碱熔-蒸馏-ICP-AES法测定载体催化剂中钌

研究了Ru/Al2O3催化剂中钌含量的测定,考察了溶样方法、测定方法、测定条件的影响。选用750℃过氧化钠熔融,以高锰酸钾和铋酸钠蒸馏分离,用电感耦合等离子体原子发射光谱法(ICP-AES)测定样品中钌含量。结果表明,方法测定含量范围0.1%~10%,精密度(RSD)为2.0%~2.5%,加标回收率为96.9% ~102.8%,可满足实际物料中钌含量测定的要求。     

碱熔-碲共沉淀-ICP-AES法测定二次资源物料中的钌

建立了碱熔分解样品、碲共沉淀分离,电感耦合等离子体发射光谱法(ICP-AES)测定含钌二次资源物料中钌含量的方法。对样品分解、钌的分离和测定、方法准确度和精密度进行了研究。约0.5 g粉末样品与5 g的过氧化钠混匀,于730 ℃马弗炉中熔融25 min,冷却后用水浸出,盐酸酸化,加氧化剂使钌保持较高价态,用碲共沉淀法分离钌,ICP-AES测定钌含量。样品加标回收率98.8%~99.8%,相对标准偏差(RSD,n=9)为:0.3%~1.0%,方法快速、简便,已应用于生产测定。     

ICP-AES法测定三氯化钌中铁、铜、钙和镁的量

建立了电感耦合等离子体发射光谱法测定三氯化钌中杂质元素含量的分析方法。通过优化仪器条件,选择合适的测定谱线、扣除背景测定样品中的杂质元素,各待测元素的精密度(RSD)为6.00%~16.4%,加标回收率为90.00%~110.0%。方法能满足三氯化钌产品中杂质元素的分析要求。     

氧化除钌-ICP-AES法测定钌化合物中的杂质元素

利用四氧化钌易挥发的特点,将钌溶液用高氯酸冒烟去除钌,用ICP-AES测定样品中杂质元素。对钌基体干扰、高氯酸用量、杂质元素分析谱线、仪器分析参数等进行了研究,确定了最佳实验条件。结果表明,采用高氯酸冒烟,可将试液中钌含量降低至50 μg/mL以下,有效消除钌对杂质元素的光谱干扰。方法具有较宽的测定范围,对三氯化钌样品中20个杂质元素测定的相对标准偏差(RSD,n=9)为2.0%~3.5%,加标回收率在86.3%~118.0%之间,可满足钌化合物中杂质元素的测定要求。     

王水不溶渣的碱性加压氧化溶解及其钌含量的测定

建立了一种以次氯酸钠作氧化剂,碱性加压氧化法溶解王水不溶渣中钌的方法。以酒精沉淀,盐酸溶解,硫脲分光光度法进行样品中钌含量的测定。方法对王水不溶渣中钌的溶解效果好,操作简单;王水不溶渣加压氧化浸出液共存的主要杂质离子Na⁺、Cl^-、Pb²⁺、Bi²⁺等(不含Os)对吸光度无影响。采用硫脲分光光度法测定样品中13.771 μg/mL钌,RSD (n=6)为1.536%,加标回收率为98.73%~102.76%。     

碱熔解-硫脲比色法快速测定钌碳催化剂中的钌

建立了碱熔解-硫脲比色法快速测定钌碳催化剂中钌的方法;对样品的预处理和显色条件进行了改进,将精密度和准确度与传统法的进行了比较。结果表明:采用过氧化钠熔解钌、盐酸转化试液、在4 mol/L盐酸介质中和60~80℃水浴保持10m in后,可较好的进行硫脲比色法测定钌;本法和传统法测得钌的质量分数和相对标准偏差分别为4.30%、4.30%和1.02%、1.21%,本法测得样品加标准回收率为98.01%~102.12%;2种方法分析结果的精密度和准确度吻合,但本法快速、简便,满足日常样品的分析要求。方法已应用于废钌碳催化剂中钌的测定。     

NiPt合金中含氧和氮量的测定

试验采用脉冲红外吸收法和热导检测法测定NiPt合金中的氧和氮含量。对TC-400氧氮分析仪的测定条件,样品的制备、清洗,称样量等进行了实验。试样氧的相对标准偏差(RSD,n=11) 5.08%~9.56%,加标回收率95~107%;氮的含量小于0.001%,加标回收率为96%~105%。方法可满足生产分析的要求。     

密闭消解-重量法测定掺铱、锇和钌的黄金饰品中金量

掺杂铱、锇和钌的黄金饰品中金的量难于用密度法或X射线荧光光谱法(XRF)测定。将样品在高压密闭条件下经过王水消解后,掺杂的难溶金属可过滤分离,以80%水合肼(用水稀释6倍)作还原剂,将滤液中的金还原成沉淀,以重量法测定金含量,金粒的纯度用火花原子发射光谱法测定。方法加标回收率为96.2%~101.6%,相对标准偏差(RSD,n=6)为0.09%~0.23%,可满足掺杂铱、锇和钌的黄金饰品中金的测定。     

水合肼-氢还原重量法测定硫酸钯溶液产品中的钯含量

采用水合肼作还原剂,还原后的金属钯黑再通氢还原纯化,建立了水合肼-氢还原重量法测硫酸钯溶液中的钯含量。在优化后的测定条件下,测定了4.00%~14.50%含量的钯,分析结果的极差、相对标准偏差(RSD,n=6)分别为0.02%、0.062%~0.16%。与GB/T 23276-2009法相比较,测定结果的准确度和精密度更高。     

(1,5-环辛二烯)氯化钌(II)多聚体的合成及表征

在无水乙醇介质中,将水合三氯化钌与1,5-环辛二烯加热回流,一步合成了(1,5-环辛二烯)氯化钌(II)多聚体[Ru(cod)Cl2]n,产率96%。用元素分析、核磁共振(¹H-NMR、¹³C-NMR)和红外光谱(IR)等分析表明产物为目标化合物。     

Microstructure and corrosion behaviors of FeCrNiBSiMox stainless steel fabricated by laser melting deposition

In this paper, FeCrNiBSiMo_x (x = 1.0, 1.5, 2.0, 2.5) stainless steels were successfully prepared using a laser melting deposition technology, with the aim to investigate the effect of Mo content on microstructure and corrosion behaviors. The results showed that the as-deposited specimens were composed mostly of α-Fe and a small amount of (Cr, Mo)₇C₃, and (Cr, Mo)₇C₃ existed in the inter-dendritic (ID) region. As the Mo content increased, grain refinement could be clearly observed, and the area of the ID region increased from 27% to 54%. The low-angle boundaries accounted for 60–70% of the grain boundaries of the as-deposited specimens. Increasing the content of Mo improved the microhardness of the as-deposited specimens from 652 HV to 813 HV. The corrosion current density of the as-deposited specimens with the Mo mass fractions of 1.0%, 1.5%, 2.0%, and 2.5% were 1.37 × 10⁻⁶, 1.02 × 10⁻⁷, 6.19 × 10⁻⁷, and 3.06 × 10⁻⁷ A/cm², respectively. The as-deposited specimen with Mo content of 1.5% had lower cumulative erosion loss and erosion loss rate than other as-deposited specimens. The FeCrNiBSiMo_x (x = 1.5) specimen exhibited excellent resistance to electrochemical corrosion and cavitation erosion.     

Microstructure and magnetron sputtering properties of tungsten target fabricated by low pressure plasma spraying

Planar and rotary tungsten targets were fabricated by low pressure plasma spraying (LPPS). Relative density, oxygen content by mass, microstructure, micro-hardness and ultimate tensile strength (UTS) of LPPS tungsten targets were all influenced by vacuum pressure. Compared with 1.3 × 10⁴ Pa and 6.5 × 10⁴ Pa, a vacuum pressure of 3.9 × 10⁴ Pa was optimal for preparing high-quality tungsten targets. Oxygen content by mass, porosity, average grain size, micro-hardness and UTS of LPPS target fabricated under 3.9 × 10⁴ Pa were about 0.18%, 2.8%, 0.9 μm, 377.8HV_0.025 and 201.1 MPa, respectively. Electron backscattered diffraction (EBSD) from the LPPS sample (fabricated under 3.9 × 10⁴ Pa) showed that proportions of 〈001〉, 〈011〉 and 〈111〉 oriented grains were 10.6%, 21.0% and 12.3% of the total, respectively. The tungsten target possessed excellent magnetron sputtering performance since most tungsten grains with a size <1.0 μm were irregularly distributed without preferred orientation. Rapid sputtering and uniform thinning on the surface of LPPS tungsten targets took place with nano-scaled sputtering pits being formed during magnetron sputtering. Smooth and continuous tungsten thin films with thickness about 320 nm can be deposited by magnetron sputtering from the LPPS samples. XRD spectra of tungsten thin films with body centered cubic structure showed that the intensity of the (110) diffraction peak was much higher than those of the (200), (211) and (220) peaks.     

Environmental embrittlement of two-phase Fe30Ni20Mn35Al15

It is shown that the ductility of lamellae-structured Fe₃₀Ni₂₀Mn₃₅Al₁₅ (in at. %), which consists of B2 and f.c.c. phases, is influenced by testing environment. Tensile tests performed in air at strain rates ranging from 3 × 10^?6 to 3 × 10^?1 s^?1 showed that the elongation to fracture and ultimate tensile strength (UTS) increased with increasing strain rates below 3 × 10^?3 s^?1, and were independent of strain rate at ～10.5% and 840 MPa for strain rates ≥ 3 × 10^?3 s^?1. In order to understand this strain-rate sensitive behavior, tensile tests were also performed in either dry oxygen or 4% hydrogen + nitrogen at different strain rates. The elongation and UTS in oxygen were insensitive to strain rate and close to those tested at 3 × 10^?3 s^?1 in air, whereas the elongation in hydrogen was 4% for strain rates ≤3 × 10^?3 s^?1 and increased to ～10.8% at 3 × 10^?1 s^?1. The reduction of ductility in air and hydrogen-charged environment at low strain rate is attributed to hydrogen embrittlement.     

Influence of oxygen partial pressure on properties of N-doped ZnO films deposited by magnetron sputtering

N-doped ZnO films were radio frequency(RF)sputtered on glass substrates and studied as a function of oxygen partial pressure(OPP)ranging from 3.0×10-4 to 9.5×10-3 Pa.X-ray diffraction patters confirmed the polycrystalline nature of the deposited films.The crystalline structure is influenced by the variation of OPP.Atomic force microscopy analysis confirmed the agglomeration of the neighboring spherical grains with a sharp increase of root mean square(RMS)roughness when the OPP is increased above 1.4×10-3 Pa.X-ray photoelectron spectroscopy analysis revealed that the incorporation of N content into the film is decreased with the increase of OPP,noticeably N 1s XPS peaks are hardly identified at 9.5×10-3 Pa.The average visible transmittance(380-700 nm) is increased with the increase of OPP(from～17%to 70%),and the optical absorption edge shifts towards the shorter wavelength.The films deposited with low OPP(≤3.0×10-4 Pa)show n-type conductivity and those deposited with high OPP(≥9.0×10-4 Pa)are highly resistive(105Ω·cm)     

Accelerated Corrosion of Fe–xCr–10Al Alloys Containing 0–20 at.% Cr Induced by Sulfur and Chlorine in a Reducing Atmosphere at 600 °C

The corrosion behavior of five Fe–xCr–Al alloys with a constant Al content of 10 at.% and Cr contents ranging from 0 at.% to 20 at.% was examined at 600 °C in a H₂–HCl–H₂S–CO₂ gas mixture providing 3.7 × 10⁻²² atm O₂, 2.4 × 10⁻¹⁴ atm Cl₂ and 3.9 × 10⁻⁹ atm S₂. All the alloys formed duplex scales containing an outermost layer of iron oxide plus an inner layer composed of mixtures of the oxides of all the alloy components. Besides, a region of internal attack of Al or Al + Cr, whose depth decreased with increasing Cr content, formed in all the alloys. The simultaneous presence of chlorine and sulfur in the gas mixture significantly accelerated the corrosion of all the alloys with respect to their oxidation in a simpler H₂–CO₂ mixture providing the same oxygen pressure, by forming thick and cracked scales. The effect was particularly large for the high-Cr alloys due to their inability to form external protective alumina scales in the present gas mixture.     

The corrosion of chromium and nickel-chromium alloys in oxygen-sulfur-carbon gases at 800°C

The simultaneous oxidation and sulfidation of Cr, Ni-10Cr, Ni-20Cr, and Ni-30Cr was studied at 800°C in three gases falling within the Cr₂O₃ stability field of the Cr-S-O system. The sulfur partial pressure remained constant at 1×10^?6 atm, whereas the oxygen partial pressure varied from 5×10²¹ to 5×10^?20 atm, and the carbon activity varied from 0.108 to 0.416. Reaction kinetics were measured, and the reaction products were characterized by X-ray diffraction, metallography, scanning electron microscopy, and X-ray energy dispersive analysis. Reaction rates decreased with increasing oxygen partial pressure and decreased with increasing chromium content of the alloys. Sulfides always formed along with Cr₂O₃, even though the gases fell within the oxide stability field. No carburization was observed even though carbon activities were sufficiently high to form carbides. The reaction mechanisms are discussed, and the absence of carburization is analyzed on the basis of a three-dimensional stability diagram.     

Impurity-controlled Mo films as diffusion barriers for Cu metallization

Effects of vacuum conditions on the oxygen content and microstructure of Mo layers used with Cu gate lines as thin-film transistor-liquid crystal display diffusion barriers were investigated. Mo was deposited using ion-beam sputtering at 1.0 × 10^?5 and 7.0 × 10^?7 Torr. The Mo layer oxygen content and the microstructure and changes in chemical composition of the Cu/Mo/SiO₂/Si layer during annealing were examined. The Mo layer microstructure was influenced by oxygen; increasing concentration increased the energy required for secondary grain growth. Growth was suppressed at high oxygen levels. Therefore, diffusion barrier performance is enhanced by finer Mo layer grain sizes.     

Optimum conditions in the thermal passivation of aisi 430 and 304 stainless steel in controlled oxygen atmosphere

The oxidation of stainless steels AISI 304 and 430 was undertaken in the temperature range 450–600°C and oxygen partial pressure range 6.7 × 10⁷ to 1.33 × 10^?5 Pa. The composition of the oxide layer formed has been analysed by AES and ESCA. Optimum conditions were determined for the formation of a ～40 nm thick oxide layer with a high chromium content. Attention is drawn to the role of the chromium content of the bulk in the passivation process.