جستجوی مقالات مرتبط با کلیدواژه "rare-earth" در نشریات گروه "مواد و متالورژی"

Magnesium has little resistance to corrosion and therefore its production and use are quite limited. The problem of corrosion associated with these alloys has been alleviated to some extent by the advantages obtained from fine coatings. An additional dense barrier against corrosion is created, using coatings obtained from sol-gel. As an alternative for Cr-based conversion coatings, rare-earth elements-based ones are been increasingly investigated for Mg and its alloys due to being eco-friendly. Because of chemical inertness, low friction, and high hardness, diamond-like carbon (DLC) coatings have exhibited the best protection for Mg and its alloys. In this review, we shed light on recent advancements in novel coatings for Mg alloys including hybrid, rare-earth conversion, composite polymeric (polymer composite is a multi-phase material in which reinforcing fillers are integrated with a polymer matrix), and DLC coatings.  

The effect of samarium oxide was examined on the sintering, microstructure, and grain growth behaviors of (Co, Nb)-doped SnO2-based ceramics prepared by co-precipitation method. The sintered samples were studied through x-ray diffraction (XRD), scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS) analyses. The microstructure observations revealed that the samples were near fully dense at a sintering temperature of 1200°C for 1h. The samarium doping prevented accelerated grain growth of the SnO2-based ceramic in the final stage of the sintering. The mean grain size of the SnO2-based ceramic without Sm2O3 doping was 2.70µm, which was reduced to 0.887µm for the sample doped with 0.05mol% Sm2O3. The grain size reduction of samples doped with Sm2O3 could be attributed to the segregation of Sm2O3 at the grain boundaries.