Difference between revisions of "Pure metals and metallic alloys"
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* [[Macroscale style machinery at the nanoscale]] | * [[Macroscale style machinery at the nanoscale]] | ||
* [[Atomic precision]] | * [[Atomic precision]] | ||
| − | * [[Passivation]] | + | * [[Passivation (disambiguation)]] |
| − | * [[Gem-gum]] | + | * [[Nanoscale surface passivation]] (old: [[Surface passivation]]) |
| + | * [[Macroscale surface passivation]] | ||
| + | * [[Passivation layer mineral]] | ||
| + | * Gem-gum: [[The defining traits of gem-gum-tec]] | ||
* [[Gemstone-like compound]] | * [[Gemstone-like compound]] | ||
| + | * [[Oxidation]] & [[Diffusion]] | ||
| + | * [[Metallic contact welding]] (related to [[Seamless covalent welding]]) | ||
Revision as of 13:19, 13 December 2023
Why these are to first approximation a bad choice for stiff cog&gear style nanomachinery nanomachinery and gemstone-like compounds are the way to go instead:
- tendency to surface diffusion – some atoms do not stay where put at room temperature
- tendency to oxidation – for all but a few noble metals which are generally too rare for large scale structural purposes
- incompatibility with nanoscale passivation – making seamless covalent welding the default. (Related: Catenation)
- ...
Stoichometric intermetallic compounds sometimes fair somewhat better:
Despite still being electrically conductive and optically reflective in the human visible spectral range,
their bonds have a bore covalent character.
This makes them less ductile and more brittle, which is ...
- an undesirable property form macroscale parts with many high strain internal defects
- a desirable property for nanoscale parts with on average no defects
Some gemstones that contain non-mentals too are also still metallic in optical and conductivity and optical properties (similar to inter-metallic compounds). Examples include:
- pyrite FeS (iron sulfides)
- hematite and magnetide (iron oxides)
- titanium nitride and some other XY-type compounds where X=metal Y=nonmetal
Related
- Macroscale style machinery at the nanoscale
- Atomic precision
- Passivation (disambiguation)
- Nanoscale surface passivation (old: Surface passivation)
- Macroscale surface passivation
- Passivation layer mineral
- Gem-gum: The defining traits of gem-gum-tec
- Gemstone-like compound
- Oxidation & Diffusion
- Metallic contact welding (related to Seamless covalent welding)
