Available online at www.sciencedirect.com
Scripta Materialia 65 (2011) 416–419 www.elsevier.com/locate/scriptamat
Preparation of white alumina spherical composite magnetic abrasive by gas atomization and rapid solidification Zhang Gui-xiang,a,b Zhao Yu-gang,b,⇑ Zhao Dong-biao,a YinFeng-shi,b and Zhao Zeng-dian,c a
College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People’s Republic of China b School of Mechanical Engineering, Shandong University of Technology, Zibo 255049, People’s Republic of China c College of Chemical Engineering, Shandong University of Technology, Zibo, 255049, People’s Republic of China Received 9 May 2011; accepted 17 May 2011 Available online 23 May 2011
White alumina (WA) spherical composite magnetic abrasive can be prepared directly by a process that combines gas atomization and rapid solidification. The structure and phase composition of this material were characterized by scanning electron microscopy and X-ray diffraction analysis. The results show that the composite magnetic abrasive has good sphericity, and the WA grains are tightly embedded uniformly and densely into the surface layer of matrix which consists of Fe–Si–Al–Ni soft magnetic alloy. Ó 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Gas atomization; Rapid solidification; Powder processing; Spherical composite magnetic abrasive
Magnetic abrasive finishing (MAF) is an excellent method of finishing and has attracted wide attention in the field of aeronautics, astronautics, industrial production, etc., in which the finishing operation is the critical and most expensive phase of the production of metal and alloy parts [1–5]. Magnetic abrasive is the most critical material in the MAF process [6,7]. The performance requirements of magnetic abrasive for MAF are as follows [8,9]: good soft magnetic properties; strong processing capacity; and strong bonding between the ferromagnetic matrix phase and hard abrasive ceramic grains, i.e. long service life. In addition, a simple preparation process, low cost and a spherical shape are desired. The ideal structural model of a single magnetic abrasive grain is shown in Figure 1. It is a kind of composite powder, generally consisting of ferromagnetic matrix phase and hard abrasive ceramic grains. Although several methods to prepare magnetic abrasives have been reported in the open literature—sintering [10], bonding [11], plasma spraying [9,12], etc.—these methods are usually time consuming, complex and costly.
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