合金腐蚀，也就是所谓的“失锌现象”，在20世纪50年代已经从阀门产品中根除。但是，由于近来在美国国外生产的锻造或铸造阀门材料越来越多采用高锌合金（通常称为“黄铜”），因此“失锌现象”又开始有所回潮。De-alloying corrosion, known as ”Dezincification,“ was effectively eradicated from valve products in the 1950s. Today, however, this problem has returned with the increased use of high-zinc alloys (commonly referred to as ‘Yellow Brass’) in forged and cast valves typically produced outside the United States.
失锌现象有选择地从合金中将锌排泄出去，使得材料变得多孔、铜含量过大，从而降低材料强度。使用中的阀门出现失锌想象时的物理特征包括：在外表面出现白色粉末或矿物污点。
Dezincification selectively removes zinc from the alloy, leaving behind a porous, copper-rich structure that has little mechanical strength. The physical attributes of an in-service valve with Dezincification includes a white powdery substance or mineral stains on its exterior surface.
如何解决这个问题？在所有青铜阀门的金属部件中，其水路部分的化学成分中锌的含量绝对不能超过15%。作为一种基本要求，美国尼伯科青铜消防阀门都具有“抗失锌”特性，质量更加优异，使用寿命更加长。
What’s the cure? On all bronze valves the metal components in the waterway must not contain more than 15% zinc in their chemical makeup. As a standard NIBCO bronze fire protection valves are made to be “Dezincification Resistant,” which is a seal of quality and longevity.