New Problems of Boiler Corrosion after Coupling Combustion of Coal and Biomass and Anti-Corrosion Technologies

This study explores the corrosion issues arising from the coupled combustion of coal and biomass and proposes potential solutions.Biomass,as a renewable energy source,offers advantages in energy-saving and carbon reduction.However,the corrosive effects of alkali metal compounds,sulfur(S)and chlorine(Cl)elements in the ash after combustion cannot be underestimated due to the high volatile content of biomass fuels.We investigate the corrosion mechanisms,as well as the transfer of Cl and alkali metal elements during this process.Comparative corrosion analyses are conducted among coal-fired boilers,pure biomass boilers and boilers with coupled combustion.Various biomass types in co-firing are studied to understand different corrosion outcomes.The main factors influencing corrosion include the physicochemical properties of biomass feedstock,furnace temperature and heating surface materials,with the chemical composition and ash content of biomass playing a dominant role.Currently,the methods used for anti-corrosion include water washing pretreatment of biomass feedstock,application of novel alloys and coatings and the development of additives to inhibit fouling,ash deposition and corrosion.Efficient inhibitors are economical and easy to produce.Additionally,biomass can be converted into biomass gasification gas,although challenges related to tar still need to be addressed.

Anti-Corrosion and Reconstruction of Surface Crystal Plane for Zn Anodes by an Advanced Metal Passivation Technique

For the aqueous Zn-ion battery,dendrite formation,corrosion,and interfacial parasitic reactions are major issues,which greatly inhibits their practical application.How to develop a method of Zn construction or treatment to solve these issues for Zn anodes are still great challenges.Herein,a simple and cheap metal passivation technique is proposed for Zn anodes from a corrosion science perspective.Similar to the metal anticorrosion engineering,the formed interfacial protective layer in a chemical way can sufficiently solve the corrosion issues.Furthermore,the proposed passivity approach can reconstruct Zn surface-preferred crystal planes,exposing more(002)planes and improving surface hydrophilicity,which inhibits the formation of Zn dendrites and hydrogen evolution effectively.As expected,the passivated Zn achieves outstanding cycling life(1914 h)with low voltage polarization(<40 mV).Even at 6 mA cm^(−2) and 3 mA h cm^(−2),it can achieve stable Zn deposition over 460 h.The treated Zn anode coupled with MnO_(2) cathode shows prominently reinforced full batteries service life,making it a potential Zn anode candidate for excellent performance aqueous Zn-ion batteries.The proposed passivation approach provides a guideline for other metal electrodes preparation in various batteries and establishes the connections between corrosion science and batteries.

Atomic-Scale Layer-by-Layer Deposition of Fe SiAl@ZnO@Al_(2)O_(3) Hybrid with Threshold Anti-Corrosion and Ultra-High Microwave Absorption Properties in Low-Frequency Bands

Developing highly efficient magnetic microwave absorb-ers(MAs)is crucial,and yet challenging for anti-corrosion properties in extremely humid and salt-induced foggy environments.Herein,a dual-oxide shell of ZnO/Al_(2)O_(3) as a robust barrier to FeSiAl core is introduced to mitigate corrosion resistance.The FeSiAl@ZnO@Al_(2)O_(3) layer by layer hybrid structure is realized with atomic-scale precision through the atomic layer deposition technique.Owing to the unique hybrid structure,the FeSiAl@ZnO@Al_(2)O_(3) exhibits record-high micro-wave absorbing performance in low-frequency bands covering L and S bands with a minimum reflection loss(RLmin)of-50.6 dB at 3.4 GHz.Compared with pure FeSiAl(RLmin of-13.5 dB,a bandwidth of 0.5 GHz),the RLmin value and effective bandwidth of this designed novel absorber increased up to~3.7 and~3 times,respectively.Fur-thermore,the inert ceramic dual-shells have improved 9.0 times the anti-corrosion property of FeSiAl core by multistage barriers towards corrosive medium and obstruction of the electric circuit.This is attributed to the large charge transfer resistance,increased impedance modulus|Z|0.01 Hz,and frequency time constant of FeSiAl@ZnO@Al_(2)O_(3).The research demonstrates a promising platform toward the design of next-generation MAs with improved anti-corrosion properties.

Preparation technology and anti-corrosion performances of black ceramic coatings formed by micro-arc oxidation on aluminum alloys

In order to prepare ornamental and anti-corrosive coating on aluminum alloys, preparation technology of black micro-arc ceramic coatings on Al alloys in silicate based electrolyte was studied. The influence of content of Na2WO4 and combination additive in solution on the performance of black ceramic coatings was studied; the anticorrosion performances of black ceramic coatings were evaluated through whole-immersion test and electrochemical method in 3.5% NaCl solution at different pH value; SEM and XRD were used to analyze the surface morphology and phase constitutes of the black ceramic coatings. Experimental results indicated that, without combination additives, with the increasing of Na2WO4 content in the electrolyte, ceramic coating became darker and thicker, but the color was not black; after adding combination additive, the coating turned to be black; the black ceramic coating was multi-hole form in surface. There was a small quantity of tungsten existing in the black ceramic coating beside α-Al2O3 phase and β-Al2O3 phase. And aluminum alloy with black ceramic coating exhibited excellent anti-corrosion property in acid, basic and neutral 3.5% NaCl solution.

A Comparative Study on Several Anti-Corrosion Materials for Power FGD System

In the study organic-inorganic hybrid composite, epoxy modified silicone coating and vinyl ester flake mastic were comparatively used as several anti-corrosion materials that provided protection for flue gas desulfu-rization (FGD). The relationship between curing conversion rate of hybrid polymer and temperature was investigated by differential scanning calorimeter (DSC). The adhesion strength, coefficient of thermal expansion and flame retardant properties of three anti-corrosion materials were measured and analyzed. A corrosion test in 8% H2SO4 and 5% HCl at temperature cycle of 40°C~ 160°C was applied to study corrosion resistance of several anti-corrosion materials. Gravimetric measurement and morphological observation of three materials before and after corrosion test were comparatively analyzed in the paper. The small weight change and good morphological structure of hybrid composite during corrosion test demonstrate that hybrid composite has better anti-corrosion properties than epoxy modified silicone coating and vinyl ester flake mastic.

Influence of graphene on the anti-corrosion performance of epoxy-based coatings

In this work, graphene-modified epoxy-based anti-corrosion coatings were prepared and the influence of graphene on the anti-corrosion performance of the epoxy-based coatings was investigated with water contact angle test ,chemical solution immersion test, and electrochemical test. The water contact angle and chemical solution resistance of the epoxy-based coatings were improved with an increase in graphene content from 0 to 0.4%. These results prove that addition of graphene can significantly improve the hydrophobicity and impermeability of epoxy- based coatings. However, when the graphene content was increased to 0.5%, the performance of the epoxy-based coatings decreased because of graphene aggregation. Tafel polarization results show that graphene addition can significantly reduce the corrosion current density and corrosion potential of epoxy-based coatings, which enhance their anti-corrosion performance.

Investigation of anti-corrosion property of hybrid coatings fabricated by combining PEC with MAO on pure magnesium

Novel hybrid coatings on pure magnesium were prepared by combining plasma electrolytic carburizing(PEC)with micro-arc oxidation(MAO)to further enhance the anti-corrosion property in this paper.Scanning electron microscopy(SEM)was used to observe the microstructure of the coatings,meanwhile,energy dispersive spectrometry(EDS)and X-ray diffraction(XRD)were separately used to investigate the elemental as well as phase compositions of the coatings.The anti-corrosion property of the coatings was evaluated by potentiodynamic polarization curves as well as electrochemical impedance spectroscopy(EIS).The results show that PEC process is closely related with the effects of adsorption as well as diffusion of the activated carbon atoms,and it can provide a favorable pretreatment surface with predesigned chemical composition to obtain a new kind of phase,namely Si C with superior corrosion resistance and chemical stability,in the following PEC+MAO hybrid coatings.Meanwhile,PEC preprocessing also can afford an excellent micro-structure to increase the coating thickness as well as to improve the compactness of the PEC+MAO hybrid coatings.During the fabrication process of the PEC+MAO hybrid coatings,an overlapping phenomenon in regard to coating thickness can be observed instead of heaping up layer by layer.Compared with both single PEC surface modification layers as well as single MAO coatings,the PEC+MAO hybrid coatings exhibit more superior anti-corrosion property.Especially,the EIS data reveal that the PEC+MAO hybrid coatings can act as an effective protection system to provide relatively excellent long-range anti-corrosion protection.Note also that employing same MAO technique for both single MAO treatment as well as PEC+MAO combining procedure is the key to this research.

An electrochemical method for evaluating the resistance to cathodic disbondment of anti-corrosion coatings on buried pipelines

Methods for evaluating the resistance to cathodic disbondment （RCD） of anti-corrosion coatings on buried pipelines were reviewed. It is obvious that these traditional cathodic disbondment tests （CDT） have some disadvantages and the evaluated results are only simple figures and always rely on the subjective experience of the operator. A new electrochemical method for evaluating the RCD of coatings, that is, the potentiostatic evaluation method （PEM）, was developed and studied. During potentiostatic anodic polarization testing, the changes of stable polarization current of specimens before and after cathodic disbonding （CD） were measured, and the degree of cathodic disbondment of the coating was quantitatively evaluated, among which the equivalent cathodic disbonded distance AD was suggested as a parameter for evaluating the RCD. A series of testing parameters of the PEM were determined in these experiments.

The Effect of Cerium Dioxide (CeO_2) in an Anti-corrosion and Self-lubricating Coating

The effect of cerium dioxide(CeO_2)as an additive on the structure and properties of a melting type coating has been studied by means of microhardness measurement,scanning electron microscopy and thermal analysis. The results show that cerium dioxide can modify the microstructure and tribological properties of the coating. Model LIC-23 composite coating which contains CeO_2 performs well as a self-lubricating coating in hydrochloric acid solution.

An Abrasion Resistant TPU/SH-SiO_(2) Superhydrophobic Coating for Anti-Icing and Anti-Corrosion Applications

As a passive anti-icing strategy,properly designed superhydrophobic coatings can demonstrate outstanding performances.However,common preparation strategies for superhydrophobic coatings often lead to environmental pollution,high energy-consumption,high-cost and other undesirable issues.Besides,the durability of superhydrophobic coating also plagues its commercial application.In this paper,we introduced a facile and environment-friendly technique for fabricating abrasion-resistant superhydrophobic surfaces using thermoplastic polyurethane(TPU)and modified SiO_(2)particles(SH-SiO_(2)).Both materials are non-toxicity,low-cost,and commercial available.Our methodology has the following advantages:use of minimal amounts of formulation,take the most streamlined technical route,and no waste material.These advantages make it attractive for industrial applications,and its usage sustainability can be promised.In this study,the mechanical stability of the superhydrophobic surface was evaluated by linear wear test.It is found that the excellent wear resistance of the superhydrophobic coating benefits from the characteristics of raw materials,the preparation strategy,and the special structure.In anti-icing properties test,the TPU/SH-SiO_(2)coating exhibits the repellency to the cold droplets and the ability to extend the freezing time.The electrochemical corrosion measurement shows that the asprepared superhydrophobic surface has excellent corrosion resistance that can provide effective protection for the bare Q235 substrates.These results indicate that the TPU/SH-SiO_(2)coating possesses good abrasion resistance and has great potential in anti-corrosion and anti-icing applications.

A novel anti-corrosion coating for magnesium alloy

A novel enviromental protective water based metallic coating were prepared on the surface of AZ91D magnesium alloy. The properties and structure of the coating were investigated by adhension test, hardness test, heat resisting test, neutral salt spray test and scanning electron microscopy (SEM). The results show that the coating has a stepped structure which can achieve good adhesion of first-grade, heat resistance temperature of 400℃, hardness of HV_ 0.50/30210 and anti-corrosion time of 250h in salt spray test. Meanwhile, the film forming and corrosion mechanism of the coating were also put forward based on the results of the Fourier transform infrared spectroscopy (FTIR) test and electrochemical impedance spectroscopy (EIS) test.

Preparation of a TiO_(2)@o-Vanillin@TEOS-APTES Nanocontainer and Its Anti-Corrosion Performance on Steel

A TiO_(2)@o-vanillin@TEOS-APTES nanocontainer was prepared by an experimental process in which,firstly,2-hydroxy-3-methoxybenzaldehyde(o-vanillin)was loaded in a TiO_(2) container to obtain TiO_(2)@o-vanillin.Then,TiO_(2)@o-vanillin was encapsulated by tetraethyl orthosilicate(TEOS).Finally,3-aminopropyl triethoxysilane(APTES)was used to modify the obtained sample.The morphology,structural phase and thermal stability of the TiO_(2)@o-vanillin@TEOS-APTES nanocontainer were analyzed using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR),X-ray diffractometry(XRD)and thermal gravimetric analysis(TG).The release rate of o-vanillin was investigated using an ultraviolet-visible(UV-vis)spectrometer.The anti-corrosion performances of the epoxy,epoxy@o-vanillin and epoxy@TiO_(2)@o-vanillin@TEOS-APTES coatings on steel sheets were evaluated using an electrochemical method and scarification experiments.The results showed that the impedance value of the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating was two orders of magnitude higher than that of the blank epoxy coating,and one order of magnitude higher than that of the epoxy@o-vanillin coating.The maximum inhibition rate of the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating on the steel can reach 97.3%.The scarification experiments confirmed that the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating had the best anti-corrosion performance.

Anti-Corrosion Test on Basal Slope Protection Materials

Through the introduction of the anti-corrosion test schemes, the test equipments and the test procedure for three kinds of basal slop protection materials including fence, mixed stump and geo-textile, this paper comes to a conclusion about the analysis of the anti-corrosion test, revealing that among all of the common basal slop protection materials, mixed stump and fence are with Class II anti-corrosion property, while the geo-textile is with the first-class anti-corrosion property.

航天员出舱活动用移动扶手原型设计与试验验证

针对空间站舱外固定扶手难以满足航天员复杂舱外作业需求的问题,提出一种航天员出舱活动用的移动扶手,并对其进行了参数设计与试验研究。首先,在充分考虑着舱外服加压航天员手部施力特性的基础上,对舱外移动扶手操作机构的几何尺寸和弹簧刚度进行了参数设计。其次,为满足航天员在轨出舱单手操作移动扶手的人机工效学需求,对操作机构进行了自锁设计,并利用ADAMS对操作机构进行了动力学仿真分析,仿真结果表明,各操作机构能够实现自锁功能,且操作力符合着服加压航天员手部施力特性。最后,研制了舱外移动扶手原理样机,从功能、环境适应性及人机工效学方面进行了试验验证。试验结果表明:所述方案可顺利完成舱体扶手夹持、长度和角度调节,且实测操作力与理论值基本吻合,在力学和热学环境试验前后操作力无明显变化,各操作机构满足空间站舱外低轨环境及人机工效学要求。

舱外航天服除湿装置除湿及再生特性

在舱外航天服环境控制与生命保障系统中,除湿装置能够对介质气体中湿气进行去除,可有效提高CO_(2)分压传感器的测量灵敏度。为适应舱外航天服的使用模式、出舱时间,同时延长除湿装置在舱外航天服中的使用次数,提出了使用舱外航天服氧瓶剩余氧气进行硅胶吹扫再生的方法,为分析除湿装置的除湿特性、再生特性以及使用模式对其性能影响,首先对比了氯化钙、变色硅胶和细孔硅胶等干燥剂的物理特性和除湿性能;其次,采用纯氧吹扫的方式对变色硅胶进行了除湿再生试验研究;最后,对比分析了除湿装置使用模式对其除湿性能的影响特性。试验结果表明:CaCl_(2)颗粒的除湿效果优于变色硅胶,但吸湿后CaCl_(2)干燥剂会出现坍塌短路的现象;在相同试验条件下,变色硅胶的连续除湿时间为32 h,而细孔硅胶的连续除湿时间为23 h;除湿过程经过暂停后,除湿特性发生变化,间断模式的出口绝对湿度随着除湿时间的增加而有所增大,并且高于正常模式下的出口绝对湿度。变色硅胶的物理特性稳定且在满足除湿要求下的除湿时间较长,更适用于该系统中的除湿装置;且变色硅胶经过纯氧吹扫后可循环使用,具备多次除湿功能;间断模式会造成硅胶内部含水量的重新分配,降低除湿装置内硅胶的整体吸湿能力。本研究为舱外航天服环境控制与生命保障系统中除湿装置干燥剂的选择以及再生特性的优化提供了基础数据和理论指导。

空间站机械臂人机系统设计与验证

在充分调研国际空间站机械臂人机系统设计的基础上,结合中国空间站机械臂人机协同作业需求,建立了空间站机械臂“管理-设计-验证”全周期人机设计体系,通过人机项目规划、人机功能分配等管理要素,针对性地开展了空间机械臂人机系统详细设计,最后,从仿真分析、地面验证、在轨验证三大方面对人机系统进行了全要素全流程的验证,结果表明空间站机械臂人机系统设计合理,可应用于后续航天员出舱活动,保障航天员出舱活动安全、高效。研究结果将为空间机械臂人机系统设计与验证提供体系借鉴和工程指导。

空间站电动工具开关按钮性能退化特性加速寿命试验与可靠性评估

面向中国空间站在轨寿命评估与延寿需求,以舱外电动工具开关按钮为对象,开展综合考虑在轨长期贮存与短期作业交替影响的加速寿命试验,设置多温度水平,研究开关按钮性能退化特性和失效机理,并采用基于伪寿命分布的可靠性评估方法开展评估工作。加速寿命试验结果显示:开关按钮在50℃和80℃温度下出现按压力松弛现象,按压力退化与时间呈线性关系;在110℃和140℃温度下出现卡滞、卡死和润滑脂溢出现象,且按压力迟滞量在贮存后期显著增大。可靠性评估结果显示:开关按钮满足10年寿命末期可靠度0.9954的指标要求。文章所述研究方法可为空间站内其他长期贮存单机的可靠性评估提供借鉴。

空间站舱外电子设备维修性设计及验证

天宫空间站舱外布置了大量电子设备用来实现通信、控制、供配电、热控等功能,这些舱外电子设备的维修性设计成为保障空间站长期在轨运营的必要手段。为解决空间站舱外电子设备在轨维修难度大的问题,通过对出舱维修难点进行分析,提出了舱外电子设备的通用维修性设计方法,并以空间站舱外电子设备为例,对其机械设计、电气设计、总装布局等方面的维修性设计方法进行研究,并通过地面试验验证了维修性设计方法的合理性与正确性。

Robustα-Fe_(2)O_(3)/Epoxy Resin Superhydrophobic Coatings for Anti-icing Property

α-Fe_(2)O_(3)/epoxy resin composite superhydrophobic coating was prepared withα-Fe_(2)O_(3) nanoparticles and epoxy resin by spin coating method.The coating without epoxy resin has higher contact angle(CA)and lower ice adhesion strength(IAS),but the mechanical properties are poor.Theα-Fe_(2)O_(3)/epoxy resin composite superhydrophobic coating exhibits good mechanical durability.In addition,compared with the bare aluminum substrate,the Ecorr of the composite coating is positive and the Jcorr is lower.The inhibition efficiency of the composite coating is as high as 99.98%in 3.5 wt%NaCl solution.The difference in the microstructure caused by the two preparation methods leads to the changes in mechanical properties and corrosion resistance of composite superhydrophobic coating.

Hexagonal boron nitride based slippery liquid infused porous surface with anti-corrosion, anti-contaminant and anti-icing properties for protecting magnesium alloy

In an era where the concept of green development is deeply rooted, magnesium(Mg) alloy as a light metal has a long-term development prospect in the process of energy saving, emission reduction and environmental improvement. However, anti-corrosion performance of Mg alloy is poor due to the high chemical activity and low equilibrium potential, which limits the development of Mg alloy products.Herein, three-dimensional mesopore hollow polypyrrole spheres(MHPS) were prepared, and the MHPS was inserted into the middle of the stacked hexagon boron nitride(h-BN) lamellae, which allowed the hBN to be separated forming a further composite with abundant pore structure. Subsequently, the MHPS/hBN-OH composite was uniformly sprayed on the Mg alloy surface via simple spraying method to form the superhydrophobic surface(SHS). Finally, the slippery liquid infused porous surface(SLIPS) was successfully fabricated by applying drops of silicone lubricant on the superhydrophobic coating surface. After a series of characterization and testing, the results showed that the stacking of h-BN lamellae was significantly reduced after h-BN was successfully embedded by MHPS. In addition, the fabricated SLIPS have excellent self-cleaning, mechanical stability, anti-icing and anti-corrosion properties. Therefore, the method of embedding polymer microspheres not only offers a new strategy for h-BN exfoliation, but also the successful prepared SLIPS largely retards the corrosion of Mg alloy while providing new ideas for the development of SLIPS.