Definition
A copper-tin alloy with a higher tin content than standard bronze, producing a harder, more wear-resistant metal used for bushings, bearings, and valve guides in aircraft engines and accessories.
Plain English
A tougher version of bronze made by adding more tin, so it stands up better to friction and wear in parts that take a lot of rubbing or pressure.
Context Anchor
Seen in aircraft maintenance and materials discussions, especially when identifying metals used in bushings, bearings, and other wear surfaces.
Derivation
Bronze comes from the Italian 'bronzo,' meaning a copper-tin alloy. 'Hard' here simply describes the alloy's increased hardness compared to ordinary bronze, achieved by raising the tin content.
Why Pilots Care
Pilots don't normally handle hard bronze directly, but knowing the term helps when reading maintenance manuals or parts catalogs that specify it for wear-critical engine components.
Intuition Check
Hard does not mean unbreakable here. It means the bronze resists wear and surface damage better than softer bronze alloys.
Example Sentence 1
The valve guides are made of hard bronze to resist wear from the constant motion of the valve stems.
Example Sentence 2
Hard bronze bushings in the rocker arms reduce friction during engine operation.