, increase the quantity of hydration products, and enhance the peak stress and elastic modulus of the mixture. The maximum increases were 94.9% and 43.1%, respectively. Parameters a and b reflect the peak stress and brittleness of the mixture, respectively. The incorporation of Argon–Oxygen Decarburization slag can make the mixture less brittle and improve its properties. The incorporation of Argon–Oxygen Decarburization slag can protect the mixture from damage. The maximum decrease is 40.2%.

Compositional Optimization of Sputtered SnO2/ZnO Films for High Coloration Efficiency

We performed an electrochromic investigation to optimize the composition of reactive magnetron-sputtered mixed layers of zinc oxide and tin oxide (ZnO-SnO2). Deposition experiments were conducted as a combinatorial material synthesis approach. The binary system for the samples of SnO2-ZnO represented the full composition range. The coloration efficiency (CE) was determined for the mixed oxide films with the simultaneous measurement of layer transmittance, in a conventional three-electrode configuration, and an electric current was applied by using organic propylene carbonate electrolyte cells. The optical parameters and composition were measured and mapped by using spectroscopic ellipsometry (SE). Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) measurements were carried out to check the SE results, for (TiO2-SnO2). Pure metal targets were placed separately from each other, and the indium–tin-oxide (ITO)-covered glass samples and Si-probes on a glass holder were moved under the two separated targets (Zn and Sn) in a reactive argon–oxygen (Ar-O2) gas mixture. This combinatorial process ensured that all the compositions (from 0 to 100%) were achieved in the same sputtering chamber after one sputtering preparation cycle. The CE data evaluated from the electro-optical measurements plotted against the composition displayed a characteristic maximum at around 29% ZnO. The accuracy of our combinatorial approach was 5%.

Data‐Driven Approach Using a Hybrid Model for Predicting Oxygen Consumption in Argon Oxygen Decarburization Converter

Accurately controlling oxygen supply in argon oxygen decarburization (AOD) process is invariably desired for efficient decarburization and reducing alloying elements consumption. Herein, a data‐driven approach using a hybrid model integrating oxygen balance mechanism model and a two‐layer Stacking ensemble learning model is successfully established for predicting oxygen consumption in AOD converter. In this hybrid model, the oxygen balance mechanism model is used to calculate the oxygen consumption based on industrial data. Then the model calculation error is compensated using an optimized two‐layer Stacking model that is identified as (random forest (RF) + XGBoost + ridge regression)‐RF model by evaluating different hybrid model frameworks and Bayesian optimization. The results show that, in comparison to conventional prediction model based on oxygen balance mechanism, the present hybrid model greatly improves the control accuracy of oxygen consumption in AOD industrial production. The hit rate and mean absolute error of the present hybrid model for predicting oxygen consumption are 84.8% and 330 Nm3, respectively, within absolute oxygen consumption prediction error ±600 Nm3 (relative error of 3.8%). This data‐driven approach using the present hybrid model provides one pathway to efficient oxygen consumption control in AOD process.

Comparative study of RF sputtered Fe2O3- and Fe3O4-doped indium saving indium tin oxide thin films

In present work the properties of iron-doped indium tin oxide (ITO) films with reduced to 50 mass% indium oxide content prepared by co-sputtering of ITO and Fe2O3 targets and ITO and Fe3O4 targets in mixed argon–oxygen atmosphere were studied by various methods. The influence of different working gas flow rates, RF power of iron oxide targets, type of doping oxide and heat treatment temperatures on the electrical, optical, structural, and morphological properties of the films was characterized by means of four-point probe method, ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction and atomic force microscopy.

Electrochromic Thin‐Film Nickel‐Oxide Coatings for Systems with Adjustable Light Transmission

In this study, results on the effect of technological parameters of the nickel(II)‐oxide thin‐film deposition process, obtained through chemical vapor deposition in an argon–oxygen environment using bis‐(ethylcyclopentadienyl)‐nickel (EtCp)2Ni, on their electrochromic properties, are presented. It is shown that the films lose ability to electrochromic coloring in alkaline environments as their thickness increases up to 170 nm. The introduction of small ozone additions of 0.1 vol% O3 into the gas phase leads to a decrease in the NiO films deposition rate, the formation of a rougher layer with an average grain size up to 71.4 nm, capable of coloring in light brown. Additional cathodic treatment of NiO films at a potential of −0.8 V for 30 s in alkaline environments containing fullerene C60(OH)24 leads to the modification of the surface layer and the formation of NiO–C carbon‐containing nanocomposite coatings with enhanced contrast and the ability to retain the colored state after polarization is turned off, i.e., possessing optical memory properties. Using NiO–C nanocomposite and indium–tin–oxide films, which have opposite coloring mechanisms, in the structure of an electrochromic device allows for an increase in the grade of glass darkening, significantly reducing energy consumption, improving operational characteristics, and life span.

The effect of slag variability in the attempted manufacture of AYF (alite-ye'elimite-ferrite) cement clinker at both laboratory and pilot scale

The production of AYF (alite-ye'elimite-ferrite) clinker was tested at laboratory and semi-industrial scale using by-products from the metallurgical industry: AOD slag; ladle slag; and fayalitic slag. Alite could be produced with ye'elimite using fluorine originating from AOD (argon oxygen decarburisation) slag as a mineraliser. After a successful laboratory demonstration, the clinker production was scaled to a semi-industrial trial. It was discovered that the reason for the absence of alite formation in a semi-industrial demonstration was that the AOD slag from the specific batch did not perform the designed mineralisation effect for alite formation. This study demonstrates that alite-ye'elimite can be produced at 1260 °C at laboratory scale by using fluorine mineralisation originating from an industrial by-product – in this case, AOD slag. However, the utilisation of by-products for delicate reactions requires detailed determination of the properties of the slag, as the variability from the same source yields different clinker chemistries and mineral phases.

Estimation of reflection loss of lossy dielectric powders using coaxial line based guided wave technique for conventional cement based microwave absorber applications

Coaxial transmission line technique to determine Plane Wave Reflection Loss of dielectric powders is proposed. The technique provides rapid determination of suitability of powders as conductive filler for Microwave Absorbers, specifically cement based Absorber. Ash by-product from steel industry including Argon Oxygen Decarburization (AOD), Acid Recovery Station (ARS) and Electric Arc Furnace (EAF) are considered over frequency range 1–12 GHz. Scattering parameters (S-matrix) of ash filled coaxial lines are measured. Short-Open technique is adopted. Formulation to compute reflection loss from measured S11 is presented. Teflon, with known reflection loss, is considered for validation. A 10 % error in computed results is observed in range 1–4 GHz, and 10–15 % in range 4–12 GHz. Broadband MAM characterization employing Free Space Methods involve enormous material requirement, frequency dependent prototype dimensions and anechoic chambers. The error percentage notwithstanding, the technique provides rapid estimates, enabling smart selection of conductive fillers, providing cost and time reduction.

In-Line Co-Processing of Stainless Steel Pickling Sludge Using Argon Oxygen Decarburization Slag Bath: Behavior and Mechanism

Stainless steel pickling sludge (SSPS) is classified as hazardous solid waste, while Argon Oxygen Decarburization (AOD) slag is challenging to utilize due to the leaching toxicity of Cr. This study introduces a novel in-line co-processing technique for AOD slag and SSPS, parallel to the steelmaking process, aimed at metal recovery, sulfur fixation, and slag detoxification: pre-treatment-AOD slag bath approach. The transformations and migrations of sulfur and metal elements, such as Fe and Cr, in the co-processed mixture were analyzed using thermogravimetric–mass spectrometry (TG-MS) and scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS). The results indicated that sulfur in SSPS could be transformed from CaSO4 to CaS under controlled low pre-reduction temperatures (below 800 °C), facilitating its stabilization in the slag and achieving a sulfur fixation rate of over 99%. Metal elements, including iron and chromium, first formed a small portion of spinel (FeCr2O4) during the pre-reduction phase, then Fe-Cr or Fe-Cr-C-based alloy particles were rapidly formed at high temperatures and in the presence of reducers in the slag bath (1550 °C), aggregating and growing spontaneously, ultimately achieving a metal recovery rate of over 95%. Furthermore, a reaction model for SSPS briquettes in the AOD slag bath was established to further reveal the mechanisms of sulfur, iron, and chromium stabilization and migration, thereby providing a basis for the harmless disposal of both materials. The product alloys are expected to be used as additives in stainless steel production, while the harmless slag could be safely utilized in the preparation of cementitious auxiliary materials.

Preparation and Mechanism Analysis of Stainless Steel AOD Slag Mixture Base Materials.

To promote resourceful utilization of argon oxygen decarburization (AOD) slag, this research developed a new three-ash stabilized recycled aggregate with AOD slag, cement, fly ash (FA), and recycled aggregate (RA) as raw materials. The AOD slag was adopted as an equal mass replacement for fly ash. The application of this aggregate in a road base layer was investigated in terms of its mechanical properties and mechanistic analysis. First, based on a cement: FA ratio of 1:4, 20 sets of mixed proportion schemes were designed for four kinds of cement dosage and AOD slag replacement rates (R/%). Through compaction tests and the 7-day unconfined compressive strength test, it was found that a 3% cement dosage met the engineering requirements. Then, the unconfined compressive strength test, indirect tensile strength test, compressive rebound modulus test, and expansion rate test were carried out at different age thresholds. The results showed that the mixture's strength, modulus, and expansion rate increased initially and then stabilized with age, while the strength and modulus initially increased and then decreased with increasing R. Secondly, based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) used to analyze the mechanism, it was found that the strength, modulus, and expansion rate of the new material can be promoted by blending AOD slag, due to its ability to fully stimulate the hydration reaction and pozzolanic reaction of the binder. Finally, based on the strength and modulus results, R = 3% was identified as the optimal ratio, which provides a reference point for the effective application of AOD slag and RA in road base materials.

Evidence for molecular tungsten ionic species presence in impurity‐seeded hydrogen plasma in contact with W surfaces

AbstractWe performed an investigation of tungsten ionic species presence in hydrogen plasmas in contact with a tungsten surface, both in the presence of air impurities and when injected with argon. The study was carried out in a magnetron sputtering system complemented with mass spectrometry diagnostics. Our findings reveal that these plasmas encompass a diverse range of tungsten molecular ionic species in the mass range of 180–250 amu, broadly described as WHxNyOz+ (x = 0–3; y = 0–2; z = 0–3). The validity of these results was further confirmed through dedicated mass spectrometry investigations involving tungsten sputtering discharges in argon–nitrogen and argon–oxygen mixtures.

Etching of a fluoropolymer coating synthesized by the hot wire chemical vapor deposition method in a low-frequency induction discharge plasma

The process of plasma etching for the formation of a biphilic pattern in a continuous homogeneous fluoropolymer coating on a copper substrate is studied. Argon or oxygen plasma of low frequency ferromagnetic amplified induction discharge is used to etch a fluoropolymer coating. Plasma etching was carried out through a mask with parallel slits. The etching rate in argon plasma was 10 nm/min, the etching rate in oxygen plasma was 60 nm/min. Biphilic surfaces were obtained, consisting of fluoropolymer strips on a copper surface. It has been shown that when using both argon plasma and oxygen plasma, it is possible to create biphilic surfaces by etching a continuous homogeneous fluoropolymer coating through a mask. Moreover, oxygen plasma is better suited for this because it has a higher etching rate and weakly changes the wettability of the surface.

Investigation on the Attainment of High-Density 316L Stainless Steel with Selective Laser Sintering.

Due to the low density of the green part produced by selective laser sintering (SLS), previous reports mainly improve the sample's density through the infiltration of low-melting metals or using isostatic pressing technology. In this study, the feasibility of preparing high-density 316L stainless steel using 316L and epoxy resin E-12 as raw materials for SLS combined with debinding and sintering was investigated. The results indicated that in an argon atmosphere, high carbon and oxygen contents, along with the uneven distribution of oxygen, led to the formation of impurity phases such as metal oxides, including Cr2O3 and FeO, preventing the effective densification of the sintered samples. Hydrogen-sintered samples can achieve a high relative density exceeding 98% without losing their original design shape. This can be attributed to hydrogen's strong reducibility (effectively reducing the carbon and oxygen contents in the samples, improving their distribution uniformity, and eliminating impurity phases) and hydrogen's higher thermal conductivity (about 10 times that of argon, reducing temperature gradients in the sintered samples and promoting better sintering). The microstructure of the hydrogen-sintered samples consisted of equiaxed austenite and ferrite phases. The samples exhibited the highest values of tensile strength, yield strength, and elongation at 1440 °C, reaching 513.5 MPa, 187.4 MPa, and 76.1%, respectively.

Plasma Anneal As a Stress Control Method in Low Temperature Al2O3 ALD Coatings

The control of mechanical physical stress is an important requirement in a variety of applications, such as flexible electronics or thick optical coatings where film stress can cause delamination. Traditionally, in thermal ALD it has been difficult to control the stress. Al2O3 deposited at low temperature is consistently found to have a tensile stress level in the range of a 300 to 450 MPa ( refs 1-3). It is well established that In magnetron sputtering , film stress can be controlled straightforwardly using the Argon pressure during deposition, as this affects the level of bombardment of the growing film with energetic particles.Paranjpe et al ( ref 1) have demonstrated that the use of a plasma anneal leads to densification and transition of the stress from tensile to compressive. The process consists of a sequence of deposition of a thin layer ( e.g. 5 nm) by thermal ALD, followed by exposure to a low energy plasma. The atomic displacements caused by low energy ions from the plasma tend to lead to filling of nanoscopic voids and point defects, thus releasing tensile stress.In this presentation, we will review an in depth study of the effect of various process parameters on the ability of a capacitively coupled in-situ plasma anneal to control stress. The following parameters will be reviewed: Gas composition: Argon plasmas, Oxygen plasmas and Argon oxygen mixtures are compared. Gas Pressure: The effect of gas pressure on plasma characteristics and the resulting modification of the coating is studied RF Power: RF Power was varied between 0 and 300 W ( 1.32 W/cm2) Plasma duration : The duration of the plasma treatment was varied from 0 to 60 seconds.A process window was identified where the plasma anneal can be used as an effective, controllable tool to reduce stress in the coatings. This is illustrated in fig. 1, which shows the substrate warpage (“bow”) observed in 75 mm thick PET foils with a 50 nm Al2O3 coating deposited at 90 °C. It can be seen that the untreated coating (0 sec plasma) has a bow corresponding to a tensile stress of 370 MPa, in accordance with literature values. As the plasma anneal time increases, the stress value decreases. Applying a 60 sec plasma every 5 nm allows to deposit a virtually stress free coating. Simultaneously with the stress reduction, an increase of the optical index and a slight reduction of the thickness are observed, consistent with a densification of the coating.

Production of Nitrogen‐Alloyed Stainless Steels in Argon Oxygen Decarburization Converter: Kinetics and Modeling of Nitrogenation and Denitrogenation

The study aims to comprehend the behavior of nitrogen in the argon oxygen decarburization (AOD) process during the production of nitrogen‐alloyed stainless steels, where the precise adjustment of nitrogen content plays a crucial role in enhancing productivity. Furthermore, the objective is to investigate the rate of change in nitrogen content when blowing a mixture of nitrogen and argon, instead of using pure nitrogen or argon alone. Hence, both nitrogenation and denitrogenation cases are examined, and kinetic models are developed. While solution thermodynamics can predict the final nitrogen content, the kinetics are influenced by the gas flow rate, steel temperature and composition, and levels of the surface active elements in the steel. By integrating a previously developed thermodynamic equilibrium equation with the kinetic models, nitrogen contents in the range of 0.150–0.400% can be reliably predicted. Consequently, the equations can be applied to predict nitrogen content during both the nitrogenation and denitrogenation stages in the reduction and desulfurization phases of the AOD process.

Nitrogen Control in Production of N-Alloyed Stainless Steels in AOD Converter: Application of Sieverts’ Law

In numerous stainless steels, nitrogen is used as an alloying element to improve mechanical and corrosion properties. The typical nitrogen content is up to 0.5 pct. A common method for alloying is to blow nitrogen gas into an Argon Oxygen Decarburization (AOD) converter. Depending on the steel composition, operating practice, and process conditions, the hitting grade of the N content can be a problem. According to Sieverts’ law, nitrogen solubility depends on the nitrogen partial pressure. In this study, the applicability of Sieverts’ law to control the nitrogen content in stainless steels was investigated by test trials in an industrial AOD converter using N2–Ar mixtures. The validity was established in a wide range of nitrogen content (0.1–0.4 pct) and large variety of alloying (Cr, Ni, Mo, Mn) with considerable influence on N solubility. The validity was well established by approaching the equilibrium N content both from above and below. As a conclusion, the nitrogen content can be controlled by regulating the partial pressure of nitrogen in the blowing gas mixture. For practical purposes, the final nitrogen content can be predicted in different situations and guide graphs were drawn to determine the required N2–Ar ratio. These tools can be utilized when designing blowing practices for the AOD converter for nitrogen-alloyed stainless steels.

Modeling Decarburization in the AOD Converter: A Practical CFD-Based Approach With Chemical Reactions

Gas-blowing technology is widely used in converter steelmaking to homogenize liquid steel and accelerate chemical reactions, with Argon oxygen decarburization (AOD) being the dominant process for stainless steelmaking. Due to the harsh environment, it is advisable to study the phenomenon using small-scale physical models and numerical simulations before conducting industrial-scale trials. This paper presents a practical computational fluid dynamics (CFD) approach for simulating the AOD process, with chemical reactions considered. This approach can simulate the entire process in a reasonable time using a standard workstation. The simulation employs a Finite Volume Method CFD approach to handle mass, momentum, and energy transfer, and a local equilibrium assumption is utilized. The study shows that a practical approach can be used to model the initial stage of decarburization in the AOD process with a reduced accuracy in mass transport calculations. The accuracy of the simulation is validated using industrial data, and good agreement is found.

Effect of oxygen and nitrogen sensitization on structural, optical and electrical properties of PbSe thin films

An effective two-step sensitization technique was implemented in PbSe thin films, leading to a remarkable improvement in the optoelectronic performance of PbSe photodetectors. The phase composition, surface and cross-sectional morphology, temperature-dependent carrier concentration and mobility as well as the detectability of PbSe films after sensitization were systematically investigated using characteristic techniques. The optimal PbSe film oxygen sensitized at 450 °C exhibited a room-temperature photodetection with a carrier concentration of 5.31 × 1016 cm−3, carrier mobility of 16.52 cm2/V−1s−1, and detectivity of 2.25 × 109 Jones. High-temperature argon heat treatment and oxygen sensitization of PbSe films are expected to suppress recombination losses and significantly improve the optoelectronic properties of sensitized PbSe films due to enhanced carrier separation and transport. The enhanced photoresponse mechanism of the PbSe films through two-step sensitization method was also discussed. These results suggest that the proposed method can be applied to high-performance lead selenide photodetectors.

Influence of exposure of customized dental implant abutments to different cleaning procedures: an in vitro study using AI-assisted SEM/EDS analysis

PurposeDental implant abutments are defined as medical devices by their intended use. Surfaces of custom-made CAD/CAM two-piece abutments may become contaminated during the manufacturing process in the dental lab. Inadequate reprocessing prior to patient care may contribute to implant-associated complications. Risk-adapted hygiene management is required to meet the requirements for medical devices.MethodsA total of 49 CAD/CAM-manufactured zirconia copings were bonded to prefabricated titanium bases. One group was bonded, polished, and cleaned separately in dental laboratories throughout Germany (LA). Another group was left untreated (NC). Five groups received the following hygiene regimen: three-stage ultrasonic cleaning (CP and FP), steam (SC), argon–oxygen plasma (PL), and simple ultrasonic cleaning (UD). Contaminants were detected using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) and segmented and quantified using interactive machine learning (ML) and thresholding (SW). The data were statistically analysed using non-parametric tests (Kruskal–Wallis test, Dunn’s test).ResultsSignificant differences in contamination levels with the different cleaning procedures were found (p ≤ 0.01). The FP–NC/LA groups showed the most significant difference in contamination levels for both measurement methods (ML, SW), followed by CP–LA/NC and UD–LA/NC for SW and CP–LA/NC and PL–LA/NC for ML (p ≤ 0.05). EDS revealed organic contamination in all specimens; traces of aluminum, silicon, and calcium were detected.ConclusionsChemothermal cleaning methods based on ultrasound and argon–oxygen plasma effectively removed process-related contamination from zirconia surfaces. Machine learning is a promising assessment tool for quantifying and monitoring external contamination on zirconia abutments.Graphical

Investigation of the acicular aragonite growth behavior in AOD stainless steel slag during slurry-phase carbonation

This study presents a novel method for producing acicular aragonite using argon oxygen decarburization (AOD) slag while controlling the reaction temperature, reaction time, stirring speed, and the magnesium-to‑calcium stoichiometric ratio. This approach provides steel plants with an opportunity to decrease their CO2 emissions and promote efficient resource utilization and CO2 storage through the production of high-quality value-added products. The experimental results showed that reaction temperature was the most significant factor affecting the carbonation efficiency of AOD slag, followed by reaction time, stirring speed, CO2 partial pressure, and the liquid-to-solid ratio (L/S). The study also found that elevated temperature and prolonged reaction duration favored the preferential precipitation of aragonite. Additionally, raising the temperature and the magnesium-to‑calcium stoichiometric ratio was shown to enhance the formation of aragonite, affecting its crystal growth orientation and dimensions. The optimal combination of reaction parameters for the preparation of acicular aragonite was found to be the reaction time of 8 h, the magnesium-to‑calcium stoichiometric ratio of 0.8, the reaction temperature of 120 °C, and the stirring speed of 200 r·min−1. Under these conditions, the resulting acicular aragonite exhibited excellent overall uniformity, a large aspect ratio, and a smooth crystal surface, with a content of 91.49 %, a single crystal length ranging from 9.86 to 32.6 μm, and a diameter ranging from 0.63 to 2.15 μm. This study provides valuable insights into the efficient production of acicular aragonite from steel slag while reducing CO2 emissions and promoting the sustainable use of resources.

Low Temperature Wafer Bonding of Silicon Carbide/Aluminum Nitride

Because of the wide energy gap material properties and high compatibility with existing silicon material processing, silicon carbide (SiC) has become the preferred material for power management chips that have been used in electric vehicles. On the other hand, aluminum nitride (AlN) material has become the first choice for carrying wafers due to its high strain-resistant mechanical properties, strong dielectric coefficient, excellent thermal conductivity, and high etching resistance. In this study, the surface chemistry of silicon carbide was changed into an AlN-based material to perform wafer bonding processing to develop low-temperature bonding technology for silicon carbide/aluminum nitride materials. We found through experiments that it is quite difficult for a SiC wafer to bond with an AlN wafer even if the surfaces ofthe SiC wafer and the AlN wafer are subjected to conventional surface activation treatment using oxygen plasma or argon plasma. The possible reason is that although the surface of the SiC wafer is bombarded by oxygen or argon plasmas to generate some dangling bonds, the chemical properties of Si-C and Al-N, such as electronegativity, make it difficult to generate chemical bonds between the matching surfaces of SiC/AlN. Through a material modification technology, a high-temperature sputtering method is used to make highly active AlN clusters sputtered from the target directly bond with SiC and finally form a thin AlN layer that strongly adheres to the surface of the SiC wafer. And then through the bonding of AlN/AlN homogeneous materials, although the surface roughness measurement (RMS) cannot satisfy the condition of being less than 5 angstroms for wafer bonding, the goal of low-temperature bonding can be achieved by capillary bonding. Therefore, the SiC surface is changed into an AlN-based thin layer by high-temperature sputtering, which can further chemically bond with the AlN wafer surface by capillary bonding to achieve the low-temperature bonding of SiC/AlN, as shown in Figure 1.Reference1. Shao-Ming Nien, Jian-Long Ruan, Yang-Kuao Kuo, and Benjamin Tien-Hsi Lee, Low-temperature rough-surface wafer bonding with aluminum nitride ceramics implemented by capillary and oxidation actions, Ceramics International, Volume 48, Issue 6, 2022 Figure 1