Paper Title:
A New Process and Structure of Al2O3/LaPO4 Composites
  Abstract

LaPO4 was added to Al2O3 ceramic matrix to improve the machinability of the composites. Different from the traditional way of making Al2O3/LaPO4 composite, coating method is introduced. In the present work, LaPO4-coated α-Al2O3 powders were synthesized through the heterogeneous precipitation method and sintered into Al2O3/LaPO4 composites by pressureless sintering at 1600°C for 2h. The phase components and microstructure of Al2O3/LaPO4 composites are presented according to variations of lanthanum phosphate (LaPO4) content (10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%). From the TEM image, it can be seen that the coated powders have a clear core-shell structure and the thickness of the coating varies from 5 to 15 nm approximately. X-ray diffraction analysis showed that only Al2O3 and LaPO4 phases exist in the Al2O3/LaPO4 composites which indicated that there is good chemical compatibility between Al2O3 and LaPO4 phase. Microstructure development of Al2O3/LaPO4 composites has been explored by SEM, the coating structure became less recognized after sintering, layered and fiber shaped LaPO4 was obviously observed in the Al2O3/LaPO4 composites with the increase of LaPO4 addition. The LaPO4 inhibited grain growth of Al2O3 by distributing at the Al2O3 grain boundaries. The weak interface of Al2O3/LaPO4 and layered soft LaPO4 phase can be responsible for the machinability of the composites.

  Info
Periodical
Advanced Materials Research (Volumes 79-82)
Edited by
Yansheng Yin and Xin Wang
Pages
2227-2230
DOI
10.4028/www.scientific.net/AMR.79-82.2227
Citation
Q. J. Zheng, X. Wang, X. R. Liu, Y. S. Yin, "A New Process and Structure of Al2O3/LaPO4 Composites", Advanced Materials Research, Vols. 79-82, pp. 2227-2230, 2009
Online since
August 2009
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Price
$32.00
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