Normally sterling silver, which is polluted with impure materials stands a greater risk of corossion rather than sterling silver, which is although more expensive yet the risk of corrosion is of a much lesser degree. Not just the risk of corrosion but also the problem of tarnishing is quite a common occurrence with sterling silver having impurities. From a chemical perspective, silver has a very low level of reaction with oxygen or with water at room temperatures, so the formation of silver oxide is usually out of the question.
However even in pure sterling silver, the presence of copper could contribute towards forming a chemical reaction with oxygen. Moreover the black silver sulphide whose chemical formula is Ag2S is few of the most insoluble salts if added in an aqueous solution. This property of black silver sulphide does contribute towards separating silver ions from other positive ions. Another substance that leads to corossion is Sodium Chlorida or common salt that is used for everyday use.
However even in pure sterling silver, the presence of copper could contribute towards forming a chemical reaction with oxygen. Moreover the black silver sulphide whose chemical formula is Ag2S is few of the most insoluble salts if added in an aqueous solution. This property of black silver sulphide does contribute towards separating silver ions from other positive ions. Another substance that leads to corossion is Sodium Chlorida or common salt that is used for everyday use.