纳米柱状多孔WO3- x /TiO2 薄膜的电致变色性能

采用反应磁控溅射在掠射角度α=0°和α=80°的条件下制备氧化钨（WO_3-x）薄膜,然后在其表面沉积二氧化钛（TiO₂）。利用X射线衍射仪（XRD）、场发射扫描电镜（FE-SEM）和X射线光电子能谱仪（XPS）对WO_3-x/TiO₂薄膜的晶体结构、表面/断面形貌以及表面化学成分进行表征。在三电极体系1 mol/L LiClO₄/PC溶液中,采用电化学工作站和紫外-可见分光光度计测试了WO_3-x/TiO₂薄膜的电致变色性能。XRD结果表明,WO_3-x/TiO₂薄膜为非晶态结构,与掠射角度无关。当掠射角度为80°时,获得了纳米柱状多孔薄膜。从 W 4f和Ti 2p的XPS谱图确认氧化钨为亚化学计量比的WO_3-x,而氧化钛为满足化学计量比的TiO₂。与致密薄膜相比,纳米柱状多孔薄膜需要较低的驱动电压且具有较快的响应速度。纳米柱状多孔薄膜的电荷容量为83.78 mC,是致密薄膜电荷容量30.83 mC的2倍以上。在±1.2 V驱动电压下,注入和脱出离子扩散速率分别为D_in=5.69×10^-10 cm²/s和D_de= 5.08×10^-10 cm²/s。与纯WO₃薄膜相比,WO_3-x/TiO₂薄膜的电致变色循环稳定性更好。纳米柱状多孔薄膜在可见光范围内具有较大的光调制幅度,因此其光密度变化（ΔOD）大于致密薄膜。     

Ti-Cu-Ni-Nb-Al-Zr-Hf非晶钎料合金真空钎焊Ti50Al50 接头的界面组织与剪切强度

在钎焊温度1140~1220 ℃、钎焊时间30 min的工艺参数下,采用Ti-9.5Cu-8Ni-8Nb-7Al-2.5Zr-1.8Hf（质量分数,%）非晶钎料成功实现了Ti₅₀Al₅₀ (at%)合金的真空钎焊连接,并研究了钎焊温度对钎焊接头的显微组织、剪切强度的影响规律。结果表明,在任何钎焊温度下获得的Ti₅₀Al₅₀钎焊接头均有3个界面反应层且每个反应层都含有α₂-Ti₃Al和Ti₂Cu(Ni) 2个物相。随着钎焊温度的增加,α₂-Ti₃Al和Ti₂Cu(Ni)在钎焊接头中的尺寸与分布发生了明显的变化,尤其是等温凝固层Ⅱ中的Ti₂Cu(Ni)相。1200 ℃下稳定存在的连续α₂-Ti₃Al层Ⅰ对母材和钎料原子的相互扩散具有阻隔壁垒作用,温度一旦超过1200 ℃,α₂-Ti₃Al相变得不稳定使得连续α₂-Ti₃Al层被打破从而失去阻隔壁垒效应。在钎缝中析出且弥散分布的α₂-Ti₃Al对焊缝中物相的形成可以起到抑制形核和细化晶粒的作用。随着钎焊温度升高,Ti₅₀Al₅₀钎焊接头平均抗剪切强度先增加后减小,在钎焊温度1180 ℃、钎焊时间30 min时钎焊接头的抗剪切强度最大,达184 MPa。剪切断口表面呈典型解理断裂特征且α₂-Ti₃Al占绝大多数。     

高分子辅助沉积法制备Sm x Nd1- x NiO3 外延薄膜

采用高分子辅助沉积法制备掺杂不同钐（Sm）含量的Sm_xNd_1-xNiO₃外延薄膜（钐掺杂量x=0.5,0.55,0.6）。X射线衍射（特征θ-2θ扫描、摇摆曲线和φ-scan）和扫描电子显微镜的测试结果表明,制备的薄膜结晶性和外延性良好,与衬底的（001）取向保持一致。电阻率-温度曲线表明制备的外延薄膜均表现出金属绝缘体转变现象。随着Sm掺杂量的提高,金属绝缘体转变温度逐渐升高;当x=0.55时,外延薄膜的转变温度在室温附近。并且高分子辅助沉积法可以简单有效地制备热致变色外延薄膜。     

基于第一性原理的石榴石型Li7La3Zr2O12 固态电解质的设计与合成

基于密度泛函理论（DFT）的第一原理方法计算了四方相和立方相中2种不同的Li₇La₃Zr₂O₁₂（LLZO）固体电解质材料的能带结构,晶格参数,态密度和成键特性。基于理论计算结果,通过电子结构特性解释了四面体相的离子电导率低于立方相的离子电导率的原因。基于LLZO的第一性原理计算,设计了2种晶体结构的LLZO材料,并通过高温固相法制备并分析了不同烧结时间的LLZO颗粒的性能。探索了合成工艺参数对Li₇La₃Zr₂O₁₂性能的影响。立方晶Li₇La₃Zr₂O₁₂（C-LLZO）的平均晶格大小为a=b=c=1.302 246 nm,而四方Li₇La₃Zr₂O₁₂（T-LLZO）的平均晶格大小为a=b=1.313 064 nm,c=1.266 024 nm。在1000 ℃下烧结12 h的C-LLZO为纯立方相,在室温（25 ℃）下最大离子电导率为9.8×10^-5 S·cm^-1。T-LLZO在室温（25 ℃）下的离子电导率为5.96×10^-8 S·cm^-1,在800 ℃下烧结6 h具有纯的四方相结构,与计算结果基本吻合。     

Al-Si合金中 α-Al依附于AlB2 异质形核的原子机制

利用固体与分子经验电子理论分别计算了α-Al,AlB₂与(Al-Si)B₂的价电子结构与结合能。结果表明,AlB₂最外层的Al-Al原子层相对不稳定,随着Al-Si熔体中Si含量的增加,α-Al和AlB₂的结合能均降低。根据计算结果,提出了Al-Si合金中α-Al在AlB₂上异质形核的一种全新原子机制。加入Si后,一定量的Si原子进入AlB₂,在AlB₂表面形成稳定的Al-Si二元原子结构层,提高了AlB₂表面的稳定性。这种稳定的二维Al-Si原子层在随后的异质形核过程中起着重要的过渡作用,是AlB₂成为α-Al有效异质核心的原子机制。     

非平衡磁控溅射La-Ti/WS2 自润滑薄膜的摩擦磨损行为

要满足航天器机械转动部件在恶劣工况下的工作,需研制高硬度、低摩擦系数的固体润滑薄膜。采用非平衡磁控溅射法分别制备了纯WS₂薄膜、Ti掺杂WS₂复合薄膜和La-Ti掺杂WS₂复合薄膜。分析了薄膜的微观形貌、成分、硬度和摩擦学性能。结果表明,与纯WS₂薄膜和Ti/WS₂复合薄膜相比,La-Ti/WS₂复合薄膜的微观结构更加致密。La-Ti/WS₂复合薄膜的硬度H和弹性模量E也显著提高。此外,La-Ti/WS₂复合薄膜的摩擦系数减小,并且H/E比值增大,La-Ti/WS₂复合薄膜的磨损率降低。结果表明,La的掺杂有助于在摩擦接触表面形成稳定的转移膜,提高La-Ti/WS₂复合薄膜的耐磨性和承载能力。     

0.74BiFe1- x Ga x O3-0.26BaTiO3 高温无铅压电陶瓷的相变行为及电性能

准同型相界（MPB）对提升压电陶瓷的压电性能具有重要的作用。BiFeO₃-BaTiO₃体系的准同型相界通常位于0.70BiFeO₃-0.30BaTiO₃组分附近。然而，对于BiFeO₃-BaTiO₃体系，BaTiO₃含量越高其居里温度越低。因此，在较低的BaTiO₃含量组分附近构建准同型相界是使其同时获得良好的压电活性和高居里温度的有效策略。采用固相法制备了0.74BiFe_1-xGa_xO₃-0.26BaTiO₃（x=0~0.05）系列无铅压电陶瓷，研究了Ga含量对其物相结构与电性能的影响。结果表明：随着Ga含量的增加，陶瓷样品从三方相逐渐向赝立方相转变。当x≤0.01，陶瓷样品为三方相结构；而当0.04≤x≤0.05，陶瓷样品为赝立方结构，在0.02≤x≤0.03形成了准同型相界（三方-赝立方）。另外，由于容忍因子的升高，该系列陶瓷的居里温度随着Ga含量的增加而略有降低。位于准同型附近的陶瓷样品表现出良好的压电活性和较高的居里温度。     

MD模拟加载温度对Ni3Al基合金加工表面的影响

为改善Ni₃Al基合金的纳米切削表面质量以获得更好的服役状态,结合纳米级分子动力学模拟和微观切削实验,探讨了加载温度（300~1050 K）与切削力、表面形貌的关联性。分子动力学模拟结果显示,在纳米切削Ni₃Al基合金过程中,加载温度为750 K时的切削力波动相对于其他温度最小;当加载温度在600~750 K时,影响表面形貌的凸起原子数量最少,即表明加载温度为750 K左右时,Ni₃Al基合金可以获得较高的表面质量。Ni₃Al基合金微观切削实验表明,当加载温度在600~750 K时,加工表面轮廓可以获得较高的平整度,间接验证了在Ni₃Al基合金纳米切削的分子动力学仿真结果的可行性。研究结果表明,选取合适的加载温度是改善Ni₃Al基合金纳米切削加工表面质量的有效途径。     

Ar/N2-Ar共溅射Ti掺杂对Ta2O5 涂层光学和力学性能的影响

为了探索Ar/N₂-Ar共溅射Ti掺杂对Ta₂O₅涂层光学性能和力学性能的影响,采用射频和直流磁控共溅射技术在玻璃基底表面制备了Ta₂O₅、N₂-Ta₂O₅、Ti-Ta₂O₅和N₂-Ti-Ta₂O₅涂层。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、原子力显微镜（AFM）表征了Ta₂O₅、N₂-Ta₂O₅、Ti-Ta₂O₅和N₂-Ti-Ta₂O₅涂层的微观结构和表面形貌;通过紫外可见分光光度计测试了涂层的光学参数;采用纳米压痕仪测试了涂层的硬度和杨氏模量。XRD测试结果表明,Ta₂O₅、N₂-Ta₂O₅、Ti-Ta₂O₅和N₂-Ti-Ta₂O₅涂层主要以Ta₂O₅为主体的非晶相结构组成。SEM和AFM结果显示,沉积在玻璃基底上的涂层未出现大面积空隙,溅射粒子在基底表面均匀堆积生长,并且涂层沉积厚度基本一致,厚度误差在5%以内。分别引入N₂和Ti及N₂-Ti共掺杂,均可降低Ta₂O₅涂层的粗糙度。光学测试结果表明,分别引入N₂和Ti元素,可以提高Ta₂O₅涂层的平均透射率至81%以上,而N₂-Ti共掺杂制备的N₂-Ti-Ta₂O₅涂层平均透射率降低。力学测试结果显示,与Ta₂O₅涂层对比,N₂-Ta₂O₅和N₂-Ti-Ta₂O₅涂层的硬度显著增大,Ti-Ta₂O₅涂层硬度基本一致。弹性指数（H/E）和塑性指数（H³/E²）表明,N₂-Ta₂O₅涂层和N₂-Ti-Ta₂O₅涂层具备更好的断裂韧性和抗塑性变形能力。在玻璃表面制备Ta₂O₅掺杂N₂和Ti元素的涂层,可以实现以N₂-Ta₂O₅涂层和N₂-Ti-Ta₂O₅涂层为代表的、同时具备优异光学性能和力学性能的多功能涂层。     

激光沉积Mg2Si/Al的原位反应动力学

通过激光沉积制备了原位Mg₂Si/Al复合材料,建立了其动力学模型。结果表明,激光功率（温度）、富Mg层厚度、Si颗粒大小及Al含量是影响原位生成Mg₂Si/Al复合材料的速率及程度的主要因素。增加激光功率（温度）、降低富Mg层厚度、缩小Si颗粒大小及减少Al含量使原位反应的速率及程度提高。     

Effects of sulfur pressure on the sulfidation behavior of 310 stainless steel

High-temperature sulfidation behavior of 310 stainless steel was studied over the temperature range of 700–900°C above a pure sulfur pool with the sulfurvapor range of 10^–4–10^–1 atm. The corrosion kinetics followed the parabolic rate law in all cases. The corrosion rates increased with increasing temperature and sulfur pressure. The scales formed on 310 stainless steel were complex and multilayered. The outer scale consisted of iron sulfide (with dissolved Cr), (Fe, Ni)₉S₈ and chromium sulfides (Cr₂S₃ and Cr₃S₄ with dissolved Fe), while the inner layer was a heterophasic mixture of Cr₂S₃, Cr₃S₄, NiCr₂S₄, and Fe₁–_xS. Platinum markers were found to be located at the interface between the inner and outer scales, suggesting that the outer scale grew by the outward transport of cations (Fe, Ni, and Cr), and the inner scale grew by the inward transport of sulfur. The formation of Cr₂S₃, Cr₃S₄, and NiCr₂S₄ partly blocked the transport of iron through the inner scale, resulting in a reduction of the corrosion rates as compared with the results in the literature.     

Effects of Mo and Al Additions on the Sulfidation Behavior of 310 Stainless Steel

The high-temperature sulfidation behavior of 310stainless steel (310SS) with Mo and Al additions (up to10 at.%) was studied over the temperature range700-900°C in pure-sulfur vapor over the range of 10^-3 to 10^-1 atm. Thecorrosion kinetics followed the parabolic rate law inall cases and the sulfidation rates increased withincreasing temperature and sulfur pressure. Thesulfidation rates decreased with increasing Mo and Al contents and it wasfound that the addition of 10 at.% Mo resulted in themost pronounced reduction among the alloys studied. Thescales formed on 310SS with Mo additions were complex, consisting of an outer layer of ironsulfide (with dissolved Cr), (Fe,Ni)₉S₈, andCr₂S₃/Cr₃S₄(with dissolved Fe), and an inner heterophasic layer ofFe_1-xS,Cr₂S₃/Cr₃S₄,NiCr₂S₄,Fe_1.25Mo₆S_7.7, FeMo₂S₄, andMoS₂. The scales formed on 310SS with Mo andAl additions had a similar mixture as above, except thatAl_0.55Mo₂S₄ was alsoobserved in the inner layer. The formation ofMoS₂ andAl_0.55Mo₂S₄ partly blocked the transport of cations throughthe inner scale, resulting in the reduction of thesulfidation rates compared to 310SS.     

LaSrCuO4粉体微结构对Ag/LSCO电接触材料性能的影响

以硝酸镧、硝酸铜、硝酸锶等为原料,分别采用固相法、溶胶-凝胶法和共沉淀法合成了不规则颗粒状(LSCO_g)、介孔状(LSCOm)和片层状(LSCOl)的LaSrCuO_4(LSCO)粉体。采用高能球磨并结合初压-初烧-热压工艺制备出Ag/LSCO电接触材料。利用X射线衍射(XRD)、扫描电镜(SEM)、金属电导率仪、维氏硬度计和电寿命试验机等对粉体形貌及电接触材料的物理和电学性能进行了表征。结果表明:与Ag/LSCO_(m)、Ag/LSCO_l材料相比,Ag/LSCO_(g)电接触材料表现出更加优异的物理性能,其电阻率为2.37μΩ·cm,硬度为800MPa,密度为9.32g/cm~3;但电学性能差异较小,其在AC220V12A开断状态下的燃弧能量为400 mJ、燃弧时间为23 ms,关合状态下的燃弧能量为1500 mJ,燃弧时间为68ms。Ag/LSCO电接触材料的主要失效形式是液滴喷溅,微裂纹和孔洞。     

不同催化剂对镁合金表面SiO_2-ZrO_2涂层耐蚀性的影响

镁合金表面溶胶凝胶涂层存在易析出氢气、涂层缺陷多及防腐性能提升不明显等问题。为改善这些问题利用Ce(NO_3)_3催化制得SiO_2-ZrO_2溶胶并旋涂3层于AZ91D镁合金表面,并与HCl催化制得的镁合金表面SiO_2-ZrO_2溶胶涂层进行对比分析。采用扫描电镜和傅里叶红外光谱等分析涂层微观形貌和化学成分;通过接触角测试涂层亲疏水性;利用极化曲线和电化学阻抗谱对比研究不同催化剂加入的溶胶凝胶层在3.5%NaCl溶液中的耐腐蚀性能。结果显示:与HCl催化制得的镁合金表面SiO_2-ZrO_2溶胶涂层相比,Ce(NO_3)_3催化制得的涂层表面微观缺陷少;接触角由84.2°增大到93.5°;同镁合金基体自腐蚀电流密度1.480×10~(-4) A/cm~2相比,HCl催化和Ce(NO_3)_3催化涂层的自腐蚀电流密度分别为2.562×10~(-6) A/cm~2和7.821×10~(-7) A/cm~2,其耐蚀性提升明显;HCl和Ce(NO_3)_3催化涂层阻抗极化电阻值由镁合金基材的224.9Ω分别增大至4 401Ω和53 888Ω,HCl催化涂层的失效时间为1 d,Ce(NO_3)_3催化涂层失效时间延长为3 d。可见,两种催化剂制备的涂层,Ce(NO_3)_3催化涂层防护更持久,耐蚀性更好。     

Effect of some ternary additions on the sulfidation of Ni-Mo alloys

Five ternary additions, Cr, Ti, Mn, V, and Al were studied at equi-atomicpercent levels (17 a/o) for their effect on the sulfidation behavior of Ni-19a/o Mo (28–30 w/o) over the range of 600–800°C in 0.01 atm S₂. Al was by far the most effective addition. A linear decrease in log k_p vs. Al content was observed up to 7.5w/o Al, beyond which no further change was observed. All alloys followed the parabolic rate law. Arrhenius plots gave activation energies of 36.9–41.2 Kcal/mol for alloys containing Ti, Cr, Mn, and V, whereas the activation energies for Al-containing alloys were 47.2 Kcal/mol, indicating that a different diffusion process was involved. Complex scales were formed on all alloys, consisting of an outer layer of Nis_1+x and complex inner layers which depended upon alloy composition. Two alloys, those with Cr and Mn, formed intermediate layers of Cr₂S₃ and MnS, respectively, but these layers had little effect on the kinetics. MoS₂ was a constituent of the inner scales except for the alloys with Al. A ternary sulfide, Al_0.55Mo₂S₄ and Al₂S₃ were observed. The presence of the mixed sulfide was always associated with the low sulfidation rates. The formation of MoS₂ on alloys results in a different, less-protective behavior than for MoS₂ formed on pure Mo. This effect is due to the intercalation of Ni into MoS₂ in octahedral positions between the weakly bonded layers of covalently bonded sheets of trigonal prisms. The size of Al⁺³ is too small to be intercalated, and thus MoS₂ is destabilized by Al.     

Effect of Y2O3 additions on the plasticity of sintered Cr2O3

We have carried our constant strain-rate compression tests on polycrystalline Cr₂O₃ and Cr₂O₃ doped with 0.09 wt. % Y₂O₃ to establish whether there exists an effect of Y₂O₃ on the plasticity of Cr₂O₃. This study is motivated by previous work on the oxidation of alloys containing reactive-element additions. In that work, it has been observed that the addition of oxygen-active elements, such as Y to alloys that form Cr₂O₃ or Al₂O₃ oxide layers upon exposure at high temperature, strongly enhances the adhesion of the oxide layer to the base alloy as compared with alloys without reactive-element additions. We have found that at 1200°C (1) chromia exhibits limited plasticity at high temperatures, and (2) the presence of Y in the oxides does not enhance plasticity compared with addition-free oxides.     

The combined effect of refractory coatings containing reactive elements on high temperature oxidation behavior of chromia-forming alloys

The high temperature oxidation behaviors of chromia-forming alloys (F17Ti and Fe-30Cr alloys) have been studied at 1273 K under isothermal conditions and at 1223 K under cyclic conditions, in air under the atmospheric pressure. To extend the oxidation lifetime, coatings have been applied onto the alloy surfaces. Al₂O₃ and Cr₂O₃ films doped with Sm₂O₃ or Nd₂O₃ were prepared via the metal-organic chemical vapor deposition technique. Single Cr₂O₃, Al₂O₃, Nd₂O₃ and codeposited Cr₂O₃-Nd₂O₃, Al₂O₃-Nd₂O₃, Al₂O₃-Sm₂O₃ coatings drastically improved the chromia-forming alloy high temperature oxidation behavior, since they decreased the oxidation rate and enhanced the oxide scale adhesion. Results showed that a critical amount of reactive element (Nd or Sm) in chromia or alumina coatings (11-18 at.%) was needed to observe the most effective effect. The fast precipitation of NdCrO₃ or NdTi₂₁O₃₈ and the segregation of reactive elements at the chromia grain boundaries slowing down outward cation transport and consequently blocking the chromia grain growth, was supposed to be the main reasons of the beneficial effect ascribed to the reactive elements in chromia scales.     

Effect of Nb on the high-temperature sulfidation behavior of cobalt

The sulfidation behavior of Co-Nb alloys containing up to 30wt.% Nb was studied in sulfur vapor at a pressure of 0.01 atm in the temperature range of 600–700°C. Increasing niobium content decreased the sulfidation rate, following the parabolic rate law. An activation energy of 25.6 kcal/mole was obtained for Co-10Nb, Co-20Nb, and Co-25Nb, while a value of 20.5 kcal/mole was found for Co-30Nb. All were two-phase alloys, consisting of solid solution -Co and the intermetallic compound, NbCo₃. The two-phase alloys formed a rather thick outer layer of cobalt sulfides and a heterophasic inner layer that was complex. The inner layer always contained the mixed sulfide CoNb₂S₄ which, depending on the alloy composition, coexisted with cobalt sulfide, NbS₂, and / or NbCo₃ particles. Short-time sulfidations showed that the solid solution initially sulfidized rapidly to form nodules of cobalt sulfide, whereas the NbCo₃ phase formed a thin protective layer of NbS₂. The nodules grew laterally until they coalesced into the continuous, outer thick layer, while the NbS₂ completely or partially reacted with the cobalt sulfide to form CoNb₂S₄. Platinum markers were always found at the interface between the inner and outer scales, the location of the original metal surface.     

改进型镁扩散法制备高临界电流密度MgB2超导体性能研究

本文采用一种改进型镁扩散法成功制备出密度达到1.95g/cm₃的MgB₂超导块材。论文研究了不同的热处理条件对MgB₂块材的超导转变温度(T_c)和临界电流密度(J_c)性能的影响。采用最佳热处理条件制备的MgB₂超导体T_c和J_c分别达到了38.1K和0.53MA/cm₂(10K,自场)。为了改进镁扩散法MgB₂超导体中弱的高场磁通钉扎性能,本文还研究了nano-Pr₆O₁₁和C掺杂对MgB₂超导体的临界电流密度和不可逆场(H_irr)的影响。结果表明C掺杂的MgB₂超导体临界电流密度在10K,6T下达到了10₄A/cm₂,该结果比未掺杂MgB₂超导体在同样条件下性能提高了两个量级,甚至比固态反应法制备的nano-C掺杂MgB₂超导体性能更好。利用该方法制备的nano-Pr₆O₁₁掺杂的MgB₂超导体在10K,2T下也比未掺杂样品J_c提高达9.4倍。根据大量的实验结果和理论分析我们提出基于改进型镁扩散法和化学掺杂,包括纳米粒子和C掺杂,很有可能是一种制备高性能MgB₂超导体非常有效的途径。     

Protective effect in sulfuric acid media of alumina and ceria oxide layers electrodeposited on stainless steel

The influence of thin layers of Al₂O₃ and Ce₂O₃-CeO₂, electrodeposited on stainless steel OC4004, on the corrosion behaviour of the systems Al₂O₃/SS, Ce₂O₃-CeO₂/SS and Al₂O₃-Ce₂O₃-CeO₂/SS has been studied in sulfuric acid medium. A pronounced stabilizing effect on the passive state of steel and enhancement of its corrosion resistance has been established both for the samples as deposited and for the thermally treated Ce₂O₃-CeO₂/SS systems. In comparison to them the layers of Al₂O₃ have a substantial impact on the corrosion resistance of the Al₂O₃/SS system only in the cases when the system is not subjected to thermal treatment. The consecutive deposition of Al₂O₃ and Ce₂O₃-CeO₂ films on SS gives as a result an outstanding corrosion-protective effect, whereupon the corrosion potential of the system Al₂O₃/Ce₂O₃-CeO₂/SS is shifted in positive direction with ∼ 0.3 V for the samples as deposited and with ∼ 1 V—for the thermally treated samples. The so established favourable effect has been explained by the increased concentration of chromium oxides in the surface passive film, caused by the presence of cerium oxides, as well as by their action as cathode, effective with respect to the reduction corrosion reaction, shifting strongly the potential (at which this reaction is occurring) in positive direction.