Rapid Growth of SiO2 Nanofibers on Silicon-Bearing Alloys
Rapid Growth of SiO2 Nanofibers on Silicon-Bearing Alloys
复制标题
含硅合金上 SiO2 纳米纤维的快速生长
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
David J. Young
中科院分区：
文献类型：
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作者：
P. Carter;Brian Gleeson;David J. Young
将Ni-Si和Co-Si合金在1130°C下暴露于Ar-CO 2和Ar-CO-CO2气体导致从合金表面快速生长结晶SiO2纳米纤维。纤维的横截面为圆形，直径约50 nm，相当规则地间隔开，大致垂直于合金表面排列，并且占约50体积%。均匀厚的反应产物层，其中孔隙空间是连续的。纤维为石英晶体，不含可检测的镍或钴，无明显缺陷。二氧化硅产物的质量根据抛物线动力学以比纯硅氧化的速率快约3个数量级的速率增长。质量传输计算表明，反应气体物种是CO2，而不是O2。在合金次表面区域内实现了局部平衡，其中保持了硅到表面的扩散通量。在Ni-Si合金的情况下，反应速率显示为与SiO（g）扩散通过二氧化硅包覆层的孔隙空间的控制一致。
Exposure of Ni–Si and Co–Si alloys to Ar–CO2 and Ar–CO–CO2 gases at 1130°C led to rapid growth of crystalline SiO2 nanofibers from the alloy surfaces. The fibers were circular in cross section, of diameter about 50 nm, rather regularly spaced, aligned approximately normal to the alloy surface, and made up about 50 vol.% of a uniformly thick reaction-product layer in which the pore space was continuous. The fibers were crystobalite, containing no detectable nickel or cobalt and free of gross defects. The mass of silica product grew according to parabaolic kinetics at rates about 3 orders of magnitude faster than the rate at which pure silicon oxidized. Mass-transport calculations showed that the reactant-gas species was CO2 not O2. Local equilibrium was achieved within the alloy subsurface regions where a diffusive flux of silicon to the surface was maintained. Reaction rates are shown in the case of Ni–Si alloys to be consistent with control by SiO(g) diffusion through the pore space of the silica nanofiber layer.