55%Al-Zn-1.6%Si合金热浸镀工艺及耐蚀研究

TECHNOLOGY AND ANTICORROSION PERFORMANCE OF HOT-DIP 55%Al-Zn- 1.6%Si ALLOY COATING

钢管热浸镀 55% Al- Zn- 1 .6% Si合金 ,采用熔剂助镀 ,浸镀温度 61 0～ 62 0°C,浸镀时间 1 5～ 2 0 s,空气速冷至 30 0°C(冷却速度 1 0°C/s)然后缓冷至室温。合金热浸镀层厚 2 6～ 32 μm。金相和 X光衍射分析表明 ,55% Al-Zn- 1 .6% Si合金具有 α相和 β相 ,腐蚀优先从 β相开始。采用中性盐雾试验、浸泡试验对该合金镀层的耐蚀性进行了研究 ,并将结果与热镀锌、热镀铝进行了对比。铝锌合金镀层的耐蚀性在工业大气和冷水中比热镀锌高出 1 .5～ 4倍 ,而在热水中要高出 8～ 1 0倍。

The hot dip 55%Al Zn 1 6%Si alloy coating provides good anticorrosion performance and wide application The hot dip technology consists of heating in flux, immersing into the metal melt (610~620°C) for short time (15~20s) and then quick cooling (10°C/s) The thickness of hot dip Al Zn Si coating is 26~32μm. Metallographic and X ray diffraction analyses indicate that the 55%Al Zn 1 6%Si alloy coating possesses of α phase and β phase Corrosion of this alloy initiates from β phase The anticorrosion performance was studied by Normal Salt Spray (NSS), dip testing The test results were compared with hot dip zinc coating and hot dip Al coating The protection of the hot dip Al Zn Si coating is much more effective than the zinc coating: 1 5~4 times in cold water and 8~10 times in hot water