Definition
A hard, brittle, silvery-white metallic element (chemical symbol Sb, atomic number 51) used in aviation primarily as an alloying agent. It is added to soft metals like lead and tin to increase their hardness, strength, and resistance to wear. Common aviation uses include lead-acid battery plates, soft solders, and bearing alloys (babbitt metal).
Plain English
A metal that is mixed in small amounts with other softer metals to make them harder and longer-lasting. You will find it inside aircraft batteries and in the soft metal used for bearings and solder.
Context Anchor
Seen in aircraft battery descriptions, battery maintenance material, and discussions of lead-based battery plate construction.
Derivation
The chemical symbol Sb comes from the Latin 'stibium,' the old name for the element. The English word 'antimony' likely comes through Medieval Latin from Arabic 'al-ithmid.' Knowing the symbol comes from 'stibium' explains why battery and metallurgy references sometimes use 'Sb' rather than 'An.'
Why Pilots Care
Pilots rarely handle antimony directly, but understanding that battery plates and bearing metals depend on it helps when reading maintenance literature about battery service life or bearing wear.
Intuition Check
Antimony is not battery acid and it is not the main battery material. In this context, it is a small added metal used to improve lead parts in the battery.
Example Sentence 1
The lead plates in the aircraft's battery contain a small amount of antimony to make them strong enough to resist vibration damage.
Example Sentence 2
Mechanics check the antimony percentage when replacing worn bearing material in older engines.