Chromium evaporation and oxidation characteristics of alumina-forming austenitic stainless steels for balance of plant applications in solid oxide fuel cells

The chromium (Cr) evaporation behavior of several different types of iron (Fe)-based AFA alloys and benchmark Cr₂O₃-forming Fe-based 310 and Ni-based 625 alloys was investigated for 500 h exposures at 800 °C to 900 °C in air with 10% H₂O. The Cr evaporation rates from alumina-forming austenitic (AFA) alloys were ~5 to 35 times lower than that of the Cr₂O₃-forming alloys depending on alloy and temperature. The Cr evaporation behavior was correlated with extensive characterization of the chemistry and microstructure of the oxide scales, which also revealed a degree of quartz tube Si contamination during the test. Long-term oxidation kinetics were also assessed at 800 to 1000 °C for up to 10,000 h in air with 10% H₂O to provide further guidance for SOFC BOP component alloy selection.     

Promising alloys for intermediate-temperature solid oxide fuel cell interconnect application

The formation of a low Cr-volatility and electrically conductive oxide outer layer atop an inner chromia layer via thermal oxidation is highly desirable for preventing chromium evaporation from solid oxide fuel cell (SOFC) metallic interconnects at the SOFC operation temperatures. In this paper, a number of ferritic Fe–22Cr alloys with different levels of Mn and Ti as well as a Ni-based alloy Haynes 242 were cyclically oxidized in air at 800 °C for twenty 100-h cycles. No oxide scale spallation was observed during thermal cycling for any of these alloys. A mixed Mn₂O₃/TiO₂ surface layer and/or a (Mn, Cr)₃O₄ spinel outer layer atop a Cr₂O₃ inner layer was formed for the Fe–22Cr series alloys, while an NiO outer layer with a Cr₂O₃ inner layer was developed for Haynes 242 after cyclic oxidation. For the Fe–22Cr series alloys, the effects of Mn and Ti contents as well as alloy purity on the oxidation resistance and scale area specific resistance were evaluated. The performance of the ferritic alloys was compared with that of Haynes 242. The mismatch in thermal expansion coefficient between the different layers in the oxide scale was identified as a potential concern for these otherwise promising alloys.     

抗弹陶瓷的犁削机理和自锐作用研究

研制了铬刚玉抗弹陶瓷，其抗弹能力比标准均质钢有很大的提高，通过分析讨论，其主要抗弹机制为犁削机理和自锐作用。     

Role of deposition parameters on microstructure and mechanical properties of chromium oxide coatings

Chromium oxide coatings were deposited by reactive magnetron sputtering on high speed steel (HSS) substrate under various oxygen flow rates and radio frequency (RF) powers. The effect of deposition conditions on the microstructure, hardness and critical load of chromium oxide coating failure was studied. The results indicated that a crystalline chromium oxide coating formed at a high oxygen flow rate and a low RF power exhibited a higher hardness and a lower critical load as compared to a chromium oxide coating with an amorphous microstructure.     

四丁基氢氧化胺模板磷酸铝对铬(Ⅵ)吸附性能的研究

研究了四丁基氢氧化胺模板磷酸铝对水中重金属离子铬(Ⅵ)的吸附特性。结果表明:四丁基氢氧化胺模板磷酸铝对铬(Ⅵ)吸附的最佳pH值和铬(Ⅵ)的初始质量浓度分别为2.0和40mg/L,且其吸附等温线符合Freundlich模型。     

悬浮液进样-火焰原子吸收光谱法测定茶叶中的微量铬

将茶叶悬浮于琼脂胶体中制成悬浮液 ,直接喷入空气 -乙炔火焰 ,用火焰原子吸收光谱法测定茶叶中的微量铬 ,方法简便、快速、灵敏度和精密度高、测定结果与用灰化法处理样品一致 ,检验表明 ,两种样品前处理方法之间无显著性差异。相对标准偏差为 3.4 %～ 6 .1% ,加标回收率为 95 .7%～ 10 3.8 %。     

微萃取原子吸收法检测水中微量铬

采用分散液液微萃取分离技术结合火焰原子吸收法,提出了一种新的环境水样中痕量铬的检测方法。用吡咯烷二硫代氨基甲酸铵做螯合剂,四氯化碳做萃取剂,乙醇做分散剂。选定并优化了萃取的影响参数。这些参数包括萃取剂和分散剂的类型以及它们的体积、萃取时间、酸碱度和螯合剂的用量等等。通过条件优化,Cr（Ⅵ）和总铬富集率分别达到270和259。校准曲线在1～50μg·L^-1的浓度范围内呈线性,Cr（Ⅵ）和总铬的检出限分别为0.12和0.15μg·L^-1,相对标准偏差分别为2.1%和2.7%。（N=5）该法简便快速,用于自来水、井水和河水中铬的形态分析,结果较满意。     

电感耦合等离子体发射光谱法测定锆材中的铪、铁、铬

建立了电感耦合等离子体发射光谱法(ICP-AES)同时测定锆材中铪、铁、铬元素含量的方法。样品用硝酸-氢氟酸溶解,探讨了基体锆对元素铪、铁、铬以及铪、铁、铬相互之间的干扰情况,确定了铪、铁、铬元素最佳分析谱线分别为264.141nm,238.204nm,267.716nm。线性相关系数r≥0.9999,加标回收率均为95%~105%,铪、铁、铬的相对标准偏差小于3%(n=11)。该方法简便、快速、准确,满足锆材日常生产的检测要求。     

铬基钨镍钼高耐磨合金耐磨机理及产业化

本文研究了铬基钨镍钼高耐磨合金的耐磨机理。重点分析了铬基钨镍钼高耐磨合金的铸造工艺流程、铸造用废砂回收再生树脂砂的利用技术以及基于铬基钨镍钼高耐磨合金的耐磨产品。结果表明:铬基钨镍钼高耐磨合金的各种成分在不同工况中具有良好的耐磨性能。