Magnetic Products

As a result of a lengthy R&D project by the Goudsmit Group a high energy corrosion resistant magnet has been developed which operates up to a maximum temperature of 200oC and has a maximum energy product of 53MGOe. The corrosion behaviour of the new Neoflux S-grade magnets is close to being similar to the corrosion behaviour of mild steel. The microstructure has been adjusted using suitable additive elements, leading to the replacement of the inter-granular Nd-rich phase by other corrosion stable inter-granular phases. The corrosion weight losses under the very severe conditions of a HAST test (Highly Accelerated Stress Test or Pressure Cooker Test, 120-130ºC, 100% humidity and 2.5-3 bar pressure) are insignificant after several days of testing. The typical weight losses of the Neoflux S-grades after 7 days of testing are approximately 1-2 mg/cm2. Figure 1 compares Goudsmit GSNS-grade magnets to traditional GSN-permanent magnets of Goudsmit and customary Chinese GSN-35SH permanent magnets. The typical measured weight losses of the S-grade magnets are about 20-50 times lower than the weight losses of customary Chinese GSN-35SH permanent magnets. Figure 1: the typical weight losses under HAST conditions specified for maximum operating temperatures of 150ºC. Another very important advantage of the Neoflux S-grade magnets is the increase of the Curie-temperature of the RE2FE14B compound ( RE = Rare-Earths), causing improved thermal coefficients of the remanence and coercivity.

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