Effects of Y_2O_3/Y on Si-B co-deposition coating prepared through HAPC method on pure molybdenum

In order to clarify the effects of reactive element Y on the properties of Si-B co-deposition coating on Mo substrate, the Si-B-Y2O3 and Si-B-Y co-deposition coatings were prepared at 1300 ℃ for 5 h by using the pack mixtures 16Si-4B-xY2O3/Y- 4NaF-（76–x）Al2O3 （wt.%,x=0, 0.5, 1, 2, 4, 8）. X-ray diffraction （XRD）, energy dispersive spectroscopy （EDS） and wavelength dis-persive spectroscopy （WDS） techniques were used to analyze the structure and oxidation behavior of these coatings. The results re-vealed that the Si-B-Y2O3 and Si-B-Y co-deposition coatings had the same structure with that of the Si-B co-deposition coating. However, Y was incorporated into these coatings and the thicknesses of these coatings were thicker than that of the Si-B co-deposition coating. In addition, the Si-B-Y co-deposition coating demonstrated better cyclic oxidation resistance than the Si-B co-deposition coating at 1100 ℃. The modifying mechanism of Y on the Si-B co-deposition coating was discussed.

Electrolytic Co-Deposition Mechanisms, Texture Layers, and Residual Stresses in Nanocomposite Coatings Processes: A Review

The composite coating has gained wider attention due to its property to protect materials used in energy, bridges, offshore platforms, underground pipelines, and the aviation industry from corrosion and deterioration. In this work, a literature review was conducted about the processes of nanocomposite coating, the mechanisms of electrolytic co-deposition, the texture of layers, and the residual stresses. An important aspect, residual stress, was emphasized, which represents the persistent stress after removing the external force affecting a metal in the plastic region. Because it cannot be measured directly and may be determined by measuring strain and indirect methods, the sources and methods for measuring residual stresses (XRD, SEM, TEM, EDS) were described in the last section to provide a comprehensive overview. Based on the thorough analysis of the published literature, it was concluded that nanoparticles could be electrodeposited with Ni on an Al substrate using a direct current and Ni sulfamate as an electrolytic solution, and Nickel will not reside on the oxide layer covering Al, so chemical changes are needed to prepare the Al surface. In addition, texture changes with the thickness of the coated layer must be investigated.

Microstructure and high temperature oxidation resistance of Si-Y co-deposition coatings prepared on TiAl alloy by pack cementation process

In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.

Experimental study on the microstructural and anti-corrosion behaviour of Co-deposition Ni-Co-SiO_2 composite coating on mild steel

Mild steel is commonly used in the construction of Pipeline. The major problem of this Pipeline is corrosion. Effort is make my researchers to combat this problem. In this work Co-deposition of Ni-CoSiO_2 composite coating on mild steel was reported with the view to reduce this problem. The SiO_2 was varies from 5 to 25 wt% in the deposition. The microstructure, hardness values and potentiodynamic polarization in simulated sea water were determined. The results show that XRD pattern of the Ni Co deposited mild steel revealed the presence hard phases of NiO, Co_5Ni, Co_2Ni_3, Ni Co5 while that of Ni-CoSiO_2 deposited mild steel revealed the presence harder phases of NiOSiO_2, CoNi_7Si_2, Co_5Ni_2Si_3. The NiCo-25 SiO_2 deposited sample has smaller particle size than Ni-10 Co coating. Coating thickness of 110.7 mm was obtained for Ni-10 Co coating, while coating thickness of 135.7, 157.7, 165.0 mm were obtained at Ni-10 Co-x SiO_2(x=10, 15, 25 wt%). 99.90% corrosion resistance was achieved at Ni-Co-25 SiO_2. This improvement in corrosion resistance after composites coating could be attributed to the hard and fine structure obtained after coating.

Si-Al-Y Co-deposition Coatings Prepared on Ti-Al Alloy for Enhanced High Temperature Oxidation Resistance

Si-Al-Y co-deposition coatings were prepared on Ti-Al alloy by pack cementation processes at 1 050 ℃ for 4 h with different halide activators in the packs for enhancing the high temperature oxidation resistance of Ti-Al alloy. The structure, constituent phases, formation process and oxidation behavior of the coatings were investigated. The experimental results showed that the coatings prepared respectively with NaF and NH_4Cl as activators were composed of a（Ti, X）_5Si_4,（Ti, X）_5Si_3（X represents Nb and Cr）, and TiSi_2 outer layer, a TiAl_2 inner layer and an Al-rich interdiffusion zone. However, the constituent phases changed into TiSi_2 in the outer layer and（Ti, X）_5Si_4 and（Ti, X）_5Si_3 phases were observed in the middle layer of the coating prepared with AlCl_3·6H_2O activator. Among the halide activators studied, the coating prepared with AlCl_3·6H_2O was thicker and denser, which is the only suitable activator for pack Si-Al-Y co-deposition coatings on a Ti-Al alloy. The oxidation results show that the coating can protect the Ti-Al alloy from oxidation at 1000 ℃ in air for at least 80 h. The excellent oxidation resistance of the coating is attributed to the formation of a dense scale mainly consisted of TiO_2, SiO_2 and Al_2O_3.

Effects of submicron diamonds on the growth of copper in Cu-diamond co-deposition

Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from （220） to （200）. Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane （220） grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane （200） grew in the process of co-deposition. It was inferred that copper plane （200） was propitious to the deposition of submicron diamonds.

Ti+C+N FILM PREPARATION AND ITS PROPERTIES BY LOW ENERGY CO-DEPOSITION ON STEEL

The Ti+C+N film was co-deposited on H13 steel by Filtered Vacuum Arc PlasmaDeposition (FVAPD) operated with a modified cathode. The co-deposited layer was effective for theimprovement of surface hardness and corrosion resistance. The nano-hardness value of theco-deposited film is 1.3 times more than that of undeposited sample. The corrosion behaviormeasurement shows that the corrosion resistance for acid corrosion and pitting corrosion wasimproved greatly. It is owing to the formation of the new ternary ceramic phase TiC_(0.7) N_(0.3) inthe co-deposited layer. The mechanism of property improvement is discussed.

Ferronickel preparation using Ni-Fe co-deposition process

Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium dodecyl sulfonate concentration were investigated.Electrochemical experiments demonstrate that iron's electrodeposition plays a leading role in the Ni-Fe co-deposition process,and the co-deposition nucleation mechanism accords with a progressive nucleation.Temperature increase does favor in increasing nickel content in the ferronickel(Ni-Fe co-deposition products),while Fe^(2+) concentration increase does not.When solution pH is higher than 3.5,nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe^(2+).With the current density of 180 A/m^2,Na_2SO_4 concentration of 100 g/L and Ni^(2+) concentration of 60 g/L,a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C,Fe^(2+) concentration of 0.3 g/L,solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.

Growth behaviors and emission properties of Co-deposited MAPbI_(3) ultrathin films on MoS_(2)

Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.

纯钼表面包埋Si-B共渗涂层的显微组织及低温氧化行为

在纯钼表面进行包埋Si-B共渗,研究B改性MoSi2涂层的结构及其在600℃下的氧化行为。利用XRD,EDS,WDS分析涂层的相组成和结构,并结合热力学计算分析涂层的组织形成。结果表明:采用16Si-4B-4NaF-76Al2O3渗剂在1100~1400℃下可制备Si-B共渗涂层,涂层由外向内可分为五层:最外层MoSi2,次外层MoSi2+MoB,第三层Mo5Si3,第四层MoB和最内层Mo2B;涂层主体为MoSi2,渗入的B在与基体反应形成Mo-B化合物层的同时,还在MoSi2中形成MoB相;涂层的生长以Si,B原子向内扩散为主;在600℃氧化时涂层中的B向表面扩散并氧化生成B2O3。

Si-B_4C复合抗氧化剂对MgAlON材料高温氧化行为的影响

研究了Si-B4 C复合抗氧化剂对MgAlON材料高温氧化行为的影响。通过对氧化后试样脱色层的厚度、相组成、氧化产物中尖晶石相的晶格常数及显微结构的研究发现 ,该复合抗氧化剂能显著改善MgAlON材料的高温抗氧化性能。抗氧化机理在于 :在相对较低的温度 (1 1 0 0℃以下 )下 ,SiO2 和B2 O3作用形成低粘度、低挥发性、低氧扩散系数的硼硅酸盐玻璃而有效地封闭气孔和裂纹 ;在较高温度下 ,硼硅酸盐玻璃中的SiO2 和B2 O3又能和MgAlON氧化产物中的α Al2 O3作用 ,形成由莫来石和Al18B4 O33构成的致密氧化物层 。

还原气氛下Si-B_2O_3-TiO_2系反应的热力学分析

通过热力学计算 ,探讨Si-B2 O3 -TiO2 系在还原性气氛下TiB2 ,Ti(C ,N)的可能性、生成途径以及产物在此体系中的相对稳定性。结果表明 :Si-B2 O3 -TiO2 系在还原性气氛下TiB2 的生成有 2种可能性 ,生成物中TiB2 要比TiN和TiC稳定。在 1843K左右 ,TiC和TiN可以形成固溶体Ti(C ,N)。

CeO2掺杂Si-B复合涂层的制备及氧化行为

采用两步包埋渗的方法在钼基体表面制备了不同CeO 2掺杂量的Si-B复合涂层,通过XRD、EDS和SEM分析了CeO 2掺杂对Si-B复合涂层在1150℃氧化前后表面物相和截面形貌的影响,并采用失重法研究了CeO 2掺杂前后Si-B复合涂层在1150℃下氧化160 h的氧化动力学行为。结果表明:适量CeO 2的掺杂对Si具有一定的催渗效果,当CeO 2掺杂量为1%(质量分数)时,所制备的Si-B复合涂层的厚度最大且均匀致密,但随着CeO 2掺杂量的增加,涂层厚度有所减小。CeO 2掺杂Si-B复合涂层在1150℃下氧化前70 h的氧化速率常数值(1.48×10-4 mg 2/(cm 4·h))较未掺杂时明显降低,这表明CeO 2掺杂Si-B复合涂层的高温抗氧化性能较好。

Mo-Si-B三元硅化物显微组织及氧化行为研究

采用电弧熔炼法制备了4种不同成分的Mo-Si-B合金,利用XRD和SEM-BSE对其显微组织进行了分析,以及利用TGA,XRD和SEM-BSE对其在1200℃的氧化行为进行了研究。显微组织分析表明:4种合金均由Mo,Mo5SiB2(T2),Mo3Si三相组成。氧化结果显示:T2相含量最多的合金有最好的抗氧化性;在Si含量相同的条件下,具有共晶组织的合金抗氧化性最好。氧化后的合金由表面氧化层、中间层和基体组成。对表面氧化层的相结构进行了XRD和BSE分析,发现表面氧化层主要由非晶SiO2组成。

Processing and oxidation of co-deposited Ni-Al coatings

Electrodeposited Ni matrix/Al microparticles or nanoparticles dispersed composite coatings (termed as EMCCs or ENCCs) are developed from a Ni-based electrolyte bath. The Al microparticles are in a size range of 1 -5 μm and the Al nanoparticles in an average size of 75 nm. The Al content in coatings increases with increase in the particle content in the bath. Particle size effect on the degree of codeposition is not significant. However, codeposition of Al nanoparticles instead of microparticles promotes more homogenous growth of Ni deposits on {111}, {200} and {220} planes. The oxidation at 1 050 ℃ of the as-deposited composite coatings shows that at a comparable Al content, ENCC of Ni-Al exhibits a better oxidation resistance than EMCC of Ni-Al due to the fast formation of an alumina scale during the transient stage of oxidation.

Anisotropic Magnetoresistance Effect in Amorphous and Nanocrystalline Fe(Cu,Nb)-Si-B Alloys

The magnetoresistance effect and magnetic properties in amorphous and nanocrystalline Fe(Cu, Nb)-Si-B ribbons have been investigated, it was observed that the anisotropic magnetoresistance (AMR) of nanocrystalline alloy is much smaller than that of amorphous alloy, Indicating that the anisotropy of nanocrystalline alloy becomes smaller after crystallizing, and the smallest AMR is coincident with the excellent soft magnetic characteristics. It is believed that the smaller magnetic crystalline anisotropy is the origin of the excellent soft magnetic characteristics of nanocrystalline alloy.

Hydrogen Concentration of Co-Deposited Carbon Films Produced in the Vicinity of Local Island Divertor in LHD

In international thermonuclear experimental reactor （ITER）, one of major concerns is an in-vessel tritium inventory from a point of safety. It is believed that the carbon-tritium co-deposited film produced by the erosion of carbon diverter walls has a high tritium concentration. However, no systematic evaluation for the tritium concentration has been conducted yet. In the present study, the carbon-hydrogen co-deposited films were prepared at the wall of pumping duct in Local Island Divertor experiments of LHD, in order to evaluate the tritium concentration of the co-deposited films produced in ITER. The hydrogen concentration was obtained by measuring the amount of retained hydrogen in the film and the mass density of the film. The hydrogen concentration of the co-deposited carbon film at the wall not facing to the plasma with a low temperature was extremely high, 1.3 in the atomic ratio of H/C. This value is triple times higher than the previous value obtained so far. The crystal structure of the co-deposited carbon film observed by Raman spectroscopy showed very unique structure （polymeric aC：H）, which is well consistent with the high hydrogen concentration. The present study suggests that the tritium concentration of the co-deposited film in ITER depends on the wall position and becomes quite high as high as T/C-0.65. The results obtained contribute to evaluate the in-vessel tritium inventory owing to the co-deposited carbon films.

Effect of heat treatment on microstructure and mechanical property of extruded 7090/SiC_p composite

The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy （TEM） and energy dispersive spectrometry （EDS）. Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O （5 nm） layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.

Effects of current density on preparation and performance of Al/conductive coating/α-PbO_2-Ce O_2-TiO_2/β-Pb O_2-MnO_2-WC-ZrO_2 composite electrode materials

Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy（EDXS）, anode polarization curves, quasi-stationary polarization（Tafel） curves, electrochemical impedance spectroscopy（EIS）, scanning electron microscopy（SEM）, and X-ray diffraction（XRD）. Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential（0.610 V at 500 A/m2） for oxygen evolution, the best electrocatalytic activity, the longest service life（360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2）, and the lowest cell voltage（2.75 V at 500 A/m2）. Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed.

One step synthesis of high efficiency nickel/mesoporous TiO_2 hybrid catalyst for hydrogen evolution reaction

Nickel-Ti O_2 hybrid catalysts are synthesized by electrodeposition and their catalytic activity with respect to the hydrogen evolution reaction is analyzed.Two types of titanium oxide particles,which are commercial particles of dense Ti O_2 and mesoporous TiO_2 particles synthesized by an aerosol method,are incorporated into the matrix of the nickel catalyst.Both nickel catalysts containing Ti O_2 particles presented higher catalytic activity than the conventional nickel Watts catalyst.Mesoporous TiO_2-modified nickel catalyst showed the highest catalytic activity towards HER in alkaline medium.In addition,this type of nickel catalyst increases its catalytic activity after ageing treatment,which is an indication of an increase in the electro-active area of the electrode.