汽缸套合金铸铁的渗硼及渗层生长动力学研究

Study of Boronizing and Kinetics of Boronized Layer of Cast Alloy Iron

为研究铸铁表面渗硼层组织和生长动力学,对合金铸铁在850℃、880℃、910℃、940℃、970℃、1 000℃分别进行3 h、5 h、7 h、9 h的固体渗硼处理。用光学显微镜对渗层的横断面形貌进行拍摄和观察,用X射线衍射分析仪分析出渗硼层物相,用显微维氏硬度测量渗层的硬度梯度,分析了渗硼生长动力学。结果表明,渗硼能够明显提高材料表面的硬度。相同渗硼时间,渗硼层厚度随着渗硼温度的提高而增加;相同渗硼温度,时间延长渗硼层厚度增加。且提高渗硼温度比延长时间对渗硼层厚度影响更加明显。

To make a study of boronizing and kinetics of cast alloy iron for cylinder liner,it is at 850 ℃,880 ℃,910 ℃,940 ℃,970 ℃,1 000 ℃ for 3,5,7,9 h,respectively.The microstructure of the boride layers is observed by optical microscope.The boride formed in the coating layer is analyzed by X-ray diffraction analytical instrument and vickers hardness tester is used to test the hardness of boronizing layer.The results show that the surface hardness of the cast alloy iron parts boronized is improved significantly.The thickness of boriding layer increases with the temperature and time increasing.Effect of temperature on the growth of boronizing layer is greater than the time.