Ceramics

Name

Description

Synthesis

Disadvantages

Advantages

Links

Phase transformation toughened zirconia(Zr02)

Monoclinic-stable phase, larger volume

 

Tetragonal phase-smaller volume, unstable at RT, but stabilized temporarily by 3% yittria(Y2O3),

 

 

Higher strength-crack propagation causes  phase transformation from tetragonal to monoclinic.  The increase in volume stops crack.

 

SiC whiskers

Whiskers-small, 200/1 aspect ratio, defect free

 

 

High strength/modulus

 

 

SiC fiber

 

Yajima approach

 

 

 

B4C yarn

 

Carbon fiber precursor, rapid

 

High strength/modulus

 

TiB2 fiber

 

 

 

 

 

Carbon fiber

 

PAN (polyacrylnitrile) precursor

 

 

I. High modulus

II. Activation with chromic acid for bonding with composite matrix

 

TiN fiber

 

 

 

 

 

Diamond

coating

I. 30 million year-old volcanoes

II. High pressures