电流密度对TC4钛合金表面熔盐电解渗硼的影响

Effect of Current Density on Boriding on TC4 Titanium Alloy by Molten Salt Electrolysis

以TC4钛合金为基体进行熔盐电解渗硼,利用辉光放电光谱仪（GDOES）、扫描电镜（SEM）、X射线衍射仪（XRD）和显微硬度计研究电流密度对渗硼层厚度、成分、组织、相结构及硬度的影响。结果表明：电流密度在50～90 m A/cm2时,渗硼层晶粒随电流密度的增加由粗大变得细小,渗硼层厚度先增大后减小,电流密度为60 m A/cm2时渗硼层厚度最大。渗硼层不含Al,而V则易固溶于硼化物中。渗硼层主要由Ti B和Ti B2组成,在（111）晶面择优生长。渗硼层的显微硬度相对基体硬度提高了5倍。

TC4 titanium alloy was borided by molten salt electrolysis.The effect of current density on the thickness, composition, microstructure, phase and hardness of borided layer was studied by glow discharge optical emission spectroscopy （GDOES） , scanning electron microscopy （ SEM）, X-ray diffraction （XRD） and microhardness tester.The results show that,with current density increasing from 50 to 90 mA/cm2, the grain size of borided layer gradually becomes smaller, and the thickness of borided layer increases first and then decreases.When the current density is 60 mA/cm2, the thickness of borided layer reaches the maximum.The borided layer does not contain Al,and V dissolves in the borides to form solid solution.The borided layer consists of TiB and TiB2 with preferred orientation of （ 111 ） lattice plane.The mierohardness of the borided layer is increased by 5 times than that of the matrix.