Fe-Ga磁致伸缩粉末制备及涂层组织及性能研究

The microstructure and properties study of Fe-Ga magnetostrictive powder and coating

以纯Fe和Ga金属为原料,采用气雾化法制备粒径为10~150μm的Fe-Ga磁致伸缩合金粉末,通过超音速火焰喷涂技术沉积Fe-Ga合金涂层。采用SEM、XRD、纳米压痕仪、拉伸试验机和磁致伸缩测试仪表征粉末和涂层的形貌、组织结构和性能。研究结果表明,气雾化粉末具有单一的α-Fe相,粉末球形度高。选择粒径为30~60μm的Fe-Ga粉末作为超音速火焰喷涂的原料,制备的涂层具有典型的层状结构,结合致密,局部区域出现孔洞,平均孔隙率小于1.2%。不同厚度涂层仍保持α-Fe相结构,但存在衍射峰的偏移,无其他新相形成;涂层硬度分布均匀,平均硬度高于4.5 GPa,基材与涂层之间结合较好,结合强度高于70 MPa;400μm厚Fe-Ga涂层的磁致伸缩系数为3.0×10^(-5),验证了采用超音速火焰喷涂技术在被检测试件上沉积磁致伸缩涂层方法的可行性,有望解决磁致伸缩导波长期在线监测难的问题。

Fe-Ga magnetostrictive alloy powder with particle size of 10-150μm is prepared by aerosolization method using pure Fe and Ga metals as raw materials,and Fe-Ga coating is prepared by high velocity oxy-fuel spraying(HVOF)process.The microstructure and properties of the coating are characterized by the SEM,X-ray diffraction,indentation tester,tensile tester and the magnetostrictive tester.The results show that the aerosolized powder has a singleα-Fe phase and high powder sphericity.The Fe-Ga powder with a particle size of 30-60μm is selected as the raw material for HVOF,and the prepared coating has a typical lamellar structure with dense bonding and pores in local areas,and the average porosity is less than 1.2%.The coating with different thicknesses still maintains the structure ofα-Fe phase,but there is a shift in diffraction peaks,and no other new phase are formed.The micro-hardness distribution of the coating is uniform,and the average hardness is higher than 4.5 GPa.The interface bonding between coating and substrate is good with the bonding strength higher than 70 MPa.The magnetostriction coefficient of Fe-Ga coating with a thickness of 400μm is 30×10^(-6),indicating the feasibility of preparing magnetostrictive coatings by HVOF,which is expected to realize the long-term online monitoring of magnetostrictive guided waves.