Pilling-Bedworth ratio
The Pilling - Bedworth ratio ( PBR or PBR of Pilling - Bedworth ratio) is in chemistry and materials science, the ratio of the volume of the unit cell of a metal oxide to the volume of the unit cell of the corresponding metal. Can be judged from the PBV whether a metal in dry air by forming a protective oxide layer ( passivation) is permanently resistant.
Definition
M is the molar mass, ρ is the density, V is the ( molar ) volume and n is the number of metal atoms in the molecular formula of the oxide.
Effect
On the basis of measurements can show the following relationship: