Hardness
There exist various definitions of the hardness : for a solid (mineral or metal) and for water.
Hardness of a solid
Hardness of a mineral
The hardness of a Minéral is its capacity to resist abrasion or the stripe. One characterizes it by means of the scale of hardness Mohs, by comparison with standard materials.See also
- Glossary of the minerals
- Mineralogy
Hardness of a metal
The hardness of a Métal is its capacity to resist the deformation. One determines it by means of tests standardized (Brinell, Meyer, Vickers, Rockwell) by measuring the depth, the diameter or another parameter of the print made by a punch according to the test.See Hardness (material).
current Meaning for the word " dureté"
These two hardnesses are distinct from the current Acception of “hardness” which recovers a resistance to the shocks (example: “hardened Porcelain”); for this subject, the use of the term impact strength is more suitable. However, they remain related to the facility (in other words: variation of energy) with which the material, subjected to a constraint (hydrostatic pressure, shearing), reacts. Hardness (in general) can result in the expression of constant mechanics, like the Module of compressibility or the modulus of rigidity (expressed in Pascal).
Water
Hardness the water
The Hardness the water is its content of Ion S Calcium or Magnésium. One expresses it in French degrees : a degree for 4 Mg Ca or 2,4 Mg Mg per liter. Water is known as soft in lower part of 15 degree French and known as lasts beyond 35°f. One uses a Water-softener to soften water until approximately French 5°.
total Hardness of water
The total Dureté of water is the sum of permanent hardness and temporary hardness.
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