Intergranular corrosion test of nut
Tianjin Rong Da Testing Co., Ltd. contact: Wang Jingfu
Cell phone: 13102238283 QQ:3144667033
Telephone: 022-23892103
Intergranular corrosion, in some environments, the dissolution rate of the grain boundary is much larger than the dissolution rate of the grain itself, it will produce the selective partial corrosion along the grain boundary, which is called intergranular corrosion. The combination of intergranular corrosion and intergranular failure greatly reduces the mechanical strength of the metal. But after the occurrence of surface corrosion of metals and alloys still maintain certain metallic luster, do not see signs of destruction, but the binding force between grains decreased and the deterioration of mechanical properties, can not withstand the strike, so it is a very dangerous corrosion. Usually occurs in brass, aluminium alloy and stainless steel, nickel base alloy.
The uneven change of grain boundary structure caused by the heat (such as sensitization treatment) and the stress (cold working deformation), also has a great influence on the intergranular corrosion.
The vast majority of metals and alloys are polycrystalline, and many grain boundaries appear on their surfaces. Grain boundary is a relatively loose and disordered region, which can easily lead to the phenomenon of impurity atom enrichment, grain boundary adsorption and precipitation of second phase. The dissolution rate of grain boundary of metal and alloy in corrosive medium is different from that of the grain itself. In some environments, the dissolution rate of the grain boundary is much larger than the dissolution rate of the grain itself, it will produce the selective partial corrosion along the grain boundary, which is called intergranular corrosion,. The uneven change of grain boundary structure caused by the heat (such as sensitization treatment) and the stress (cold working deformation), also has a great influence on the intergranular corrosion.