If the metal contact ring corrosive medium, and the corrosion of the metal itself is intolerant, it will have a surface corrosion, which is leaking, the early wear and tear, damage, and other audible.

• 如果金属环表面接触腐蚀介质，而金属本身又不耐腐蚀，就会产生表面腐蚀，其现象是泄漏、早期磨损、破坏、发声等。