Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》
Abstract： Ingeneral,high- temperature salt- corrosion may usually induce mechanical stresses and phase transformation within ZrO2，as the main componentof thermal barrier coatings (TBCs), therewith further cause the failure of TBCsfor hot section components of gas turbine. Yb/Y co-doped zirconia (YbYSZ) powder was synthesized by a coprecipitation- calcination method, thenYbYSZ ceramic pallets were obtained by cold pressing and subsequent sintering at high temperature. The corrosion behavior of thepallets coated with a film of powder mixture CaO-MgO-Al2O3-SiO2 (CMAS) was examined in air at 1250℃ for different time intervals. The elemental diffusion and phase transformationwith YbYSZ after high-temperature corrosion wereinvestigated by XRD, SEM and EDS. The results showed that among othersthe elementYbin YbYSZ reacted preferenyially with CMAS and dissolved into the molten saltCMAS. The loss of Yb could suppressed the segragation of Y from the rest YbYSZ.Consequently, it stabilized the metastable tetragonal phase (t'-zirconia). The optimal dose of Yb is 5 mass% for the minimal yield of monoclinic ZrO2 in the YbYSZ after corrosion test.
Subjects: Materials Science >> Ceramics submitted time 2023-02-01
Abstract： The study deals with the use of different amounts of MgO or tetraethyl orthosilicate (C8H20O4Si, TEOS), from 0.04 wt %, 0.06 wt %, 0.08 wt %, 0.4 wt %, 0.6 wt % to 0.8 wt %, respectively, as additional sintering aids during the vacuum sintering of transparent Ce3+ doped Y3Al5O12 (Ce:YAG) ceramics to investigate their effect on microstructure and luminescence properties. A comparative study was carried out by using X - ray diffraction, scanning electron microscopy/energy dispersive X - ray spectroscopy, optical and photo-luminesce spectra, as well as electroluminescent spectra. The dominant garnet phase was obtained even when adding 0.8 wt % of MgO or TEOS, while adding MgO led to finer average grain size (~ 5 - 10 μm) and more homogenous distribution compared to TEOS (~ 20 - 25 μm) in Ce:YAG ceramics. Adding a large amount of MgO was found to result in the segregation of MgO in Ce:YAG ceramics, while an excess of TEOS led to the segregation of Al2O3. A strong absorption peak at 308 nm was observed in Ce:YAG ceramics with MgO sintering aids, which was ascribed to the existence of Ce4+ induced by a charge compensation effect of Mg2+. The optimum transmittance reached 80% @ 800 nm in Ce:YAG ceramics when adding 0.6 wt % TEOS, which also exhibited a maximum luminous efficacy of 106 lm/W. Si4+ was experimentally proved to have a better optimization effect on luminous efficacy compared to Mg2+.
Subjects: Library Science，Information Science >> Library Science submitted time 2018-08-27
Abstract： " Abstract [Purpose] To reveal function of non-academic columns in Nature for enhancing academic influence of papers in Chinese scientific and technological journals. [Methods] Analyzing components of non-academic columns, contents of essays and targeting readers, and counting words, citations, self-references of essays in non-academic columns of 4 issues of the Nature published in recent 18 years. [Findings] The main function of the non-academic columns is to interpret Nature's academic papers through science communication, and the second function is to build a favorable environment for Nature itself, but rather than to simply obtain citations and self-references so that Nature can elevate the impact factor based on Scientific Citation Index. [Conclusions] The non-academic columns promoted/interpreted Nature's academic papers to be widely read, accepted and applied in the reader’s research through non-academic essays in the form of science communication, which may be one of key notes for Nature success. Chinese journals of science and technology should learn its advertisement ways and methods for academic papers. Among them, the short essays with around 120 words in English or 180 words in Chinese may easily be applied.
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