The role of milling liquids in processing of metal-ceramic-precursor powders

Journal
Ceramic engineering and science proceedings  
Volume
33
Issue
8
Start Page
135
End Page
145
Citation
Ceramic Engineering and Science Proceedings 8 (33): 135-145 (2013)
Contribution to Conference
36th International Conference on Advanced Ceramics and Composites, 2012, Daytona Beach, Florida  
Publisher DOI
10.1002/9781118217528.ch15
Publisher
Wiley-Interscience
Reaction bonding of aluminum oxide (RBAO) and the reactive sintering of metal-alumina composites (s-MAC) are encouraging concepts for the preparation of highly dense components exhibiting specific properties. Precursor powders should be adapted for conventional powder metallurgical (PM) techniques. Thus, the focus is on the preparation of precursor powders for RBAO and s-MAC processing, exemplified by Al-Al2O3 and Cr-Al 2O3 powders, respectively. For both variants, a fine grained, homogenous precursor is the essential prerequisite - particularly, if the goal for reactive synthesis routes is complete densification by pressureless sintering. The precursor powders had been wet grinded in an attrition mill. Organic milling liquids with different properties were investigated. The characterization is based on stability considerations of the milling suspensions. The comparison of the particle size distributions with the results of the sedimentation trails indicates the existence of different hard agglomerate structures build up in the milling process. According to the solvent properties the milling results can be classified not only to polar and nonpolar, but rather to polar protic, polar aprotic and nonpolar solvents. In addition, the influences of the powder characteristics on the corresponding reaction bonding or reaction sintering mechanism are examined.
DDC Class
570: Biowissenschaften, Biologie