WHISKER ALIGNMENT BY SLIP EXTRUSION

被引:23
作者
FARKASH, M
BRANDON, DG
机构
[1] Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa
来源
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 1994年 / 177卷 / 1-2期
关键词
D O I
10.1016/0921-5093(94)90499-5
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Si3N4 or Al2O3 ceramic slips containing 20-30 vol.% SiC whiskers and small quantities of a dispersant and gelling agent were prepared by ultrasonic dispersion and ball milling. The viscosity was minimized by adjusting the pH of the slip and the amount of organic additives. The slip was extruded into a gelling solution through a hypodermic syringe fitted with a 0.5 mm internal diameter stainless steel needle. The conversion of the extruded slip into a flexible thread was accomplished by an ion exchange reaction in the gelling solution. The orientation of the whiskers in the extruded thread was determined by infiltrating an epoxy resin into the dried thread and measuring the distribution of the angle between the whiskers visible on a polished cross-section and the extrusion direction. The degree of whisker alignment in the thread was defined in terms of a statistical orientation factor f0 which varied from 0 to 1 as the whisker distribution changed from randomly oriented to complete alignment in the extrusion direction. Optimum whisker alignment was achieved at large needle length-to-diameter ratios, low slip viscosities and high extrusion velocities.
引用
收藏
页码:269 / 275
页数:7
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