Some interesting term related to water
Pilling- bedworth rule :- Protective and non- Protective nature of oxide layer mainly depends on pilling-bedworth rule
According to this rule an oxide is protective or non- porous if the volume of metal oxide is greater then the volume of metal from which it is formed on the other hand oxide layer is non- protective or porous if the volume of metal oxide is less than the volume of the metal from which it is formed because it cannot prevent the diffusion or access of oxygen to the fresh metal surface below
Pilling-bedworth ratio
= voume of the metal oxide formed /volume of the metal consumed
Thus Li, Na, k, etc. And Mg, Ca, Sr, etc. form porous oxides of volume less than the volume of metals and promotes corrosion continuously non-stop.
On the other hand metal like Al forms oxides of volume higher than the volume of metal due to the absence of any pores in the oxide film the rate of corrosion rapidly decreases to zero
Pilling-bedworth ratio
= voume of the metal oxide formed /volume of the metal consumed
Thus Li, Na, k, etc. And Mg, Ca, Sr, etc. form porous oxides of volume less than the volume of metals and promotes corrosion continuously non-stop.
On the other hand metal like Al forms oxides of volume higher than the volume of metal due to the absence of any pores in the oxide film the rate of corrosion rapidly decreases to zero
No comments:
Post a Comment