Energy Diffraction Spectrum Research Articles

Double Pulse Electrodeposition of Cu-Ga Precursor Layer for CuGaS2 Solar Energy Thin Film

A novel technique for synthesis of CuGaS2 solar energy thin film is presented. It is associated with double pulse electrodeposition of Cu-Ga precursor layer followed by thermal annealing treatment in sulfur atmosphere. The influence of several flexible parameters including pulse deposition potential and agitation rate on the compositions, crystal structure and morphology of the films were investigated. A relative negative shift of the higher pulse deposition potential results in the increasement of Ga content. A higher agitation rate results in higher Cu/Ga ratio and the emergence of CuS secondary phase after annealing in sulfur atmosphere. The crystal size increases with decreasing the higher pulse deposition potential. Several characterization methods including X-ray diffraction (XRD), scanning electron microscope (SEM), energy diffraction spectrum (EDS), ultraviolet–visible (UV–vis) spectra, impedance spectroscopy, and Raman spectrum are used to characterize the synthesized CuGaS2 polycrystalline thin films. Based on the experimental results, a probable formation mechanism of the CuGaS2 thin films was proposed and briefly discussed.

Friction and Wear Behavior of CaO-MgO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> Glass-Ceramics Prepared by Waste Casting Sands

CaO-MgO-Al2O3-SiO2 glass-ceramics were produced by using waste casting sands as a main raw material. Friction and wear tests for the glass-ceramics were conducted with M-200 wear tester against GCr15 steel wheel. The worn morphologies, wear mechanisms and compositions of the glass-ceramics were observed and analyzed with scanning electron microscope (SEM) and energy diffraction spectrum (EDS). The results show that under the dry friction sliding the glass-ceramics present high wear rate and friction coefficient, with wear mechanisms are dominantly brittle spalling and some with adhesive wear. By an addition of 10% pure aluminum, the density of the glass-ceramics and wear resistance can be improved with their friction coefficient being lowered. Under oil lubrication sliding, the friction coefficient of glass-ceramics decreases and their wear resistance increases extremely, whose reason is that small pores within the glass-ceramics play an role on oil storage.

Effect of interlayers on the structure and properties of TiAlN based coatings on WC-Co cemented carbide substrate

Two interlayers (Ti and Cr) have been evaluated with respect to their influence on the structure and growth of TiAlN based coatings on WC-Co cemented carbide by a non-commercial hybrid PVD (physical vapor deposition) coater by Sichuan University in China. The structure and the growth morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The diffusion of interlayer was tested by Energy Diffraction Spectrum (EDS). Nanoindentation techniques and Rockwell HRC indentations were carried out to investigate the mechanical properties. The results show that the structure and the growth style change in the coatings on Cr interlayer, and this can be explained by thermodynamic theories. Cr interlayer exhibits a better diffusion compared with Ti interlayer, partly resulting in the transition from columnar crystal to equiaxed crystal. Columnar crystals disappear with the addition of Si, too. Due to the diffusion of Cr interlayer and the growth style changes in the coating, a transition zone is formed, and it is estimated to improve the adhesion. Good adhesion occurs in the coating with Cr interlayer. The hardness of TiAlN on Cr interlayer increases, and the Ti/(Ti,Si,Al)N coating shows the hardness as high as 40.0Gpa.

Microwave absorption property of Ni–Co–Fe–P-coated flake graphite prepared by electroless plating

Ni–Co–Fe–P alloy coating was covered on surface of flake graphite by electroless plating process. Morphology, composition, structure, magnetic property and microwave absorbing property of the Ni–Co–Fe–P alloy plating were characterized by scanning electron microscopy (SEM), energy diffraction spectrum (EDS), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), vibrating sample magnetometer (VSM) and vector network analyzer, respectively. The results indicated that uniform Ni–Co–Fe–P alloy plating was deposited on surface of flake graphite by the electroless plating and the coating was composed of 9.75wt% Fe, 7.98wt% Co, 4.13wt% P and 78.14wt% Ni. The Ni–Co–Fe–P alloy plating was stable in the air and the plated flake graphite was magnetic. The complex relative permittivity (ɛ=ɛ′−jɛ″) and permeability (μ=μ′−jμ″) of the samples were measured in the range of 0.1–10GHz. The reflection loss (RL) was calculated using the theory of absorbing wall, and the results showed that the minimum RL of the plated flake graphite with a thickness of 3mm was −12.8dB at 4.6GHz. The plated flake graphite is a kind of ideal microwave absorbing material.

Sliding wear behavior of Cr–Mo–Cu alloy cast irons with and without nano-additives

• The nano materials were used to modify the performance of alloy cast iron. • The hardness of alloy cast iron with nano-additives increased greatly. • The wear resistance of alloy cast iron with nano-additives increased notably. • The grinding efficient of alloy cast iron with nano-additives was dramaticlly better than that of alloy cast iron without nano-additives. In this paper, the microstructures of Cr–Mo–Cu alloy cast irons with and without nano-additives were characterized by scanning electron microscope (SEM) and energy diffraction spectrum analyser (EDS). The dry sliding wear tests were carried out using a pin-on-disk wear tester against GCr15 steel balls under fixed normal load and rotating velocity. The study aimed to illustrate the effect of graphite morphology on the sliding wear behavior of Cr–Mo–Cu alloy cast irons. The experimental results showed that the graphite morphology of Cr–Mo–Cu alloy cast iron is affected by nano-additives. They are transformed from thick-long flake to thin-short vermicular shape, and the hardness increased notably. The wear test results indicated that the wear rate of Cr–Mo–Cu alloy cast irons decreases with addition of nano-additives while the wear rate of the GCr15 steel ball worn against with the alloy cast iron modified by nano-additives increases. The graphite morphology plays a significant role in the wear performance of the alloy cast iron. The analysis of worn surfaces and wear debris indicated that the dominant wear mechanism for the alloy cast iron without nano-additives is adhesive wear and plough. However, the percent of oxidation wear mechanism for the alloy cast iron with nano-additives increases.

Solute Distribution and Segregation during Solidification of Mg-6Al Alloys

Solute distribution and segregation in solidification will largely influence the characteristics of solidification microstructure and precipitation order of the second phase. In this paper, the solid-liquid interfaces of Mg-6Al alloy with different temperature were obtained by rapid quenching based on a special melting furnace and were analyzed using scanning electron microscopy, energy diffraction spectrum and Thermo-Calc calculation tool. It was found that the primary α-Mg phase grew through cystiform dendrite interface. The solute partition coefficient and dendrite segregation rate for Al in the solid phase of Mg-6Al alloy basically had little change with decrease of the temperature. The dendrite become fine, and the solute partition coefficient decreased, while dendrite segregation rate of Al in the dendrite boundaries increased, because of the addition of Zn to Mg-6Al alloys.

CdO activated Sn-doped ZnO for highly sensitive, selective and stable formaldehyde sensor

Sn-, Ni-, Fe- and Al-doped ZnO and pure ZnO are prepared by coprecipitation method, and characterized by scanning electron microscope (SEM), energy diffraction spectra (EDS) and X-ray diffraction (XRD). Their formaldehyde gas sensing properties are evaluated and the results show that 2.2mol% Sn dopant can increase the response of ZnO by more than 2 folds, while other dopants increase little response or even decrease response. Further, CdO is used to activate ZnO based formaldehyde sensing material. It is demonstrated that 10mol% CdO activated 2.2mol% Sn-doped ZnO has the highest formaldehyde gas response, with a linear sensitivity of ∼10/ppm at lowered work temperature of 200°C than 400°C of pure ZnO, and high selectivity over toluene, CO and NH3, as well as good stability tested in 1 month.

Effect of (Mn + Cr) addition on the microstructure and thermal stability of spray-formed hypereutectic Al–Si alloys

Microstructures and thermal stability of hypereutectic Al–Si alloys with or without (Mn + Cr) addition, prepared via Spray Forming technique, are studied and compared with traditional cast alloys with same composition, using scanning electron microscopy with energy diffraction spectrum, X-ray diffraction, transmission electron microscopy and differential scanning calorimeter. The results show that the Fe-bearing and primary silicon phases in SF-3C alloy can be refined to less than 10 μm, especially in SF-MC21 alloy the Fe-bearing phase is refined into uniformly distributed α-Al(Fe,Mn,Cr)Si phase particles with sizes smaller than 5–6 μm, contributing to the decrease/elimination of the deleterious effect of needle-like Fe-bearing phases. The results of different heat treatments show SF-MC21 alloy possesses excellent thermal stability than SF-3C alloy which is unstable below 750 K for the coarsening of β-Al 5FeSi phase and formation of Al 7Cu 2Fe phase. The study indicates that both the existence of thermodynamically stable α-Al(Fe,Mn,Cr)Si particles and the increase of solidus temperature of SF-3C alloy induced by adding (2Mn + 1Cr) elements contribute to the high thermal stability of SF-MC21 alloy. Contemporarily, combined the phase reactions or transformation occurred during the melting and solidification processes of both spray-formed hypereutectic Al–Si alloys, the microstructure formation of spray-formed alloys is discussed.

Electroless preparation and characterization of magnetic ICF PS targets

Magnetic inertial confinement fusion (ICF) polystylene (PS) targets were prepared by electroless plating technology. An alkaline bath including nickel sulfate as the source of nickel and sodium sub-phosphate as the reducing agent was used to prepare electroless Ni–P deposits. Morphology, composition, structure, phase transformation behaviour and magnetic property of the magnetic ICF targets were characterized by scanning electron microscopy (SEM), energy diffraction spectrum (EDS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM), respectively. The results showed that the magnetic plating was composed of Ni and P, and there was only 7.6 wt.% of P in the deposited coating. The joint between the Ni–P coating and the ICF PS target is very tight, and the thickness of Ni–P magnetic plating is about 1 μm. The plated ICF PS targets, which were magnetic, could be used in magnetic suspension experiment.

Electroless preparation and characterization of magnetic Ni–P plating on polyurethane foam

Magnetic Ni–P plating was coated on surface of polyurethane (PU) foam by electroless plating technique. Morphology, composition, structure, thermal decomposing behavior and magnetic property of PU foam before and after plating were characterized by scanning electron microscopy (SEM), energy diffraction spectrum (EDS), X-ray photoelectron spectroscopy (XPS), infrared spectrometer (IR), X-ray diffraction (XRD), thermogrametric analysis (TG) and vibrating sample magnetometer (VSM), respectively. The results showed that the Ni–P plating was composed by particles whose diameters were in the range of 1–2 μm. Because of the Ni–P plating coated on surface of PU foam, peak intensity of the plated PU foam in IR and XRD were lower than those before plating. TG curves of PU foam before and after plating were composed of two decomposing stages. Because part of Ni in Ni–P plating was oxidized, TG curve of the plated PU foam was uptilt during 650–1000 °C. The plated PU foams are magnetic and can be used in some special application.

Effect of forging and heat treatment on the microstructure of in situ TiC/Ti-1100 composites

In this paper, 1 vol.% TiC/Ti-1100 composite was fabricated using in situ technologies, and the β transus temperature of the composite was tested by metallographic techniques. The ingots after breakdown were forged in various temperature ranges, i.e. in the β phase field, in the (α + β) phase field, started in the β phase field and finished in the (α + β) phase field and in the upper α field. Microstructure of the composite after this four type forgings was studied by optical microscopy (OM) and transmission electron microscopy (TEM). Silicide precipitated from the present composites was studied using TEM and energy diffraction spectrum (EDS). It was found that there is an increase about 100 K in β transus temperature compared to monolithic Ti-1100 alloy. Different typical microstructures were obtained after forging in different temperature ranges. Long axis direction of shuttle-shaped silicide has geometric connection with the direction of laths of α phase.

Growth mechanism of compound at interface of Ti-6Al-4V joint brazed with 72Ag-28Cu filler alloy

The growth process of Ti-Cu compound at the interface of a Ti-6Al-4V/72Ag-28Cu (wt-%) joint was analysed using X-ray diffraction, SEM, and energy diffraction spectra. According to the investigated results, when the joint was brazed for a relatively short holding time, atoms of Ti and Cu diffused into the interface would combine into Ti2Cu by eutectoid reaction during the cooling stage. As the holding time is beyond the critical brazing time, Ti2Cu compound decomposed owing to a large amount of Ti in the base metal dissolving into the brazing zone and the relatively gentle concentration gradient of Cu, thus resulted in the solid dissolving of Cu into Ti. In this case, the resulting joints exhibited high strengths. On the basis of the analysis mentioned above, a concept 'critical brazing time' was proposed.

Influence of particle size on reactivity of quartz powder: J.C.Benezet, A.Benhassaine. (Ecole des Mines d'Alès, Alès, France.) Powder Technol., vol 103, no 1, 1999, 26–29

Ni–Co–Fe–P alloy coating was covered on surface of flake graphite by electroless plating process. Morphology, composition, structure, magnetic property and microwave absorbing property of the Ni–Co–Fe–P alloy plating were characterized by scanning electron microscopy (SEM), energy diffraction spectrum (EDS), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), vibrating sample magnetometer (VSM) and vector network analyzer, respectively. The results indicated that uniform Ni–Co–Fe–P alloy plating was deposited on surface of flake graphite by the electroless plating and the coating was composed of 9.75 wt% Fe, 7.98 wt% Co, 4.13 wt% P and 78.14 wt% Ni. The Ni–Co–Fe–P alloy plating was stable in the air and the plated flake graphite was magnetic. The complex relative permittivity (ɛ = ɛ′ − jɛ″) and permeability (μ = μ′ − jμ″) of the samples were measured in the range of 0.1–10 GHz. The reflection loss (RL) was calculated using the theory of absorbing wall, and the results showed that the minimum RL of the plated flake graphite with a thickness of 3 mm was −12.8 dB at 4.6 GHz. The plated flake graphite is a kind of ideal microwave absorbing material.

Dry sliding wear of a Ti50Ni25Cu25 particulate-reinforced aluminum matrix composite

The objective of this article is to characterize the sliding wear behavior of a 30 vol pct Ti50Ni25Cu25 particulate-reinforced aluminum matrix composite under dry conditions. The transformation temperatures of Ti50Ni25Cu25 particles were measured before and after the compounding procedure by the differential scanning calorimeter (DSC) method. The wear tests were carried out on a pin-on-disc machine. A 10 vol pct SiC particulate-reinforced composite and pure aluminum were chosen as the comparison specimens. The results indicate that Al-30 vol pct Ti50Ni25Cu25 composites exhibit higher wear resistance than their unreinforced matrices and are comparable with Al-10 vol pct SiC composites in this experiment. A self-adaptive mechanism that contributes to the wear resistance of an Al-30 vol pct Ti50Ni25Cu25 composite is proposed. Scanning electron microscopy (SEM) and energy diffraction spectrum (EDS) examinations were carried out to investigate the wear mechanism and interface reactions. The results indicate that the interfacial reaction is a predominant factor in determining the wear behavior of the Ti50Ni25Cu25/Al composite.