Y含量对18CrMnB齿轮钢表面粉末包埋渗Nb层性能的影响

Effect of Y Content on the Properties of Powder Embedded Nb Coating on the Surface of 18CrMnB Gear Steel

为进一步优化18CrMnB齿轮钢的渗Nb工艺,以18CrMnB齿轮钢为基体,通过掺杂稀土Y的固体粉末包埋法在其表面制得Nb渗层,测试了渗层组织结构、性能与稀土Y加入量(质量分数)之间的关系。结果表明:当在渗层中添加稀土元素后,得到了外形规则的颗粒,并且大部分颗粒的尺寸都很细小,形成了致密的组织结构。还可以看到夹杂着许多Al_(2)O_(3),确保渗层可以跟基体形成紧密结合。当Y加入量提高后,Nb渗层的硬度先增高后降低,加入1%的稀土时获得了最高硬度。渗层都主要由NbC构成,还有部分Y_(2)O_(3)组织。加入稀土后渗层具有更低的摩擦系数,加入1%稀土时渗层达到了最小的摩擦系数。加入稀土后得到的渗层具有更低的摩擦系数,渗层表面较为光滑,并且其组织也比较致密。

In order to further optimize the Nb infiltration process of 18CrMnB gear steel,a Nb impregnated coating was prepared on the surface of 18CrMnB gear steel by solid powder embedding method doped with rare earth Y.What’s more,the relationship between the structure and properties of the impregnated coating and the content of rare earth Y(mass fraction)was tested.Results showed that when the rare earth elements were added to the permeable layer,the particles with regular shape were obtained,and most of the particles had very small size,forming dense tissue structure.Many Al_(2)O_(3)were mixed to ensure that the seepage layer formed a close bond with the matrix.When the amount of Y was increased,the hardness of Nb impregnated layer first increased and then decreased,and the maximum hardness was obtained when 1%rare earth was added.The permeation layer was made up of NbC and part of Y_(2)O_(3).The permeability layer had lower friction coefficient after adding rare earth,and the minimum friction coefficient was reached when adding 1%rare earth.The permeation layer obtained had lower friction coefficient,smoother surface and denser structure after adding rare earth.