Hot Substrate Research Articles

Spontaneous Takeoff of Single Sulfur Nanoparticles during Sublimation Studied by Dark-Field Microscopy.

The Leidenfrost effect describes a fascinating phenomenon in which a liquid droplet, when deposited onto a very hot substrate, will levitate on its own vapor layer and undergo frictionless movements. Driven by the significant implications for heat transfer engineering and drag reduction, intensive efforts have been made to understand, manipulate, and utilize the Leidenfrost effect on macrosized objects with a typical size of millimeters. The Leidenfrost effect of nanosized objects, however, remains unexplored. Herein, we report on an unprecedented Leidenfrost effect of single nanosized sulfur particles at room temperature. It was discovered when advanced dark-field optical microscopy was employed to monitor the dynamic sublimation process of single sulfur nanoparticles sitting on a flat substrate. Despite the phenomenological similarity, including the vapor-cushion-induced levitation and the extended lifetime, the Leidenfrost effect at the nanoscale exhibited two extraordinary features that were obviously distinct from its macroscopic counterpart. First, there was a critical size below which single sulfur nanoparticles began to levitate. Second, levitation occurred in the absence of the temperature difference between the nanoparticle and the substrate, which was barely possible for macroscopic objects and underscored the value of bridging the gap connecting the Leidenfrost effect and nanoscience. The sublimation-triggered spontaneous takeoff of single sulfur nanoparticles shed new light on its further applications, such as nanoflight.

Toe-biting in captive Pogona vitticeps

In this note, we describe the rare behaviour of toe-biting observed in captive Pogona vitticeps. This behaviour occurred in individually-housed lizards in both juveniles and adults, and in rare instances, resulted in the loss of several toes. Toe-biting was associated with loose substrates, hot substrates, and periods of ecdysis. In form, this behaviour is similar to grooming behaviours noted in other lizards. However, the function of toe-biting is difficult to discern, as it is not consistently related to any particular stimulus, occurs rarely and quickly, and occasionally resulted in significant injury. We therefore suggest that toe-biting may function to clean the back toes, but may also have no function or be caused by internal stressors.

Impact of a suspension drop onto a hot substrate: diminution of splash and prevention of film boiling.

In the present study, the effect of graphite lubricant additives on the dynamics of a single drop impact onto a heated surface has been investigated in the nucleate boiling and thermal atomization regimes. In the nucleate boiling regime the drop impact is accompanied by the nucleation and expansion of multiple vapor bubbles. The drop residence time at the substrate is determined by the time of its mass loss due to splash and evaporation. At higher temperatures, above the Leidenfrost point, impact may lead to drop rebound. In this experimental and theoretical study the effect of additives on the outcome of drop impact, in particular, the addition of solid graphite particles, is investigated. The residence time of the drop has been measured for various initial drop temperatures and suspension concentrations. The addition of the particles leads to some increase of the residence time, while its dependence on the substrate temperature follows the scaling relation obtained in the theory. Moreover, the presence of the particles in the drop leads to suppression of splash and a significant increase of the drop rebound temperature, which is often associated with the Leidenfrost point. These effects are caused by the properties of the deposited layer, and pinning of the contact line of the entire drop and of each vapor bubble, preventing bubble coalescence and drop rebound. The phenomena are also explained by a significant increase of the liquid viscosity caused by the evaporation of the bulk liquid at high wall temperatures.

Marangoni effect of surfactant droplet in transition boiling and formation of secondary droplet

The dynamic processes of surfactant droplets impacting onto substrates of varied temperatures have been widely studied in heat transfer, cooling and printing. In this work, we observe the impacting process of aqueous droplets of surfactants SDS, CTAB, and Triton X-100 on a hot aluminum plate via a high-speed camera, in order to study the dynamics of different surfactant droplets impacting on a hot aluminum substrate. Experimentally, it is discovered that the surfactant droplets in transition boiling produce a secondary droplet of non-wetting state in the final stage of evaporation. The analysis demonstrates that after the droplet impacts the substrate, a temperature gradient is created between the top of the droplet and the triple-phase contact line, increasing the surfactant concentration near the triple-phase contact line as compared with that of the top. The top liquid is maintained by the Marangoni effect, which is caused by the concentration gradient. In the final stage of the evaporation process, the residual droplet gradually shrinks into a sphere. It is detached from the substrate and taken off under the impulse force of the bubble explosion at the bottom, generating the secondary droplet. The radius of the secondary drop increases with the raising of initial concentration of the drop, but ultimately reaches the saturation size. This work explains the role of surfactants in forming secondary droplets. Additionally, this work provides a reference for understanding the physical mechanism of Leidenfrost effect and the controlling of boiling heat transmission.

Augmenting the Leidenfrost Temperature of Droplets via Nanobubble Dispersion.

Droplets may rebound/levitate when deposited over a hot substrate (beyond a critical temperature) due to the formation of a stable vapor microcushion between the droplet and the substrate. This is known as the Leidenfrost phenomenon. In this article, we experimentally allow droplets to impact the hot surface with a certain velocity, and the temperature at which droplets show the onset of rebound with minimal spraying is known as the dynamic Leidenfrost temperature (TDL). Here we propose and validate a novel paradigm of augmenting the TDL by employing droplets with stable nanobubbles dispersed in the fluid. In this first-of-its-kind report, we show that the TDL can be delayed significantly by the aid of nanobubble-dispersed droplets. We explore the influence of the impact Weber number (We), the Ohnesorge number (Oh), and the role of nanobubble concentration on the TDL. At a fixed impact velocity, the TDL was noted to increase with the increase in nanobubble concentration and decrease with an increase in impact velocity for a particular nanobubble concentration. Finally, we elucidated the overall boiling behaviors of nanobubble-dispersed fluid droplets with the substrate temperature in the range of 150-400 °C against varied impact We through a detailed phase map. These findings may be useful for further exploration of the use of nanobubble-dispersed fluids in high heat flux and high-temperature-related problems and devices.

Aggregation and Conductivity in Hot-Grown Petroporphyrin Films

As a follow-up to our study on aggregation of metal-etioporphyrin complexes (Colloids Surf. A. Physicochem. Eng. Asp. 2022, 648, 129284), we considered thin films of three isomers of copper(II) etioporphyrin deposited on hot substrates. Despite the almost identical absorption spectra of isomers, their solid-state superstructures differ remarkably both in form and size. The lateral conductivity of films is much less sensitive to an isomer-type, regardless of the substrate temperature. However, the dark conductivity of cold-grown films is about two orders of magnitude higher than that of hot-grown films, whereas the photoconductivity of the latter is 100–1700 times greater, depending on the isomer.

Explosive boiling of water films based on molecular dynamics simulations: Effects of film thickness and substrate temperature

This paper deals with investigations of mechanisms governing explosive boiling of water films on hot copper substrate with plain surface. The investigations are based on results of molecular dynamics (MD) simulations in which film thickness (7.5 nm, 17 nm and 25.5 nm) and substrate temperature (800 K, 700 K and 600 K) are set as parameters. Analyses of heating transients, which lead to explosive boiling event, are done comparing the following quantities for considered MD configurations: time instant of explosive boiling onset, dynamics of vapour generation, increase of water film thickness due to thermal expansion and vapour generation, evolution of water temperature as well as heat transfer from the copper substrate to the water film. These analyses have shown that explosive boiling onset is related neither to the value of substrate temperature nor to the film thickness in a straightforward way. The investigations of temperature and per atom energy in the water region near the heating substrate surface have revealed that beside thermal also mechanical mechanisms can play significant role in triggering of explosive boiling. The mechanical mechanisms, related to pressure wave propagation in liquid film, comprise occurrence of tensile stresses which induce / intensify generation of vapour phase in the near wall region. The obtained results show that thermal effects are dominant in cases with high substrate temperature and thick liquid films as in these configurations the water temperature reaches spinodal value and explosive boiling is triggered before expansion wave reaches the near wall region. In cases when water in the near wall region is strongly overheated (but well below spinodal temperature), tensile stresses induced by expansive wave propagation cause intensive vapour generation and contribute dominantly to occurrence of explosive boiling. Finally, in cases with lower substrate temperature and thin liquid films, an interplay of thermal and mechanical mechanisms leads to explosive boiling. Beside these, the disjoining pressure seems to play a role in cases with thin liquid films.

Significance of SWCNTs and MWCNTs on the dynamics of hybrid nanofluid flow over a stretching surface

In this article, the hybrid nanofluid flow across the hot substrate of a heated sink coated with an open-cell metallic foam is explored to increase the rate of heat transfer. Two sorts of nanoparticles are considered to be specific MWCNT and SWCNT taking water as the base liquid. Tiny particles are examined because of their remarkable properties, such as exceptional thermal conductance, which is important in modern nano-technology, cooling systems, material sciences, and electronic parts. The primary goal of this extensive study is to improve heat transportation. The mathematical equations for the considered flow are the Navier–Stokes equations in the form of the Darcy–Brinkman–Forchheirmer model. Using similarity variables, a system of PDEs is converted into a system of dimensionless ODEs. The subsequent ODEs are settled by utilizing the numerical technique bvp4c in MATLAB. The significant results are presented with the guide of figures and tables. From this analysis, it is observed that the Xue model has a larger heat transport rate than the Yamada–Ota and Tiwari–Das models. Furthermore, the Xue model achieves a higher skin friction coefficient and Nusselt number values than the Yamada–Ota and Tiwari–Das models.

Droplet impact on hot substrates under a uniform electric field

Droplet impact on a hot substrate under an electric field is fundamental and crucial for electrospray cooling. However, the involved thermal–electric coupling impact electrohydrodynamic has not been well understood. In this study, the effects of an electric field on the droplet impact behavior in different thermal regimes and the subsequent dynamic mechanisms were experimentally investigated. The results showed that the vertical electric field would result in an upward liquid ejection in the film evaporation regime. In the nucleate boiling regime, the liquid pinch-off phenomenon was observed. In addition, the droplet evaporation rate was increased by approximately 23% with an electric field of 6 kV/cm. In the film boiling regime, both the residence time and bounce-off droplet height were significantly increased. The various impact phenomena were mainly explained by the competition between electrostatic and capillary pressures. The comprehensive effects of surface free charges and temperature variation on the droplet surface tension coefficient were discussed. Moreover, according to the thermal analysis, the heat transfer in the film boiling regime with an electric field was enhanced by approximately 137%. This work contributed to the development of the droplet impact dynamics under the coupling temperature and electric fields and demonstrated great promise for the electric field for thermal-fluid manipulation.

Influence of Lubricant Addition on Heat Exchange Regimes During Spray Cooling

Spray cooling is used in a variety of industries, including metallurgy, electronics, and medicine. Ease of spray generation, as well as the ability to cool relatively large surfaces or precise regions of interest, are among the key assets. Spray cooling can provide a relatively high heat flux, especially if it is accompanied by liquid evaporation. Additionally, it can be applied not only as a coolant but also as a transport medium for lubricating fluid in specific applications, such as hot die forging. Typically, the working fluid is a multi-component mixture with improved cooling and lubricating properties. Once the bulk liquid evaporates, particles or dissolved lubricant can settle on the hot solid substrate. Existence of components with various physico-chemical properties on the surface (binders, surfactants, dispersed particles, etc.) can significantly affect the spray impact, as well as the outcome of cooling regimes. Nevertheless, the accompanying thermal-hydraulic effects are still not well understood. An experimental facility for observing the impact of the multi-component spray, and characterizing heat transfer was designed for this study at the Institute for Fluid Mechanics and Aerodynamics. As a working fluid, varied mixtures of water and industrial white lubricant were used in different ratios. The visualization of spray impact and identification of the main hydrodynamic regimes were achieved using a high-speed video system. The inverse heat conduction problem was used to calculate the heat flux during continuous cooling from 445°C to 100°C taking into account temperature readings from within the substrate. Since the substrate was entirely insulated on all sides (except on the sprayed surface), the boundary conditions were well defined. The experimental data for pure water drops were compared with the results obtained using lubricating additives. It is discovered that even minimal volumes of lubricant augment the heat flux dramatically, particularly at rather high wall temperatures. The spray cooling process is accompanied by an extensive foaming near the wall and as a result, the Leidenfrost point is moved to a higher temperature, thus suppressing film boiling regime.

Infrared optical properties modulation of VO2 thin film fabricated by ultrafast pulsed laser deposition for thermochromic smart window applications

Over the years, vanadium dioxide, (VO2(M1)), has been extensively utilised to fabricate thermochromic thin films with the focus on using external stimuli, such as heat, to modulate the visible through near-infrared transmittance for energy efficiency of buildings and indoor comfort. It is thus valuable to extend the study of thermochromic materials into the mid-infrared (MIR) wavelengths for applications such as smart radiative devices. On top of this, there are numerous challenges with synthesising pure VO2 (M1) thin films, as most fabrication techniques require the post-annealing of a deposited thin film to convert amorphous VO2 into a crystalline phase. Here, we present a direct method to fabricate thicker VO2(M1) thin films onto hot silica substrates (at substrate temperatures of 400 °C and 700 °C) from vanadium pentoxide (V2O5) precursor material. A high repetition rate (10 kHz) femtosecond laser is used to deposit the V2O5 leading to the formation of VO2 (M1) without any post-annealing steps. Surface morphology, structural properties, and UV–visible optical properties, including optical band gap and complex refractive index, as a function of the substrate temperature, were studied and reported below. The transmission electron microscopic (TEM) and X-ray diffraction studies confirm that VO2 (M1) thin films deposited at 700 °C are dominated by a highly texturized polycrystalline monoclinic crystalline structure. The thermochromic characteristics in the mid-infrared (MIR) at a wavelength range of 2.5–5.0 μm are presented using temperature-dependent transmittance measurements. The first-order phase transition from metal-to-semiconductor and the hysteresis bandwidth of the transition were confirmed to be 64.4 °C and 12.6 °C respectively, for a sample fabricated at 700 °C. Thermo-optical emissivity properties indicate that these VO2 (M1) thin films fabricated with femtosecond laser deposition have strong potential for both radiative thermal management or control via active energy-saving windows for buildings, and satellites and spacecraft.

Temperature-controlled slot-die coating for efficient and stable perovskite solar cells

Currently, the main challenge in the field of perovskite solar cells (PSCs) is to transform lab-scale into industry-related processes for commercialization; however, most of the scalable fabrication has employed many processing treatments, which are incompatible with large-scale mass production. Hence, for the purpose of simple and useful scaled-perovskite film processing, the hot slot-die coating method is presented. This technique releases a hot solution through a hot slot-die head and deposits it onto a hot substrate. The temperature-controlled head and bed can have a significant impact on the perovskite morphology and device performance, and at optimal processing temperatures (head: 75 °C, bed 150 °C), the hot slot-die device shows a high power conversion efficiency (PCE) of 17.05% without other processing treatments. In addition, the optimum condition was employed to fabricate the scaled device, having a comparable PCE of 14.61%, which comes close to the cell efficiency prepared by the spin-coating method. This hot slot-die coating approach can provide a simple and useful way to fabricate the perovskite film to achieve highly efficient and reliable PSCs and acceptable potential for industrial uses.

About the 3D simulation of the boiling of liquid films and spray droplets during their contact with hot substrates

Boiling of liquids upon impact of the spray on heated surfaces is common in many practical applications. However, a comprehensive modelling approach for these phenomena is still not available in commercial software, despite decades of experimental, theoretical, and numerical research efforts. The motivation of this paper is to clarify the state of the art on the three-dimensional (3D) simulation of the boiling of liquid films and spray droplets during their contact with hot substrates. Based on recent experimental and theoretical research, this paper proposes a set of heat transfer models for 3D simulation of spray cooling considering conjugate heat transfer (CHT). These updated models and correlations were implemented in a computational fluid dynamics (CFD) solver, which already included a classical two-phase Lagrangian–Eulerian approach and CHT modelling functionality. A detailed validation of the improved modelling proposals is performed using a unique and novel database including wall surface temperature and heat flux measurements for different flow rates and spray impact velocities. Excellent agreement with experiments was obtained for all boiling regimes using a Leidenfrost-like temperature to manage the prompt heat flux change between the film boiling regime and the transition boiling regime. Most notable are the great results produced by the recent film boiling model summarized in this article.Graphical Abstract

Deposition of metal thin films using a hollow cathode hydrogen discharge

Approximately 30 to 40 years ago the group of Stan Vepřek of the University of Zurich described the fabrication of silicon thin films by formation and decomposition of silicon hydride. In their paper they described how pieces of silicon exposed to a low-pressure hydrogen plasma could promote the formation of a volatile silicon hydride. The hydride was then transported to a hot substrate which caused its thermal decomposition and the formation of the silicon film.Hollow cathodes under appropriate experimental conditions can produce a semi-resonant high-density plasma. In a previous study we used such a high-density hydrogen plasma to etch pieces of quartz but under extreme conditions, we observed that rather than etching there was deposition of a thin film of the metal used for the electrode of the hollow cathode.In this paper we describe the etching of the metal (Mo or Ta) lining of a water-cooled cylindrical hollow cathode by a high-density hydrogen plasma. The metal hydride vapour generate in the plasma by chemical sputtering was directed, by the gas flow, to the quartz substrates which were maintained at various temperatures in excess of 573 K. Here the metal hydride was thermal decomposed, and a thin film of the metal was formed. To improve the experimental reproducibility a special substrate heater was constructed such that four quartz substrates could be simultaneously exposed to the metal hydride vapour, but with each substrate at a different temperature: each approximately 30.3 K greater than the neighbouring one. In this way, depositions under identical plasma conditions could be carried out at the same time, but at four different temperatures. We report the deposition rate as a function of the substrate temperature, the hydrogen gas flow and the RF or P-DC plasma power applied to the hollow cathode.

Structural and Optical Studies of Synthesized Semiconductor NixZn1-xS Nanostructure Thin Films for Optoelectronic Device Applications

Transition metal ions like Nickel doped ZnS semiconductor materials have a wide range of optoelectronic device applications. However, the doping concentration effect on the properties of NixZn1-xS has not been reported. This study, therefore, investigated the effects of nickel (Ni) doping concentration on the structural and optical properties of synthesized NixZn1-xS nanostructured thin films prepared by low-cost Chemical Spray Pyrolysis (CSP) technique. NixZn1-xS nanostructured thin films with a thickness of 320nm and different mole ratios (𝑥 = 0.00, 0.02, 0.04, 0.06 and 0.08,) were grown by the use of spray solution on hot glass substrates at a temperature of 300oC using CSP technique. The spray solutions contain nickel acetate, zinc acetate, and thiourea as precursors for Nickel, Zinc, and Sulphur, respectively. The influence of Ni doping concentration on the structural, optical, and morphological properties were investigated using X-ray diffraction (XRD), Ultraviolet-Visible spectroscopy (UV-vis) and Scanning Electron Microscopy (SEM) respectively. The XRD analysis indicated that all the prepared films retained the ZnS cubic zinc blend structure. SEM results show that the films are composed of well crystalline grains with various shapes and densely bound to each other. The UV-vis spectroscopy shows that transmittance is moderately high and increased with increasing Ni content. The average transmittance of NixZn1-xS are 61.3%, 62.8%, 63.9%, 67.6 and 69.6% for x = 0.00, 0.02, 0.04, 0.06 and 0.08, respectively. The bandgap of Ni-doped ZnS samples is low compared to the undoped, and the value increases gradually with increasing Ni concentration. Based on the results obtained, with the enhanced structural and optical properties, NixZn1-xS films could be a useful material in the future of optoelectronic applications.

Comparative study of additively manufactured samples of tungsten with molybdenum and their applications

This article is a comparative study of tungsten (W) and molybdenum (Mo) samples manufactured by selective laser melting (SLM).Under the processing parameters different microstructural and mechanical properties like strain energy density, micro-hardness and surface morphology were investigated. Before the preparation of samples the SEM and XRD images were taken to calculate the size of micro particles of both the samples. These samples were further investigated by OM(optical microscopy),SEM(scanning electron microscope),EBSD(electron backscattering diffraction) and Vicker hardness to study the crystallographic structure, hardness, grain boundaries to understand a brief comparison between these two fourth group elements. It was identified as the cause of a very prominent structure with cracked features and a residual remains. During processing, different processing factors were examined, which separates at the edges of the grain, thereby creating thermal cracks. This due to the low eutectic melting compared to the matrix phase. These factors also result in a higher Ductile-to-Brittle Transition (DBTT). Later, during rapid cooling from the melting point, a combination of cracks with hot cracks on the borders of solid grain grains and cold cracks near weak grain edges forms a cracked network, which is often found in tungsten and molybdenum refined SLM. Neither does a very hot substrate plate prevent the formation of cracks in the metals formed by processing parameters. These materials are appropriate for high temperature up to more than 20000C such an analytic and inner wall constituents of fusion reactor or experiments. Parameters like laser power, scan speed, hatching space and the thickness of the powder layer are analyzed to achieve the high density samples. Three-dimensional printing is changing the way we make things in almost every industry, from cars to medical equipment to biotech.3D printing to prototype one of the most critical enabling technology in a building, the heat exchanger. In comparison to current designs, this next-generation heat exchanger weighs 20% less, performs 20% better, and can be produced much faster.

Impact of metallic potassium post-deposition treatment on epitaxial Cu(In,Ga)Se2

Alkali post-deposition treatments (PDTs) of Cu(In,Ga)Se2 (CIGSe) absorbers are known to improve the power conversion efficiency of the thin-film solar cell devices. The PDTs are usually carried out via evaporation of alkali fluorides in a selenium atmosphere onto a hot substrate. In this work, an alkali metal dispenser was used to evaporate pure metallic potassium onto epitaxial CIGSe absorbers. Subsequently, the absorber layers were heated in-situ to monitor chemical reactions and diffusion into the bulk. Due to the absence of grain boundaries, fluorine, and selenium, the effect of K on CIGSe absorber properties can be directly monitored. We find that potassium effectively diffuses into the bulk of epitaxial CIGSe absorber layers. The diffusion depends on the Cu-content of the CIGSe absorbers, in which Cu-depleted films present higher diffusion rates of K. Photoluminescence (PL) imaging corroborates that K in the bulk of the CIGSe absorber increases the PL yield, suggesting a passivation of defects or an increase in doping. This work highlights that alkali PDTs are not limited by interface and grain boundary modifications but also changes the absorber bulk properties, which needs to be taken into account.

Luminescence and Structural Characteristics of Lead Halide Perovskite Films Deposited In Situ by a Versatile Multisource Aerosol Assisted Chemical Vapor Deposition (AACVD) Method

AbstractMost solution‐based synthetic routes for perovskite film deposition take place under highly controlled atmospheres and cannot be easily escalated for mass production. Here, the control in situ over luminescent, morphological, and structural characteristics of hybrid and inorganic perovskite films deposited on top of hot glass substrates by multisource AACVD is reported. By simply adjusting the methylammonium chloride (MACl) to lead bromide (PbBr2) molar ratio in the N‐N dimethylformamide (DMF) precursor solution, a gradual transformation from orthorhombic PbBr2 to cubic MAPbBr2Cl hybrid perovskite films is observed, and the generation of highly luminescent MAPbBr3−xClx nanoparticulate domains in a PbBr2 matrix is easily achieved when a specific ratio is used. Additionally, the crystallization of the films is performed in situ modified by the implementation of an antisolvent stream source during deposition which in turn yields films with superior luminescence properties. Finally, an NIR emitting CsPbBr2Cl:Yb inorganic perovskite film is deposited to probe the versatility of the multisource AACVD system, by the simultaneous deposition of separated PbBr2/YbCl3·6H2O/DMF and CsCl/methanol solutions. The high degree of control on the final properties of the films indicates that AACVD could be a breakthrough for low‐cost, scalable, high‐throughput metal‐halide perovskite film deposition.

Morphology of ultrathin lithium fluoride deposited on Ag(100): Dendrites versus islands

We have investigated lithium fluoride (LiF) in the monolayer range deposited by thermal sublimation onto the (100) surface of a silver single crystal in ultrahigh vacuum. Our study combines scanning tunneling microscopy, low-energy electron diffraction, and polarized x-ray absorption spectroscopy. The results reveal that LiF grows epitaxially on Ag(100), with a morphology strongly depending on the growth temperature: at room temperature, dendritic patterns are formed with branches along the [011] and $[0\overline{1}1]$ directions, exhibiting the same lattice orientation as the substrate. Conversely, at a substrate temperature of 500 K LiF forms square islands exhibiting a moir\'e pattern, with the islands' borders oriented along the [001] and [010] directions. While the lattice constant of the surface deposited samples is close to the one of bulk fcc LiF, the appearance of a strong x-ray linear dichroism for dendritic LiF points to a tetragonal distortion arising from the LiF-substrate interaction. The less prominent dichroism and the presence of the moir\'e pattern on the square islands both suggest the relaxation of the LiF grown on the hot Ag substrate.

Microstructural and mechanical aspects of laser metal deposited H13 powder for die repair

In this study, the microstructural and mechanical properties of H13 powder deposited via laser metal deposition (LMD) on H13 hot work tool steel substrates were examined. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD) were used to analyze the grain distribution, layer development, and carbide incidence. The mechanical properties were evaluated using Vickers hardness indentations. An α-ferrite matrix consisting of α’-martensite was identified along with a crack-free interface containing Mo- and Cr-rich precipitates between the additive-deposited H13 steel and the substrate. The EBSD results showed a highly consistent combination between the deposition and the substrate, along with a structure consisting of columnar and equiaxial grains resulting from the directional solidification process. Wear resistance tests demonstrated that the H13-deposited region was in a better condition than the substrate was due to the presence of martensite and carbides in the matrix. Finally, the average hardness levels of the substrate and deposition regions were determined to be 213 HV (α-Fe) and 671 HV (α’), respectively. The smooth transition in terms of hardness between the regions also indicated a tendency for lower stress concentrations.