冷弯成型对轨道交通装备用高强不锈钢耐盐雾腐蚀性能的影响

对冷弯成型前后的国产轨道交通装备用301L高强不锈铜进行中性盐雾试验,于试验48h、72h、96h时利用sEM进行腐蚀形貌观察和采用EDS分析腐蚀后的元素组成及含量,并对冷弯前后的不锈铜进行电化学测试。结果表明,冷弯成型导致高强不锈钢耐盐雾腐蚀性能明显下降,冷弯后不锈钢点蚀严重,其点蚀电位较降冷弯前低301mV。     

Preparation and Properties of Sapphire by Edge-defined Film-fed Growth (EFG) Method with Different Growth Directions

Sapphire, belonging to hexagonal crystal system, is typically anisotropic which makes it direction-sensitive. To research the effects of growth directions on properties of sapphire, c-[0001] seed(c-sapphire) and a-[11-20] seed(a-sapphire) were used to prepare sapphire by edge-defined film-fed growth(EFG) method. The samples were analyzed through lattice integrity, dislocation and corrosion performance by double-crystal XRD, OM, AFM, SEM and EDX. It was shown that the lattice integrities of two growth-direction crystals were both well due to the small FWHM values. While the average densities of dislocation in c-sapphire and a-sapphire were 9.2×103 and 3.9×103 cm-2 respectively, the energy of dislocation in c-sapphire was lower than that in a-sapphire. During Strong Phosphoric Acid(SPA) etching, the surface of c-sapphire basically kept smooth but in a-sapphire there were many point-like corrosion pits where aluminum and oxygen atoms lost by 2:1. Our work means that it will be promising for growing c-[0001] seed sapphire by EFG if aided by parameter optimization.