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The prospects for scientific and educational - that the rate of erosion in the middle of a given metal depends on many factors, and the value of the corrosion rate, a complex function of many of these factors, which are often unstable and in a state of flux. Based on this, is the problem of corrosion of the complex problems compared to other types of failure; because the corrosion rate is not governed by the laws of certain sports could be on the basis of knowledge of the age of the metal part of the exhibition erosion. But our knowledge of the laws relating to the mobility of the electrochemical corrosion of any laws Polarization (Polarization) help us to guess corrosion rates and the impact of various factors on this rate singly or in combination.
The location of the metal in this series set forth in the following table, which depends on the value of the voltage to the metal in a solution of metal ions itself, if the value of this effort high, it means that the metal-resistant self-high for all types of corrosion in most circles, as is the case in noble metals, such as gold, platinum and silver If the value of this effort low, it means that the metal-type active. We will come to explain it more broadly in the next chapter. Table 1)
Ag = Ag + + e
Sn = Sn +2 + 2e
Mg = Mg +2 +2 e
The installation of the metallurgical metal, simple human dish rack a significant impact on the rate of corrosion, in the middle appointed. Determined composition of the metal metallurgical, chemical components of, any elements which formed the alloy, and the mechanical condition (the presence of internal stresses, and scratches, and grooves simple human dish rack at the surface simple human dish rack and so forth).
The installation metallurgical is the shape and the size and direction of the particles of metal, and sediment (Precipitates) in the areas of grain boundaries or within grains such as carbides, and the presence of impurities insoluble, such as oxides, etc., and the existence of phases (Phases) multiple or single phase and type of these phases and size. All of this is determined by the chemical components of the metal and mechanical and thermal treatment, which took place on it.
And generally have metal valuable its pure state, as well as the alloy constituent of the process is only one solution, rigid, high corrosion resistance is relatively simple human dish rack high in different settings but when the alloy is composed of more than one phase, the resistance to corrosion is less resistance to the metal base is made up of it. For example, stainless steel carbon in the atmosphere at a higher rate than the rate of steel pure iron in the middle, and the reason for that is due to act Alglvana resulting from contact all of the process of pure iron (Lafraat) and Carbide iron (Asamntait) located in the ultrastructure of the alloy, where does the process Alsmonatayt in This situation did noble metal at its contact with Lafraat, simple human dish rack so of course, simple human dish rack leads to increased corrosion rate of steel because of the existence of this phase, which is in contact with the Lafraat. As well as the alloy brass (Albrs) with a low ratio of zinc (less than 35%) higher corrosion resistance when compared to other Besbakh simple human dish rack brass in the same condition in which the proportion of zinc is higher than 35%. The reason for this is due to the metallurgical composition of the alloy in the first case, a solution simple human dish rack is usually static (phase one), while in the second case shall be composed of more than one phase where the act affects Alglvana. We have many examples that point to the failure of the metal (corrosion) under certain conditions of use due to a shift mounted metallurgical to install another, as it gets for Stainless steel type (18Cr: 8 Ni) in the area of thermal effects after welded so as to precipitate carbides in this region after perform welding process, which were not originally precipitated by the conduct of the process. Can be seen from all this that the use of the metal in its pure state, leads to get a high resistance to corrosion, and that this does not lead to any phase deposition last changed no matter what the situation thermal or mechanical him. However, do not use the metals in their pure state because of mechanical considerations, because the pure metal is of Mechanical resistance is very low. The mechanical resistance of the alloy (Strength) of the alloy by installing simple human dish rack rigid Mahlolha (Solid Solution), shall be better, because the solubility in solid state leads to impede the movement of dislocations (Dislocation), which in turn leads to increased mechanical resistance.
Different metallurgical composition of the metal formed on the cold (Cold-Worked) for the same metal when Mldna (Annealed) and this is due to the difference in size and shape and arrangement of particles in both cases, the area where the grain boundaries in the first case the largest. It is known that the grain boundaries are unstable regions (high capacity) due to the irregular atomic distribution in this region, so the resistance to corrosion when attacked by some quarters to be weak compared simple human dish rack to the corrosion resistance of the same regions of the granules that are more stable. In addition, the metal is formed on the cold encompassing the high internal stresses due to the high density of Ankhalaat and the intersection with itself and with the grain boundaries.
All this leads to the problem is to make the metal cold less corrosion-resistant metal of the same when the Mldna. It can illustrate the effect of metallurgical installation in metal corrosion resistance, many other examples, including a corrosion
