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尖晶石型Fe_(3-ω)O_4(0<ω<1/3)是磁粉和制备磁粉的中间体,也是钢铁腐蚀后常见的腐蚀产物。在已有一步合成的Fe_3O_4和自然腐蚀产物中,所得Fe_(3-ω)O_4晶体都呈块状,球状或棱锥状,但用作磁记录材料的Fe_(3-ω)O_4,必须具有针状晶体。为此,工业上至今仍不得不采取多步合成来制造磁粉。Formaron曾在脱氧的(NH_3OH)_2SO_4+Fe(NH_4)_2(SO_4)_2溶液中企图通过施加外磁场来获得针状Fe_3O_4晶体,但没有成功。最近作者等采取了新的合成路线,在外加磁场等作用下,首次一步合成Fe_(3-ω)O_4针状晶体,并弄清影响形成针状Fe_(3-ω)O_4晶体的一些主要因素。
Spinel-type Fe_ (3-ω) O_4 (0 <ω <1/3) is an intermediate of magnetic powder and magnetic powder, and is also a common corrosion product after steel corrosion. The Fe_ (3-ω) O_4 crystals obtained in the one-step synthesis of Fe_3O_4 and natural corrosion products are massive, spherical or pyramidal, but the Fe_ (3-ω) O_4 used as the magnetic recording material must have the needle Crystal. To this end, the industry still have to take multi-step synthesis to create magnetic powder. Formaron attempted to obtain acicular Fe_3O_4 crystals by applying an external magnetic field in deoxidized (NH_3OH) _2SO_4 + Fe (NH_4) _2 (SO_4) _2 solution without success. Recently, the authors have taken a new synthetic route to synthesize Fe 3-ω O 4 acicular crystals for the first time under the action of an applied magnetic field and clarify some of the major factors that affect the formation of acicular Fe 3-ω O 4 crystals .