Glass-SiB_(6)涂层在1573 K下的氧化行为研究

SiB_(6)陶瓷作为Si-B二元合金稳定相,具有良好的高温性能.为了提高碳/碳(C/C)复合材料在1 573 K下的抗氧化性,采用脉冲电弧放电沉积法(PADD)在SiC-C/C上制备了SiB_(6)涂层,并在此基础上用烧制法、热浸渍法(HD)制备了玻璃密封层.结果表明SiB_(6)在1 573 K空气中氧化会产生流体硼硅酸盐玻璃愈合涂层产生的缺陷,玻璃密封层的存在使SiB_(6)发挥了更好的作用.在烧制法制备的玻璃层的保护下,氧化105 h后试样质量增加0.06%,表现出良好的抗氧化性.熔融玻璃层和B_(2)O_(3)蒸发是涂层失效的主要原因.

HVOF喷涂CoCrWSi和Stellite-6涂层的结构与高温摩擦学性能研究

目的提高F92耐热钢基体在600、630℃下的高温耐磨性能。方法采用超音速火焰喷涂方法(High velocity oxy-fuel,HVOF)在F92表面制备CoCrWSi、Stellite-6两种涂层,利用扫描电子显微镜(Scanning electron microscope,SEM)和X射线衍射仪(X-ray diffraction,XRD)分析涂层的表面、截面形貌和物相组成,通过显微维氏硬度计(HV-1000STA)、高温摩擦磨损试验机(UMT-TRIBOLAB)、二维轮廓仪(TencorD-100)测定其显微硬度、高温摩擦学性能和磨痕体积。结果采用超音速火焰喷涂技术制备的CoCrWSi、Stellite-6两种涂层表面较平整,与基体结合紧密,内部组织均匀无裂纹,涂层的厚度约为200μm。XRD分析表明,CoCrWSi、Stellite-6涂层在室温下的物相都由γ(Co)、Cr_(7)C_(3)、CrSi_(2)组成。硬度及耐磨性能测试显示,CoCrWSi、Stellite-6涂层的维氏硬度相较于F92基体分别提高了3.12、2.68倍,F92耐热钢在600、630℃时的平均摩擦因数分别为0.87、0.86,体积磨损率分别为0.49×10^(-4)、1.11×10^(-4)mm^(3)/(N·m),其磨损机理主要为疲劳磨损、黏着磨损、氧化磨损。相较于基体,CoCrWSi涂层在2种温度下的平均摩擦因数分别降低了68%、71%,约为0.28、0.25,体积磨损率分别降低了约95%、97%,为0.20×10^(-5)、0.30×10^(-5)mm^(3)/(N·m),这主要归功于内部的Cr2O3、γ(Co)、Co_(3)O_(4)相在高温摩擦过程中具有良好的润滑效果。Stellite-6涂层也能在一定程度上改善基体的高温耐磨性能,其平均摩擦因数为0.85、0.71,体积磨损率为0.32×10^(-4)、0.57×10^(-4)mm^(3)/(N·m)。2种涂层的主要磨损机理均为磨粒磨损和黏着磨损。结论采用超音速火焰喷涂制备的CoCrWSi、Stellite-6涂层可以改善F92耐热钢在600、630℃下的耐高温滑动磨损性能,且CoCrWSi涂层的防护效果更佳。

生物质植酸改性聚氨酯涂层锦纶6织物的制备及其阻燃性能

针对聚氨酯涂层锦纶6织物阻燃性能差、熔滴严重的问题,通过采用生物质植酸对水性聚氨酯进行改性,开发环保高效的阻燃体系对锦纶6织物进行涂层改性。测试分析了涂层锦纶6织物的阻燃性能、耐水洗性能、耐静水压、热稳定性和阻燃机制等。研究结果表明:聚氨酯涂层锦纶6织物在垂直燃烧测试中完全燃烧,损毁长度为30 cm,熔滴引燃脱脂棉,植酸/植酸钠改性聚氨酯涂层锦纶6织物在垂直燃烧中能够自熄,无熔滴产生,损毁长度降低至12.4 cm,极限氧指数升高至29.0%;经过10次水洗后涂层锦纶6织物仍能自熄,具有较好的阻燃性能和耐水洗性能;涂层锦纶6织物的热分解提前,经热分解后磷元素保留在残炭中,参与成炭,植酸盐主要通过固相阻燃机制提高涂层锦纶6织物的阻燃性能。

Coupling Sb_(2)WO_(6)microflowers and conductive polypyrrole for efficient potassium storage by enhanced conductivity and K^(+) diffusivity

Although metal oxide compounds are considered as desirable anode materials for potassium-ion batteries(PIBs)due to their high theoretical capacity,the large volume variation remains a key issue in realizing metal oxide anodes with long cycle life and excellent rate property.In this study,polypyrroleencapsulated Sb_(2)WO_(6)(denoted Sb_(2)WO_(6)@PPy)microflowers are synthesized by a one-step hydrothermal method followed by in-situ polymerization and coating by pyrrole.Leveraging the nanosheet-stacked Sb_(2)WO_(6)microflower structure,the improved electronic conductivity,and the architectural protection offered by the PPy coating,Sb_(2)WO_(6)@PPy exhibits boosted potassium storage properties,thereby demonstrating an outstanding rate property of 110.3 m A h g^(-1)at 5 A g^(-1)and delivering a long-period cycling stability with a reversible capacity of 197.2 m A h g^(-1)after 500 cycles at 1 A g^(-1).In addition,the conversion and alloying processes of Sb_(2)WO_(6)@PPy in PIBs with the generation of intermediates,K_(2)WO_(4)and K_(3)Sb,is determined by X-ray photoelectron spectroscopy,transmission electron microscopy,and exsitu X-ray diffraction during potassiation/depotassiation.Density functional theory calculations demonstrate that the robust coupling between PPy and Sb_(2)WO_(6)endues it with a much stronger total density of states and a built-in electric field,thereby increasing the electronic conductivity,and thus effectively reduces the K^(+)diffusion barrier.

Surface Coating Enabling Sulfide Solid Electrolytes with Excellent Air Stability and Lithium Compatibility

All-solid-state lithium metal batteries(ASSLMBs)featuring sulfide solid electrolytes(SEs)are recognized as the most promising next-generation energy storage technology because of their exceptional safety and much-improved energy density.However,lithium dendrite growth in sulfide SEs and their poor air stability have posed significant obstacles to the advancement of sulfide-based ASSLMBs.Here,a thin layer(approximately 5 nm)of g-C_(3)N_(4)is coated on the surface of a sulfide SE(Li_(6)PS_(5)Cl),which not only lowers the electronic conductivity of Li_(6)PS_(5)Cl but also achieves remarkable interface stability by facilitating the in situ formation of ion-conductive Li3N at the Li/Li_(6)PS_(5)Cl interface.Additionally,the g-C_(3)N_(4)coating on the surface can substantially reduce the formation of H_(2)S when Li_(6)PS_(5)Cl is exposed to humid air.As a result,Li-Li symmetrical cells using g-C_(3)N_(4)-coated Li_(6)PS_(5)Cl stably cycle for 1000 h with a current density of 0.2 mA cm^(-2).ASSLMBs paired with LiNbO_(3)-coated LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2)exhibit a capacity of 132.8 mAh g^(-1)at 0.1 C and a high-capacity retention of 99.1%after 200 cycles.Furthermore,g-C_(3)N_(4)-coated Li_(6)PS_(5)Cl effectively mitigates the self-discharge behavior observed in ASSLMBs.This surface-coating approach for sulfide solid electrolytes opens the door to the practical implementation of sulfide-based ASSLMBs.

6%戊唑醇悬浮种衣剂包衣对小麦条锈病的防治效果

旨在明确6%戊唑醇悬浮种衣剂包衣处理对小麦条锈病的防治效果,为小麦条锈病的防控提供参考.以小麦品种'铭贤169'为试验材料,15%三唑酮可湿性粉剂作为对照药剂,采用播前种子包衣法,测定6%戊唑醇悬浮种衣剂对小麦条锈病的防治效果.结果表明,供试药剂6%戊唑醇悬浮种衣剂对小麦出苗安全,对苗期小麦条锈病有较好的防效,6%戊唑醇悬浮种衣剂处理的防效均显著高于15%三唑酮可湿性粉剂(P<0.05),达到88.35%以上.因此,6%戊唑醇悬浮种衣剂可在生产上作为小麦防治药剂进行推广应用.

Structural characteristics and high-temperature tribological behaviors of laser cladded NiCoCrAlY−B_(4)C composite coatings on Ti6Al4V alloy

In order to improve the hardness and tribological performance of Ti6Al4V alloy,NiCoCrAlY-B_(4)C composite coatings with B_(4)C of 5%,10%and 15%(mass fraction)were fabricated on its surface by laser cladding(LC).The morphologies,chemical compositions and phases of obtained coatings were analyzed using scanning electronic microscope(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD),respectively.The effects of B_(4)C mass fraction on the coefficient of friction(COF)and wear rate of NiCoCrAlY-B_(4)C coatings were investigated using a ball-on-disc wear tester.The results show that the NiCoCrAlY-B_(4)C coatings with different B_(4)C mass fractions are mainly composed of NiTi,NiTi_(2),α-Ti,CoO,AlB_(2),TiC,TiB and TiB_(2)phases.The COFs and wear rates of NiCoCrAlY-B_(4)C coatings decrease with the increase of B_(4)C content,which are contributed to the improvement of coating hardness by the B_(4)C addition.The wear mechanisms of NiCoCrAlY-B_(4)C coatings are changed from adhesive wear and oxidation wear to fatigue wear with the increase of B_(4)C content.

Effect of N-ion implantation and diamond-like carbon coating on fretting wear behaviors of Ti6Al7Nb in artificial saliva

The tribology behaviors of Ti6Al7Nb,its alloy with N-ion implantation,and its alloy with diamond-like carbon(DLC)coating were investigated in artificial saliva.Fretting wear tests of untreated,N-ion implanted and DLC coated Ti6Al7Nb alloys plate against a Si3N4ball were carried out on a reciprocating sliding fretting wear test rig.Based on the analysis of X-ray diffraction,Raman spectroscopy,3-D profiler,SEM morphologies and frictional kinetics behavior analysis,the damage behavior of surface modification layer was discussed in detail.The results indicated that the fretting wear behavior of Ti6Al7Nb alloy with N-ion implantation was increased with the dose increase of the implanted nitrogen ions.Moreover,the DLC-coated Ti6Al7Nb alloy with low ion implantation could improve the fretting wear behavior greatly.In addition,the Ti6Al7Nb with DLC coating had better ncorrosion resistance due to the special compact structure.All results suggested that the Ti6Al7Nb with DLC coating had better wear resistance than that with N-ion implantation in artificial saliva.

Composition and structure of coatings on Ti-6Al-4V alloy by micro-plasma oxidation in NaAlO2 solution

Compound ceramic coatings on Ti-6Al-4V alloy were prepared for different time by pulsed bi-polar micro-plasma oxidation (MPO) in NaAlO2 solution. The phase composition was studied by XRD. And the electrochemical impedance spectra (EIS) of the coatings were measured to study the structure of the coatings, combined with the surface morphology. Using the proper EIS interpreting software, the "equivalent circuit" of the coatings was established, and meanwhile fitting values of equivalent element were obtained. The results show that the coating is composed of Al2 TiO5, α-Al2O3 and rutile TiO2, of which Al2 TiO5 is the main crystalline. Increasing the MPO time, the contents of Al2TiO5, rutile TiO2 and α-Al2O3 in the surface of the coating increase. And the EIS analysis and the surface morphology of the coatings illustrates the double-layer structure of the coatings, and the outer layer is loosen and the inner layer is compact. With the increase of the oxidizing time, the surface coarse degree of the coatings and the porosity of the outer layer of the coating are increased while the compactness of the inner layer of the coating is improved.

Microstructure and Property of Al‑FeCoNiCrAl High Entropy Alloy Composite Coating on Ti‑6Al‑4V During Annealing Using MA Method

Al-FeCoNiCrAl high entropy alloy(HEA) composite coatings were prepared on Ti-6Al-4V via highenergy mechanical alloying(MA). The microstructures and phase composition of the coatings were studied. A continuous and dense coating could be fabricated at a ratio of 35%(weight fraction)Al-FeCoNiCrAl after 4 h milling.The results showed that the thickness of the composite coatings increased first and then decreased with the increase of milling time. And the hardness of coating increased with the increase of milling time. The phase changed during the annealing process. Part of the initial body-centered cubic(BCC)phase of the composite coatings changed into the L12 phase,(Ni,Co)3Al4 and σ phase after annealing above 550 ℃. Ordered BCC was found in the coatings after annealing above 750 ℃. Only BCC and ordered BCC appeared in coatings after annealing above 1 050 ℃. The hardness of the coatings after annealing at 550 ℃ and 750 ℃ was higher than before because of spinodal decomposition and high hardness σ phase. The hardness of the coatings after annealing at 1 050 ℃ decreased because residual stress released.

Behavior of NiCrAlY coating on the TC6 titanium alloy

A NiCrAlY coating was deposited on the TC6 titanium substrate by arc ion plating （ALP）. The structure and morphologies of the NiCrAlY coating were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, and the influence of vacuum heat treatment on the element diffusion behavior was studied. The results showed that the y＇-Ni3Al phase was precipitated on the NiCrAlY coating after heat treatment. The Ni3（AI,Ti）, TiNi, and Ti2Ni intermetallic layers appeared at the interface from the outside to the inside at 700℃, and the thickness of the intermetallic layers increased with the increase in temperature. At 700℃ Ti and Ni were the major diffusion elements, and the diffusion of Cr was observed when the heat treatment temperature increased up to 870℃. The violent inward diffusion of Ni at 950℃ resulted in the degradation of the NiCrAlY coating.

Preparation of Hydroxyapatite-titanium Dioxide Coating on Ti6Al4V Substrates using Hydrothermal-electrochemical Method

Ti6Al4V substrates were anodized in a 0.5 mol/L H_2SO_4 solution at applied voltages of 90-140 V.A hydroxyapatite-titanium oxide（HA-TiO2）coating was then deposited on the anodized Ti6Al4 V substrates via a hydrothermal-electrochemicalmethod at a constant current.The obtained films and coatings were characterized by X-ray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,and Fourier-transform infrared spectrometry.The microstructures of the porous films on the Ti6Al4 V substrates were studied to investigate the effect of the anodizing voltage on the phase and morphology of the HATiO_2 coating.The results indicated that both the phase composition and the morphology of the coatings were significantly influenced by changes in the anodizing voltage.HA-TiO_2 was directly precipitated onto the surface of the substrate when the applied voltage was between 110 and 140 V.The coatings had a gradient structure and the HA exhibited both needle-like and cotton-like structures.The amount of cotton-like HA structures decreased with an increase in voltage from 90 to 120 V,and then increased slightly when the voltage was higher than 120 V.The orientation index of the（002）plane of the coating was at a minimum when the Ti6Al4 V substrate was pretreated at 120 V.

激光熔覆Stellite 6合金涂层的组织和耐腐蚀性能研究

采用半导体激光器在H13钢基体表面制备了Stellite 6钴基合金涂层,利用X射线衍射仪(XRD)、光学显微镜(OM)和电化学工作站研究了不同激光功率下涂层的物相组成、显微组织及电化学腐蚀行为。结果表明,激光功率对涂层的物相组成没有明显影响,涂层均由γ-Co、CoCX和Cr7C3相组成。随着激光功率的增大,涂层由柱状晶和少量树枝晶的混合组织,转变为细小均匀的等轴晶,再至粗大的柱状树枝晶。不同激光功率下Stellite 6涂层在3.5%(质量分数)NaCl溶液中的自腐蚀电位均高于H13钢,而腐蚀电流密度均低于H13钢,且激光功率为3000 W时涂层具有最佳的耐腐蚀性能。电化学阻抗谱规律与极化曲线保持一致,表明了激光熔覆Stellite 6合金涂层可以有效提高H13钢的耐腐蚀性能。

Effects of different pack aluminizing fillers on the aluminide coatings of Ti-6Al-4V alloy and their high-temperature oxidation behaviors

The aluminide coating process of Ti-6Al-4V alloys with different fillers(100wt.% Al_2O_3,50wt% Y_2O_3+50wt.% Al_2O_3 and 100wt.% Y_2O_3) for improvement of the oxidation resistance were investigated.The results show that the filler does not only participate in the aluminizing process,but also has much effect on the coating composition.The XRD analysis reveals that the aluminide coating with filler Al_2O_3 is predominant with TiAl_3 and TiAl phases;while the aluminide coatings with filler Y_2O_3+Al_2O_3 are predominant with Ti_3Al phase.The oxidation kinetics shows that different fillers affect greatly the oxidation resistance of aluminide coating,and the oxidation resistance of aluminized specimens with pack aluminizing filler Al_2O_3 are about 5-8 times than that of the aluminized specimens with other pack aluminizing fillers.

Study on High Temperature Corrosion Performance and Protective Coatings of Mo-containing Intermetallic Alloy IC6

Oxidation and hot corrosion behaviors of Ni3Al-Mo (IC6) alloy were studied. Surface protective coatings were also developed for the engineering application of the alloy. The sputtered NiCrAlY coating may greatly improve the oxidation and hot corrosion resistance of IC6 alloy by forming a protective Al2O3 scale, and the coating shows little effect on the mechanical properties of IC6 alloy.

Improving the stability,lithium diffusion dynamics,and specific capacity of SrLi_(2)Ti_(6)O_(14)via ZrO_(2)coating

SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermore,ZrO_(2)coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film.As a result,the redox polarization was reduced,and the reversibility of the electrochemical reaction was enhanced.Particularly,SLTO-ZrO_(2)-2 sample delivers a high initial lithiation capacity of 283.6 mA h g^(-1),and the values maintain at 251.7,228.0,207.4,175.3,and 147.7 mA h g^(-1)at the current densities of 0.13,0.26,0.54,1.31,and 2.62 A g^(-1),respectively.Our experiment also confirmed that SLTO materials coated with ZrO_(2)are suitable for high power density applications,and the lithiation specific energy efficiency of SLTO-ZrO_(2)-2 is 200%as high as that of pure SLTO at a power density of 1257 W kg^(-1).

玻璃基TiO_(2)/Bi_(2)MoO_(6)薄膜的生长及性能研究

采用溶胶-凝胶法和水热法制备TiO_(2)/Bi_(2)MoO_(6)薄膜,采用X射线衍射(XRD)、紫外可见光谱、接触角测试等技术对薄膜的晶相组成、接触角等微观结构进行表征分析,研究了热处理温度、TiO_(2)/Bi_(2)MoO_(6)复合薄膜玻璃的层数对产品亲水性、透过率和光催化性能的影响,结果表明:TiO_(2)/Bi_(2)MoO_(6)复合后的薄膜可以改善纯TiO_(2)薄膜的亲水性能,随着Bi_(2)MoO_(6)复合量的增大,复合物的降解效率提高,当450℃下在紫外光照射90min时光催化性能最好,对罗丹明B的降解率达到42.72%。

表面包覆CaSn(OH)_6的锌酸钙的制备及其性质

采用化学沉积法在四边形锌酸钙表面包覆一层金属锡化合物。利用X射线衍射、扫描电子显微镜、电化学阻抗谱、Tafel曲线以及充放电循环(用做锌镍电池的负极材料)等方法,对包覆前后的锌酸钙样品进行表征。结果表明:包覆物化学组成为CaSn(OH)6,该包覆物在锌酸钙的表面分布均匀,沉积较为致密;包覆后的锌酸钙材料具有更好的耐腐蚀性能,且其电化学循环性能良好,经过135次循环后,电池放电容量仍保持设计容量的65.5%。

(NaPO_3)_6对AZ91D镁合金微弧氧化陶瓷层电化学腐蚀特性的影响

在Na2SiO3-KOH电解液体系中添加一定量的(NaPO3)6,利用微弧氧化(MAO)技术在AZ91D镁合金表面制备了原位生长的陶瓷层.采用动电位极化和电化学阻抗谱(EIS)技术研究了添加(NaPO3)6前后,制备的陶瓷层在3.5%(w)NaCl溶液中的室温电化学行为.结果表明,添加(NaPO3)6后,陶瓷层的自腐蚀电位显著上升,自腐蚀电流密度明显减小.这主要是由于(NaPO3)6增加了反应过程中基体镁合金表面的"氧空位"和溶液中PO34-的含量,促使元素Mg在金属/膜层(M/F)界面上快速形成相应氧化物,从而增加了陶瓷层的厚度和致密性.根据电化学反应体系和陶瓷层的特殊结构,建立了合理的等效电路,并结合EIS数据,分析了添加(NaPO3)6提高陶瓷层耐电化学腐蚀性能的机理.

不同(NaPO_3)_6浓度对镁合金微弧氧化膜的影响

为了考察不同(NaPO3)6浓度对镁合金微弧氧化膜的影响,将AZ91D镁合金在碱性(NaPO3)6溶液中进行微弧氧化处理.结果表明:在(NaPO3)6溶液中获得含有MgO、MgAlO4、α-Al2O3等高熔点高耐蚀性物相的陶瓷质氧化膜,显著提高镁合金的耐蚀性.随着(NaPO3)6质量浓度的增加,微弧氧化过程的起弧电压逐渐降低,获得的微弧氧化膜层逐渐增厚,其耐蚀性也逐步提高,但(NaPO3)6质量浓度的增加对耐蚀性提高的贡献存在一个临界值.当膜层表面出现龟裂般的微裂纹时,其对耐蚀性的恶化将会增强,削弱由于膜厚增加及膜层中优质耐蚀物相的存在对耐蚀性的提高.