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With the development of new materials and technology, high entropy alloy (HEA) nitride films have attracted much attention of researchers due to their excellent optical properties and mechanical properties. Herein, a novel SS/NbMoTaWN (HEAN)/NbMoTaWON (HEAON)/SiO2 coatings are prepared, which shows a high spectral selectivity of α/e = 0.944/0.12. The preparation and optimization of the coating are studied by combining experiments with ellipsometric program and CODE software. High temperature thermal stability test is performed in depth, which proves that the coating could bear 400 °C in air for 2 h, and 600 °C for 2 h in vacuum. Long-term thermal stability researches indicate that the SSACs still keep good optical properties (α = 0.902, e = 0.106) even after annealing at 600 °C for 100 h. The failure mechanism is analyzed by XRD and Raman spectra. In addition, neutral salt spray test is performed to investigate the anti-corrosion ability, which indicates the coating has a good optical performance after soaking in 3.5 wt% NaCl solution for 30 days. Obviously, this work provides a new strategy to construct solar absorber coatings based on NbMoTaW high entropy alloy.

High entropy alloys (HEAs), which is at the expense of high cost compared to traditional alloy, should not be confined to the mechanical properties, but should be employed to devise a novel combination with unique functional and mechanical performances. In this work, high entropy alloy nitride (HEAN) is utilized as a novel double absorption layer to improve solar absorption in the high temperature solar selective absorbing coatings (SSACs). Our primary motivation is to lower thermal emittance (e) and enhance solar absorptance (α). In order to realize this goal, coating design (CODE) software is employed to design and optimize the proposed HEAN based SSACs using appropriate dielectric function model. The ultimate as-deposited coating shows good optical properties with a high α value of 0.965 and a low e value of 0.086 (at 82 °C). The estimate of thermal stability tests indicates that HEAN based SSACs has the ability to resist instability in high working temperature, which keeps good optical properties (α = 0.925, e = 0.070) after annealing at 600 °C for 10 h.

Solar selective absorber coatings (SSACs), with the characteristics of efficient harvesting and conversion of solar energy into the heat work fluid, are considered to be one of the key components f...

Recent advances in high-entropy alloys have spurred many breakthroughs in the fields of high-temperature materials and optical materials and they provide incredible application potentialities for photothermal conversion systems. Solar-selective absorbers (SSAs), as key components, play a vital role in photothermal conversion efficiency and service life. The most pressing problem with SSAs is their inconsistent optical performance, an instability constraint induced by thermal stress. A feasible method of improving performance stability is the introduction of high-entropy materials, such as high-entropy alloy nitrides. In this study, enabled by an intrinsic MoTaTiCrN absorption layer, the solar configuration achieves greatly enhanced, exceptional thermotolerance and optical properties, leading to the formation of a scalable, highly efficient, and cost-effective structure. Computational and experimental approaches are employed to achieve optimum preparation parameters for thicknesses and constituents. The crystal structure of high-entropy ceramic MoTaTiCrN is fully investigated, including thickness-dependent crystal nucleation. High-temperature and long-term thermal stability tests demonstrate that our proposed SSA is mechanically robust and chemically stable. Moreover, a low thermal emittance (15.86%) at 500 °C promotes the photothermal conversion efficiency. In addition, due to the exceptional spectral selectivity (α/ε = 92.3/6.5%), thermal robustness (550 °C for 168 h), and photothermal conversion efficiency (86.9% at 550 °C under 100 sun), it is possible for our proposed SSA to enhance the practical realization of large-area photothermal conversion applications, especially for concentrated solar power systems.

The most recent advances in high-entropy materials provide impetus for the development of high-performance materials, simultaneously providing high-temperature robustness and excellent functional properties owing to the high configurational entropy and distorted lattices. Thus, in this work, double-layer high-entropy alloy nitride HfNbTaTiZrN with a well-designed metal content gradient is employed to fabricate a solar selective absorber coating (SSAC). We extensively investigated whether the coating meets the definition of a high-entropy material from the points of elemental analysis and phase structure, combined with thermodynamic calculation. Remarkably, the new, tailored SSAC exhibits an exceptionally high solar absorptance (α = 96%) and a suppressed thermal emittance (e = 8.2%) at 82 °C and omnidirectional absorption. Investigations of the long-term thermal stability indicate that the HfNbTaTiZrN-based SSAC due to the entropy-driven structural stabilization could endure heat treatment at 600 °C for 168 h, retaining a performance criterion (PC) value less than 0.05, which implies the feasibility of practical applications. More importantly, the photothermal conversion efficiency (η), which is utilized to quantitatively evaluate the performance at elevated temperatures, reaches 90.1% at a working temperature of 550 °C under 100 suns, and even after annealing at 600 °C for 168 h, the efficiency drop is still less than 5%. Overall, the combination of thermal robustness and photothermal conversion efficiency at working temperatures less than 600 °C provides significant potential to maximize solar energy harvesting and pioneers an opportunity to explore simultaneous multifunctional applications of high-entropy alloys.

The functional application of high entropy alloys, which emerge as a novel multi-principal component alloy, has been constantly expanding in the field of solar photothermal harvesting from optical materials to high temperature materials due to their excellent properties. A solar spectrally selective absorbing coating requires such materials that show not only outstanding optical properties but also prominent thermal stability. It is desirable but challenging to fabricate high performance solar absorbing coatings. A prospective strategy for the preparation of solar absorbing coatings is the introduction of high entropy alloys. In this work, we have developed a simple, cost-conscious, scalable and highly efficient solar selective absorbing coating using a single layer high entropy nitride AlCrTaTiZrN by choosing appropriate elemental compositions. The as-deposited coatings show an outstanding spectral selectivity of α/e = 92.8%/5.1% or 91.6%/5.1%. High temperature thermal stability tests are performed in depth, indicating that the coating could endure annealing treatment at 800 °C for 2 h with insignificant reflectance spectrum variation. A prolonged period of thermal stability characterization presents that this coating could maintain good optical performance after annealing at 650 °C for 300 h. Furthermore, high temperature thermal emittance can be suppressed to as low as 15.4% at 600 °C, which contributes to the state-of-the-art photothermal conversion efficiency under 100 suns (87.7% at 600 °C, and 84.6% at 650 °C). Overall, the high entropy nitride AlCrTaTiZrN based coating contributes to good thermal stability and optical properties, showing great potential for extensive applications in solar energy harvesting.

The newly increasing development of abruptly high entropy alloy nitride (HEAN), especially the refractory HEAN, manifests excellent mechanical, corrosion resistance , and optical properties, which exhibits a wide application prospect in the field of coatings. Herein, we develop a high entropy nitride NbMoTaWN-based solar selective absorber coatings (SSACs), providing a potential to strengthen structural and optical advance through component selection and structure design. The coating exhibits a high solar absorptance (α) of 0.936 and a low thermal emittance ( e ) of 0.126 at 82 °C. Investigation on structural and optical robustness demonstrates that the NbMoTaW HEAN-based SSAC could endure heat treatment at 500 °C for 10 h in vacuum environment. In addition, through the evolution of XRD and Raman spectra after annealing, the failure mechanism of coatings annealed in vacuum at 500 °C for 10 h and 400 °C in air for 5 h are obtained. Obviously, the advantages such as low-cost preparation, easily scalable production, convenient technology process, and repeatability in this work promise potentially valuable applications for photothermal conversion techniques.

With the rapid advance of science and technology, it is essential to research and develop new intrinsic solar absorber coatings with the simple production process and excellent photo-thermal conversion efficiency. Herein, we have developed a novel AlCrMoTaTiN intrinsic absorber layer by radio frequency (RF) reactive sputtering method via adjusting the deposition time and the flow rate of N2. The AlCrMoTaTiN intrinsic absorber layer exhibits a high absorptance of 0.752 and a low emittance of 0.074 at 82 °C. The AlCrMoTaTiN/Al2O3 solar absorber coating is deposited by using Al2O3 works as an anti-reflective layer and the spectral selectivity (α/e) is 0.929/0.082. This coating also possesses a good thermal stability, which can be stabilized at 300 °C in air and 500 °C in vacuum for 2 h, respectively. In addition, a prolonged period of thermal stability characterization is carried out, which indicates that this coating could keep good optical performance after annealing at 600 °C for 100 h. The corresponding failure mechanism is obtained by analyzing the Raman spectroscopy and XRD. Obviously, the AlCrMoTaTiN/Al2O3 solar absorber coating has a broad application prospect in large-scale and efficient industrial production.

A novel TiC-TiN/Al2O3 tandem solar selective absorbing coating was successfully deposited on Si (1 0 0) and stainless steel (SS) substrates by reactive RF magnetron sputtering deposition. The spectral characteristics, microstructure, thermal stability and solar-thermal conversion efficiency of the coating before and after a long annealing in vacuum were investigated systematically. The optical constants of the coating are measured by an Ultraviolet–visible-near-infrared (UV/Vis/NIR) spectrometer, and the chemical composition analysis, structure information and surface morphology are investigated using XRD, XPS and FESEM. An excellent absorptance (α = 0.92) and a low emittance (e = 0.11) at 82 °C are obtained by the as-prepared coatings. After annealed at 500 °C for 100 h in vacuum, there is no significant change in micromorphology and optical properties of the coating, which produces a good solar-thermal conversion efficiency. These results indicate that it can be applied as a potential coating material to a high temperature concentrated solar power (CSP) system.

In this paper, prehydrolysis was used as the first treatment of poplar slab for producing high-grade dissolving pulp, the optimum prehydrolysis conditions of poplar were obtained as followings: liquid ratio 1:6, H2SO41.0%, the highest temperature of 160±5°C, heating time of 90min, holding time of 120min. Hydrolyzed poplar slab was cooked to determine the effects of various alkali charges on pentosans, alpha-cellulose, kappa number, and degree ofpolymerization (DP). The optimum cooking process conditions of poplar were obtained as followings: alkali dosage 24%, sulfidity 5% ,the highest temperature of 160±5°C, heating time of 60min, holding time of 120min.Cooked pulps were bleached using Op-Q-P sequence. As a consequence, the poplar slab dissolving pulp of pentosan 3.73%, alpha-cellulose 95.13%,kappa number1.58, brightness 86.4%ISO, degree of polymerization (DP) 488.84 was obtained in our laboratory.

Aluminium silicate fiber is an excellent high-temperature material which is widely used in special paper industry in recent years. Due to its property of hardly interweave into the paper and the low strength of the single inorganic fibers paper, it is difficult to make a general basis weight paper. In response to these issues, the strength of the paper was improved by adding some plant fibers. This study takes advantage of good resistance to high temperature of inorganic adhesive and bonding capacity of organic intensifier. Meanwhile two inorganic adhesives (waterglass and ludox) and one organic adhesives carboxymethy starch (CMS) were used in the process of preparing the aluminium silicate paper. The physical properties and insulation properties of the paper which prepared from the difference conditions were studied. The experiment results showed that the adhesive of waterglass and ludox can improve the properties of resistant to high temperature. The adding dosages were 10% and 7.5ml, respectively. The best ratio of alumina silicate fiber to conifier fiber is 7 to 3.The using of CMS can decrease the amount of the plant fiber and its best usage is 10%.

The stickies in pulp and paper machinery especially in the blankets will cause a lot of problems such as paper defects, increasing the time of machine shut down . Therefore, Inhibiting the Stickies of blanket is very important to regular production. In this study,we mainly studied on the inhibition of Stickies in the blanket with enzyme. The processed blanket was treated by several kinds of enzymes. The results showed that the optimum enzyme treatment conditions were obtained as followings:PH of 7, temperature of 50°C, 2×104U/g of cellulose enzyme, 2×103U/g of amylase and 104U/g of lipase. The blankets obtained better cleaning situation under this conditions.

The layer of Al-modified austenitic stainless steel was formed by laser cladding with pre-placed FeNiCrAl powder on 304SS surface. No porosity and free of cracks was observed at power density of 31.25 w·s·mm-2. The microstructure of cladded layer was observed by OM (optical microscope) and SEM (scanning electron microscope). Compared with 304 (the substrate), laser cladding FeNiCrAl layer exhibit excellent pitting resistance in mixed acid solution. Anodic polarization curve indicated that the corrosion potential of laser cladding layer was 70 mV higher than that of 304SS (-345.7 mV), while self-corrosion current density of 304SS was 2.4 times as high as that of laser cladding layer.

An approach for fabricating functionally graded specimens of Co-based alloy and molybdenum disilicide (MoSi2) compositions via Selective Laser Cladding (SLD) is presented. The focus aimed at using the functionally graded material (FGM) concept to gradually grade powdered compositions of MoSi2 within a base material of Co-based alloy. A high power CO2 laser was used to process the material compositions to a high density with gradual but discrete changes between layered compositions. The graded specimens initially consisted of 100% Co-based alloy with subsequent layers containing increased volume compositions of MoSi2 (0-80wt.%). Specimens were examined for porosity, phase composition and microstructure. It was found that crack sensitivity of layer can be reduced by adding Co-based alloy into the pure MoSi2 powder.

The tensile test of casting ferritic stainless steel was conducted on SHIMADZU AG-10 at different temperatures of 300, 500, 600, 700, 800, and 950°C, respectively. The engineering stress-strain curves with the thermal deformation at the different temperatures, the tensile strength and elongation curves were obtained. Metallographic test samples were prepared and the morphology of deforming zone was observed by optical microscopy. The experimental results showed that the tensile strength of the test samples decreased with increasing temperature. From 300 to 500°C, the work hardening occurred and the tensile strength increased with increasing engineering strain. The softening occurred and the tensile strength decreased with increasing engineering strain at temperatures from 600 to 950°C. The strength of 430 stainless steel decreased, and the plasticity increased with the increase in temperature. The fractures were basically intergranular fractures within the range of 300~950°C. A transition occurred to the form of fracture from the ductile to the brittle, which might be related to the nitrogen atom in the 430. Grain deformation along specimen tensile direction concentrated in the necking region, where appeared banded structure in martensite. The organization at the edge of the sample was fine, while the organization at the central region was coarser.

According to the arrangement of atoms, the solid materials can be divided into the crystals and the non-crystals. Short for quasi-periodicity crystal, quasicrystal, also known as the "quasi crystal" or "mimetic crystal", is an intermediate between crystals and non-crystals. Three mathematical laws hidden in the quasicrystal are Penrose puzzles, Fibonacci sequence and golden section, and the uniqueness of quasicrystals is five rotational symmetry nonexistent in common crystals. A few quasicrystals (such as Al65Cu20Fe10Mn5, Al75Fe10Pd15) are stable phases, while most of the quasicrystals belong to the metastable products, both of which are formed largely by the method of rapid cooling. Quasicrystal materials have a very high hardness, low coefficient of friction and non-stick characteristic, of which the unique performance is successfully applied in the frying pans, razor blades and surgical tools.

In this paper, we studied the possibility of wood powder in place of mechanical pulp in paper making to get high bulkness, also the dry-bleaching method of wood powder, the strength enhancement and retention effect for wood powder during paper making were all introduced and analyzed in detail.

The residues from wheat straw pulping mainly include uncooked chips and fiber bundles. In order to achieve high quality pulp, the residues require removal from the system. It was not necessary that the residues were re-cooked because of its high contents of non-cellulosic constituent. The achievement of low density foamed buffer material with the residues of wheat straw pulping would make the second pollution problem of the residues be solved, and achieve a replacer of foamed plastic material. The paper discussed the producing techniques of foamed buffer material with the residues of wheat straw pulping. The result showed that the best foamed properties of the residues were achieved with proper dosage of natural bonding agent like wheat flour, inorganic foamed agent, crosslink agent, and proper foamed temperature. The density and compression of foamed buffer material with the residues of wheat straw pulping were achieved with 60 kg /m3 and 60 kPa respectively at the optimum foaming condition.

The paper studied the possibility of using the whole stalk kenaf as a raw material for producing high yield and good quality bleachable pulp. The stem of kenaf has two distinct parts: the bast and the core. which have markedly different chemical components and fiber morphology. In general, the length of bast fiber ranges from about 2-2.5mm, while that of the core varies from about 0.5-0.8mm, so it is important to achieve a balance of the bast fiber and the core during pulping. The study indicated that using the selected continuous cooking conditions, the properties of kenaf pulp approached to the hardwood pulp and would be easily bleached.