Passivation layer mineral
Contents
Passivation layer minerals of today's industrial metals
We do have daily skin contact with these minerals without even realizing it.
Often these minerals are naturally present as ores from which the metals are extracted.
- Al aluminum - Al2O3 - aluminum oxide - corundum - ruby - sapphire
- Ti titanium - TiO2 - wikipedia: titanium dioxide - rutile - anatase - brookite
- related: ZnS sphalerite Mohs 3.5-4
- Zn zinc - ... - ZnO - wikipedia: zinc oxide - zincite
- Sn tin - SnO2 - wikipedia: tin dioxide - cassiterite
- Cu copper - wikipedia: patina ... See: Salts of oxoacids#Carbonate minerals – Malachite & Aurite – also copper sulfate CuSO4(H2O)x
- Ni nickel - wikipedia: nickel fluoride - nickel oxides - busenite Nickel minerals can cause allergies through prolonged skin contact.
- Cr chromium ...
- V vanadium, Nb niobium ...
- Fe iron - Fe3O4 - wikipedia: magnetite ... just rust
wikipedia: passivation in general
- PbS Galena [1] Mohs 2.5-3 (soft)
Passivation of passivation layer minerals
Here an interesting problem occurs. To prevent two atomically precisely flat blocks from fusing seamlessly together on contact their surfaces must look differently than their insides. Specifically it is often a good idea to cover the whole surface with lone pairs of electrons. But further oxidation of an already oxidized material will probably not work or be rather unstable [to investigate for every specific situation]. What should be doable almost always is hydrogen passivation. (Such passivation may cause higher friction due to high lateral spacing between the small hydrogen atoms sitting atop larger atoms and the low lateral stiffness of the single bonded hydrogen atoms) It may be necessary to find a special solution for each indivitual material - nitrogen phosphorus and sulfur may often be useful for plugging surfaces closed. (See: Surface passivation)
Notes
- (wiki-TODO: Add everyday metal and corresponding gemstone pic-pairs -- for optically pleasing illustration)
Related
External links
Wikipedia:
Passivation layer minerals can be found in ...
- electrolytically anodized surfaces. They are micro-crystalline porous and monolithic though. Wkidedia: Anodizing
- heat tinting aka temer(ing) color. Wikipedia: Tempering (de: Anlauffarbe) – (Related: "Color emulation")
- patinas created by weathering. Wikipedia: Patina
