Minerals and Metals in Ancient India v1.c27.s2.t2.20

v1.c27.s2.t2.20

There is an enrichment of P in the rust (0.35 per cent P in Fe), as compared to the substrate. Wranglén (1970: 766) believes that phosphorus evenly distributed as a solid solution in the ferrite has probably contributed more to the formation of the protective surface film than the heterogeneously distributed inclusions of phosphate slags. The larger proportion of silicon on the surface (compared to that in the bulk) is explained through the proven presence of quartz which is the consequence of sandstorms common in the Delhi area. MgO and CaO on the surface might have arisen due to sandstorm or from the slag in the body of the pillar.