Surface Chemical Processes Research Articles

Sintering Mechanism and Leaching Kinetics of Low-Grade Mixed Lithium Ore and Limestone

With the rapid development of new energy fields and the current shortage of lithium supply, an efficient, clean, and stable lithium resource extraction process is urgently necessary. In this paper, various advanced detection methods were utilized to conduct a mineralogical analysis of the raw ore and systematically study the occurrence state of lithium; the limestone sintering process was strengthened and optimized, elucidating the sintering mechanism and analyzing the leaching process kinetics. Under an ingredient ratio of 1:3, a sample particle size of 300 mesh, a sintering temperature of 1100 °C, a sintering time of 3 h, a liquid–solid ratio of 2:1, a leaching temperature of 95 °C, and a leaching time of 1 h, the leaching rate of Li reached 90.04%. The highly active Ca–O combined with Si–O on the surface of β–spodumene to CaSiO4, and Al–O was isolated and combined with Li to LiAlO2, which was beneficial for the leaching process. The leaching process was controlled by both surface chemical reactions and diffusion processes, and Ea was 27.18 kJ/mol. These studies provide theoretical guidance for the subsequent re-optimization of the process.

Kinetics study on the temperature-dependent reduction of aqueous U(VI) by natural pyrite

Previous studies have indicated that acid-washed pyrite is inert toward aqueous U(VI) under most pH conditions at ambient temperature, even though insoluble UO2 is the thermodynamically predicted product for the reduction of U(VI) by pyrite. Considering the exothermic nature of nuclear waste, the interaction between uranyl nitrate/acetate and natural pyrite was studied at temperatures ranging from 25 °C to 85 °C and at pH values between ∼4.0 and ∼9.5, to simulate the scenarios encountered in a high-level radioactive waste repository. The results revealed that the reactivity of pyrite toward aqueous U(VI) significantly increased with rising temperature, and the reaction could be described by a pseudo-first-order kinetic equation. Activation energies were calculated to be 79.4 ± 10.6 and 45.7 ± 3.8 kJ⋅mol−1 for the reduction of uranyl nitrate, and 78.2 ± 5.2 and 42.2 ± 5.8 kJ⋅mol−1 for the reduction of uranyl acetate, at pH values of ∼4.5 and ∼5.0, respectively. These values indicate that the reaction is controlled by the surface chemical processes. In addition, the complete reduction of aqueous U(VI) to UO2 product was first observed for the reactions at pH ∼4.0 to ∼5.5 when the temperature was ≥75 °C. Conversely, non-stoichiometric UO2+x(s) (0 < x ≤ 0.67) was found at lower temperatures within the same pH range, and also at 85 °C with a reaction pH of ∼9.5. Moreover, the ratio of reduced U(IV/V) on pyrite surfaces increased gradually over time, indicating that reaction time played a significant role in the reduction products. The findings are essential not only for the safety assessment of the high-level radioactive waste repository, but also for understanding the metallogenic mechanism of U(IV)-bearing ore deposits under the relevant anaerobic and hydrothermal conditions.

On the Electrochemical Activation of Nanoporous Reduced Graphene Oxide Electrodes Studied by In Situ/Operando Electrochemical Techniques

AbstractDue to the difficult access of the electrolyte into the nanoconfined space of nanoporous reduced graphene oxide (rGO) electrodes, achieving the optimal electrochemical performance of these devices becomes a challenge. In this work, the dynamics of interfacial‐governed phenomena are investigated during a voltage‐controlled electrochemical activation of nanoporous rGO electrodes that leads to an enhanced electrochemical performance in terms of areal capacitance and electrochemical impedance. In situ/operando characterization techniques are used to reveal the dynamics of the irreversible material changes introduced during the activation process, including ionic diffusion and water confinement within the nanopores, along with the reduction of oxygenated groups and the decrease of the rGO interlayer distance. Furthermore, operando techniques are used to uncover the origin of the complex polarization‐dependent dynamic response of rGO electrodes. The study reveals that the reversible protonation/deprotonation of remaining functional groups and the cation electro‐adsorption/desorption process in the graphene basal plane govern the pseudocapacitive performance of nanoporous rGO electrodes. This work brings new understanding of the complex interplay between surface chemistry, ion confinement, and desolvation processes occurring during electrochemical cycling in nanoporous rGO electrodes, offering new insights for designing high‐performing electrodes based on nanoporous rGO.

Understanding adsorption mechanisms and metal ion selectivity of superparamagnetic beads with mesoporous CMK-3 carbon and commercial activated carbon

This study investigates, the adsorption capacities of synthesized magnetic hybrid beads containing ordered mesoporous carbon (CMK-3) and commercial activated carbon (commercial AC) for Cd (II), Ni (II), and Hg (II) ions adsorption in single and ternary systems. The order of maximum adsorption capacity was Cd (II) > Ni (II) > Hg (II) in both beads and systems. L13 beads containing CMK-3 exhibit superior adsorption efficiency compared to L3 beads with commercial AC, attributed to the large surface area, enhanced accessibility to adsorption sites, and the presence of O=C bonds, as well as other elements such as F−. Adsorption of all metal ions was described by Freundlich isotherm in L3 beads in both systems, meanwhile in L13 beads, Langmuir and Freundlich models described adsorption differently in both systems and among metal ions, indicating a more complex process. According to the reported maximum adsorption capacity values, L3 beads exhibit a greater affinity for Hg (II) ions, while L13 beads show a higher affinity for Cd (II) and Ni (II) ions. Adsorption in both beads occurred through several mechanisms involving surface complexation, ion-exchange, precipitation, physical and chemical processes. These findings highlight the importance of material design in optimizing adsorption performance for environmental applications, with potential for further enhancement of adsorption capacities and selectivities through future research.

3D Printable Multifunctional Electrochemical Nano‐Doped Biofilament

AbstractFused deposition modeling (FDM) represents a state‐of‐the‐art 3D printing technology that holds great promise in the field of electrochemistry as a fast, in‐house, and digital fabrication method of sustainable sensors. Despite the progress in FDM, existing practical 3D printed sensors still require post‐printing treatment to improve their operational features, either through (electro)chemical surface activation or surface modification with external functional materials. Herein, a novel lab‐made conductive biofilament with integrated two different types of metallic nanoparticles (NPs) for the 3D printing of ready‐to‐use and multiplexed electrochemical sensors is introduced. The filament is composed of biodegradable polylactic acid as a base, polyethylene glycol dimethyl ether as a plasticizer, carbon black as a conductive filler, and nanopowder oxides of bismuth and copper as integrated functional precursor materials. The as‐printed sensors serve as multifunctional transducers for the direct and sensitive determinations of several analytes, by exploiting the different properties of the two co‐existing NPs. Particularly, heavy metals (such as lead, and cadmium) are voltammetrically quantified by amalgamation with BiNPs electrogenerated from Bi2O3, while biomarkers (such as glucose, and uric acid) are determined in enzymatic‐free modes. Determination of glucose takes advantage of the electrocatalytic properties of CuO, while uric acid is directly oxidized at the sensor.

High resistance of superconducting TiN thin films against environmental attacks.

Superconductors, an essential class of functional materials, hold a vital position in both fundamental science and practical applications. However, most superconductors, including MgB2, Bi2Sr2CaCu2O8+δ, and FeSe, are highly sensitive to environmental attacks (such as from water and moist air), hindering their wide applications. More importantly, the surface physical and chemical processes of most superconductors in various environments remain poorly understood. Here, we comprehensively investigate the high resistance of superconducting titanium nitride (TiN) epitaxial films against acid and alkali attacks. Unexpectedly, despite immersion in acid and alkaline solutions for over 7 days, the crystal structure and superconducting properties of TiN films remain stable, as demonstrated by high-resolution X-ray diffraction, electrical transport, atomic force microscopy, and scanning electron microscopy. Furthermore, combining scanning transmission electron microscopy analysis with density functional theory calculations revealed the corrosion mechanisms: acid corrosions lead to the creation of numerous defects due to the substitution of Cl ions for N anions, whereas alkaline environments significantly reduce the film thickness through the stabilization of OH* adsorbates. Our results uncover the unexpected stability and durability of superconducting materials against environmental attacks, highlighting their potential for enhanced reliability and longevity in diverse applications.

Impact of Solution {Ba2+}:{SO42-} on Charge Evolution of Forming and Growing Barite (BaSO4) Crystals: A ζ-Potential Measurement Investigation.

The impact of solution stoichiometry on formation of BaSO4 (barite) crystals and the development of surface charge was investigated at various predefined stoichiometries (raq = 0.01, 0.1, 1, 10, and 100, where raq = {Ba2+}:{SO42-}). Synthesis experiments and zeta potential (ζ-potential) measurements were conducted at a fixed initial degree of supersaturation (Ωbarite = 1000, where Ωbarite = {Ba2+}{SO42-}/Ksp), at circumneutral pH of ∼6, 0.02 M NaCl, and ambient temperature and pressure. Mixed-mode measurement-phase analysis light scattering (M3-PALS) showed that the particles stayed negative for raq < 1 during barite crystal formation and positive for raq > 1. At raq = 1, two populations with a positive or negative ζ-potential prevailed for ∼2.5 h before a population with a circumneutral ζ-potential (-10 to +10 mV) remained. We relate the observations of particle charge evolution to particle size and morphology evolution under the experimental conditions. Furthermore, we showed that the ζ-potential became more negative when the pH was increased for every raq. In addition, our results demonstrated that the type of monovalent background electrolyte did not influence the ζ-potential of barite crystals significantly, although NaCl showed slightly different behavior compared to KCl and NaNO3. Our results show the important role of surface charge (evolution) during ionic crystal formation under nonstoichiometric conditions. Moreover, our combined scanning electron microscopy and ζ-potential results imply that the surface charge during particle formation can be influenced by solution stoichiometry, besides the pH and ionic strength, and may aid in predicting the fate of barite in environmental settings and in understanding and improving industrial barite (surface chemistry) processes.

Surface Chemistry of Biologically Active Reducible Oxide Nanozymes.

Reducible metal oxide nanozymes (rNZs) are a subject of intense recent interest due to their catalytic nature, ease of synthesis, and complex surface character. Such materials contain surface sites which facilitate enzyme-mimetic reactions via substrate coordination and redox cycling. Further, these surface reactive sites are shown to be highly sensitive to stresses within the nanomaterial lattice, the physicochemical environment, and to processing conditions occurring as part of their syntheses. When administered in vivo, a complex protein corona binds to the surface, redefining its biological identity and subsequent interactions within the biological system. Catalytic activities of rNZs each deliver a differing impact on protein corona formation, its composition, and in turn, their recognition, and internalization by host cells. Improving the understanding of the precise principles that dominate rNZ surface-biomolecule adsorption raises the question of whether designer rNZs can be engineered to prevent corona formation, or indeed to produce "custom" protein coronas applied either in vitro, and preadministration, or formed immediately upon their exposure to body fluids. Here, fundamental surface chemistry processes and their implications in rNZ material performance are considered. In particular, material structures which inform component adsorption from the application environment, including substrates for enzyme-mimetic reactions are discussed.

Holocene sediment source analysis and paleoclimatic significance of core KZK01 from the eastern part of the Beibu Gulf

Identifying the sources of sediments is of great significance in reconstructing Holocene paleoclimate evolution in the Beibu Gulf and in understanding the characteristics of regional responses to changes in global climate. The Holocene paleoclimatic evolutionary history of the Beibu Gulf was investigated by chronological, geochemical, and mineralogical means using the sediments of Core KZK01 from the eastern part of the Beibu Gulf. The rare earth element (REE) distribution curves, (Gd/Yb)N and (La/Yb)N discriminant diagram, and (Gd/Lu)N and ∑LREE/∑HREE discriminant diagram indicated that the detrital materials in the eastern part of the Beibu Gulf primarily originated from Hainan Island and its proximal sources, with considerable contributions from Taiwan and Pearl River materials. Source analysis of clay minerals showed that Luzon Island was the main source of smectite, followed by Hainan Island. Rivers in Taiwan were the main sources of illite in the study area, followed by the Red River. The Red River was the main contributor of chlorite, followed by the Pearl River. Kaolinite mainly originated from Hainan Island and Guangxi. Coastal currents, surface currents, and warm currents were the main drivers of material transport. Paleoclimatic variations since the Holocene in the Beibu Gulf were divided into three stages: 12–9 cal kyr BP, 9–1.3 cal kyr BP, and 1.3 cal kyr BP to the present. During different stages of climatic evolution, drought was often accompanied by cold and humidity coexisted with warmth, and cold-dry-warm-humid alternation is characterized by significant phases. The illite crystallinity clearly recorded the extreme cold events, such as Bond Events (except Bond6) and the Younger Dryas, and the change trend was essentially consistent with the regional climate record, reflecting the control of global climate change on the process of land–sea interaction in the tropical region. Furthermore, it highlights the great potential of illite crystallinity as a proxy indicator for reconstructing the surface chemical weathering processes of the region.

State-specific slip boundary conditions in non-equilibrium gas flows: Theoretical models and their assessment

In this study, we develop and assess a new approach to modeling slip boundary conditions in gas mixtures with coupled state-to-state vibrational-chemical kinetics and surface physical and chemical processes: adsorption, desorption, vibrational energy transitions, and chemical reactions. Expressions for velocity slip, temperature jump, and mass fluxes of species are derived on the basis of the advanced kinetic boundary condition taking into account gain and loss of particles in surface processes; theoretical expressions for the mass fluxes obtained in the frame of various approaches are compared. The developed model is implemented to the fluid-dynamic solver for modeling dynamics and state-to-state air kinetics in the boundary layer near stagnation point. Several test cases corresponding to a various degree of gas rarefaction are considered. Recombination probabilities and effective reaction rates are calculated and compared to recent molecular-dynamic simulations; the proposed model yields the best agreement for the recombination rate coefficient. It is shown that temperature jump significantly affects fluid-dynamic parameters and surface heat flux; the role of heterogeneous reactions on the silica surface is weaker. In the surface heating, there is a competition between these two effects: whereas the temperature jump reduces the wall heat flux, surface reactions cause its increase, but to a lesser extent. It is concluded that the model proposed in this study describes self-consistently detailed vibrational kinetics, rarefaction effects, and surface reactions and can be applied both in continuum and slip flow regimes.

Spectroscopic Evaluation of Surface Chemical Processes Occurring in MoS2 upon Aging.

Molybdenum disulfide (MoS2) coatings have attracted widespread industrial interest owing to their excellent lubricating properties under vacuum and inert conditions. Unfortunately, the increase in MoS2 interfacial shear strength following prolonged exposure to ambient conditions (a process referred to as "aging") has resulted in reliability issues when MoS2 is employed as solid lubricant. While aging of MoS2 is generally attributed to physical and chemical changes caused by adsorbed water and/or oxygen, a mechanistic understanding of the relative role of these two gaseous species in the evolution of the surface chemistry of MoS2 is still elusive. Additionally, remarkably little is known about the effect of thermally- and tribologically-induced microstructural variations in MoS2 on the aging processes occurring in the near-surface region of the coating. Here, we employed three analytical techniques, namely, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and grazing-incidence X-ray diffraction (GIXRD), to gain insights into the aging phenomena occurring in sputtered MoS2 coatings before and after tribological testing, while also evaluating the impact of thermally-induced variations in the coating structure on aging. The outcomes of XPS analyses provide evidence that a substantial surface oxidation of MoS2 only takes place under humid conditions. Furthermore, the correlation of XPS, ToF-SIMS, and GIXRD results allowed for the development of a qualitative model for the impact of shear-induced microstructural variations in MoS2 on the transport of water in the near-surface region of this material and on the extent of surface oxidation. These results add significantly to our understanding of the aging mechanisms of MoS2 coatings used in tribological applications and their dependence on environmental conditions.

Chemical weathering of small watersheds in the upper reaches of Jinsha river on the eastern edge of the Qinghai–Tibet Plateau

Land chemical weathering is a crucial and common geological process on the Earth’s surface. Studying the surface chemical weathering process in basins is important to the net consumption rate of atmospheric CO2, climate change in geological history, and the global carbon cycle. In this study, a small watershed in the upper reaches of Jinsha River on the eastern edge of the Qinghai-Tibet Plateau is selected as the study area. By measuring the physical and chemical properties and the main ion content of the water in the watershed and by using the factor analysis method, the source of the main ion components in the water in the alpine basin and the characteristics of the chemical weathering of the basin rocks are examined. Results show that the pH value of surface water in the study area varies from 7.4 to 8.2, and the overall performance is moderately to weakly alkaline. The total salinity in the basin is between 52.42 and 398.19 mg/L, with an average value of 180.06 mg/L. The concentration of main cations in surface water follows the order Ca2+>Mg2+>Na+>K+. The concentration relationship of the main anions is in the order HCO3−>SO42−>Cl−, and the hydrochemical type is HCO3_Ca. The main source of ions in the study area is rock weathering, which is controlled by the chemical weathering of carbonate rocks. The contribution rates of carbonate (mainly dolomite and calcite dissolution), evaporite, and silicate to the dissolved matter in the river are 59.40%, 7.30%, and 3.00% respectively, and the contribution rate of CO2 in the atmosphere to the dissolved matter in the river is 30.30%. The total chemical weathering rate in the study area is 29.09 t/km2 ⋅a, which is at a low level, indicating that weak hydrothermal conditions slow down the chemical weathering process of rock minerals.

Fabricating 1D stretchable fiber-shaped electronics based on inkjet printing technology for wearable applications

Advanced microfabrication on small and curved fiber surfaces remains a critical challenge and an urgent need to develop high-performance fiber-shaped electronics and advance the next generation of wearable electronics technology. In this study, we propose the preparation of 1D stretchable fiber-shaped electronics via inkjet printing technology for wearable applications. Utilizing self-built precision rotary inkjet printing equipment and a surface chemical modification process, we achieve high-precision and customizable microfabrication onto ultra-low diameter fiber surfaces (minimum printing line width of 133 µm and a printable fiber diameter as low as 500 µm with a large curvature of 4000 m−1). More importantly, this fabricating method is non-destructive and can prepare 1D stretchable conductors by printing conductive inks with stretchable structures and optimizing various synthetic fibers, which exhibit remarkable conductivity, mechanical stability, and strain-insensitive properties in practical applications. Furthermore, we demonstrate the performance of several 1D stretchable electronics applications, including a fiber-shaped electrothermal device, triboelectric strain sensor, and supercapacitor. Our work will greatly promote the development of 1D fiber-shaped electronics and smart textiles with wearability, high performance, functional diversification, and low cost.

In situ x-ray photoelectron spectroscopy analysis of the atomic layer deposition of Al2O3 on SiO x /Si: Interface dipole and persistent surface groups

Atomic layer deposition (ALD) has become an essential technology in many areas. To better develop and use this technology, it is of the pivot to understand the surface chemistry during the ALD film growth. The growth of an ALD oxide film may also induce an electric dipole at the interface, which may be further tuned to modulate the flat band voltage for electronic device applications. To understand the associated surface chemistry and interface dipole formation process, we herein employ an in situ x-ray photoelectron spectroscopy technique to study the ALD growth of Al2O3, from trimethylaluminum and H2O, on the SiO x /Si surface. We find that an electric dipole is formed at the Al2O3/SiO x interface immediately after the first Al2O3 layer is deposited. We also observe persistent surface methyl groups in the H2O half-cycle during ALD, and the amount of the persistent methyls is particularly higher during the initial Al2O3 ALD growth, which suggests the formation of Si−CH3 on the surface. These findings can provide useful routes and insights toward interface engineering by ALD.

Molecular Structure, Dynamics, and Vibrational Spectroscopy of the Acetylene:Ammonia (1:1) Plastic Co-Crystal at Titan Conditions

The Saturnian moon Titan has a thick, organic-rich atmosphere, and condensed phases of small organic molecules are anticipated to be stable on its surface. Of particular importance are crystalline phases of organics, known as cryominerals, which can play important roles in surface chemistry and geological processes on Titan. Many of these cryominerals could exhibit rich phase behavior, especially multicomponent cryominerals whose component molecules have multiple solid phases. One such cryomineral is the acetylene:ammonia (1:1) co-crystal, and here we use density functional theory-based ab initio molecular dynamics simulations to quantify its structure and dynamics at Titan conditions. We show that the acetylene:ammonia (1:1) co-crystal is a plastic co-crystal (or rotator phase) at Titan conditions because the ammonia molecules are orientationally disordered. Moreover, the ammonia molecules within this co-crystal rotate on picosecond time scales, and this rotation is accompanied by the breakage and reformation of hydrogen bonds between the ammonia hydrogens and the π-system of acetylene. The robustness of our predictions is supported by comparing the predictions of two density functional approximations at different levels of theory, as well as through the prediction of infrared and Raman spectra that agree well with experimental measurements. We anticipate that these results will aid in understanding geochemistry on the surface of Titan.

(Electro)Chemical Processes of Poly(Ethylene Oxide)‐Based Electrolyte on Cu Surface during Lithium Secondary Battery Operation

Understanding the surface electrochemistry of polymer electrolytes under battery operating conditions is of great importance for tuning the solid electrolyte interphase (SEI) in lithium batteries with polymer electrolytes. Herein, the surface (electro)chemical process of poly(ethylene oxide) (PEO) lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) (PEO10LiTFSA) electrolyte on the Cu electrode is studied by operando attenuated total reflection infrared (ATR‐IR) and ex situ X‐ray photoelectron spectroscopy (XPS) techniques coupled with the interfacial resistance obtained from electrochemical impedance spectroscopy (EIS). Linear sweep voltammogram of the Cu electrode in PEO10LiTFSA electrolyte suggests the SEI‐like layer formation involves three reduction steps. Operando ATR‐IR, ex situ XPS, and EIS reveal the corresponding (electro)chemical processes and their effect on the interfacial resistance; LiTFSA and residual H2O and CO2 are first reduced, forming an inorganic SEI‐like layer without affecting the interfacial resistance. Subsequently, the PEO matrix reduces into several decomposed products, including CC components, responsible for the most resistive SEI‐like layer. Finally, PEO‐decomposed species with CC components further reduce into alkyl‐related species, leading significant reduction of the resistance of the SEI‐like layer. The study successfully reveals the complex surface (electro)chemical process at the PEO electrolyte–Cu electrode interface, and may serve as a model system for understanding SEI component and interfacial resistance relationship in the polymer electrolyte system.

Understanding surface chemical processes in perovskite oxide electrodes

Significantly different surface chemical compositions in SOCs are correlated with the dynamic mass transport phenomena such as Sr segregation, Cr evaporation and redeposition and linked with the material's oxygen transport properties.

Upscaling of mass and heat transport applied to reactive packing catalytic porous media

In various intensified processes, the presence of reactive catalytic packing is essential. These can be visualized as multiscale systems where a diverse mass, energy transfer, and chemical reaction occurs in the catalytic porous medium (i.e., the catalyst layer). This reactive microscopic scale structure influences efficiency. Given the hierarchical nature of the packing in the intensification systems, this paper proposes the derivation of an upscaled model that describes the first-order surface chemical reaction process in this catalyst layer. The upscaling is carried out using the volume averaging theory. The resulting model includes effective coefficients which depend on the transport and reaction parameters influenced by the unit cell geometry. The model is validated by comparing average temperature and concentration profiles obtained from numerical experiments using pore representations of a catalyst packing. The results show the effective parameters that can be used to design catalytic structures in the intensified process.

Model Predictions of Wave Overwash Extent Into the Marginal Ice Zone

AbstractIn the marginal ice zone (MIZ), where ocean waves and sea ice interact, waves can produce flows of water across ice floe surfaces in a process known as wave overwash. Overwash potentially influences wave propagation characteristics, floe thermodynamics, and floe surface biological and chemical processes. However, the extent of the MIZ affected by overwash and its dependence on prevailing wave and ice conditions is unknown. In this paper, we propose a model of overwash extent caused by irregular incoming waves into a MIZ consisting of a random floe field. We validate the overwash extent model against laboratory experiments. We use the model to study mild to extreme incoming waves to floe field characteristics of the spring–summer ice retreat and autumn–winter ice advance and with compact ice edges. Overwash is typically predicted to extend a few kilometers and is generally greater for the autumn–winter advance than the spring–summer retreat. The model predictions provide a basis for improved understanding of the impacts of ocean waves on the ice cover. We also apply the model to incoming waves and a floe field with a diffuse ice edge representative of conditions during a field experiment, predicting overwash extents up to 16 km. During the field experiment, the wave and ice floe properties were intermittently monitored by a camera system, demonstrating how the sparse field data available on overwash can be advanced.

Effects of the hardness and roughness on the plastic deformation properties of electroplated gold bumps during thermocompression bonding

Within the scope of this work, an optimization approach of existing investigations on electroplated hard gold contacts is to be developed, which have an initial Vickers hardness of 103 HV. These investigations envisage the height-controlled bonding of structures in the multichip integration of optical components. The investigations relate to the influence of material hardness and roughness on the plastic deformation behaviour during bond formation by thermocompression bonding (TCB). Furthermore, pre-treatments such as mechanical surface planarization and chemical surface activation using atmospheric pressure plasma are employed prior to the bonding process to enable the reduction of the bonding parameters pressure and temperature and consequently contribute to control the plastic deformation during thermocompression and reduce the typical plastic deformation range of 30 % to a deformation range below 5 %. The previous investigations were performed on gold contacts, which have been thermally annealed prior to the bonding process and resulted in a plastic deformation range up to 30 %. With the new approach, i.e. throughout the material hardening and altering the surface condition, a plastic deformation range below 3 % was successfully obtained. The attainable bonding temperatures and bonding pressures were between 190 °C–250 °C and 145 MPa–230 MPa, respectively. The bonding time varied between 30 s and 60 s.