α -
ΙδρώταςΟ ιδρώτας αποτελείται από νερό,
ανόργανα άλατα, λιπαρά οξέα κλπ.
β - Ανοξείδωτος χάλυβας: τύποι διάβρωσης
Pitting Corrosion on stainless steelThe passive layer on stainless steel can be attacked by certain chemical species. Chloride ion is the most common of these and is found in everyday materials such as
salt and bleach. Harsh pitting corrosion is a localized damage that eats pits into stainless steel. In addition to chloride ion, can be caused by elevated temperatures for extended amounts of time
or lack of oxygen to the surface.You can avoid pitting corrosion by ensuring that stainless steel does not come into prolonged contact with harmful chemicals or by choosing a grade of steel which is more resistant to attack.
Crevice Corrosion on stainless steelStainless steel requires a supply of oxygen to make sure that the passive layer can form on the surface. In very tight crevices it is not always possible for the oxygen to gain access to the stainless steel surface thereby causing it to be vulnerable to attack. Crevice corrosion is avoided by sealing crevices with a flexible sealant or by using a more corrosion resistant grade.
General Corrosion on stainless steelNormally stainless steel does not corrode uniformly like ordinary carbon and alloy steels. However, with some chemicals, mainly acids, the passive layer may be attacked uniformly depending on concentration and temperature and the metal loss is distributed over the entire surface of the steel. Hydrochloric and sulphuric acids at some concentrations are particularly aggressive towards stainless steel.
General corrosion can be quite destructive and happen to the entire surface at once.
Galvanic corrosion on stainless steel
If two dissimilar metals are in contact with each other and with an electrolyte (e.g. water or another solution), it is possible for a galvanic cell to be set up and to accelerate corrosion of one of the metals. It can be avoided by separating the
γ - Στη φώτο είναι Stainless Steel Rolex, που έχει φάει σκουριά σε σημείο ανάμεσα στη κάσα και το case back, το οποίο σημείο μαζεύει μπιχλα και ίδρωτα και το οποίο σημείο, δεν έρχεται σε επαφή με αέρα (οξυγόνο)
Τι λεμε λαθος;;;
