FeBSiNb非晶纳米晶复合涂层的制备及性能研究

Fabrication and Properties of FeBSiNb Amorphous and Nanocrystalline Composite Coatings

采用气雾化制备了FeBSiNb合金粉末,经过火焰喷涂后,制备了高非晶含量的FeBSiNb涂层。利用X射线衍射仪、差热分析仪、扫描电镜和透射电镜分析了粉末和涂层的表面形貌、显微组织和结构特征。结果表明:FeBSiNb合金粉末主要由晶体Fe_2B相和α-Fe(Si)固溶体组成,形状大多为近球形并伴有少量的"卫星"球。FeBSiNb非晶涂层主要由非晶相(含量85vol%左右)、Fe_2B晶体相和α-Fe(Si)纳米晶相组成。非晶涂层在531~605℃区间发生晶化,涂层的玻璃转变温度T_g为513℃,晶化温度T_x为531℃,计算得出FeBSiNb系合金形成非晶相的临界冷却速率为9.6。对涂层的摩擦磨损性能进行测试,在载荷5N,频率5Hz,时间30min摩擦条件下,FeBSiNb非晶涂层的摩擦系数仅为0.2左右,相对耐磨性约为45#钢基体的10倍。

The FeBSiNb alloy powder was prepared by gas atomization, and then the FeBSiNb amorphous coating was fabricated by flame spraying. The phase composition, morphology, microstructure and thermal stability were investigated by XRD, SEM, TEM and DSC, respectively. The results show that the FeBSiNb alloy powder is mainly composed of Fe2B crystalline phase and a-Fe（Si） solid solution, and most of the particles are near-spherical with some attached satellites. The FeBSiNb amorphous coating is composed of amorphous phase （85 vol%, based on XRD result）, Fe2B crystalline phase and a-Fe（Si） nanocrystalline phase. The crystallization of FeBSiNb amorphous coatings occurs at 531-605 ℃, the glass transition top temperature Tg is about 513 ℃ and the initial temperature Tx of the first crystallization event is about 531 v. The critical cooling rate for the glass formation of the FeBSiNb is calculated to be 9.6×10^3 Kls. Under the dry friction conditions of 5 N, 5 Hz, 30 min, the friction coefficient of FeBSiNb amorphous coating is only 0.2, and its relative wear resistance is 10 times stronger than that of the 45# steel substrate.