Discussion
The Pilling-Bedworth ratio is defined as the ratio of
Answer: A
The Pilling-Bedworth ratio is the ratio of volume of oxide to volume of metal.
It compares the volume of the oxide formed with the volume of the metal consumed to form it:
\[ \text{PBR} = \frac{M_{ox}\,\rho_{m}}{n\,M_{m}\,\rho_{ox}} \]
where n is the number of metal atoms per oxide formula unit. A ratio below 1 (as for magnesium) gives a porous, non-protective oxide; between about 1 and 2 (as for aluminium) a dense protective film; and well above 2 an oxide that cracks and spalls.
The formula contains densities and masses, which may tempt one towards the weight or density options, but the quantity defined is a volume ratio.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development