Si–Yb2O3/Yb2Si2O7/Yb2SiO5 EBC涂层组织结构及熔盐腐蚀行为研究

目的 研究Si–Yb₂O₃/Yb₂Si₂O₇/Yb₂Si O₅ 3层EBC涂层的抗熔盐腐蚀性能。方法 采用真空等离子喷涂工艺在试样表面单面制备Si–Yb₂O₃/Yb₂Si₂O₇/Yb₂Si O₅ 3层结构的EBC涂层,选用尺寸为Ф25 mm、厚度为5 mm的SiC_f/SiC复合材料基体试样,在900℃、NaCl(质量分数为50%)+Na₂SO₄(质量分数为50%)混合盐中进行连续100 h的熔盐腐蚀试验,采用光学显微镜、扫描电镜、X射线衍射仪等观察和测试3层EBC涂层熔盐腐蚀前后的形貌,分析其组织结构以及该EBC涂层在熔盐腐蚀过程中的化学反应机理。结果 经过连续100 h、900℃的熔盐腐蚀,基体SiC_f     

Novel Plasma Reactor with Rotary Helix Electrode Used in Coupling of CH4 at Atmospheric Pressure

At the ambient temperature and pressure a glow discharge plasma was used as a new approach for the coupling of methane with the newly-developed rotary multidentate helix electrode. In the presence of hydrogen, the effects of the input peak voltages and gas flow rates on methane conversion, C2 single pass yield and selectivity were investigated, and then the results were compared with those from the three-disc multidentate electrode. This demonstrated, on an experimental scale, that the rotary multidentate helix electrode was better than the multidentate three-disc electrode as there was little accumulation of coke, and the C2 yield per pass was 69.85% and C2 selectivity over 99.14% with 70.46% methane conversion at an input peak voltage of 2300 V and 60 ml/min gas flow rate.     

Effects of Deposition Temperature on the Structure and Hardness of BN Films Prepared by a Gradient Temperature Method

采用温度梯度法,通过MW-ECR射频磁控溅射在硅片基底上制备了六方和立方混合的氮化硼薄膜。研究了薄膜的键结构,化学成分和力学性能。结果显示,对于氮化硼立方相的出现存在温度阈值,薄膜的硬度随沉积温度提高而提高。相对于传统薄膜制备方法,温度梯度方法具有更高的效率。     

单电极冷等离子体射流制备碳纳米颗粒

采用常压单电极氩冷等离子体射流分解乙醇/去离子水溶液制备碳纳米颗粒。相对于传统制备方法,该方法不需要加热,也不需要使用催化剂,不会引进杂质。采用扫描电镜对产物进行表征,发现通过调节放电参数可以很好地控制产生的碳纳米颗粒粒径,对类辉光模式,颗粒平均粒径2～10 nm,可以形成均匀的薄膜;对丝状放电模式,颗粒平均粒径增加到80～300 nm。     

低温等离子体催化甲烷转化的工艺研究进展

介绍了低温等离子体催化甲烷转化的研究概况,从工艺方法、反应器及反应机理方面评述了近些年国内外采用低温等离子体催化甲烷转化的研究情况和发展趋势.