Okuno O, Nakano T, Hamanaka H, Kinouchi Y
Shika Zairyo Kikai. 1989 Jul;8(4):539-45.
Nd-Fe-B magnets have a very high maximum energy product (BH max), which is defined as the attractive strength between a magnet and opposing magnetic materials. Permendur (Fe-49 Co-2 V) has the greatest magnetic saturation (Bs), which makes it strongly magnetized. If magnetic retainers were made with Nd-Fe-B magnets and a permendur yoke, they would be small and have strong retention. The purpose of this investigation was to develop small dental magnetic devices with Nd-Fe-B magnets and permendur yokes. The magnetic devices form sandwich-type magnetic circuits with magnetic stainless steel keepers. A 4 x 3 x 2 mm rectangular prism Nd-Fe-B magnet was used. The magnet was sandwitched between the semi-columnar yokes. To protect the magnet from corrosion, the devices were encapsulated with 304 stainless steel by silver brazing and adhesion bonding of a stainless steel tube and foil. The optimum cross-sectional area of the yoke was determined experimentally. The dimensions of the devices were phi 5 x 3.5 mm for 4 x 3 x 2 magnet. The breakaway retention for a keeper of magnetic stainless steel (Type XM 27) was 852 g on average. This breakaway retention is sufficient for dental prosthetic applications.
钕铁硼磁体具有非常高的最大能量积（BH max），它被定义为磁体与相对磁性材料之间的吸引力强度。坡明德（Fe-49 Co-2 V）具有最大的磁饱和度（Bs），这使其能够被强烈磁化。如果用钕铁硼磁体和坡明德磁轭制作磁性固位体，它们将会体积小且固位力强。本研究的目的是开发带有钕铁硼磁体和坡明德磁轭的小型牙科磁性装置。这些磁性装置与磁性不锈钢保持器形成三明治式磁路。使用了一个4×3×2毫米的长方体钕铁硼磁体。该磁体夹在半柱状磁轭之间。为了保护磁体免受腐蚀，这些装置通过银钎焊以及不锈钢管和箔的粘结，用304不锈钢进行封装。通过实验确定了磁轭的最佳横截面积。对于4×3×2磁体，装置的尺寸为直径5×3.5毫米。磁性不锈钢保持器（XM 27型）的平均脱离固位力为852克。这种脱离固位力足以用于牙科修复应用。
