Intergranular Corrosion in Stabilized 310 Stainless Steel

The intergranular corrosion in stabilized 310 stainless steel polycrystals has been investigated from a view point of crystallographic structure of the grain boundary. The relative orientation of each grain was characterized by the Coincidence Site Lattice (CLS) model, and the Plane Matching model. For the quantitative characterization of corrosion, a scanning electron microscope with two secondary electron detectors was used to provide the profile of the corrosion groove. It was found that Σ= 3 boundaries and some certain CSL boundaries have a high resistance against the intergranular corrosion. The “random” boundaries were corroded in a different extent, particularly high corrosivity. It is concluded that the grain boundaries having low Σ-values do not necessarily provide low corrosivity. It is shown that the dissolution rate depending on the surface orientation of grains also plays an important role in the morphology of intergranular corrosion, and was found to be lowest at (100) and increases as the surface normal changes towards (110), and more so towards (111)

Structure of twinned {113} defects in high-dose oxygen implanted silicon-on-insulator material

Conventional and high resolution electron microscopy (HREM) were used to study the structure of {113} defects in high-dose oxygen implanted silicon. The defects are created with a density of 10 cm below the buried oxide layer in the substrate region. The HREM images of the {113} defects are similar to the ribbon-like defects in bulk silicon. It is proposed that there is a third possible structure of the defects, in addition to coesite and/or hexagonal structures. Portions of some defects exhibit the original cubic diamond structure which is twinned across {115} planes. The atomic model shows that the {115} interface is a coherent interface with alternating five and seven-membered rings and no dangling bonds