【摘要】 研究了含0.38%Si(质量分数)的Q345钢预镀镍后热镀锌时镀层的生长和组织形成。结果表明:预镀一薄层镍可有效抑制含Si>0.3%的低合金高强度结构钢热镀锌时生成超厚、表面灰暗的锌层,镍层越厚,锌层生长越慢。在浸锌时,镀镍层先与Zn反应生成Ni Zn合金相γ,和γ,镍层消耗完后,出现Fe Zn合金相δ和Ni Zn合金相δ2,最后Ni Zn相消失,镀层为连续的δ相和分散在η相中的块状ζ相;Ni Zn相形成连续致密的层状组织是抑制锌层快速生长的主要原因。更多还原

【Abstract】 High strength low alloy structure steel (Q345) specimens containing 0.38 wt% Si were electroplated with 2.5～10.0 μm nickel layer firstly and then galvanized in molten Zn at 733 K for various time. Formation and growth of alloy layer on the surface of specimens was examined. The results showed that electroplating prior to galvanizing was an effective way to reduce excessive coating thickness and gray surface appearance. The thicker the electroplating Ni was, the slower the alloy layers grew. Ni\|Zn alloy layer γ’ andγwas first formed on the surface of electroplating Ni deposit. After the Ni layer was consumed, Fe\|Zn alloy layer δ and Ni\|Zn alloy layers δ\-2 appeared. Then δ\-2 disappeared and the final microstructure was composed of continuous δ layer and massive ζ dispersed in the η layer. Inhibition of rapid growth of hot\|dip galvanizing coating on the high silicon steel resulted mainly from the continuous and compact Ni \|Zn alloy layer.更多还原