Interstitial-free (IF) steel specimens were coated by hot-dip aluminizing process bearing bath composition as Al-6.9% Si-1.4% Mg and bath temperature at 800 °C. Dipping time varied for 0.5, 1, 3 and 6 min. The objective of the present study is to conduct a systematic investigation to identify and analyse the formation of various phases and compounds in the coating. Studies on aluminizing of steel had indicated the presence of an intermetallic layer adjacent to steel substrate. In this study, the morphological features obtained after hot dipping at 800 °C were investigated. For the application of aluminized steel sheets in industry for manufacture of tubes and pipes, the adherence of the aluminized coating must be ensured. This property of the coating is influenced by the morphological features of the coating. Aluminizing being thought of a possible substitution of galvanizing owing to its promise to evolve lesser volume fraction of intermetallic phases and consequently known to generate a ductile coating. The entire coating consists of an outer Al-Si topcoat and a thin intermetallic layer which composed of an outer θ-FeAl₃ and inner η-Fe₂Al₅ layers. The thickness of intermetallic layers was found to increase with the increase of dipping time in a near parabolic manner.The phases formed on the IF steel substrates were characterized by scanning electron microscopy with EDS, X-ray diffraction, EPMA and EBSD techniques.Interesting findings from XRD include the presence of Al₃FeSi₂ (τ₄) and Al₂FeSi (τ₃) phases, which normally appear after annealing of aluminised sheet. A distinct elemental Si peak was found in XRD study. Presence of Mg in the form of Mg₂Si was also found in XRD and supported by EPMA investigation. Presence of several ternary Al-Fe-Si (τ₃, τ₄, τ₅) and binary FeAl₃ and Fe₂Al₅intermetallic phases were identified by composition profile analysis from SEM based EDS and GDOES and further confirmed by EBSD. Presence of Si humps in the top and intermetallic layer attributed by the presence of Si-bearing phases or elemental pro-eutectic Si in Al-Si alloy were also indicated in SEM-EDS and GDOES study. Variation of surface topographical features of the HDA steel substrates with increasing dipping durations were examined and reported for the first time by using AFM. Formability tests were conducted by bending the samples 180° over a mandrel. None of the specimens showed any tendency of flaking exhibiting excellent bonding of the coating with IF steel substrate.

无间隙（IF）钢试样通过热浸镀铝工艺制成，镀液成分为Al-6.9％Si-1.4％Mg，镀液温度为800°C。浸泡时间分别为0.5、1、3和6分钟。本研究的目的是进行系统的研究，以鉴定和分析涂层中各种相和化合物的形成。对钢进行渗铝的研究表明，存在与钢基材相邻的金属间层。在这项研究中，研究了在800°C的热浸后获得的形态特征。为了将镀铝钢板应用于制造管材的工业中，必须确保镀铝涂层的粘附性。涂层的这种性能受涂层的形态特征影响。镀铝被认为是镀锌的一种可能替代品，因为它有望产生更少的金属间相体积分数，因此可以产生延展性涂层。整个涂层由外层Al-Si外涂层和由外层θ-FeAl组成的薄金属间层组成₃个内η -铁₂的Al ₅层。发现金属间层的厚度随着浸入时间的增加以近似抛物线的方式增加。通过扫描电子显微镜，EDS，X射线衍射，EPMA和EBSD技术对IF钢基底上形成的相进行了表征。从XRD包括Al的存在₃硅铁₂（τ ₄）和Al ₂硅铁（τ ₃）相，其通常出现镀铝板退火后。在XRD研究中发现了一个明显的元素Si峰。以Mg ₂的形式存在Mg在XRD中也发现了Si，并得到了EPMA调查的支持。若干三元的Al-Fe-Si系的存在（τ ₃，τ ₄，τ ₅）和二进制的FeAl ₃和Fe ₂的Al ₅通过基于SEM的EDS和GDOES的成分分布分析确定了金属间相，并由EBSD进一步确认。SEM-EDS和GDOES研究还表明，由于Al-Si合金中存在含硅相或元素共晶硅，导致在顶层和金属间层中出现了硅峰。使用AFM首次检查并报道了HDA钢基材表面形貌特征随浸渍持续时间的增加而变化的情况。通过在心轴上将样品弯曲180°进行可成型性测试。没有一个样品显示出任何剥落的趋势，表明涂层与IF钢基材的粘结性极好。