超声波化学预镀改善烧结Nd-Fe-B表面Ni-P合金结合力

Improved adhesion of electroless Ni-P coatings on sintered Nd-Fe-B magnets by pre-plating in ultrasonic field

采用超声波化学预镀方法,研究超声波功率对Ni-P镀层与烧结Nd-Fe-B磁体结合力的影响。采用扫描电镜观察镀层与磁体的表面和截面组织形貌,采用X射线衍射仪测定镀层的相组成和晶体结构。结果表明,随超声功率的增加,Ni-P镀层与磁体的结合力逐渐提高,当超声功率为150W时,镀层结合力达到最大值。与无超声场下的Ni-P化学镀层相比,经超声波预镀工艺获得的镀层组织均匀、结构致密,镀层与磁体结合紧密。分析超声波改善镀层与磁体结合力的机理,认为超声波的搅拌作用和空化作用有助于提高镀层与磁体的结合力。

The effects ofpre-plating in ultrasonic field on the adhesion of electroless Ni-P coatings to sintered Nd-Fe-B magnets were investigated. The adhesion of Ni-P coatings to magnets with different ultrasonic power was measured by an adhesion tester. The surface and cross-sectional morphologies of the coatings were observed through SEM. The phase structure of the coatings was identified by X-ray diffraction patterns. The results show that the adhesion of Ni-P coating to Nd-Fe-B magnet was enhanced with increasing ultrasonic power. When increasing ultrasonic power up to 150 W, the adhesion strength reaches the maximum. Synchronously, a uniform and compact deposit can be obtained by pre-plating in ultrasonic field. It is suggested that the ultrasonic pre-plating contributes to the improvement of adhesion through two ways： stirring and cavitation action.