H2S/CO2环境中Gemini表面活性剂对L360钢的缓蚀性能

采用静态失重法、动电位极化法和电化学阻抗法研究了三种Gemini表面活性剂12-2-12,16-2-16和18-2-18在H2S/CO2环境中对L360钢的缓蚀性能,并探讨了缓蚀机理.研究表明,在本试验条件下,三种表面活性剂均表现出一定的缓蚀性能,其中,12-2-12效果最优,16-2-16其次,18-2-18缓蚀效果...     

一种新型的咪唑啉类缓蚀剂CPA-1对N80钢在CO2环境下的缓蚀性能评价

目的考察一种新型的咪唑啉类缓蚀剂CPA-1对N80钢在CO_2环境下的缓蚀性能。方法通过失重法、电化学阻抗谱和极化曲线,研究了在不同温度下缓蚀率和缓蚀剂浓度之间的关系,利用扫描电子显微镜和扫描电化学显微镜对表面形貌进行了观察分析,根据等温吸附模型研究了咪唑啉缓蚀剂在N80钢表面的吸附类型。结果失重结果表明,缓蚀剂的缓蚀效率随浓度的增大而升高,当温度为40℃、缓蚀剂质量浓度为250 mg/L时,缓蚀率达到95%;温度升高至80℃时,缓蚀率下降至87%。电化学试验表明,咪唑啉类缓蚀剂对阴极和阳极反应均有抑制作用。表面形貌分析表明,缓蚀剂能有效改善金属表面的腐蚀程度。结论咪唑啉类缓蚀剂CPA-1属于混合型缓蚀剂,对N80钢具有较好的缓蚀性能。缓蚀机理为通过吸附方式在金属表面形成一层吸附膜抑制金属腐蚀,吸附方式遵循Langmuir吸附等温模型,物理吸附和化学吸附均会在金属表面发生。     

硫酸介质中Gemini表面活性剂对碳钢的吸附缓蚀性能

通过失重法和极化曲线法研究了阳离子季铵盐型Gemini表面活性剂Π-14-3及其添加卤离子的复配体系对A3钢在硫酸溶液中的缓蚀性能及其机理.结果表明,表面活性剂分子Π-14-3对A3钢在0.5 mol/L的硫酸中具有很好的缓蚀性能;在缓蚀剂浓度很低时,通过加入一定量的卤离子,可以得到较高的缓蚀性能,从而降低其应用成本;在硫酸介质中,Gemini表面活性剂在金属表面的吸附符合Langmuir吸附机理.     

原油与高压CO_2共存条件下咪唑啉缓蚀剂的作用行为研究

采用动态失重挂片、高温高压电化学测试、接触角测试及扫描电镜等手段,在80℃、2.5 MPaCO_2条件下模拟饱和CO_2油田采出水,研究原油与高压CO_2共存条件下咪唑啉缓蚀剂对N80钢的缓蚀作用。结果表明:在含有咪唑啉缓蚀剂的腐蚀介质中加入原油后,电极的开路电位有所增加,电极的电荷传递电阻显著变大,碳钢对水的润湿性明显降低,缓蚀剂在金属表面覆盖更完整,原油显著增强了咪唑啉缓蚀剂的缓蚀性能。     

改性咪唑啉缓蚀剂抗H2S/CO2腐蚀性能研究

本文在合成1-(2-氨乙基)-2-十五烷基咪唑啉(A)的基础上,利用硫代氨基脲对其进行改性,制备了一种1-(2-氨基-硫脲乙基)-2-十五烷基咪唑啉(B)新型缓蚀剂。通过失重法和电化学方法研究了A、B两种缓蚀剂在H2S、CO2共存条件下对Q235钢的缓蚀性能,探讨了其在Q235钢表面的吸附行为。结果显示,改性后的缓蚀剂B具有更优的抗H2S、CO2腐蚀的缓蚀性能,最高缓蚀效率在92%以上。两者在Q235钢表面均是单分子层吸附,属于以化学吸附为主的混合吸附。最后采用量子化学方法对两种缓蚀剂的缓蚀机理进行了分析。     

咪唑啉和季铵盐类缓蚀剂对P110S钢的缓蚀作用和机理研究

采用失重法、极化曲线、电化学阻抗谱(EIS)和扫描电镜(SEM)研究了咪唑啉和季铵盐缓蚀剂在H_2S/CO_2环境中对P110S钢的缓蚀作用和缓蚀机理。结果表明,咪唑啉缓蚀剂和季铵盐缓蚀剂均为阳极型缓蚀剂;在120℃,H_2S分压为0.55 MPa、CO_2分压为0.80 MPa的环境中,两种缓蚀剂均有一定的缓蚀作用,能有效抑制P110S钢的腐蚀;添加浓度为200 mg·L~(-1)时,咪唑啉缓蚀剂的缓蚀效率可达87.23%。     

CO2饱和NaCl溶液中松香基咪唑啉季铵盐的缓蚀吸附行为

以松香和二乙烯三胺为原料合成了松香基咪唑啉,并采用氯乙酸钠对合成产物进行季铵化改性,得到水溶性松香基咪唑啉季铵盐.通过失重法和电化学方法测试了该季铵盐在60℃的CO2饱和3%NaCl溶液中对Q235钢的缓蚀性能.结果表明,水溶性松香基咪唑啉季铵盐对Q235钢有很好的缓蚀作用,150 mg/L用量时缓蚀率超过90%.该缓蚀剂是一种以阳极抑制为主的缓蚀剂,遵循Langmuir吸附等温式,在钢表面发生自发吸附,存在较强的吸附作用力.     

Cr13钢在含饱和CO_2介质中腐蚀的影响因素

利用极化曲线和失重法,研究了H_2S、Cl~-、温度等因素对Cr13钢在饱和CO_2介质中腐蚀行为的影响。试验表明,在50℃、Cl~-浓度为50g/L时,随溶液中H_2S含量增加,Cr13钢自腐蚀电流密度增大,钢的腐蚀速率上升,腐蚀受阴极浓差极化控制。50℃,H_2S浓度为0.06mol/L时,当Cl~-浓度低于50g/L时,随着Cl~-浓度增加,Cr13钢腐蚀速率上升;当Cl~-浓度高于50g/L时,随Cl~-浓度增加,Cr13钢的腐蚀速率下降。在H_2S浓度为0.06mol/L,Cl~-浓度为50g/L时,随温度升高,Cr13钢腐蚀速率增加。     

高温高压H2S/CO2环境缓蚀剂分子结构与缓蚀性能关系的研究

用静态和动态腐蚀失重法研究喹啉季铵盐、吡啶季铵盐、曼尼希碱和咪唑啉季铵盐四种不同主体类型缓蚀剂在高温高压H₂S/CO₂环境中N80钢的缓蚀性能,并结合扫描电子显微镜（SEM）和X射线光电子能谱（XPS）表面分析技术研究了不同缓蚀剂主体分子结构与缓蚀性能的关系。结果表明,四类缓蚀剂的缓蚀效率的大小顺序是：喹啉季铵盐>吡啶季铵盐>曼尼希碱>咪唑啉季铵盐。喹啉季铵盐与其他三种缓蚀剂主体分子结构相比具有更好的抗硫性能,其对N80钢具有良好的吸附性能,可形成抗腐蚀性介质渗透能力强的致密均匀和稳定不易分解的有机膜。其缓蚀剂用量为0.15%时,缓蚀率可达97%。     

氯离子与咪唑啉复配缓蚀剂的合成与应用

利用油酸和二乙烯三胺为原料合成咪唑啉季铵盐缓蚀剂后,在50℃、5%的盐酸介质中用静态失重法对咪唑啉季铵盐与阴离子表面活性剂和无机阴离子的研究,得到了一个与咪唑啉季铵盐有最佳复配效果的复配体,咪唑啉季铵盐与I-复配比为1:1(质量比)时,缓蚀剂的缓蚀效果最佳.在不同时间和不同温度下对复合型缓蚀剂的缓蚀效率进行了研究.结果表明,新型缓蚀剂对A3钢的缓蚀率达到99%以上,与单独用咪唑啉季铵盐相比,其缓蚀效率提高了0.7%左右.     

First-principles study of electronic structure and magnetic properties of orthorhombic CrGa2Sb2 and MnGa2Sb2

By the first-principles calculations, we present the results of electronic structure and magnetic properties on bulk CrGa₂Sb₂ and MnGa₂Sb₂ in an orthorhombic structure with the linear chains of transition-metal Cr and Mn atoms, using four different exchange correlation potentials: the local density approximation (LDA), the generalized gradient approximation (GGA), GGA + U, and the Tran-Blaha modified Becke-Johnson functional (mBJ). The electronic structure calculations from four exchange correlation potentials show that CrGa₂Sb₂ is a pseudogap (negative gap) material with very small density of states (DOS) at the Fermi level, while MnGa₂Sb₂ has notably higher DOS at the Fermi level compared to CrGa₂Sb₂, exhibiting stronger metallic conductivity, although the mBJ potential obtains lower DOS at the Fermi level than LDA and GGA for both CrGa₂Sb₂ and MnGa₂Sb₂. The GGA + U method with a small value (1 eV) of the on-site Coulomb interaction parameter U obtains lower DOS at the Fermi level compared to the large value of U. In agreement with the measurement data, the total energy calculations reveal that both CrGa₂Sb₂ and MnGa₂Sb₂ have a stable ferromagnetic ground state with lower energies relative to antiferromagnetic state. Based on the Heisenberg model, the magnetic exchange constants between the nearest-neighbor Cr–Cr and Mn–Mn along transition-metal linear chains are calculated to be 48.6 meV and 27.5 meV for CrGa₂Sb₂ and MnGa₂Sb₂, respectively. By the mean-field approximation method, we calculated the Curie temperature of two compounds to be above room-temperature.     

氢分子在贮氢材料Li2MgN2H2表面的吸附与解离

采用第一性原理计算方法研究了Li-Mg-N-H体系贮氢材料的放氢产物Li2MgN2H2的吸氢反应过程中的过渡态、表面电子态密度和表面能。结果表明:氢分子在Li2MgN2H2低指数表面中最低能量(100)表面的Mg-Mg-Li穴位吸附位置能够形成最稳定的吸附结构并发生解离,氢分子吸附能为-0.1898eV,解离能约为0.84eV(81kJ/mol),表明该反应所需的反应活化能仍较高,吸氢反应速度缓慢。     

Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2气氛下的腐蚀

研究了600℃时Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2 3种气氛中的腐蚀行为，Fe-15Ce合金腐蚀后发生了Ce的内氧化或形成了复杂的腐蚀产物膜，而未出现Ce的选择性氧化或硫化，这主要是合金中存在着两相及Ce在Fe中极低的溶解度的结果。Fe-15Ce合金在本实验条件下的氧化-硫化腐蚀速度低于相同温度、压力下的纯硫化。     

IrO2-MnO2中间层Ti/RuO2-TiO2-SnO2电极制备及性能

通过热分解法制备了含IrO2-MnO2中间层Ti/RuO2-TiO2-SnO2电极,采用SEM、EDX、XRD、CV等检测方法对中间层进行表征,同时采用强化加速寿命试验对电极电化学稳定性进行表征。结果表明:450℃时前躯体完全氧化并形成固溶体,制备的中间层晶粒细小,表面结构致密,电化学孔隙率小。添加中间层使Ti/RuO2-TiO2-SnO2电极强化寿命由未加中间层的7.5h提高到995.8h,远高于国家标准20h。     

Viscosities of Fe_nO-MgO-SiO_2 and Fe_nO-MgO-CaO-SiO_2 slags

1　INTRODUCTIONTheviscosityofliquidslagsisanimportantphysicalproperty .Innickelflashsmeltingprocesses ,slagscontainmainlyironoxidesandsilicainadditiontoMgO ,CaO ,Cr2 O3andAl2 O3aswellasvaluemet alsandotherimpurities .Manyinvestigationsontheviscosityofironsilicatemeltwerealreadyreport ed[14 ] .Butonlyfewstudiesarereportedontheslagsinthecompositionrangeoccurringinnickelmattesmelting.Thismaymainlybeattributedtoexperi mentaldifficultiesinviscositymeasurementsforthehighmeltingtemperatureofi…     

Thermodynamics and phase diagrams in the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3

We applied our model to the enthalpy of mixing data of the binary systems Na₂O-SiO₂, Na₂O-GeO₂, Na₂O-B₂O₃, Li₂O-B₂O₃, CaO-B₂O₃, SrO-B₂O₃, and BaO-B₂O₃. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO₂, CaO-Al₂O₃, PbO-B₂O₃, PbO-SiO₂, ZnO-B₂O₃, and ZnO-SiO₂ systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.     

La_2O_3,CeO_2掺杂Sm_2Zr_2O_7陶瓷制备及热物理性能

以Sm_2O_3, La_2O_3, ZrO_2和CeO_2为原料,采用固相反应法制备了(Sm_0.5La_0.5)_2(Zr_0.6Ce_0.4)_2O_7陶瓷.用X射线衍射(XRD),扫描电镜(SEM)研究了样品的相成分和微观组织,用激光脉冲法和推杆法测量了样品的热导率和热膨胀系数.结果表明,所制备的样品具有萤石晶体结构,且组织致密晶界清晰,并具有较低的热导率和满足热障涂层要求的热膨胀系数.     

Magnetic and related properties of Ce5CoGe2, CeCoGe and CeCo2Ge2

Magnetic susceptibility, magnetization, specific heat, electrical resistivity and thermoelectric power of polycrystalline Ce₅CoGe₂, CeCoGe and CeCo₂Ge₂ were studied at temperatures down to 2 K and in magnetic fields up to 5 T. The novel phase Ce₅CoGe₂ was found to be a ferromagnet with the Curie temperature of about 11 K, which exhibits in the paramagnetic region some features of a dense Kondo system with strong crystal field effect. The re-investigated CeCoGe was found to order antiferromagnetically below 4.6 K, while CeCo₂Ge₂ is an intermediate-valence system, in agreement with previous reports. The thermoelectric power of the latter compound is large (up to 40 μV/K) and positive in the whole temperature range studied, while in the magnetically ordered systems Ce₅CoGe₂ and CeCoGe it is mostly negative and distinctly smaller (down to −1.5 and −11 μV/K, respectively).     

Hydrophilic property of SiO2-TiO2 overlayer films and TiO2／SiO2 mixing films

The photo-induced hydrophilicity of SiO2 overlayer on TiO2 films prepared by sol-gel method was investigated by means of soak angle measurement, XPS, UV-VIS and FTIR spectra. The results show that, compared with the TiO2 film without SiO2 overlayer, when the TiO2 film is thoroughly covered by SiO2 overlayer, the hydrophilicity and the sustained effect are enhanced. It is found that the significant growth of the OH- group occurs in the surface of SiO2 overlayer. The different mechanism of enhanced hydrophilicity between SiO2 overlayer on TiO2 films and TiO2/SiO2 mixing films was analyzed. The result suggests that the photo-generated electrons created in the interface between TiO2 and SiO2 tend to reduce the Ti(Ⅳ) cation to the Ti( Ⅲ ) state, and the photogenerated holes transmit through the SiO2 layer to uppermost surface efficiently. Once the holes go up to the surface， they tend to make the surface hydrophilic. The stable hydrophilicity of SiO2 overlayer which adsorbs more stable OH groups, enhances the sustained effect, i.e. the super-hydrophilic state can be maintained for a long time in dark place.     

纳米复合W-6%ThO_2和W-2%ThO_2阴极材料的性能对比

通过真空热压烧结制备了W-6%ThO2和W-2%ThO2纳米复合阴极材料,分析表明两者的显微组织类似,纳米ThO2较均匀分布在W基体上;前者的起弧电场强度低于后者,逸出功也相应降低;两者的机械性能相差不大。