發(fā)布時間：2019-06-19 02:34

【摘要】：由于燒結釹鐵硼具有超高的永磁性能,在信息技術、通訊電子、風力發(fā)電等領域得到了廣泛的應用。但因其耐蝕性能差,使其應用范圍受到了限制。隨著燒結釹鐵硼磁體的應用快速增長,稀土釹的需求越來越多,價格也日益上漲,因此開發(fā)低成本的燒結釹鐵硼磁體并研究其耐蝕性能具有重要的研究價值。根據(jù)這一情況,本文成功制備出低成本含Ce磁體,并系統(tǒng)的研究了含Ce磁體及商業(yè)用磁體N33和N45磁體在不同腐蝕環(huán)境中的腐蝕行為,分析并比較了磁體在不同腐蝕環(huán)境中腐蝕機理及顯微結構,研究了磁體在不同電化學介質中的腐蝕行為,分析并比較了磁體在不同電化學介質中的腐蝕機理。希望為高耐蝕低成本燒結釹鐵硼永磁體的制備及其應用奠定了理論基礎。獲得的主要研究結果如下： (1)通過高壓加速實驗(HAST)研究了不同成分的磁體在在130℃、100%RH的濕熱環(huán)境中的腐蝕行為和腐蝕機理。研究發(fā)現(xiàn),此條件下N33的失重率達到83.192%,N45的失重率達到0.3846%,含Ce磁體的失重率達到0.08813%。因而Ce磁體的耐蝕性能優(yōu)于N45磁體和N33磁體。 (2)通過鹽霧實驗(NSS)研究了不同成分的磁體在中性鹽霧中的腐蝕行為和腐蝕機理。研究發(fā)現(xiàn)燒結釹鐵硼磁體在中性鹽霧中的腐蝕反應以氧化剝落為主。當腐蝕時間達到168h時,含Ce磁體的失重率達到1.6357%,N45磁體的失重率達到2.2636%,N33磁體的失重率為2.9873%。因此,含Ce磁體的耐蝕性能優(yōu)于N45磁體和N33磁體。通過顯微組織分析研究了含Ce磁體具有良好耐蝕的原因,一是由于含Ce磁體的主相晶粒較小,發(fā)生氧化剝落反應時,剝落的磁體顆粒較小,因而磁體的失重率最��；二是Ce磁體的富稀土相均勻分布于磁體主相周圍,不存在有富稀土相在主相角隅處的富集,使磁體的腐蝕通道變窄,降低了富稀土相的活性。進一步的研究表明,基體在腐蝕介質中的耐蝕性能對鎳鍍層破裂時間起著至關重要的作用,含Ce磁體由于具有低的失重率,因此電鍍Ni/Cu/Ni后,表現(xiàn)出最好耐蝕性。 (3)通過測量燒結釹鐵硼磁體在不同溶液(NaOH、NaCl、自來水)中的極化曲線及阻抗曲線,發(fā)現(xiàn)Ce磁體在NaOH、NaCl、自來水溶液中的腐蝕電位最正、腐蝕電流最小,阻抗最大,進一步解釋了Ce磁體的耐蝕性能最好的根本原因；同時磁體在這三種溶液中的腐蝕行為,說明了當磁體處于NaOH溶液中時,其耐蝕性能最好；當磁體處于NaCl溶液中時,其耐蝕性能最差。
[Abstract]:Because of its ultra-high permanent magnetic properties, sintered ND-Fe-B has been widely used in information technology, communication electronics, wind power generation and other fields. However, because of its poor corrosion resistance, its application scope is limited. With the rapid growth of the application of sintered ND-Fe-B magnets, the demand for rare earth ND-Fe-B magnets is increasing, and the price is also rising day by day. Therefore, it is of great value to develop low-cost sintered ND-Fe-B magnets and study their corrosion resistance. According to this situation, low cost Ce magnets were successfully prepared, and the corrosion behavior of Ce magnets and commercial magnets N33 and N45 magnets in different corrosion environments was systematically studied. The corrosion mechanism and microstructure of magnets in different corrosion environments were analyzed and compared. The corrosion behavior of magnets in different electrochemical media was studied, and the corrosion mechanism of magnets in different electrochemical media was analyzed and compared. It is hoped that it will lay a theoretical foundation for the preparation and application of ND-Fe-B permanent magnets with high corrosion resistance and low cost. The main results are as follows: (1) the corrosion behavior and corrosion mechanism of magnets with different components in hot and humid environment at 130 鈩，

本文編號：2502000