类金刚石膜对铝合金疏水结构耐久性能影响

为提高2024铝合金疏水及耐蚀性能,利用电化学刻蚀结合等离子体增强化学气相沉积(PECVD)技术,在其表面制备微纳米浮凸疏水结构及类金刚石(DLC)薄膜。利用接触角测量仪、电化学工作站及冲刷试验装置,对不同处理工艺下2024铝合金的疏水、耐蚀及疏水耐久性能进行了研究,并讨论了相应的作用机制。结果表明,电化学刻蚀后2024铝合金与水的静态接触角可达到130o以上,疏水性能显著提高。阻抗结果表明,刻蚀后阻抗模值提高了约8倍,腐蚀电流密度降低了两个数量级,耐蚀性能显著提高。刻蚀后镀非晶态惰性DLC膜的铝合金,其阻抗模值可达1.016×10⁷Ω·cm^-2,可有效阻碍腐蚀过程的电荷转移和离子传输电荷的传递,显著延长疏水结构的耐久性能。     

Interfacial Charge Transfer Bridge Prolongs Carrier Recombination Lifetimes of CoFe Metal-Thiolate Framework/Hematite Photoanode for Water Oxidation

Constructing heterostructural photoanodes is attractive for elevating the photoelectrochemical (PEC) performance, however, it is a long-standing challenge to achieve highly efficient interfacial charge transfer. Herein, a CoFe metal-thiolate framework (CoFe MTF)/Fe₂O₃ photoanode connected by an interfacial Fe─O─N/S bond is designed to modulate the behavior of charge carriers and improve water oxidation performance. It is disclosed that this interfacial bond functions as a direct charge transfer bridge between shallow trap states of Fe₂O₃ and CoFe MTF, leading to prolonged carrier recombination lifetimes (85 ns for CoFe MTF/Fe₂O₃ compared to 37 ns for Fe₂O₃) and enhanced charge transfer efficiency. Alternatively, a robust interfacial electric field is established in the CoFe MTF/Fe₂O₃ p–n heterojunction, facilitating efficient charge transfer. As expected, the CoFe MTF/Fe₂O₃ photoanode exhibits significant enhancement in water oxidation, resulting in a three-fold increase in photocurrent density compared to pristine Fe₂O₃. This study highlights the significance of designing interfacially bonded heterostructural photoelectrodes to regulate the transfer characters of charge carriers.     

金刚石颗粒表面镀铜层的控制氧化

为了改善熔融玻璃对金刚石颗粒的润湿,需要对镀铜金刚石颗粒在一定气氛下进行控制氧化,从而在其表面获得一定厚度的Cu₂O层.通过对金刚石颗粒表面镀铜层氧化的热力学计算,确定了在650℃、露点温度为20℃的N₂/H₂O二元混合气氛中进行氧化.氧化的动力学研究表明,在此条件下金刚石颗粒表面镀铜层的氧化符合抛物线规律,其抛物线速度常数为1.127 5×10^-12g²·cm^-4·min^-1.在动力学研究的基础上,本实验选择氧化时间为40 min.XRD实验结果表明,氧化后的金刚石颗粒表面只有Cu和Cu₂O,未生成CuO.     

Mechanical properties and microstructure evolution of KD-SA SiCf/BN/SiC CMCs oxidized at different temperatures

Silicon carbide fiber-reinforced SiC ceramic matrix composites (SiC_f/SiC CMCs) based on a domestic KD-SA SiC fiber were exposed to a wet oxygen atmosphere for 135 h at 800, 1100, and 1300°C. The evolution of the microstructure and mechanical properties of SiC_f/SiC CMCs have been systematically investigated following oxidation. For weight change, CMC-1300 showed the greatest gain (0.394%), followed by CMC-1100 (0.356%) and CMC-800 (0.149%). The volatilization of boron oxide (B₂O₃) combined with the slight oxidation of the SiC matrix at 800°C caused crack deflection and fiber pull-out. The complete dissipation of the interphase could be found when the oxidation temperature increases to 1100°C, generated a fracture surface with brittle fracture characteristics. At 1300°C, crystalline SiO₂ hindered oxygen diffusion, with evidence of fiber pull-out. Based on thermodynamic calculations and microscopic observations, we propose a mechanism to explain the thermal degradation of SiC_f/SiC CMCs. This work offers valuable guidance for the fabrication of SiC_f/SiC CMCs that are suitable for high-temperature applications.     

蒸馏—萃取联合法再生镀钌废液中的三氯化钌

传统氧化蒸馏工艺回收钌废液中钌的损失率较高,试验优化了氧化蒸馏工艺,并采用萃取法处理蒸余液。探讨了蒸馏温度、氧化剂用量、吸收剂,以及预氧化剂、萃取剂体积分数、萃取相比、反萃条件等因素对钌回收率的影响。结果表明:在蒸馏温度80℃下,以KMnO₄-H₂SO₄为氧化剂,6 mol/L HCl为吸收剂,蒸馏时间为1 h,钌蒸馏回收率最高达到89.0%;再生蒸余液时,在萃取剂为30%N503,萃取相比为1,反萃剂为2 mol/L NaOH溶液,反萃相比为1的最佳条件下,反萃率达到80.4%。蒸馏—萃取联合法再生钌的总回收率达到96.9%,比单一蒸馏法提高了7.9百分点,有效提高了钌的再生利用率。     

羟基自由基氧化对蛋清蛋白质结构的影响

研究蛋清蛋白质经过FeCl₃/抗坏血酸（Asc）/H₂O₂产生的羟基自由基氧化体系氧化后化学结构的变化。用不同浓度的H₂O₂（0、1、5、10和20 mmol/L）对蛋清蛋白质氧化3 h,研究氧化前后蛋清蛋白质羰基、游离巯基、总巯基、游离氨基、粒径分布及二级结构的变化趋势。结果表明:氧化可使蛋清蛋白质羰基含量显著升高（p<0.05）,游离巯基和总巯基含量显著下降（p<0.05）,游离氨基显著下降（p<0.05）,平均粒径逐渐增大。当H₂O₂浓度为20 mmol/L时,与对照组相比羰基含量增加2.01倍,游离氨基降低了29.1%,平均粒径增加到666 nm。在H₂O₂浓度低于5 mmol/L时,α-螺旋和β-折叠含量升高,β-转角降低;H₂O₂浓度高于5 mmol/L时蛋清蛋白质的肽链发生断裂,进一步导致蛋白质结构发生了变化。以上结果表明氧化能在一定程度上改变蛋清蛋白的结构特性。      

直接乙醇燃料电池研究面临的挑战

从热力学、动力学及乙醇渗透等方面,综述了直接乙醇燃料电池(DEFC)研究面临的挑战.从热力学角度看,在低温(＜100℃)时,乙醇的最大热力学转化效率低于14%,降低了DEFC的效率;从动力学角度看,目前对乙醇氧化活性最高的Pt-Sn催化剂仍不能使乙醇完全氧化,降低了DEFC的法拉第效率;乙醇渗透可能带来的后果,加大了研究的困难性.     

叶片电解加工机床的研制

为了能够实现按最优进给角度加工叶片,研制出三轴进给的叶片电解加工专用机床。介绍了机床的加工原理、机床结构、性能规格以及相应的控制系统。实践证明在该机床上电解加工方料毛坯,加工出的叶片经专用量具检测,叶片型面精度符合要求。     

Hot Corrosion Behaviors of Ni-14%Cr Alloys in Molten Sulfate

The corrosion behaviors and mechanism of Ni-14%Cr alloys in molten salt with Na2SO4 at 1000℃ was investigated by means of XRD analysis and SEM observation. Results show that the alloys were subjected to the accelerated corrosion in molten salt and the corrosion kinetic of the alloy obeys the parabolic law. On the other hand, the corrosion-resistance of the alloy could be improved significantly by increasing of chromium content. Corrosion products may be divided into three layers, i. e. NiCr2O4, CoCr2O4, CoN...     

Electrochemical corrosion behavior of 300M ultra high strength steel in chloride containing environment

The electrochemical corrosion behavior of 300M ultra high strength steel in chloride containing environment was investigated by potentiodynamic polarization technique, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results show that uniform corrosion occurs on 300M steel during the electrochemical measurements because no anodic passivation phenomenon is observed on polarization curves within the measurement range. The tests also show that 300M steel is highly susceptible to chloride containing solution, which is characterized by corrosion current density increasing with the addition of chlorides, and corrosion potential shifting towards positive direction and corrosion resistance decreasing, positively suggesting that chloride ions speed up the corrosion rate of 300M steel. Meanwhile corrosion products on the 300M steel surface formed during the salt spray test are too loose and porous to effectively slow down the corrosion rate. Additionally, a schematic structure of uniform corrosion mechanism can explain that 300M steel has better property of stress corrosion cracking (SCC) resistance than stainless steels.