hard lead
Học thuậtThân thiện
Definition
- Noun:
- A type of unrefined lead: A dense, metallic element (Pb) in a crude or impure state. Its physical hardness is a direct result of the other substances mixed within it, not from any intentional processing.
- A specific lead alloy: A manufactured material made by combining lead with approximately 5% antimony. This alloy is intentionally created to be harder and more durable than pure lead.
Usage Examples
- Noun:
- The old pipes were made from hard lead, which contributed to their longevity but also to water contamination.
- For this application, you need hard lead, as pure lead would be too soft and deform.
- The bullet casing was formed from a hard lead alloy containing antimony.
Advanced Usage
- The term is primarily technical and is used in contexts like metallurgy, plumbing, manufacturing, and ammunition. It distinguishes the material from "soft lead" (pure or nearly pure lead).
- In historical contexts, "hard lead" often refers to the impure lead produced by early smelting processes.
Variants and Related Words
- Soft lead: Pure or nearly pure lead, which is malleable and soft.
- Antimonial lead: Another term for the alloy of lead and antimony, synonymous with the second meaning of "hard lead".
- Lead alloy: A general term for any mixture of lead with other metals.
Synonyms
- (For the alloy): Antimonial lead, lead-antimony alloy.
- (For the impure form): Unrefined lead, crude lead.
Notes on Meaning
The word "hard lead" has two distinct but related meanings: 1. Material Science / Metallurgy: An alloy where lead is purposefully mixed with antimony to achieve specific properties like hardness, strength, and wear resistance. This is a designed material. 2. Mining / Refining: Unrefined lead ore or pig lead that is naturally hard due to the presence of various impurities like arsenic, copper, or antimony. This is a raw, unprocessed state.
The key common element is the presence of additional substances (antimony or other impurities) that make the lead harder than it is in its pure form.
Noun
- unrefined lead that is hard because of the impurities it contains
- a lead alloy that contains about 5% antimony