Development Of Surface Engineering Research Articles

A molecular dynamics study on pore structure: Performance comparison between metal foam and artificial mesh porous surface

With the development of surface engineering, porous surfaces have emerged as a significant research subject in boiling heat transfer. The latter, in turn, plays a crucial role in various industries such as power plants, distillation plants, and microelectronic technology. In this paper, the Molecular Dynamics method is adopted to investigate the wicking dynamics and boiling dynamics of two porous surfaces: foam, which exhibits randomly distributed pores, and mesh, composed of ordered square wires with relatively uniform pore sizes. Three wettability, namely hydrophilic, neutral, and hydrophobic wetting states, are assigned to the two porous surfaces de-coupling the effect of wettability from surface structure. Results reveal that, during the wicking process, the foam surface shows better wetting ability as it absorbs liquid under both hydrophilic and neutral wettability. Comparatively, the mesh surface has the fastest wicking speed under hydrophilic wettability yet it becomes non-wetting under neutral wettability. During the boiling process, the boiling dynamics differ greatly under three wettability. More importantly, the difference in surface structure makes the foam surface possess a better heat transfer whereas the mesh surface causes gentle pressure variation. Our findings provide insights into the design of artificial porous surfaces for certain purpose and their potential application.

Biofunctionalisation strategies of material surface and the inspired biological effects for bone repair

AbstractDue to trauma and disease, bone defects endanger the healthy life of human beings. At present, the gold standard for bone defect repair is still autologous bone transplantation and allogeneic bone transplantation. However, its insufficient source, potential disease transmission and immune rejection limit its clinical application. Therefore, the development of bone repair materials plays an important role in promoting bone repair. As the interface between material and tissue, the surface of the material plays an important role in the reaction after implantation, which determines the effectiveness of defect repair treatment. With the development of surface engineering and technology, bone repair materials have developed from biological inertia to biological activity by endowing various biological functions by controlling the composition, topological morphology and structure of the material surface etc. The inspired biofunctionalisation of material surface includes the capacities of inducing osteogenesis, promoting angiogenesis, antibacterial, immune regulation etc., as well as integration of postoperative repair and treatment. The authors review the biofunctionalisation of biomaterial surface and the inspired biological effects for bone repair, mainly including physical and chemical properties of material surface to regulate osteogenesis, and functional strategy of bone repair material surface.

Towards highly exposed active sites via Edge-N-rich carbon nanosheet @ porous biochar for efficient H2S catalytic oxidation

In this study, Edge-N-rich carbon nanosheet @ porous biochar (NCN@PB) was synthesized successfully from waste biomass self-assembly in a simple and green approach. The accessible and efficient utilization of edge-N enriched on the surface, together with the hybrid structure of NCN@PB improved the H2S oxidation capacity up to 390.1 mg/g at room temperature, reflecting an 8-fold enhancement compared with the blank biochar. The Density functional theory calculation, in-situ DRIFTS, and the characterization results further uncovered the desulfurization mechanism of active sites. Edge-N species decreased the barriers in critical steps governing H2S catalytic oxidation, i.e., H2S dissociation and O2 activation, especially the pyrrolic N. This strategy is beneficial for the development of surface engineering on metal-free catalysts and provides a new idea for improving the catalytic combustion activity of N-doped biochar.

Effect of a water film on the material removal behavior of Invar during chemical mechanical polishing

Understanding polishing mechanisms in water-lubricated environments has an important guiding value for surface engineering of precision devices. This work reveals the chemical mechanical polishing (CMP) mechanism of the Invar alloy under water lubrication by use of molecular dynamics simulation. The results show that the appropriate thickness of the water film and polishing speed can significantly reduce the surface roughness of the work piece and eliminate subsurface defects. With the increasing rolling speed, the variation of the surface roughness and subsurface damage thickness exhibits a trend of slowly decreasing and then reaching stability. In addition, with an increase in water film thickness, more defects were formed in the subsurface region due to greater surface stresses, although the roughness could be reduced due to an increase of passivated atoms on the work piece surface. These results would be helpful for understanding the CMP mechanism under water-lubricated conditions and for promoting the development of surface engineering for micro/nano components.

Ocular Nanomedicine.

Intrinsic shortcomings associated with conventional therapeutic strategies often compromise treatment efficacy in clinical ophthalmology, prompting the rapid development of versatile alternatives for satisfactory diagnostics and therapeutics. Given advances in material science, nanochemistry, and nanobiotechnology, a broad spectrum of functional nanosystems has been explored to satisfy the extensive requirements of ophthalmologic applications. In the present review, the recent progress in nanosystems, both conventional and emerging nanomaterials in ophthalmology from state‐of‐the‐art studies, are comprehensively examined and the role of their fundamental physicochemical properties in bioavailability, tissue penetration, biodistribution, and elimination after interacting with the ophthalmologic microenvironment emphasized. Furthermore, along with the development of surface engineering of nanomaterials, emerging theranostic methodologies are promoted as potential alternatives for multipurpose ocular applications, such as emerging biomimetic ophthalmology (e.g., smart electrochemical eye), thus provoking a holistic review of “ocular nanomedicine.” By affording insight into challenges encountered by ocular nanomedicine and further highlighting the direction of future studies, this review provides an incentive for enriching ocular nanomedicine‐based fundamental research and future clinical translation.

Fabrication of nano-copper surfaces by thermal evaporation technique to investigate nucleate pool boiling heat transfer performance of R-141b

In the present work, nano-Cu particle coatings, which were fabricated on a bare Cu surface using various thickness coating through a thermal evaporation technique, were used as heating surfaces to study the pool BHT performance of refrigerant R-141b. The heating surfaces, viz, 50 nm, 100 nm, 150 nm, and 200 nm thick nano-Cu particle coated surfaces over bare Cu heating surface are used in this experimentation. To reveal the formation of crystal structure on coated surfaces, scanning electron microscope (SEM) was used. Electron Discharge Spectroscopy (EDS) technology was employed to measure the percentage distribution of elements in the coating surfaces. Maximum heat transfer coefficient (HTC) enhancements of 10.5%, 15.7%, 26.6%, and 45.2% are observed for all the coated surfaces of thicknesses of 50 nm, 100 nm, 150 nm, and 200 nm when compared with bare Cu surfaces. Increases in HTC in nano-Cu coated surfaces were attributed to creation of high-density active nucleation sites and enhanced surface roughness. Other published data were used to predict the experimental data, with some deviations observed in the HTC. Thus, this paper is expected to gain importance due to the development of surface engineering with respect to energy conversion management and heating applications.

The Influence of Magnetron Sputtering Process Temperature on ZnO Thin-Film Properties

The important research direction in surface engineering and photovoltaics is the development of new materials that can replace the previously used expensive films. A prospective compound is zinc oxide (ZnO), characterized by optical and electrical properties similar to ITO and a lower production cost. One of the key factors influencing the properties of the ZnO thin films is the technique and parameters of their production. The comprehensive investigation results of the influence of ZnO thin-films deposition process temperature on their structure, optical properties, and adhesion are presented in the paper. ZnO films were deposited by the magnetron sputtering method. The structural characteristics of the tested films were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffractometry (XRD) and Raman spectroscopy, while the optical properties of the films were studied by the UV/VIS spectroscopy. Thickness and adhesion measurements of the obtained films were performed using the spectroscopic ellipsometry technique and the scratch test, respectively. The obtained research results showed the influence of the deposition process temperature on the morphology, crystallite size and adhesion of the thin films to the substrate. The effect of process temperature on optical properties, the value of the optical bandgap and crystal structures were analyzed and described. The results of this work have a meaning for the development of surface engineering and may serve as a clue in future studies in the field of modern photovoltaic structures.

Experimental Investigation on the Wind-driven Runback Motion of Water Droplets over Solid Surfaces with Different Wettabilities

Aircraft icing is widely recognized as one of the most serious weather hazards to flight safety. Specially designed hydro-/ice-phobic coatings are currently undergoing development for aircraft icing mitigation. It was found that hydro-/icephobic coatings would delay the ice accretion iover airframe surfaces so that the impacted supercooled water droplets could be blown away by the airflow from the airframe surface before being frozen into ice. It is of fundamental importance to understand the wind-driven runback behavior of water droplets over surfaces treated with different coatings, since the corresponding knowledge would be very helpful and essential to develop more efficient anti-/de-icing systems for aircraft icing protection. With the rapid development of surface engineering, a series of specially designed surface coatings succeed in icing mitigation using airflow to remove the remained water. While various hydro-/ice-phobic coatings/surfaces have been developed in recent years, the “state-of-the-art” icephobic coatings/surfaces can be generally divided into three categories, i.e., 1). Lotus-leaf-inspired superhydrophobic surfaces (SHS) with micro-/nano-scale surface textures to achieve very high contact angles (typically > 150°); 2). Pitcherplant-inspired slippery liquid infused porous surfaces (SLIPS) with a layer of liquid lubricant (which is immiscible with water) being sandwiched between ice and solid substrate materials; and 3). Icephobic elastic materials/surfaces with deformable structures/surfaces. SHS has a water droplet contact angle (CA) larger than 150° and a sliding angle (SA) less than 10° . SHS always has a hierarchical structure which is similar to the lotus leaf, and water droplets on SHS appear as water beads which can easily roll off the surface by wind or gravity before frozen. Another strategy to reduce ice adhesion strength to a solid surface is to use a layer of liquid lubricant, which is immiscible with water, between ice and the solid surface. The use of such lubricated surfaces was investigated as early as 1960s, and has gained increasing attentions again recently with the introduction of a concept called Slippery Liquid-Infused Porous Surfaces (SLIPS). SLIPS concept is inspired by the Nepenthes pitcher plants, which have evolved highly slippery, liquidinfused micro-textured rim to capture insects. SLIPS surfaces were not only found to be able to suppress ice/frost accretion by effectively removing condensed moisture even in high humidity conditions, but also exhibit at least an order of magnitude lower ice adhesion than most SHS coatings. More recently, elastic materials/surfaces, such as Polydimethylsiloxane or PDMS in short, which would be structurally deformed/altered dynamically upon applying extra mechanical stress, have also been suggested for icing mitigation. Elastic materials display ultra-low adhesion to ice due to their low work of adhesion and liquidlike deformability, while maintaining good mechanical durability due to their solid-like rigidity. It is found that water droplets would not only be more readily rebounding away from the surface after impingement, but also be able to roll away before frozen due to the hydrophobicity of PDMS. Considering the differences in wettabilities and mechanisms of water repellency, it is necessary to have a systematic understanding of how efficient the surfaces are when the aerodynamic force is applied to remove the adhered water droplets. In the present study, a comprehensive experimental campaign was conducted to characterize the transient runback behaviors of wind-driven water droplets over the surfaces of test plates coated with different hydro-/icephobic coatings (i.e., SHS, SLIPS and PDMS). A high-resolution Particle Image Velocimetry (PIV) system was used to achieve quantitative measurements of the velocity field of the airflow around the wind-driven water droplets on the test surfaces with different wettabilities. With the detailed PIV measurements of the airflow field around the runback water droplets and the droplet profiles, the aerodynamic forces and the adhesion forces acting on the water droplets were estimated. While Fig. 1 shows the experimental setup used in the present study, Fig. 2 to Fig. 3 given some of the typical measurement results. More measurement results and comprehensive analysis and discussions will be provided in the full version of this research paper.

Effect of porosity on wear behaviour of remanufacturing Cr3C2-NiCr coatings under oil lubrication

Remanufacturing is an advanced stage in the development of maintenance engineering and surface engineering, which is an important component of sustainable manufacturing. As a significant remanufacturing technology, thermal spraying is an important basis for the development of surface engineering. In this paper, Cr3C2-NiCr coatings with different porosity were prepared by plasma spraying, and their wear behaviour under oil lubrication was studied. The results show that the wear mechanisms of the coatings are different with difference of the porosity. Abrasive wear is the main wear mechanism of the high-porosity coating, while adhesive wear is the main wear mechanism of the low-porosity coating.

Influence of Topological Cues on Fibronectin Adsorption and Contact Guidance of Fibroblasts on Microgrooved Titanium

The choice of suitable nano- and microstructures of biomaterials is crucial for successful implant integration within the human body. In particular, surface characteristics affect the adsorption of various extra cellular matrix proteins. This work illustrates the interaction of protein adsorption and early cell adhesion on bulk microstructured titanium surfaces with parallel grooves of 27 to 35 μm widths and 15 to 19 μm depths, respectively. In contact with low concentrated fibronectin solutions, distinct adsorption patterns are observed on the edges of the ridges. Moreover, NIH/3T3 fibroblasts cultured in serum-free medium for 1 h, 3 h, and 1 day show enhanced early cell adhesion on fibronectin coated samples compared to uncoated ones. In fact, early adhesion and cell contacts occur mainly on the groove edges where fibronectin adsorption was preferentially detected. Such adsorption patterns support cellular contact guidance on short time scales since the adsorbed fibronectin proteins acted as a chemical boundary superimposing the topographical cues of the grooved microstructure. In fibronectin-free conditions, this chemical boundary is absent after cell seeding and initial cell-surface interaction. Here, cellular fibronectin released by the fibroblasts adsorbs along the grooves after 3 h and contact guidance occurs delayed. After 1 day, cell adhesion and cell morphology on uncoated and fibronectin coated titanium microgrooves were nearly equilibrated. Thus, surface structures can promote directed adsorption of low concentrated fibronectin, which, furthermore, facilitates early cell adhesion. These results give rise to new developments in surface engineering of biomedical implants for improved osseointegration.

Tailoring the surface wettability of polyimide by UV laser direct texturing in different gas atmospheres

Surface wettability modification of polyimide film was studied by UV laser direct texturing (UVLDT). The influences of laser fluence on surface microstructure, chemical composition and wettability were explored in air, O2, and N2 atmospheres, respectively. Scanning electron microscopy (SEM), surface probe profilometry, X-ray photoelectron spectroscopy (XPS), and water contact angle measurement were utilized for the characterization of laser-textured surfaces. It was found that in the same modification atmosphere, surface microstructure and roughness played a major role in changing the wetting behavior of polyimide film with varied laser fluence. However, in the three different atmospheres, when polyimide film was textured with the same laser fluence, no significant difference of surface microstructure and roughness was observed. Here, XPS analysis showed that O2 atmosphere was the most favorable environment for increasing surface oxygen-containing groups and realizing superhydrophilicity. Whereas, in N2 atmosphere, the least oxygen-containing groups were produced and the superhydrophilic surface could not be obtained. It could be inferred that the effect of different modification atmospheres on wettability was due to the change of surface chemistry. Understanding of wetting mechanism and fabricating superhydrophilic polyimide film would benefit the development of surface engineering for flexible electronics, microfluidics and adhesion applications.

Mechanisms for the Transfer of Innovative Surface Engineering Solutions to Industrial Practice on the Example of Hybrid Layers

Advanced surface engineering technologies are the basis of the intense technological development in the world over the past several decades. The rapid development of surface engineering resulted in the appearance of many new top layer solutions, such as multi-layer coatings, nanostructured coatings, and hybrid layers, which prove to be very effective in their applications. The production of layers and coatings with complex microstructure and application requirements (related to coated materials, the geometry of the engineered elements, economic viability) create a need for advanced technological and organizational solutions.This article presents a technology of manufacturing a hybrid layer: “nitrided layer + (Cr/CrN) multilayer,” intended to increase the durability of hot forging dies. Based on this example, those surface engineering fields are presented where simultaneous intensive development is necessary to ensure an efficient process of transferring innovative surface engineering solutions to the industry.

The Influence of Thickness of Layers in the Multilayer Coating of the PN + AlCrTiN<sub>multinano</sub> Hybrid Layer on Tribological Properties

One of the most perspective directions of the development of surface engineering is related to hybrid technologies. The best-known and widely used hybrid surface treatment technology is a combination of a gas or plasma nitriding process with the process of the deposition of hard antiwear coatings by means of PVD methods. The paper presents the influence of the thickness of layers in the multilayer coating on tribological properties of hybrid layers – PN + AlCrTiNmultinano obtained on the EN X32CrMoV3.3 hot working steel. The research methods concentrated on the analysis of mechanical properties, surface topography and microstructure, and tribological properties. The studies on mechanical properties included tests on hardness using the nanoindentation method and tests on adhesion using the scratchtest. The analysis of surface topography and microstructure was examined by scanning electron microscopy and scanning transmission electron microscopy. The tribological properties were examined using the ball-on-disc method. The coating was tested with alumina balls as counterparts at room temperature. The authors indicate that the PN + AlCrTiNmultinano hybrid layers are characterized by excellent mechanical properties and tribological resistance. In this paper, the authors confirmed that the thickness of layers in a multilayer coating is important in shaping the mechanical and tribological properties of the PN + AlCrTiNmultinano hybrid layer.

The comparison of antiwear and fatigue properties in higher temperature for PN+CrN and PN+AlCrTiN layer composites

One of the most perspective directions of the development of surface engineering is related to hybrid technologies. The best–known and widely used hybrid surface treatment technology is a combination of gas or plasma nitriding process with the process of deposition of hard antiwear coatings by means of physical vapour deposition (PVD) methods. The paper presents the results of two different wear tests for two different hybrid layers: PN+CrN and PN+AlCrTiN obtained on the EN X32CrMoV3.3 hot working steel. The first one presents results of ball–on–disc tribological tests carried out in the range of temperature, i.e., 25°C and 600°C. The second one presents results of fatigue tests, which indicated the changes of length and density of cracks during the forging process.

TransFair 2013 - Developments in surface engineering for the transportation industries

TransFair 2013 - Developments in surface engineering for the transportation industries

Recent Developments in Surface Engineering of Materials

Engineering approaches to improve surface properties such as surface finish/appearance, hardness/strength, wear resistance, corrosion resistance, environment resistance, and heat resistance have been known since prehistoric times. The manufacturing of several ancient objects can often be traced to processes like surface painting (use of natural pigments), machining (use of sandstone, bone, and metal tools), and heat treatments (use of soybean grains for carbonitriding of steel). While most of the modern surface engineering approaches have evolved from these processes, the past century has also witnessed rapid development of newer processes based on electroplating, thermal spraying, directed beam (ion, laser, and electron) processing, and cold spraying. These processes are now utilized for depositing a range of nanostructured, amorphous, or composite materials for multiple functionalities (hardness/wear resistance, strength/ toughness, corrosion resistance, heat/environment resistance, biocompatibility and cell adhesion, and hydrophobicity). Surface engineering is a very active area, introducing regular developments on various fronts, including fundamental research, technology development, and extension in newer applications. Some of these developments were captured at the symposium Advances in Surface Engineering: Alloyed and Composite Coatings II at the TMS 2013 Annual Meeting (San Antonio, TX; March 3–7, 2013). This symposium was sponsored by the Surface Engineering Committee of the TMS Materials Processing & Manufacturing Division (MPMD) and was partially funded by the U.S. Office of Naval Research (ONR). The symposium featured 59 presentations including 14 invited talks and several student presentations. This was a well-attended, hugely successful symposium, with discussions resulting in an important direction for the future activities of the committee. Most of the recent surface engineering developments discussed in the TMS 2013 symposium are highlighted in the articles published in this JOM issue. These articles represent the current state-ofthe-art and indicate emerging areas in surface engineering. In ‘‘Advances in Laser Surface Engineering: Tackling the Cracking Problem in Laser Deposited Ni-Cr-B-Si-C Alloys,’’ I. Hemmati et al. examine the idea of microstructural refinement for reducing the cracking tendency of Ni-Cr-B-Si-C alloys deposited by laser cladding. This work indicates that effective toughening of these alloys could not be reached solely by refinement of the hard precipitates and that the modification of the eutectic structure or disruption of its continuous network is needed. In ‘‘Nanomechanical Properties and Thermal Conductivity Estimation of Plasma Sprayed Solid Oxide Fuel Cell Components: Ceria Doped Yttria Stabilized Zirconia Electrolyte,’’ N. Mahato et al. demonstrated layered fabrication of solid oxide fuel cell (SOFC) components using an atmospheric plasma spraying method. The nanomechanical behavior of the deposited SOFC composite layers is evaluated. In ‘‘Characterization of Nanostructured and Ultrafine Grain Aluminum-Silicon Claddings using the Nano-Impact Indentation Technique,’’ J. Arreguin-Zavala et al. report that dynamic hardness of the material becomes independent of load using a nano-impact indentation technique. Their analysis shows that better correlation can be established between dry sliding wear and dynamic hardness. In ‘‘Abnormal Nitride Morphologies upon Nitriding Iron-Based Substrates,’’ Sai Ramudi Meka and Eric Jan Mittemeijer provide an overview of different nitride morphologies formed upon Sandip P. Harimkar, Chair of the Surface Engineering Committee of the TMS Materials Processing & Manufacturing Division (MPMD); Srinivasa Rao Bakshi, Vice Chair of the Surface Engineering Committee of TMS; and Arvind Agarwal are the JOM advisors for the Surface Engineering Committee. JOM, Vol. 65, No. 6, 2013

Development of surface engineering in China

Professor Tom Bell dedicated himself to the establishment of the discipline of surface engineering and contributed greatly to the development of surface engineering in China. This paper briefly overviews the four important stages in the development of surface engineering in China, i.e. single surface engineering, duplex surface engineering, nanosurface engineering and automation.

Study on wetting properties of periodical nanopatterns by a combinative technique of photolithography and laser interference lithography

This study presents the wetting properties, including hydrophilicity, hydrophobicity and anisotropic behavior, of water droplets on the silicon wafer surface with periodical nanopatterns and hierarchical structures. This study fabricates one- and two-dimensional periodical nanopatterns using laser interference lithography (LIL). The fabrication of hierarchical structures was effectively achieved by combining photolithography and LIL techniques. Unlike conventional fabrication methods, the LIL technique is mainly used to control the large-area design of periodical nanopatterns in this study. The minimum feature size for each nanopattern is 100 nm. This study shows that the wetting behavior of one-dimensional, two-dimensional, and hierarchical patterns can be obtained, benefiting the development of surface engineering for microfluidic systems.

Structure and wear resistance of the composite layers produced by glow discharge nitriding and PLD method on AISI 316L austenitic stainless steel

The rapid technical development enhances the demands on constructional materials in terms of their resistance to frictional wear, resistance to corrosion and erosion, high hardness, high tensile and fatigue strength. These demands can be satisfied by e.g. applying various surface engineering techniques that permit to modify the microstructure, phase and chemical composition of the surface layers of the treated parts. A prospective line of the development of surface engineering is the production of composite layers by combining various surface engineering methods. The paper presents the results of examinations of the phase composition and frictional wear resistance of the layers produced by hybrid processes, i.e. such that combined glow discharge assisted nitriding performed at 450 °C and 550 °C with a pulsed laser deposition of boron nitride coatings (PLD method). It has been shown that the boron nitride coatings formed on nitrided AISI 316L steel increase its frictional wear resistance.

Compatibility between tribological surfaces and lubricant additives—How friction and wear reduction can be controlled by surface/lube synergies

This paper reviews the recent trends in materials technology and lubricant additive technology in engines. The paper will review key developments in surface engineering, application of nanocomposite materials and other advanced materials (including light alloys). It will also assess the trends towards “greener” lubricant additives, driven by environmental legislation and will discuss the implications for lubrication in the next decade. The key part of the paper will be to review the extent to which materials and lubricants are being used in partnership in engineering systems to capitalize on the synergies, which can exist between surfaces and lubricants in boundary lubrication. In a similar manner there are some important antagonisms that need to be identified—an appreciation of such compatibility issues can assist engineers in selecting a lubrication system. The paper will review existing literature from outside the work conducted by the authors and will substantiate some of the important aspects of boundary lubrication surface/lubricant compatibility through reference to some recent work conducted by the authors.