In order to clarify the effects of reactive element Y on the properties of Si-B co-deposition coating on Mo substrate, the Si-B-Y2O3 and Si-B-Y co-deposition coatings were prepared at 1300 ℃ for 5 h by using the pack...In order to clarify the effects of reactive element Y on the properties of Si-B co-deposition coating on Mo substrate, the Si-B-Y2O3 and Si-B-Y co-deposition coatings were prepared at 1300 ℃ for 5 h by using the pack mixtures 16Si-4B-xY2O3/Y- 4NaF-（76–x）Al2O3 （wt.%,x=0, 0.5, 1, 2, 4, 8）. X-ray diffraction （XRD）, energy dispersive spectroscopy （EDS） and wavelength dis-persive spectroscopy （WDS） techniques were used to analyze the structure and oxidation behavior of these coatings. The results re-vealed that the Si-B-Y2O3 and Si-B-Y co-deposition coatings had the same structure with that of the Si-B co-deposition coating. However, Y was incorporated into these coatings and the thicknesses of these coatings were thicker than that of the Si-B co-deposition coating. In addition, the Si-B-Y co-deposition coating demonstrated better cyclic oxidation resistance than the Si-B co-deposition coating at 1100 ℃. The modifying mechanism of Y on the Si-B co-deposition coating was discussed.展开更多
At the top of the Lower Permian Maokou Formation limestones are developed carbonaceous cherts (Plm3), which constitute the dominant seleniferous layer of the Yutangba Se deposit. The cherts contain as much Se as 1646&...At the top of the Lower Permian Maokou Formation limestones are developed carbonaceous cherts (Plm3), which constitute the dominant seleniferous layer of the Yutangba Se deposit. The cherts contain as much Se as 1646×10-6 on average. In addition, they are rich in organic carbon, AI2O3, Si2O, but poor in S. In addition to Se, as well as Mo, Cd, V, and Co, etc are also highly enriched in the cherts. The chert samples are characterized by low ∑REE, slight LREE enrichment, relatively heavy Si isotope enrichment, and insignificant variations in δ30Si value within the range of 1.1‰-1.2‰. Generally, it can be judged from the major element, trace element and REE data and the Si isotopic characteristics that the Yutangba seleniferous cherts were formed in the shallow sea to semi-deep sea anoxic environments and their formation is controlled chiefly by bio-chemical processes.展开更多
基金Project supported by the National Natural Science Foundation of China(51401032)the Fundamental Research Funds for the Central Universities from Chang'an University(310831161012)the Fund of the State Key Laboratory of Solidification Processing in NWPU(SKLSP201216)
文摘In order to clarify the effects of reactive element Y on the properties of Si-B co-deposition coating on Mo substrate, the Si-B-Y2O3 and Si-B-Y co-deposition coatings were prepared at 1300 ℃ for 5 h by using the pack mixtures 16Si-4B-xY2O3/Y- 4NaF-（76–x）Al2O3 （wt.%,x=0, 0.5, 1, 2, 4, 8）. X-ray diffraction （XRD）, energy dispersive spectroscopy （EDS） and wavelength dis-persive spectroscopy （WDS） techniques were used to analyze the structure and oxidation behavior of these coatings. The results re-vealed that the Si-B-Y2O3 and Si-B-Y co-deposition coatings had the same structure with that of the Si-B co-deposition coating. However, Y was incorporated into these coatings and the thicknesses of these coatings were thicker than that of the Si-B co-deposition coating. In addition, the Si-B-Y co-deposition coating demonstrated better cyclic oxidation resistance than the Si-B co-deposition coating at 1100 ℃. The modifying mechanism of Y on the Si-B co-deposition coating was discussed.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 49633110) Graduate School of the Chinese Academy of Sciences.
文摘At the top of the Lower Permian Maokou Formation limestones are developed carbonaceous cherts (Plm3), which constitute the dominant seleniferous layer of the Yutangba Se deposit. The cherts contain as much Se as 1646×10-6 on average. In addition, they are rich in organic carbon, AI2O3, Si2O, but poor in S. In addition to Se, as well as Mo, Cd, V, and Co, etc are also highly enriched in the cherts. The chert samples are characterized by low ∑REE, slight LREE enrichment, relatively heavy Si isotope enrichment, and insignificant variations in δ30Si value within the range of 1.1‰-1.2‰. Generally, it can be judged from the major element, trace element and REE data and the Si isotopic characteristics that the Yutangba seleniferous cherts were formed in the shallow sea to semi-deep sea anoxic environments and their formation is controlled chiefly by bio-chemical processes.
