【摘要】 采用LSB型渗硼剂分别在渗硼温度为1123、1173和1223 K,保温时间为2、4、6和8 h的工艺参数下对球墨铸铁表面进行固体渗硼处理。用扫描电子显微镜(SEM)对渗层横断面进行了显微组织观察,用X射线能谱仪分析了沿渗层表面到心部的元素分布。用X射线衍射仪(XRD)分析出渗硼层为Fe2B单相,用显微硬度计测试渗层的硬度分布,其显微硬度值在1170~1392HV0.025之间。渗层厚度随着渗硼时间和渗硼温度的增加而增加,其范围约为35~118μm。对实验数据进行分析和拟合,得出渗层动力学曲线和等厚度图,并且经回归分析计算出硼在球墨铸铁中的扩散激活能约为175 kJ/mol。更多还原

【Abstract】 Ductile iron was boronized by pack-boronizing process using LSB powders at 1123,1173 and 1223 K for 2,4,6 and 8 h,respectively.SEM examination of boronized ductile iron revealed a nearly smooth boride coating on ductile iron.The distribution of elements of boronized samples from surface to interior was determined by energy-dispersive X-ray spectroscopy( EDS).The boride formed in the coating layer confirmed by X-ray diffraction analysis is Fe2B single phase.The hardness of boride on surface of ductile iron is from1170 to 1392 HV0.025.Depending on boronizing time and temperature,the thickness of the coating layers on boronized ductile iron is from 35 to 118 μm.After a liner regression analysis,the possibility of predicting the iso-thickness of boride layers variation was studied.Moreover,the activation energy for boronized ductile iron is 175 kJ /mol.更多还原