Preparation and performance of electrodeposited Ni-TiB₂-Sm₂O₃ composite coatings

Sm2O3 and TiB2 were used as codeposited particles in electrodeposition Ni-TiB2-Sm2O3 composite coatings to improve its performance. Ni-TiB2-Sm2O3 composite coatings were electrodeposited in the nickel sulfate,hexadecylpyridinium bromide and cetyltrimethylammonium bromide solution containing TiB2 and Sm2O3 particles. The content of codeposited Sm2O3 in the composite coating was controlled by changing the concentrations of Sm2O3 particles in the solution. The composite coatings were characterized with X-ray diffraction(XRD) and inductively coupled plasma-atomic emission spectrometer(ICP-AES) . The effects of Sm2O3 content on microhardness,wear weight loss and friction coefficient of composite coatings were investigated,respectively. The microhardness of the Ni-TiB2-Sm2O3 composite coatings was 19.35%,16.58%,2.03% higher than that of the Ni coating,Ni-Sm2O3 and Ni-TiB2 composite coatings,respectively. The wear weight loss of the Ni-TiB2-Sm2O3 composite coatings was 7,2.33,1.22 times lower than that of the Ni coating,Ni-Sm2O3 and Ni-TiB2 composite coatings,respectively. The friction coefficient of the Ni coating,Ni-Sm2O3,Ni-TiB2 and Ni-TiB2-Sm2O3 composite coatings were 0.712,0.649,0.850 and 0.788,respectively. The loading-bearing capacity and the wear-reducing effect of the Sm2O3 particles were closely related to the content of Sm2O3 particles in the composite coatings.     

Al2O3含量对Ni-W-Al2O3复合镀层性能的影响

采用直流电沉积技术在45#钢基体上制备Ni-W-Al2O3复合镀层,通过显微硬度计、摩擦磨损试验机、划痕仪等研究Al2O3颗粒含量对复合镀层的力学性能及摩擦磨损性能等的影响,并用SEM、XRD对复合镀层的表面断面形貌、物相结构进行分析.结果表明,Ni-W-Al2O3复合镀层为晶态结构,其耐磨性能明显优于Ni-W镀层,且随着Al2O3颗粒含量的增加,复合镀层的摩擦系数呈现出先减小后增大趋势.磨损形式主要表现为粘着磨损与磨粒磨损.复合镀层与基体之间结合牢固,结合力大小约为70~80 N.当Al2O3含量为5 g/L时,复合镀层的综合性能最优.     

Preparation and performance of electrodeposited Ni-TiB2-Sm2O3 composite coatings

Sm₂O₃ and TiB₂ were used as codeposited particles in electrodeposition Ni-TiB₂-Sm₂O₃ composite coatings to improve its performance. Ni-TiB₂-Sm₂O₃ composite coatings were electrodeposited in the nickel sulfate, hexadecylpyridinium bromide and cetyltrimethylammonium bromide solution containing TiB₂ and Sm₂O₃ particles. The content of codeposited Sm₂O₃ in the composite coating was controlled by changing the concentrations of Sm₂O₃ particles in the solution. The composite coatings were characterized with X-ray diffraction (XRD) and inductively coupled plasma-atomic emission spectrometer (ICP-AES). The effects of Sm₂O₃ content on microhardness, wear weight loss and friction coefficient of composite coatings were investigated, respectively. The microhardness of the Ni-TiB₂-Sm₂O₃ composite coatings was 19.35%, 16.58%, 2.03% higher than that of the Ni coating, Ni-Sm₂O₃ and Ni-TiB₂ composite coatings, respectively. The wear weight loss of the Ni-TiB₂-Sm₂O₃ composite coatings was 7, 2.33, 1.22 times lower than that of the Ni coating, Ni-Sm₂O₃ and Ni-TiB₂ composite coatings, respectively. The friction coefficient of the Ni coating, Ni-Sm₂O₃, Ni-TiB₂ and Ni-TiB₂-Sm₂O₃ composite coatings were 0.712, 0.649, 0.850 and 0.788, respectively. The loading-bearing capacity and the wear-reducing effect of the Sm₂O₃ particles were closely related to the content of Sm₂O₃ particles in the composite coatings.     

Corrosion Behavior of Electrodepositing Ni/Al2O3 Composite Coatings under the Presence of NaCl Deposit

The morphology and corrosion behavior of Ni/Al2O3 composite coatings prepared using double-pulsed electrodepositing technique after oxidized under 800℃ NaCl deposit in air environment were analyzed by scanning electrical microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrum (EDS). The results showed that the corrosion of all composite coatings was accelerated under NaCl deposits, and the corrosion products were rather porous with poor adherence to the matrix. Al2)O3 particles in the coatings can refine the grain size and improve the high temperature corrosion resistance of the coatings. Within the test scope, the more Al2O3 particles in the coatings, the lower corrosion rates could be obtained, and the corrosion mechanism was also discussed.     

Preparation and Magnetism of Gd2O3/X-NBR Composites

Series of Gd2O3/X-NBR composites were prepared by in-situ reaction at different temperatures (100 and 160 ℃) and different processing time. The influence of processing time and processing temperature on dispersion of Gd2O3 was investigated, and the relationship between magnetic property and temperature was also discussed. The results show that, the mass magnetizability (χg) descends as temperature rising. Processing temperature and time do not exhibit evidenced effects on the mass magnetizability (χg). All the composites show to be antiferromagnetic.     

Preparation and Luminescence of SrAi2O4:Eu2+, Dy3+ Nano-Particle

SrAl2O4: Eu2 , Dy3 nano-particle luminescence material was prepared by sol-gel method. Influences of synthesis conditions on the particle size and luminescence properties of SrAl2O4: Eu2 , Dy3 were studied. The synthesis process and the properties of the samples were analyzed by DTA, TGA, XRD, SEM. The result suggested that the formation of SrAl2O4: Eu2 , Dy3 sol is a slow heat release process beginning at 500 ℃ and peaking at 759 ℃.SrAl2O4: Eu2 ,Dy3 crystalline was formed at 1100 ℃. The luminescence properties of the SrAl2O4: Eu2 , Dy3 nanoparticle were compared with the conventional SrAl2O4: Eu2 , Dy3 particles. The average particle size of the product is about 30 nm. The excitation spectrum of the sample shows a broad band with peaks at 240, 330, 378 and 425 nm. The emission spectrum is a broadband spectrum with a peak at 523 nm.     

Preparation and photoluminescence of Tb3+ doped SrAl2O4 phosphor by composite combustion method

High-efficient Tb3 activated SrAl2O4 phosphor was synthesized by a combined combustion-solid-state reaction method. The precursor of SrAl2O4:Th3 phosphr was prepared via a combustion process, and then the as-prepared powder was heated in a reductive am-bient of activated carbon at 1250 ℃ for 1 h. The results of X-ray diffraction, scanning electron microscopy, and photoluminescence spectra revealed the influence of the dosage of urea and heated process on the crystallinity, morphology, and photoluminescence of the phosphor.Comparing with tradidonal solid-sate reaction, the crystallinity and emission intensity of the SrAl2O4:Th3 phosphor were improved by this two-step process.     

Preparation and characterization of flower-like SrAl2O4:Eu2+,Dy3+ phosphors by sol-gel process

A flower-like Eu2+ and Dy3+ co-doped SrAl2O4 long-lasting phosphorescent (LLP) phosphor was synthesized via the inorganic- salt-based sol-gel method.The crystal structure,morphology and optical properties of the composite were characterized.X-ray diffraction diffu-sion (XRD) data and DSC-TG curves of the phosphor revealed that the SrAl2O4 crystallites have been formed after the precursor was calcined at 900 °C and to be single-phase SrAl2O4 at 1100 °C.The SEM photographs indicated that the sample exhibited ...     

Preparation and Spectra Properties of BaO-Al2O3-P2O5-Sm2O3 System Protection Glasses

The forming-regions of phosphate glasses doped with high Sm2O3 contents were studied by two step melting method. The relationship between absorption spectrum and rare earth contents was also discussed. The spectra of BASP glasses were measured by spectrophotometer. The results show that the forming regions will shrink with the increase of Al2O3 and it is difficult to form glass when [PO4]/[AlO4]＜2. The forming regions tend to be a closed elliptical, and the intensity of characteristic absorption peak increases gradually with the increase of Sm2O3, the absorption lines broadens non-uniformly and there is approximate linear relation between optical density at the 1064 nm wavelength and Sm2O3 content.     

Probe into deposition mechanism of double pulse electrodepositing Ni-W-P matrix composite coatings containing CeO₂ and SiO₂ nano-particles

Ni-W-P matrix composite coatings reinforced by CeO2 and SiO2 nano-particles were prepared on common carbon steel surface by double pulse electrodeposition and the deposition mechanism was discussed.The results showed that the composite coatings with amorphous structure were obtained as-deposited.The initial growth behavior had alternatives and the nucleation was inhomogeneous because of obvious composition fluctuation.With the pulse deposition time increasing,some pearlite microstructures of the substrate were covered by some deposits and the composition fluctuation disappeared.Forward pulse currents promoted to form a great number of atomic beams composed of Ni,W and P atoms or CeO2 and SiO2 nano-particles as the core,which inhabited the growth of atomic beams.Reverse pulse currents eliminated concentration polarization and dissolved some surface boss of atomic beams.The solution of W and P atoms within Ni grains and embedding of CeO2 and SiO2 nano-particles within Ni-W-P matrix metal made atomic arrangement disordered.Finally,the atomic beams grew to amorphous small particles.     

Al_2O_3La_2O_3Y_2O_3/Cu复合材料的电弧侵蚀特性研究

采用喷射沉积和内氧化法制备出Al2O3La2O3Y2O3/Cu复合材料,研究该材料在直流20 V/20 A的工作条件下触点的电弧侵蚀特性,并与Al2O3/Cu材料进行了对比分析.利用电子天平、扫描电镜等方法分析电弧侵蚀后触点的质量变化和表面微观结构.结果表明,通过添加Y2O3、La2O3稀土氧化物颗粒,可有效降低触头材料的材料转移量.Al2O3La2O3Y2O3/Cu材料的抗熔焊性和抗烧损性优于Al2O3/Cu材料的性能.在直流阻性负载条件下Al2O3La2O3Y2O3/Cu阳极触头表面形成凹坑,阴极触头表面形成凸起,触点表面显示出浆糊状凝固物和喷发坑等电弧侵蚀形貌特征.     

Bi2O3、Dy2O3掺杂对8YSZ导电性能的影响

用柠檬酸溶胶-凝胶法制备了分别掺Bi2O3和Dy2O3的8YSZ前驱体凝胶,凝胶在500℃预烧,压制成圆片状后在1 300℃煅烧2 h。分别研究Bi2O3和Dy2O3的不同掺量对试样的致密度、电导率的影响。结果表明Bi2O3可促进试样的烧结,在300～400℃掺Bi2O3可提高试样的电导率,在400～700℃掺Bi2O3使试样的电导率下降。在8YSZ试样中掺Dy2O3后,试样的致密度、电导率均降低。     

Effect of La2O3 on granular bainite microstructure and wear resistance of hardfacing layer metal

The purpose of this work was to investigate the effect of La2 O3 on the granular bainite microstructure and wear resistance of hardfacing layer metal. The hardfacing layer metals with different contents of La2 O3 were prepared. The microstructures of the hardfacing layer metals were observed by field emission scanning electron microscopy(FESEM) and transmission electron microscopy(TEM). The hardness and wear resistance of the hardfacing layer metals were measured respectively. The results indicated that with the increasing content of La2 O3, the amount of granular bainite increased, while that of martensite decreased and that of retained austenite did not change obviously. When the content of La2 O3 was 2.55 wt.%, the volume fraction of the granular bainite in the hardfacing layer metal was 73.2%. Meanwhile, the wear resistance of the hardfacing layer metal was the largest, which was 12100 min/g. The mismatch between the face(100) of LaAlO3 and the face(100) of δ-Fe was 7.1%. Therefore, LaAlO3 could act as moderate effective heterogeneous nuclei of δ-Fe and the granular bainite could be refined.     

Oxidation of Al2O3-30%TiCN-0.2%Y2O3 Composite

Thecuttingtoolmaterialshavegoodoxidationre sistance ,buttheyareoxidizedathightemperature(about 10 0 0℃ )duringoperation .Themechanicalpropertyofthecuttingtoolmaterialswillbechange d[1,2 ] .Therefore ,researchonoxidationbehaviorofcuttingtoolsmaterialsathi…     

Al2O3-Y2O3 Nano- and Micro-Composite Coatings on Fe-9Cr-Mo Alloy

Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.     

Preparation and Characterization of Sol-Gel Derived Au Nanoparticle Dispersed Y2O3：Eu Films

Gold nanoparticles dispersed Y2O3 films were prepared through a sol-gel method by using yttrium acetate and Au nanoparticles colloid as precursors. The films were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and UV-VIS absorption spectra. XRD patterns and TEM images of Y2O3 ＋ Au films give the same resuits on structure and particle size as that of pure Y2O3 films. The surface plasma resonance （SPR） of Au nanoparticles in Y2O3 ＋ Au film was observed around 550 nm in the absorption spectrum and its position shifts to red with increasing annealing temperature is caused by the increase of dielectric constant of Y2O3 matrix and the size of Au nanoparticles. The second and third order nonlinear optical effects of Y2O3 ＋ Au films were also observed. The photoluminescent properties of Y2O3 ： Eu ＋ Au films were investigated and results indicate that there exist an energy transfer from Eu^3 ＋ to Au nanoparticles and this energy transfer decreases the emission of Eu^3 ＋ in Y2O3 ： Eu ＋ Au film.     

Effect of La_2O_3 on the wear behavior of MoSi_2 at high temperature

Wear behaviors of MoSi2 doped with La2O3 against SiC under different loads at 1000 oC in air were investigated by using an XP-5 type high temperature friction and wear tester. The worn surfaces and phases of the samples were analyzed by scanning electron microscopy (SEM) and X-ray diffraction, respectively. Results showed that the addition of La2O3 could obviously improve wear resistance of MoSi2. Because of the formation of MoO3 phase on the worn surface, La2O3/MoSi2 composite mainly exhibited oxidation and abrasive wear, which was different from the wear form of MoSi2 such as adhesion, oxidation and abrasion.     

Physicochemical properties of a novel composite polymer electrolyte doped with vinyltrimethoxylsilane-modified nano-La2O3

Nano-La2O3 was modified with the vinyltrimethoxylsilane by hydrolysis and a novel poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) based composite polymer electrolyte doped with the modified nano-La2O3 was prepared by phase inversion method. The physicochemical properties were studied by SEM, FT-IR, XRD, TG and electrochemical methods. The results of FT-IR indicated that the nano-La2O3 was successfully modified with vinyltrimethoxylsilane. The XRD analysis showed that the incorporation of modified nano-La2O3 into the polymer electrolyte membranes could effectively reduce the crystallinity of PVDF-HFP, and the characterizations also suggested that thermal stability and electrochemical stability window could reach to 382°C and 5.1V, respectively; the reciprocal temperature dependence of ionic conductivity followed Vogel-Tamman-Fulcher (VTF) relation, ionic conductivity at room temperature was up to 3.5×10-3S/cm and lithium ions transference number was up to 0.42; the interfacial resistance increased at initial value about353Ω/cm2 and reached a steady value about 559Ω/cm2 after 5d storage at 30°C. The fabricated Li/As-prepared electrolytes/LiCoO2 coin cell showed excellent rate and cycle performances.     

Photoluminescent properties of Ca2Gd8(SiO4)6O2: Dy3+ phosphor films prepared by sol-gel process

There are growing interests on phosphor thin films owing to their potential application in high-resolution devices such as cathode ray tubes and flat panel display devices. The solution-based sol-gel method is one of the most important techniques for the synthesis of vari-ous functional coating films. Compounds with the apatite structure are very suitable host lattices for various luminescent ions. Ca2RE8(SiO4)6O2 ( RE=Y, Gd, La ) is a kind of ternary rare-earth-metal silicate with oxyapatite structure, which has been used as host mate-rial for the luminescence of various rare earth and mercury-like ions. In this article, Ca2Gd8(SiO4)6O2:Dy3 phosphor films were dip-coated on quartz glass substrates through the sol-gel process. X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) spectra, as well as lifetimes were used to characterize the resulting films. AFM study revealed that the phosphor films consisted of homoge-neous particles. The Dy3 showed its characteristic emission in crystalline phosphor films, i.e., 4F9/2–6H15/2 and 4F9/2–6H13/2.