微弧氧化处理对AA7075铝合金在3.5%NaCl溶液中局部腐蚀行为的影响(英文)

采用微弧氧化法在AA7075铝合金上生成氧化铝膜层,并对氧化铝膜层在3.5%NaCl溶液中的腐蚀和应力腐蚀开裂行为进行测试。采用电化学阻抗谱来研究膜层随浸泡时间的变化,构建合适的等效电路图。对常载荷应力腐蚀开裂测试后的试样进行金相观察。结果表明,微弧氧化膜可以有效避免富Cu、Fe金属间化合物相引发的严重局部腐蚀而导致的合金过早失效。

Solvent-free aerobic oxidation of ethylbenzene over supported Ni catalysts using molecular oxygen at atmospheric pressure

We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation of ethylbenzene activities was measured in a round bottom flask immersed in oil bath at known reaction temperature. The physicochemical characteristics of the catalysts were examined by BET surface area, XRD, FT-IR and the oxidation activities were correlated with the acidities of the catalysts obtained by TPD of NH3. It was observed that both hydroxyapatite and USY （13% Na2O） supported Ni catalysts displayed higher ethylbenzene conversion and 80% selectivity towards acetophenone.

Al-Cu-Li合金AA2195在低应变速率和3.5%NaCl溶液中的抗裂性能

研究Al-Cu-Li合金AA2195在3.5% NaCl环境中的耐蚀和抗裂性能,并将其与另一高强合金AA2219进行比较。采用浸泡腐蚀和恒电位极化实验测定合金的总耐蚀性能;采用低应变速率测试法确定合金的应力腐蚀开裂(SCC)性能。利用SEM-EDS和光学测量技术对合金样品进行表征以研究其腐蚀形貌、元素含量和腐蚀深度的变化。用韧性的减少量作为估算合金应力腐蚀开裂(SCC)敏感性的一个参数。结果表明,由于较低的腐蚀速率、较小的腐蚀深度和宽度,AA2195合金比AA2219合金具有更好的耐蚀性能。然而,两种合金的SCC参数(ε_(NaCl)/ε_(air))均大于0.90,说明此两种合金均具有较好的抗裂性能。断裂样品的SEM-EDS结果表明,两种合金均为典型的脆性断裂形貌。