•Laser cladding material system on titanium alloys is reviewed entirely.•Research progresses on laser cladding for different functions are summarized.•The existing problems and the corresponding ...solutions are discussed.•Potential trend of development is forecasted based on the latest research progress.
Titanium and its alloys are restricted in the field of application. Laser cladding, as a kind of surface modification technique, is employed to fabricate coatings with improved wear resistance, high temperature oxidation resistance and good biocompatibility on titanium and its alloys. Apart from laser cladding process parameters, material selection is vital to obtain the improved properties mentioned above. In this paper, recent developments of different material system are summarized and the developments in laser cladding for functional coatings with high wear resistance, good corrosion and oxidation resistance, and better medical biocompatibility are reviewed. Besides, the existing problems and the corresponding solutions are discussed. Finally, the trend of development in the future is forecasted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Titanium and its alloys are expected to be ideal materials for biomedical applications. Various approaches have been used for biological properties improvement. Among various surface modification ...techniques, micro-arc oxidation (MAO), which can produce porous, adhesive and bioactive coatings for implantation, has aroused considerable attention. This paper gives a brief overview of biological assessment of bioactive coatings. It focuses mainly on the strategies of improving biological properties of MAO coated titanium and its alloys. The influence of the electrolyte, process parameters, pretreatment and post-treatment on the coating characteristics (surface micrograph, adhesion strength and biological compatibility etc.) is detailed in this article. MAO assisted by other methods to achieve superior biocompatibility is also discussed. Finally, the trend of development in the future is forecasted.
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•Electrolyte and electrical parameters play important roles in micro-arc oxidation.•SBF immersing is the most widely used method in biological assessment of bioactive coatings.•More cells are adsorbed and proliferate on a well crystallized HA coating than on an amorphous HA coating.•The use of hybrid methods could prepare high content of Ca–P ceramic coatings or crystallized HA directly.•Further discussion of the mechanism of micro-arc oxidation is extremely needed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Bone defects are a common disease threatening the health of many people. Calcium phosphate (CaP) is an ideal bone substitutive material that is widely used for bone repair due to its excellent ...biological properties including osteoinductivity, osteoconductivity and biodegradability. For this reason, investigation of these properties and the effects of various influencing factors is vital for modulating calcium phosphate during the design process to maximally satisfy clinical requirements. In this study, the latest studies on the biological properties of CaP biomaterials, including hydroxyapatite (HA), tricalcium phosphate (TCP), and biphasic calcium phosphate (BCP), have been summarized. Moreover, recent advances on how these properties are altered by different factors are reviewed. Considering the limited mechanical strength of CaP materials, this study also reviews CaP composites with different materials as improvement measures. Finally, perspectives regarding future developments of CaP materials are also provided.
This article reviews the recent advances and various factors affecting the improvement of the biological properties of calcium phosphate for bone repair.
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IJS, KILJ, NUK, UL, UM, UPUK
Articular cartilage (AC) defects lack the ability to self-repair due to their avascular nature and the declined mitotic ability of mature chondrocytes. To date, cartilage tissue engineering using ...implanted scaffolds containing cells or growth factors is the most promising defect repair method. Scaffolds for cartilage tissue engineering have been comprehensively researched. As a promising scaffold biomaterial for AC defect repair, the properties of chitosan are summarized in this review. Strategies to composite chitosan with other materials, such as polymers (including collagen, gelatin, alginate, silk fibroin, poly-caprolactone, and poly-lactic acid) and bioceramics (including calcium phosphate, calcium polyphosphate, and hydroxyapatite) are presented. Methods to manufacture three-dimensional porous structures to support cell attachment and nutriment exchange have also been included.
Properties of chitosan/polymer and chitosan/bioceramic composite scaffolds for articular cartilage defect repair are reviewed.
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IJS, KILJ, NUK, UL, UM, UPUK
Nitrogen‐doped porous carbon nanosheets (N‐CNS) are synthesized by hydrothermal carbon coating of g‐C3N4 nanosheets followed by high‐temperature treatment in N2. g‐C3N4 serves as a template, nitrogen ...source, and porogen in the synthesis. This approach yields N‐CNS with a high nitrogen content and comparable oxygen reduction reaction catalytic activities to commercial Pt/C catalysts in alkaline media.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Efficient capture of solar energy will be critical to meeting the energy needs of the future. Semiconductor photocatalysis is expected to make an important contribution in this regard, delivering ...both energy carriers (especially H2) and valuable chemical feedstocks under direct sunlight. Over the past few years, carbon dots (CDs) have emerged as a promising new class of metal‐free photocatalyst, displaying semiconductor‐like photoelectric properties and showing excellent performance in a wide variety of photoelectrochemical and photocatalytic applications owing to their ease of synthesis, unique structure, adjustable composition, ease of surface functionalization, outstanding electron‐transfer efficiency and tunable light‐harvesting range (from deep UV to the near‐infrared). Here, recent advances in the rational design of CDs‐based photocatalysts are highlighted and their applications in photocatalytic environmental remediation, water splitting into hydrogen, CO2 reduction, and organic synthesis are discussed.
Carbon dots (CDs) have emerged as promising materials for various photocatalytic reactions owing to their tunable light‐harvesting range and outstanding electron‐transfer efficiency stemming from their intrinsic nanostructures. Recent advances in the rational design of CD‐based photocatalysts and their applications in photocatalytic environmental remediation, hydrogen evolution by water splitting, CO2 reduction, and organic synthesis are highlighted.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Additive manufacturing (AM) especially laser additive manufacturing (LAM), a novel manufacturing technique of layer-by-layer forming according to geometric model, provides a decent option for ...materials processing. It owns advantages of rapid prototyping, customization, high material utilization, and the ability to form complicated structures. This paper reviews popular LAM techniques of selective laser sintering/melting, laser metal deposition and laser direct writing. The development status of metallic materials including pure metal, steel, superalloy, titanium and aluminum alloy is presented. The challenges and application limitations of LAM are involved and the development trend in the future is forecasted. In summary, this paper gives an overview of metal LAM expecting to made helpful suggestions on future research and development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Carbon quantum dots (CQDs) have attracted widespread interest for photocatalytic applications, owing to their low cost and excellent electron donor/acceptor properties. However, their advancement as ...visible‐light photosensitizers in CQDs/semiconductor nanocomposites is currently impaired by their poor quantum yields (QYs). Herein, we describe the successful fabrication of a series of nitrogen‐doped CQDs (NCDs) with N/C atomic ratios ranging from 0.14–0.30. NCDs with the highest N‐doping level afforded a remarkable external QY of 66.8 % at 360 nm, and outstanding electron transfer properties and photosensitization efficiencies when physically adsorbed on P25 TiO2. A NCDs/P25‐TiO2 hybrid demonstrated excellent performance for hydrogen evolution in aqueous methanol under both UV and visible‐light illumination relative to pristine P25 TiO2. Controlled nitrogen doping of CQDs therefore represents a very effective strategy for optimizing the performance of CQDs/semiconductor hybrid photocatalysts.
Dots the way, a‐ha, a‐ha, I like it: N‐doped carbon quantum dots (NCDs) with high N/C atomic ratios (0.14–0.30) were fabricated by a facile hydrothermal process. N‐doping suppressed nonradiative quenching in the NCDs, delivering photoluminescence quantum yields as high as 68 %. NCDs/P25‐TiO2 composites showed good activity for photocatalytic H2 evolution under both UV and visible illumination, which can be attributed to efficient excitation wavelength‐dependent interfacial charge transfer.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
CdS nanoparticle‐decorated Cd nanosheets (CdS NP/Cd NSs) are successfully fabricated for the first time via a facile oxidation–sulfurization treatment of Cd nanosheets. Due to the high electrical ...conductivity and visible light reflectivity of Cd nanosheets, the obtained CdS NP/Cd NSs heterostructures show significantly enhanced activities for visible light‐driven photocatalytic H2 production compared to other reference CdS photocatalysts.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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