Si-Al ordering in nephelines

تشکیل فاز مولایت در فرایند اکسید شدن سیستم‌های Al2O3+Si، Al+Si و SiO2+Al

در این مقاله، اثر ترکیب مواد اولیه بر ویژگی?های فازی و ریزساختاری بدنه?های مولایتی بررسی شده است. سه سیستم SiO2+Al, Al2O3+Si و Al+Si با فرض اکسید شدن کامل عناصر Al و Si انتخاب شدند. مواد اولیه در محیط الکل اتیلیک توسط همزن مغناطیسی، مخلوط و پس از سپس خشک شدن، و گرانول? سازی شده و در گستره دمایی�C1600-700 حرارت دیدند. نتایج نشان می?دهد که در سیستم Al2O3+Si پس از دمای �C1450 فاز مولایت تشکیل می?ش...

Ordering of Si atoms on the fivefold Al-Pd-Mn quasicrystal surface

Silicon atoms are found to form an ordered overlayer on the fivefold surface of the icosahedral Al-Pd-Mn quasicrystal. Using scanning tunneling microscopy, the adsorption site is identified as the center of truncated clusters which are building blocks of the bulk structure. Comparison with theoretical models suggests that this site is favored because of bonding to Mn atoms. Disciplines Condense...

احیاء کربومتالوترمی TiO2توسط Al و Si

Ordering of vacancies on Si ( OO 1 ) ’

Missing dimer vacancies are always present on the clean Si(OO1) surface. The vacancy density can be increased by ion bombardment (Xe+, Ar+), etching (0,, Bra,&, etc.) or Ni contamination. The equilibrium shape at low vacancy concentrations (~0.2-0.3 monolayers) of these vacancy islands is elongated in a direction perpendicular to the dimer rows of the upper terrace, whereas for higher vacancy c...

Revealing heterogeneous nucleation of primary Si and eutectic Si by AlP in hypereutectic Al-Si alloys.

The heterogeneous nucleation of primary Si and eutectic Si can be attributed to the presence of AlP. Although P, in the form of AlP particles, is usually observed in the centre of primary Si, there is still a lack of detailed investigations on the distribution of P within primary Si and eutectic Si in hypereutectic Al-Si alloys at the atomic scale. Here, we report an atomic-scale experimental i...