氧化促进剂对铁粉磷化及铁粉芯软磁性能的影响  

Effects of oxidation accelerator on phosphating of iron powders and soft magnetic properties of iron powder cores

作　　者：刘向阳 傅嘉迁 于永亮 李松林[1] LIU Xiangyang;FU Jiaqian;YU Yongliang;LI Songlin(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;Shandong Luyin New Material Technology Co.,Ltd.,Laiwu 271105,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]山东鲁银新材料科技有限公司,莱芜271105

出　　处：《粉末冶金材料科学与工程》2022年第3期327-335,共9页Materials Science and Engineering of Powder Metallurgy

摘　　要：以还原铁粉为基体粉末,探究氧化促进剂Na_(2)MoO_(4)、NaNO_(2)及其复合添加对铁粉在NaH_(2)PO_(4)磷化液中磷化反应的影响,通过扫描电镜、X射线衍射仪、傅里叶红外光谱仪,振动样品磁强计以及软磁交流测量仪对磷化前后的铁粉和铁粉芯进行结构与性能表征。结果表明:铁粉在质量分数为5%的NaH_(2)PO_(4)磷化液中反应速度过快,无法生成完整均匀的包覆层,铁粉芯的软磁损耗虽有降低,但磁导率的频率稳定性不佳,铁粉经NaH_(2)PO_(4)磷化的表面磷化层主要由Fe_(3)(PO_(4))_(2)、FePO_(4)组成。在NaH_(2)PO_(4)磷化液中添加NaNO_(2),虽然促进了磷酸盐的生成,但包覆不均匀,其包覆层主要由FePO_(4)组成;在NaH_(2)PO_(4)磷化液中添加Na_(2)MoO_(4)或Na_(2)MoO_(4)+NaNO_(2)复合氧化促进剂可以使铁粉表面生成均匀的包覆层,大幅度降低铁粉芯的涡流损耗,其包覆层主要由FePO_(4)和Fe_(2)(MoO_(4))_(3)组成。其中Na_(2)MoO_(4)+NaNO_(2)复合添加对磷化反应的改善效果最好,400℃热处理后的铁粉芯电阻率为194.2μΩ·m,在测试励磁场强度B_(m)=50 mT,测试频率f=100 kHz条件下,铁粉芯的磁导率为92.5,软磁损耗为142.0 W/kg。The effects of oxidation accelerator Na_(2)MoO_(4),NaNO_(2) and their compound addition on the phosphating reaction of iron powder in NaH_(2)PO_(4) phosphating solution were investigated using reduced iron powder as matrix powder.The structure and properties of iron powder before and after phosphating and iron powder cores were characterized by scanning electron microscopy,X-ray diffractometer,Fourier transform infrared spectrometer,vibration sample magnetometer and soft magnetic AC measuring instrument.The results show that iron powder in 5%mass fraction of NaH_(2)PO_(4) phosphating solution cannot form a complete and uniform coating with the rapid reaction speed.The soft magnetic loss of iron powder cores decreases,but the frequency stability of magnetic permeability is bad.The surface phosphating layer structure of iron powder phosphated by NaH_(2)PO_(4) is mainly composed of Fe_(3)(PO_(4))_(2) and FePO_(4).The addition of NaNO_(2) in NaH_(2)PO_(4) phosphating solution promotes phosphate generation,but the coating isn’t uniform,and the coating layer is mainly composed of FePO_(4).Adding Na_(2)MoO_(4) or Na_(2)MoO_(4)+NaNO_(2) composite oxidation accelerator to NaH_(2)PO_(4) phosphating solution can generate uniform coating layer on the surface of iron powders and greatly reduce the eddy current loss of iron powder cores.The coating layer is mainly composed of FePO_(4) and Fe_(2)(MoO_(4))_(3).The compound addition of Na_(2)MoO_(4)+NaNO_(2) compound addition has the best improvement effect on phosphating reaction.After heat treatment at 400℃,the resistivity of iron powder cores is 194.2μΩ·m,under the condition of B_(m)=50 mT,f=100 kHz,the magnetic permeability of iron cores is 92.5,and the soft magnetic loss is 142.0 W/kg.

关 键 词：磷酸盐包覆 磷酸二氢钠 氧化促进剂 铁粉芯 软磁性能 

分 类 号：TB321[一般工业技术—材料科学与工程]