新型磁性附着体永磁体材料的筛选

Screening of permanent magnetic materials for new magnetic attachments

目的检测使用不同牌号钕铁硼永磁体制作的磁性附着体的磁力和磁感应强度。方法选取牌号分别为N45、N48、N50、N52的4种钕铁硼永磁体，采用闭路磁场中的“杯型”结构制作磁性附着体，按永磁体牌号不同分为4组：A（N45）组、B（N48）组、C（N50）组、D（N52）组，以MagfitDX800磁性附着体作为对照（E组），每组10对。测试并记录每组磁性附着体的磁力和磁感应强度。结果A组、B组、C组、D组、E组磁性附着体实际测量的磁力值分别为（330．83±26．43）gf、（376．17±25．67）gf、（428．87±30．44）gf、（489．30±28．27）gf、（418．53±28．76）gf（1gf=9．8mN），总体差异具有统计学意义（F=135．424，P〈0．001）。采用LSD检验两两比较显示，D组磁性附着体的磁力最大，与其他4组比较差异均有统计学意义（均P〈0．001）；A组磁性附着体的磁力最小，与其余4组组间比较，差异均具有统计学意义（均P〈0．001）；B组磁力大于A组，小于C、D、E组（均P〈0．001）；C组与E组间的磁力差异无统计学意义（P=0．155）。各组磁性附着体外表面的磁感应强度均小于400G，符合磁场泄露安全标准。结论新型磁性附着体选用钕铁硼N52作为永磁体材料，可明显提高磁性附着体的磁力，有望广泛应用于临床。

Objective To determine the magnetic force and magnetic induction intensity of attachments made of NdFeB permanent magnets with different grades. Methods The 4 types of magnetic attachments were included in the study, and divided into 4 groups （A, B, C, D） based on different grades of NdFeB permanent magnets （N45, N48, N50, N52）, respectively; the MagfitDXSO0 magnetic attachment was included in the control group （E） （n=10 pairs each）. All magnetic attachments were structured by cup- shape in the closed magnetic field. The magnetic force and magnetic induction intensity of magnetic attachments in each group were measured and recorded. Results The actually measured magnetic force of the magnetic attachments in groups A, B, C, D and E were （330.83±26.43） gf, （376.17±25.67） gf, （428.87±30.44） gf, （489.30±28.27） gf, （418.53±28.76） gf（1 gf=9.8 mN）, respectively, with overall statistical difference among groups （F=135.424, P〈0.001 ）. When all the groups were compared in pairs and determined by LSD test, the maximum magnetic force of the magnetic attachment was found in group D, with statistically significant difference compared with the other 4 groups （all P〈0.001 ） ; the minimum magnetic force of the magnetic attachment was found in group A, with statistically significant difference compared with the other 4 groups （all P〈0.001 ） ; the magnetic force in group B was stronger than that in group A but weaker than those in groups C, D and E （all P〈0.001）. There was no statistically significant difference in the magnetic force between groups C and E （P=0.155）. The magnetic induction intensity of the magnetic attachment surface in each group was less than 400 G, which was consistent with the safety standards of magnetic leakage. Conclusion The new magnetic attachments made of NdFeB N52 as the permanent magnetic material can significantly improve the magnetic force of the magnetic attachments, and is promising for widespread use in clinical practice.