Barium ferrite ferrite has better packing properties. BaFe can be reduced to a smaller size and higher packing density because of its circular structure and can be stacked better. Barium ferrite Barium ferrite, abbreviated BaFe, BaM, is the chemical compound with the formula BaFeO. This and related ferrite materials are components in magnetic stripe cards and loudspeaker magnets. BaFe is described as Ba(Fe)(O). The Fe centers are ferromagnetically coupled. This area of technology is usually considered to be an application of the related fields of materials science and solid state chemistry. Barium ferrite is a highly magnetic material, has a high packing
Pewter known as "trifling metal" or "trifle", was used for holloware and is made up of fine metal with approximately 4% lead. The last type of pewter, known as "lay" or "ley" metal, was used for items that were not in contact with food or drink. It consisted of tin with 15% lead. These three alloys were used with little variation until the 20th century. Older pewters with higher lead content are heavier, tarnish faster, and oxidation gives them a darker silver-gray color. Pewters containing lead are no longer used in items that will come in contact with the human body