The present study reports on iron silicides produced on 31CrMoV9 steel by pack cementation method. Pack siliconizing was carried out using metallic silicon, ammonium chloride and alumina at 1000-1100-1200°C and with varying deposition time of 3-5-7 hours in an open atmospheric furnace. The morphology and structure of silicide layers were analyzed by optical microscope, SEM- EDS. It was observed that there was a good bonding between matrix and silicide layers which are smooth, homogenous, dense and having no remarkable porosity. Dominant phases of Fe₃Si as well as some FeSi were detected by XRD analysis. Layer thickness was measured from the surface to the matrix and changed from 40 to 800 μm which was increased with increasing process time and temperature. Observation of silicide layer growth obtained at 1200°C were much more higher than that of 1000 and 1100°C. Hardness profile showed that there was no diffusion zone. The matrix hardness is 225 HVN while the hardness of coating layer raised to 1021 HVN with the process time and temperature. Activation energy for growing of siliconizing layer was determined as 292 kj/molK according to kinetic study. It can be claimed that optimum siliconizing layer was obtained up to 1100°C for 5 h due to formation of layer having smoother morphology, less porosities and oxygen impurities, and adequate thickness.

中文翻译：

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填充硅化的31CrMoV9钢的特性

本研究报告了通过填充胶结法在31CrMoV9钢上生产的硅化铁。使用金属硅，氯化铵和氧化铝在1000-1100-1200°C下在开放式常压炉中以3-5-7小时的不同沉积时间进行填充硅化。用光学显微镜SEM-EDS分析了硅化物层的形貌和结构。观察到基质和硅化物层之间具有良好的结合，它们是光滑的，均匀的，致密的并且没有明显的孔隙率。Fe _3的主要相通过XRD分析可以检测到Si和一些FeSi。测量了从表面到基质的层厚度，层厚度从40变为800μm，随着处理时间和温度的增加而增加。观察到在1200°C下获得的硅化物层生长远高于1000和1100°C下的生长。硬度分布表明没有扩散区。随着处理时间和温度的升高，基体硬度为225 HVN，而涂层的硬度提高到1021 HVN。根据动力学研究，用于硅化层生长的活化能确定为292 kj / molK。可以断言，由于形成的层具有更光滑的形态，较少的孔隙率和氧杂质以及足够的厚度，所以在1100℃下获得了最佳的硅化层5小时。