X-ray Photoelectron Spectroscopy Study of High- and Low-Temperature Forms of Zirconium Titanate

X-ray photoelectron spectroscopy (XPS) spectra were measured for the high-temperature forms (quenched from 1500°C) of zirconium titanate and its solid solutions, the low-temperature forms (quenched from 1000°C), and cubic Ba(Zr_1/2Ti_1/2)O₃. Two distinct differences in the XPS spectra were noted between the high- temperature forms. The O 1 s spectrum of the high-temperature form consisted of two peaks of nearly equal intensities with a spacing of 2.2 eV, which was larger than the corresponding spacing of 1.6 eV, for Ba(Zr_1/2Ti_1/2)O₃, while the spectrum of the low-temperature forms was almost a single peak. The high-temperature form had an unassignable spectrum with a binding energy of 25 eV between the peaks of Zr 4 p and O 2 s . The unassignable spectrum could be a molecular orbital which had been hypothesized to form in these compounds.     

Enhanced Properties of Tin(IV) Oxide Based Materials by Field-Activated Sintering

The densification of SnO₂ (0.9 mol)–Sb₂O₃ (0.1 mol) solid solution without any additives was studied by conventional and field-activated sintering technique (FAST). FAST sintering achieved a relative density value of 92.4% at 1163 K for 10 min versus 61.3% in conventional sintering at 1273 K for 3 h. An abnormal reduction of the IR transmittance and a semiconductor defect structure with only one donor level in the SnO₂ energy gap were noticed in the FAST-sintered as compared with the conventionally sintered Sn_0.82Sb_0.18O₂ solid solution. A high charge carrier concentration (i.e., electronic conduction) was shown in the FAST-sintered sample by conductivity measurements and the negative values of the Seebeck coefficient.     

火焰原子吸收光谱法测定锡锭中镉铋铁

研究了介质浓度,基体排除,共存元素等对火焰原子吸收光谱法测定锡锭中镉、铋、铁的影响.方法的相对标准偏差小于6%,加标回收率在95%～106%之间,灵敏度镉为0.0097μg*mL-1*1%-1,铋为0.19μg*mL-1*1%-1,铁为0.050μg*mL-1*1%-1,方法简便,准确可靠.     

Electrical Conductivity of Cadmium Oxide—Antimony Oxide System Ceramics

The electrical conductivity of Cd₂Sb₂O_6.8 and Cd₆Sb₂O₁₀ semiconductive ceramics was examined from −78° to 1000°C under oxygen, nitrogen, argon, air, methane, and CO /CO₂ atmospheres. The existing form of excess CdO in the crystal lattice structure, the relationship between oxygen vacancies and the atmosphere, the conduction mechanism in different temperature regions, the associated defect structure, and phase-transition properties were analyzed. The activation energy and mobility of the carriers were calculated.     

X-ray Photoelectron Spectroscopy Characterization of Ion-Beam Sputter-Deposited Calcium Phosphate Coatings

X-ray photoelectron spectroscopy (XPS) analysis of sputter-deposited calcium phosphate coatings on titanium substrates revealed four distinct zones. The ambient-exposed surface exhibited elevated concentrations of carbon because of atmospheric contamination. The bulk zone contained relatively constant concentrations of calcium, oxygen, phosphorus, and fluorine indicating the chemistry for calcium fluoride (CaF₂) and fluorapatite (Ca₅ (PO₄),F) formation. The transitional zone exhibited elevated titanium and oxygen photoelectron peaks suggesting the coexistence of calcium phosphate compounds within the titanium oxide. The substrate was shown to be identical to the passivated titanium surface prior to deposition.     

Synthesis and Structural Characterization by X-ray Absorption Spectroscopy of Tin-Doped Mullite Solid Solutions

The formation of solid solutions between tin cations and mullite by calcination at 1400°C of amorphous precursors prepared by pyrolysis of aerosols is reported. The oxidation state of the tin cations and the position that they occupy in the mullite structure have been analyzed using XAS (XANES and EXAFS) spectroscopy, which shows that the tetravalent tin cations are located at the octahedral positions of the Al³⁺ ions, which induces cell expansion. The limit of tin incorporation under the experimental conditions reported here correspond to a tin/mullite mole ratio of ∼5%, which is within the range previously reported for other tetravalent cations (4%–6%).     

用X射线光电子谱(XPS)法研究粘接配位键机理

本文用X射线光电子谱(XPS)法对环氧胶和被粘物(钢和氧化铝)粘接界面各元素的化学状态进行了研究。结果表明:界面处元素N、O、Fe、Al发生了化学位移,从而证实了粘接界面配位键的存在。     

Hydrolysis Deposition of Thin Films of Antimony-Doped Tin Oxide

Thin films of antimony-doped tin oxide have been obtained by a new technique, the so-called hydrolysis deposition method, in which hydrolyzed solids are precipitated from metal fluoride solutions. Mixed solutions of SnF₃ and SbF₃ produce antimony- and fluorine-doped tin oxide films. The amount of antimony can be controlled in a wide range by adjusting the initial fluoride concentrations of the solution. The film containing 2.9 mol% antimony heated at 500°C has an electrical resistivity of 1.0 × 10⁻³Ω·cm, which is lower than previously obtained by wet-chemical techniques.     

二正辛基氧化锡的合成研究

以溴辛烷与锡粉在复配型催化剂存在下直接反应,合成了二正辛基二溴化锡,反应产物直接在碱液中水解得到二正辛基氧化锡,此方法简化了工艺,提高了产率。     

纳米掺锑氧化锡粉末的制备及表征

以 SnCl4·5H2O和SbCl3乙醇溶液为原料,采用离子交换除氯水解法得到无氯离子的掺锑氢氧化锡胶体沉淀,以正丁醇作脱水剂对胶体进行共沸干燥处理,所得的掺锑氢氧化锡干微粉经热处理后得到了四方形金红石结构的掺锑氧化锡纳米粉末.用TG-DTA、IR、BET、BJH、XRD、TEM等方法对粉体的结构、物相、形貌进行了表征.     

Determination of InN/Diamond Heterojunction Band Offset by X-ray Photoelectron Spectroscopy

Diamond is not only a free standing highly transparent window but also a promising carrier confinement layer for InN based devices, yet little is known of the band offsets in InN/diamond system. X-ray photoelectron spectroscopy was used to measure the energy discontinuity in the valence band offset (VBO) of InN/diamond heterostructure. The value of VBO was determined to be 0.39 ± 0.08 eV and a type-I heterojunction with a conduction band offset (CBO) of 4.42 ± 0.08 eV was obtained. The accurate determination of VBO and CBO is important for the application of III-N alloys based electronic devices.     

Powder-Based Tin Oxide Microcomponents on Silicon Substrates Fabricated by Micromolding in Capillaries

With the introduction of soft lithography and micromolding in capillaries, low-cost microfabrication with liquid materials has become possible. In this article, we demonstrate how to fabricate porous ceramic lines of 10 μm width and several millimeter length on silicon wafer substrates by using colloidal suspensions of tin oxide. Microchannels of poly(dimethylsiloxane) (PDMS) served as molds that were spontaneously filled owing to capillary forces with suspensions of 0.1–40 vol% solid loading. The resulting ceramic lines have a height of about 7 μm and therefore differ from the usual ceramic thin film coatings. The capillary filling characteristics were observed under the microscope, and the implications of rheology and suspension chemistry are discussed and evaluated. Using the same capillaries, even smaller lines (2–3 μm width) of powder particles could easily be prepared by adjusting only the solid content of the suspensions.     

Subsolidus Phase Relations and Transparent Conductors in the Cadmium-Indium-Tin Oxide System

Subsolidus phase relations have been determined in the CdO–InO_1.5–SnO₂ system at 1175°C. A cubic-bixbyite solution In_{2−2 x} (Cd,Sn)_{2 x} O₃ (0 < x < 0.34), a cubic spinel solution (1− x )CdIn₂O₄– x Cd₂SnO₄ (0 < x < 0.75), and an orthorhombic-perovskite solution Cd_{1− x} Sn_{1− x} In_{2 x} O₃ (0 < x < 0.045) having the GdFeO₃ structure have been discovered. The CdO phase field exists over a small range of InO_1.5 (<3%) and SnO₂ (<1%). Orthorhombic Cd₂SnO₄ (Sr₂PbO₄ structure) and rutile SnO₂ appear to be point compounds with negligible solubility. The vertical section between spinel CdIn₂O₄ and orthorhombic Cd₂SnO₄ was determined between 900° and 1175°C. The spinel phase field (1− x )CdIn₂O₄– x Cd₂SnO₄ was found to extend between x = 0 and x = 0.75 at 1175°C or x = 0.78 at 900°C. All of the phases in this system appear to allow small excess quantities of the donors In and/or Sn (vs cation stoichiometry) which may be the source of the electrons that give these oxides their n-type character. The electrical and optical properties of bulk and thin-film specimens in this system are compared and contrasted with each other and the relative merits of each are assessed.     

Indium Tin Oxide@Carbon Core-Shell Nanowire and Jagged Indium Tin Oxide Nanowire

This paper reports two new indium tin oxide (ITO)-based nanostructures, namely ITO@carbon core–shell nanowire and jagged ITO nanowire. The ITO@carbon core–shell nanowires (~50 nm in diameter, 1–5 μm in length,) were prepared by a chemical vapor deposition process from commercial ITO nanoparticles. A carbon overlayer (~5–10 in thickness) was observed around ITO nanowire core, which was in situ formed by the catalytic decomposition of acetylene gas. This carbon overlayer could be easily removed after calcination in air at an elevated temperature of 700°C, thus forming jagged ITO nanowires (~40–45 nm in diameter). The growth mechanisms of ITO@carbon core–shell nanowire and jagged ITO nanowire were also suggested.     

掺锑氧化锡纳米晶体的制备及性能研究

以SnCl4.5H2O和SbCl3乙醇溶液为原料,用离子交换除氯水解法制备得到无氯离子的前驱体掺锑氢氧化锡胶体沉淀。采用了乙酸异戊酯有机溶剂作脱水剂以消除掺锑氢氧化锡胶体干燥过程中硬团聚的形成,并和常用的正丁醇共沸溶剂进行了粉体性能的比较。用BET、XRD和TEM等方法对前驱体和掺锑氧化锡纳米粉体进行表征。结果表明,乙酸异戊酯溶剂比正丁醇溶剂更有效防止了粉体干燥过程中硬团聚的形成;将乙酸异戊酯干燥所得掺锑氢氧化锡干粉经热处理后得到了高比表面积的掺锑氧化锡纳米粉体,并对晶粒的生长过程进行了研究。     

Aging Process of Metal/Epoxy Laminates Investigated with X-ray Photoelectron Microscopy and Spectroscopy

In this article we describe the application of X-ray photoelectron spectroscopy to epoxy/dicyandiamide laminates on zinc galvanized steel which were aged under different environmental conditions involving high humidity and temperatures.

X-ray photoelectron microscopy allows us to identify the distribution of chemical elements with a lateral resolution of 10μm. Areas selected in the microscopy mode were then analyzed in the spectroscopy mode in order to get information on the local chemical composition.

We compared the spectroscopic features of the aged but freshly delaminated surfaces of samples stored under ambient conditions at room temperature with samples exposed to the “Kataplasmann” and the “KWT” test, respectively. Furthermore, a comparison was made with a model sample which was prepared in vacuum and on which the curing process was investigated.

Though there is no substantial loss in the lap-shear strength of the samples, we find drastic spectroscopic changes in the Kataplasma and KWT treated samples compared with the sample kept at room temperature. We conclude that the chemical changes induced by these tests cause an internal interphase boundary between the epoxy/metal interface and the bulk adhesive along which delamination occurs. Comparison with the behavior of the water-vapor-treated model sample gives evidence that hydrolysis is the main reaction in these tests.

The results described here complement our former study.¹     

Chemical States of Copper and Tin in Copper Glazes Fired under Various Atmospheres

R — O , N — R , and O — R firing operations produce copper red glazes resulting from the formations of Cu₂O, metallic copper, and both Cu₂O and metallic copper, respectively. The symbols O , N , and R denote oxidizing, neutral, and reducing atmospheres, respectively, and in the set of symbols, the former corresponds to the heating atmosphere and the latter to the successive cooling atmosphere. All other firing operations such as R — R and R — N fail to produce red glazes. The formation mechanisms of metallic copper and Cu₂O are postulated from a microscopic viewpoint.     

Aging Process of Metal/Epoxy Laminates Investigated with X-ray Photoelectron Microscopy and Spectroscopy

In this article we describe the application of X-ray photoelectron spectroscopy to epoxy/dicyandiamide laminates on zinc galvanized steel which were aged under different environmental conditions involving high humidity and temperatures.

X-ray photoelectron microscopy allows us to identify the distribution of chemical elements with a lateral resolution of 10μm. Areas selected in the microscopy mode were then analyzed in the spectroscopy mode in order to get information on the local chemical composition.

We compared the spectroscopic features of the aged but freshly delaminated surfaces of samples stored under ambient conditions at room temperature with samples exposed to the “Kataplasmann” and the “KWT” test, respectively. Furthermore, a comparison was made with a model sample which was prepared in vacuum and on which the curing process was investigated.

Though there is no substantial loss in the lap-shear strength of the samples, we find drastic spectroscopic changes in the Kataplasma and KWT treated samples compared with the sample kept at room temperature. We conclude that the chemical changes induced by these tests cause an internal interphase boundary between the epoxy/metal interface and the bulk adhesive along which delamination occurs. Comparison with the behavior of the water-vapor-treated model sample gives evidence that hydrolysis is the main reaction in these tests.

The results described here complement our former study.¹     

Evolution in Microstructural Properties of Cetyltrimethylammonium Bromide-Templated Mesoporous Tin Oxide upon Thermal Crystallization

Mesoporous crystalline SnO₂ was synthesized using a supermolecule-templating process, in which cetyltrimethylammonium bromide (CTAB) was introduced into a homogenously peptized tin oxyhydroxide sol, followed by calcination in air. The templated powders were calcined either with or without being subjected to a hexamethyldisilazane (HMDS) pretreatment, and the microstructures were characterized as a function of calcination temperature up to 800°C. Organized mesostructure was initially obtained, and grain growth on calcination was the primary factor that destabilized the mesostructure. Compared with the conventional sol–gel process, the templating process promotes the formation of mesoporosity, enlarges pore volume, and drastically slows grain growth. The HMDS treatment further inhibits grain growth above 400°C. The combination of these processes facilitates formation of fully crystallized mesoporous SnO₂ materials with very large surface areas. Fully crystallized mesoporous SnO₂ that has a surface area of 220 m²/g has been thus obtained by calcination up to 500°C.