TiN Surface Research Articles

Effect of Pulse Electrodeposition Mode on Microstructures and Properties of Ni-TiN Composite Coatings

Mild steel is a kind of material commonly used in the chemical industry and to manufacture machinery, farm tools, and other parts in order to improve the surface performance of the parts and prolong their service life. The Ni-TiN composite coating was fabricated through ultrasonic electroplating using a Ni-based sulfamic acid bath with added nano-TiN particles. The effects of three distinct current modes, direct current (DC), positive pulse current (PC), and positive–negative pulse current (PNPC), on various aspects of the coating, including surface morphology, TiN content and distribution, interface bonding strength, microhardness, friction and wear properties, as well as corrosion resistance, were investigated. The findings demonstrated that, in comparison to DC electroplating, PC electrodeposited Ni-TiN composite coatings yielded finer grains, smoother surfaces, reduced surface cracks, increased interface bonding strength, and enhanced corrosion resistance. Furthermore, PNPC electrodeposited Ni-TiN composite coatings showed higher interface bonding strength than those of PC electrodeposited Ni-TiN coatings and had the densest structure, leading to the best corrosion resistance. Pulse current electroplating enhanced the incorporation of nano-TiN particles, with a higher deposition rate observed in positive–negative pulse current electroplating compared to positive pulse current electroplating. Furthermore, the PNPC electrodeposited coating displayed improved microhardness and demonstrated the best friction and wear properties, while the DC electroplated coating displayed the least favorable performance in these aspects.

Study on the Adsorption Behavior and Pitting Mechanism of Nb and S on the TiN Surface in High-Strength Anti-seismic Rebar

Study on the Adsorption Behavior and Pitting Mechanism of Nb and S on the TiN Surface in High-Strength Anti-seismic Rebar

Carbon nanotube heat absorber for efficient direct-heating of liquid tin in a solar receiver

A new approach that use vertically-aligned carbon nanotubes (VACNT) as heat absorbers is proposed for efficient direct solar heating of liquid tin in a solar receiver integrated with beam-down optics. Plate-type CNT heat absorbers were prepared by adjusting the concentration of CNTs in the processing solvent m-cresol. The prepared CNT absorber exhibited an increase in bulk density and the formation of a densely packed nanotubes skeleton with a higher CNT concentration in m-cresol. Thermal conductivity, a key design factor for solar absorbers, showed a stronger correlation with skeletal density than with bulk density. Heat absorption characteristics of the solar liquid tin receiver (50 mm-i.d., 60 mm-high) with the CNT absorbers integrated with a Fresnel lens (0.98 m i.d.) were determined. The tin temperature in the receiver with the CNT absorber reached a maximum of 728 °C. Bare tin exhibited system efficiency of 27.7 % and receiver efficiency of 38.3 %, but tin heating through the CNT plates exhibited system efficiency of up to 48.4 % and receiver efficiency of 64.3 %, showing a system heat absorption rate 1.75 times higher. The thermal absorption efficiency was proportional to the skeletal density of the plates, and the thermal absorption of the system was dominated by the efficient transfer of absorbed heat in the energy absorption region. The energy flow and heat loss in the receiver system were analyzed. Although the bare tin receiver exhibited a high heat loss of 27.1 % owing to the low emissivity or high reflectivity of the tin surface, the heat loss in the CNT absorber plates with high absorptivity was only 0.9 %. The flat plate-shaped transmission window in the receiver caused significant reflective heat loss and convective heat loss owing to head-on wind. Based on the energy flow analysis, improvement approaches for enhancing the thermal efficiency of the proposed receiver system are suggested.

Ejection of molten tin in the presence of a hydrogen plasma

One of the significant obstacles left if the development of a fusion power plant is the development of Plasma Facing Components (PFCs) that can withstand the large heat and particle flux incident on the first wall and divertor region. As solid PFCs struggle with microstructure growth, sputtering and melting, liquid metals have been a popular potential replacement. Liquid metal's use as a PFC has been increasing due to its ability to self-repair damage as well as pump lost fuel and waste particles to create a low recycling edge. Currently, tin, lithium and lithium eutectics are the commonly considered liquid metals for use as a fusion PFC. It is therefore important to research the Plasma Material Interaction (PMI) between a hydrogen plasma and the liquid metal PFC candidates. This work, conducted at the Center for Plasma Material Interaction (CPMI), investigated how a molten tin surface reacts when exposed to a hydrogen plasma, building off observations by ASML of particles being ejected from a molten tin surface in the presence of a hydrogen plasma. With the ejection of tin affecting ASML's systems as well, since ejected tin can travel around their systems and cause contamination of equipment or wafers that can be destructive to the lithography process. So, for this work, molten tin was exposed to a hydrogen plasma, of varying electron densities and temperatures, and any ejected particles were collected on a witness plate to determine the particle sizes, angular distribution and mass flux. This work found the ejected tin particles range in size from 10′s ofnms to 10′s of microns and that the mass flux of tin from the molten surface is in the 10′s of mgm2*s, increasing with increased atomic hydrogen flux to the molten tin surface. Showing macroscopic amounts of molten tin are ejected in the presence of a hydrogen plasma, therefore showing tin may not be a suitable fusion PFC material.

First-Principles computation-driven mechanism study of tungsten growth on alumina surfaces with TiN nano-islands

Strong comprehension of the tungsten film deposition process on Al2O3 substrate with TiN adhesion layer is essential to achieve high quality metal gate, but the fundamental mechanism of this process is yet to be fully understood. This study employs first-principles density functional theory (DFT) calculations to explore the mechanisms of tungsten film growth on alumina surfaces while focusing on amorphous/α-Al2O3 and interfaces with TiN nano-islands. Tungsten atoms are strongly bonded on the Al2O3/TiN interface compared to their bonding on the Al2O3 or TiN surface, regardless of the crystallinity of Al2O3. Moreover, amorphous Al2O3 surfaces exhibit stronger adsorption energies and present higher diffusion barriers for tungsten atoms compared to their crystalline counterparts, α-Al2O3, and TiN surfaces, which were also confirmed by electronic structure analysis. This enhanced adhesion on amorphous substrates suggests a potential pathway through which improve the step coverage and uniformity of tungsten thin films while addressing common issues such as void formation and non-uniform layering in high-aspect-ratio structures. Post-deposition annealing can help create crystalline tungsten films with superior conductivity. The insights gained from this work offer a computational perspective on the atomic-level interactions governing tungsten deposition, and they are expected to help producing high-quality thin films in semiconductor technologies.

Modelowanie cyfrowe w celu przewidywania zagrożenia osuwania się gruntu na wybranym obszarze; Przypadek testowy Ponzano (Włochy)

Creating a digital model is one of the aims of the geotechnical engineers, to predict the land sliding hazard which occur in different regions in the world. In February 2017, an extensive landslide occurred in the hamlet of Ponzano as a sloped area in the Abruzzo region in Italy. In this regard, predicting the land sliding hazard is one of the important issues to prevent hazard to the civilizations. In this project we created a model in the 3D dimension through the Plaxis 3D numerical solution software from the data based of the region Abruzzo in 2007 to evaluate the land sliding hazard before happened and then compare the results with the data from the drone data surveyed recently in the 2022. In this regard, the data from the Abruzzo resources from 2007 imported into the QGIS as the open-source cross-platform software to analysis the geospatial data and then imported into the Recap software to work on the point cloud data and then imported into the Civil 3D software to create a solid surface from the TIN surface and finally since the solid surface contains a large number of irrelative details, they were imported into the Rhinoceros software to create a NURBS surface to be smoothed for better performance in the analysis. The NURBS surface imported into the Plaxis and all of the geometry and geotechnical engineering parameters by considering the investigated geotechnical survey that was conducted in parallel in the area, defined for the model. The “Hardening Soil” model considered for the 1st layer as the “clay and lime” and the “Hoek-Brown” model defined for the 2nd layer as the “marl-flysch”. A fine mesh elements distribution assessed also for the model. The phases defined as the “gravity” to define the unit weight of the soil layers, the “plastic” phase to calculate the instant deformations and the “consolidation” to analyze the plastic deformations in the sloped area of the model. In parallel, the drone data achieved in 2022, were imported into the CloudCompare as the 3D point cloud processing software and different methods such as the “segment”, “statistical outlier Filter”, “CSF filter”, “noise filter”, “cross section” etc. were performed to clean the data and then imported into the Recap software to work on data and then imported into the Civil 3D software to create solid surface of the current data after the land sliding. In this regard, to evaluate the displacement occurred from the year 2007 toward the 2022, a TIN volume surface as the colored map created through the Civil 3D software to show the displacements in the z direction and all of the results were compared with the Plaxis 3D numerical solution software. The results showed that the colored map with the displacement in the positive and negative direction of the z is the same of the analyzed model and the values match each other’s and we created a digital model of the selected area to predict the land sliding hazard in the region in the following.

Stabilization of liquid tin surfaces under D plasma irradiation by a capillary porous system

Liquid metal divertors are discussed as a potential alternative to divertor components made entirely of solid materials such as tungsten. However, liquid metal interaction with H isotope plasmas poses entirely new challenges, including the stability of the liquid surface. In this article, the interaction of low-temperature D plasmas with both free liquid tin surfaces, and the liquid metal confined in a capillary porous system (CPS) is presented. Free surfaces showed intolerable instabilities due to formation of gas bubbles in the melt, as opposed to a strong stabilizing effect of the CPS. A tendency of liquid tin to well up and entirely cover the surface of the CPS may be beneficial in terms of quickly re-establishing a tin surface after depletion by transient overloading. On the other hand, this appears to counteract efforts to fully suppress superficial bubble formation and bursting, and the resulting ejection of tin droplets by designing a CPS with very small pores.

Resilient Growth of a Highly Crystalline Topological Insulator-Superconductor Heterostructure Enabled by an Ex Situ Nitride Film.

Highly crystalline and easily feasible topological insulator-superconductor (TI-SC) heterostructures are crucial for the development of practical topological qubit devices. The optimal superconducting layer for TI-SC heterostructures should be highly resilient against external contamination and structurally compatible with TIs. In this study, we provide a solution to this challenge by showcasing the growth of a highly crystalline TI-SC heterostructure using refractory TiN (111) as the superconducting layer. This approach can eliminate the need for in situ cleavage or growth. More importantly, the TiN surface shows high resilience against contaminations during air exposure, as demonstrated by the successful recyclable growth of Bi2Se3. Our findings indicate that TI-SC heterostructures based on nitride films are compatible with device fabrication techniques, paving the way to the realization of practical topological qubit devices in the future.

Insights into Electrochemical CO2 Reduction on Metallic and Oxidized Tin Using Grand-Canonical DFT and In Situ ATR-SEIRA Spectroscopy.

Electrochemical CO2 reduction (CO2R) to formate is an attractive carbon emissions mitigation strategy due to the existing market and attractive price for formic acid. Tin is an effective electrocatalyst for CO2R to formate, but the underlying reaction mechanism and whether the active phase of tin is metallic or oxidized during reduction is openly debated. In this report, we used grand-canonical density functional theory and attenuated total reflection surface-enhanced infrared absorption spectroscopy to identify differences in the vibrational signatures of surface species during CO2R on fully metallic and oxidized tin surfaces. Our results show that CO2R is feasible on both metallic and oxidized tin. We propose that the key difference between each surface termination is that CO2R catalyzed by metallic tin surfaces is limited by the electrochemical activation of CO2, whereas CO2R catalyzed by oxidized tin surfaces is limited by the slow reductive desorption of formate. While the exact degree of oxidation of tin surfaces during CO2R is unlikely to be either fully metallic or fully oxidized, this study highlights the limiting behavior of these two surfaces and lays out the key features of each that our results predict will promote rapid CO2R catalysis. Additionally, we highlight the power of integrating high-fidelity quantum mechanical modeling and spectroscopic measurements to elucidate intricate electrocatalytic reaction pathways.

Influence of electrodeposition parameters on the fabrication of Ni–Co/SiC + TiN composite films through pulse current electrodeposition

In this investigation, pulsed current electro-deposition (PCE) was used to prefabricate Ni–Co/SiC + TiN composite coatings (NCSTCCs) on mild steel surfaces. The research focused on the influence of two electrodeposition parameters, pulse frequency (PF) and duty cycle (DC), on NCSTCF features including microscopic surface morphology, crystal orientation, grain size, microhardness, SiC and TiN nanoparticles (NPs), deposition quantity, and corrosion resistance properties. The results indicated that NCSTCCs produced under a 10% DC showed minimal SiC and TiN contents with a percent volume of just 5.6 v/v% and 5.4 v/v% respectively under the fixed condition of 60 Hz PF. However, the three-dimensional surface diagram indicated that the Ni–Co/SiC + TiN composite film deposited at 50% DC and 10 Hz PF displayed the highest SiC and TiN contents (11.6 v/v% and 11.7 v/v%) among all the films. Furthermore, NCSTCCs deposited under 50% DC and 10 Hz PF had peak microhardness at 667.4 kg/mm2, while the composite film achieved a microhardness of 514.1 kg/mm2 when prepared using 10% DC and 60 Hz PF. Moreover, when the DC and PF were at 50% and 10 Hz respectively, the Ni–Co/SiC + TiN composite film presented the maximum charge transfer resistance (4915.7–4927.2 Ω·cm2), indicating an excellent corrosion resistance.

Deformation mechanism of soft metal tin in micro machining

The deformation mechanism in the micro machining of soft metal tin significantly influences its machined surface quality. In this work, microscratching tests along different orientations are performed on the tin surface. Activation of slip systems induces the appearance of surface slip band, lattice rotation and stable cutting force. The crucial role of loading orientation in slip system activation and lattice rotation is investigated. The misorientation around 62° is detected in the region of the activated slip band, whereas the misorientation angle of the other deformation region is less than 15°. In addition, a part of the lattice rotation would be recovered to original orientation along with time.

Highly area-selective atomic layer deposition of device-quality Hf1-xZrxO2 thin films through catalytic local activation

Area-selective atomic layer deposition (AS-ALD) has garnered significant attention as a promising bottom-up patterning process for sub-10 nm scale technology, offering unmatched atomic-scale precision and pattern alignment capabilities in 3D nanofabrication. In this study, we present a groundbreaking methodology for achieving highly selective deposition of Hf1-xZrxO2 (HZO) thin films through catalytic local activation on noble metal surfaces (Ru and Pt) and TiN surfaces, without the need for surface inhibitory materials. To achieve inherent selectivity on metal surfaces, we employ O2 gas as a mildly oxidizing reactant and utilize cyclopentadienyl-tris(dimethylamido)-hafnium(zirconium) [Hf(Zr)Cp(NMe2)3] precursors, which require strong oxidizing agents, for HZO film formation. By catalytically dissociating O2 molecules, we successfully achieved area-selective deposition of HZO films greater than ∼7 nm on both blanket Ru versus Si substrates and Pt/Si-patterned substrates. Furthermore, we demonstrate the selective deposition of antiferroelectric HZO thin films with high dielectric constants of 34 and 31 on Ru and TiN substrates, respectively, using the inherent AS-ALD method combined with post-ozone treatment. Importantly, this catalytic local activation approach for achieving inherent deposition selectivity expands the potential utility of 3D bottom-up nanopatterning processes in next-generation nanoelectronic applications.

Self-isolating electrode deposition process using the area-selective MoO2 and MoO3 atomic layer deposition technique

The traditional patterning process for semiconductor devices typically involves multiple steps, including thin film deposition across the entire substrate, selective removal of unwanted regions through lithography and etching, and subsequent isolation. While area-selective deposition process has been employed to eliminate the need for lithography and etching, the isolation step remains essential. In this study, we suggest an innovative approach to achieve “self-isolation electrode formation” using MoO2 and MoO3 as electrode and inter-metallic insulator materials. In a single deposition batch and subsequent post-deposition annealing (PDA) process, deposited MoOx (x: 2∼3) thin films exhibited transformation into highly crystalline MoO2 and MoO3 with low crystallinity, depending on whether they were deposited on TiN or SiO2 surfaces. We conducted comprehensive analyses, including chemical and electrical characterizations, as well as first-principles calculations based on density-functional theory, to elucidate the underlying mechanisms responsible for the differential reduction and crystallization of MoOx thin films. Finally, we successfully demonstrated the formation of self-isolation electrodes within a vertical structure, accomplished through a single-step process involving MoOx deposition and subsequent PDA. This novel approach, built upon advanced area-selective deposition techniques, holds great promise for the development of state-of-the-art semiconductor devices.

DIAGNOSTICS OF INSTRUMENTAL MATERIALS BASED ON THE RESULTS OF MODELING OF COATINGS OF INSTRUMENTAL MATERIAL

Computer modeling makes it possible to predict the adhesion properties of various materials and monolayers in the material at the atomic level. As a result of this approach, it is possible to diagnose the operational properties of the tool material according to the calculated values of the adhesion energy of the layers in the tool coating. The issues of studying the adhesive properties of monolayers successively deposited on a hard alloy VK8 are considered. The adhesive properties of Ti, TiN and (Ti, Cr, Al)N layers with each other and with WC92-Co8 hard alloy are investigated. The dependence of the adhesion energy of titanium to WC and Co surfaces depending on the thickness (from one to three atomic layers) of the deposited titanium layer has been studied. For four variants of the compound structure (Ti, Cr, Al)N the adhesion energy of this compound to the TiN surface is calculated. An approach to predicting rational coatings has been developed. It consists in the calculation (control) of the adhesion energy and the use of the adhesion energy value to diagnose a rational coating option for an instrumental hard alloy VK8.

First-principles study of F adsorption by TiN with its oxide surface in three-dimensional NAND flash memory

Three-dimensional (3D) NAND flash memory is a key technology in the field of mainstream memory solutions, which is primarily due to its extremely low bit cost. The architecture of 3D NAND, characterized by its vertically stacked design, substantially enhances the capacity of individual chips. This advancement is completely consistent with the demands for high-capacity data storage in contemporary environments, securing its widespread adoption in diverse application scenarios. As storage density increases, the complexity of process integration increases, bringing new challenges. The word lines in 3D NAND are typically filled by using gate replacement techniques, and compared with chemical vapor deposition (CVD), atomic layer deposition (ALD) is favored for its superior step-coverage, especially for depositing tungsten (W) at the gate. However, due to the complexity of the replacement gate deposition structure, fluorine (F) residues are found in the voids of the tungsten metal gate filling structure and diffuse into the surrounding structure under subsequent process conditions, corroding other films such as silicon oxide and degrading device performance and reliability. To alleviate the problem of fluorine attack, a thin layer of titanium nitride is usually deposited as a barrier layer before deposition of tungsten gate, which blocks the fluorine in the tungsten gate and prevents its diffusion into the oxide layer. Previously, there were studies to increase the ability to stop F diffusion by varying the thickness of the F blocking layer (TiN). However, increasing the thickness of TiN will further increase the complexity of high aspect ratio etching in the 3D NAND process, which will have adverse effect on subsequent processes. To further minimize the effect of fluorine erosion, residual fluorine elements can be removed by introducing annealing in the subsequent process flow. In the actual 3D NAND process, elemental fluorine (F) is adsorbed and accumulates on the TiN surface, and is further activated by subsequent high-temperature processes, leading to severe fluorine erosion. The delay between TiN deposition and subsequent processing steps is hypothesized to facilitate fluorine adsorption due to the oxidation of TiN. This work corroborates this hypothesis through first-principles calculations, and demonstrates the role of TiN oxidation in fluorine adsorption. In this work, we evaluate the effect of this oxidation on the fluorine-blocking effectiveness of the TiN barrier layer. We simulate the adsorption of fluorine-containing by-products on TiN and its oxides, providing theoretical insights into mitigating fluorine attack. The higher degree of oxidation of TiN is more likely to cause F adsorption, and Ti exposed surface TiN is more prone to oxidation, which is more likely to cause F adsorption in unoxidized condition and oxidized condition. Based on these insights, we implemente an ammonia purge treatment in 3D NAND manufacturing, which effectively minimizes fluorine attack, reducing the leakage probability of word line by 25% and wafer warpage by 43%.

Nanometric cutting of plasma modified polycrystalline tin

Soft and low-melting-point polycrystalline tin holds considerable promise in the field of advanced lithography. However, its machinability is significantly hindered by the grain size, posing substantial limitations on its practical utility. Herein, a novel approach involving oxidation-enhanced plasma modification is presented to obtain a grain coarsening layer, thereby enhancing machinability. The effects of cutting mode and feed rate are examined, revealing that plasma modification results in the formation of a millimeter-scale grain coarsening layer. Consequently, the tin surface with a surface roughness of 0.98 nm in Sa after cutting is effectively achieved, benefiting applications in ultra-short light wavelength sources.

In-Situ Reflectance Absorption Infra-Red Spectroscopy (RAIRS) Study on ALD of HfO2 on TiN and Pt Electrodes

Ferroelectricity in hafnia fluoride analogues has been widely investigated for nonvolatile memory applications. Although ALD of HfO2 technology is enough mature for CMOS technology, hafnia-based ferroelectrics still suffer from major reliability issues such as relaxation, imprint, fatigue, and breakdown.1 These reliability characteristics are thought to be related to the interface conditions between the ferroelectric film and the electrode. Thus, many reports suggested routes to enhance reliability and ferroelectric characteristics by modifying the interface states of the metal-ferroelectric-metal (MFM) capacitors. Unfortunately, only few reports disclose direct observation on evolution of interface formation and its mechanism. Recently, it is reported that scaling down the ferroelectric hafnia-based films to a few nm range dramatically improves the MFM capacitors’ reliability where the series capacitance and surface effect dominate, making it crucial to understand the interface properties carefully.2 In this presentation, we perform In-situ characterization using reflectance absorption infrared spectroscopy (RAIRS) to monitor the surface reaction and interface formation while HfOx ALD using TDMA-Hf with various oxidation reactants, such as H2O, O3, and anhydrous H2O2. TiN and Pt bottom electrodes are investigated at 250 °C. The RAIRS results show that the initial exposure of the oxidant generates the most amount of oxidation on the TiN surface by showing Ti-O and TiN-O peaks which were not observed for the Pt substrate. Moreover, the Ti-O and TiN-O peak area increase versus the dosing time of oxidant was minimum for H2O, and O3 showed continuous peak increase even after 12 s exposure. Interestingly, for the H2O2 case, there was almost no peak increase in the Ti-O bond region like H2O, but the TiN-O and TiO-O peaks appeared after the first 3 s and saturated after 6 s exposure. Also, not only on the TiN substrate, the peak for O-O stretching was observed for the Pt substrate as well, indicating that the H2O2 generates self-limiting peroxide bonds on the surface with a minimum interface formation. This suppressed interface formation with superior film properties using H2O2 might be the reason behind the robust reliability of the H2O2-based HZO capacitor. We are going to report reliability characteristics in conjunction with interface evolution.Acknowledements: We thank to YEST and KEIT for supporting the project through ISTD Program (No.20010806). This work is also supported by GRC-LMD program (task#3001.001) through SRC. The BRUTE hydrogen peroxide was provided by RASIRC. Ozone generator for TMEICReferences 1 J. Mohan et al., ACS AELM, 4, 4 (2022). 2 K. Toprasertpong et al., ACS AMI, 14 (2022).

Hydroxyl-Bonded Ru on Metallic TiN Surface Catalyzing CO2 Reduction with H2O by Infrared Light.

Synchronized conversion of CO2 and H2O into hydrocarbons and oxygen via infrared-ignited photocatalysis remains a challenge. Herein, the hydroxyl-coordinated single-site Ru is anchored precisely on the metallic TiN surface by a NaBH4/NaOH reforming method to construct an infrared-responsive HO-Ru/TiN photocatalyst. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (ac-HAADF-STEM) and X-ray absorption spectroscopy (XAS) confirm the atomic distribution of the Ru species. XAS and density functional theory (DFT) calculations unveil the formation of surface HO-RuN5-Ti Lewis pair sites, which achieves efficient CO2 polarization/activation via dual coordination with the C and O atoms of CO2 on HO-Ru/TiN. Also, implanting the Ru species on the TiN surface powerfully boosts the separation and transfer of photoinduced charges. Under infrared irradiation, the HO-Ru/TiN catalyst shows a superior CO2-to-CO transformation activity coupled with H2O oxidation to release O2, and the CO2 reduction rate can further be promoted by about 3-fold under simulated sunlight. With the key reaction intermediates determined by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and predicted by DFT simulations, a possible photoredox mechanism of the CO2 reduction system is proposed.

The effect of Ti-based surface layer on AlSi thin film as a high-performance anode for the lithium-ion battery

Significant volume changes during cycling and the instability of the solid electrolyte interphase (SEI) are the main challenges that limit the practical application of silicon-based anodes. TiN and TiO2 were selected as surface layers and deposited on the HCl-etched AlSi (AlSi’) thin films by atomic layer deposition (ALD) to enhance the electrochemical performance of the anode. The surface layers with excellent mechanical strength can effectively suppress the volume expansion of the AlSi thin film and maintain excellent electrical contact between the film and the substrate during cycling. The effects of TiN and TiO2 surface layers on the composition and growth of the SEI layer on the AlSi’ film anode have been discussed in detail. The TiO2 surface layer was found to inhibit the continuous growth of the SEI layer and promote the formation of a mechanically robust and stable SEI layer. The AlSi’/TiO2(8 nm) anode shows a high initial discharge capacity of 2802 mA h g-1 with an initial coulomb efficiency (ICE) of 88% at 0.8 A g-1, and it maintains a capacity retention rate of 83% after 500 cycles. Moreover, the AlSi’/TiO2(8 nm) anode exhibits outstanding rate performance, as it sustains a capacity of 1710 mA h g-1 after 500 cycles at 5 A g-1, and maintains a capacity above 1032 mA h g-1 even at 30 A g-1.

The dominant role of surface chemistry on coking resistance of passivating coating

Passivation coatings with excellent coking inhibition performance play an important role in active cooling technology and ethylene cracking furnace. However, different coating types possess different coking resistance, and the dominant factor remains unclear. Herein, a novel strategy of isolative analysis for coke in coating underwent RP-3 supercritical cracking is proposed to account for the role of carburization and surface chemistry. The carburization amount of TiN coating after cracking experiment was obtained from the model constructed by artificial carburization of standard TiN-coated samples. Introduced TiN/SiO2 coating owned different surface chemistry contrast to the TiN coating, additive of density-functional-theory calculations to reveal the correlation between surface chemistry and coke amount. The results indicated that carburization contributed little to the total coke amount of TiN coating, and non-negligibly, the coke diffused rapidly along the grain boundaries, threatened the integrity of coating. More importantly, the main coke belonged to the part that adhered to the coating surface. The strongly adsorbed 3d-4σ*/2π*bonded coking precursors (C2H2), were presented on the TiN surface, while the great flexibility of amorphous SiO2 made it non-adsorbent to C2H2, leading to weak coke adhesion on the TiN/SiO2 surface and strongly adherent coke on TiN surface. These results reveal that surface chemistry influenced coke adhesion and dominated coking resistance of coating.