| Effect of Process Parameters and Binder Concentration on
Mechanical Properties of Phosphate Bonded Alumina |
Pankaj Kumar, A. N. Tiwari and Parag Bhargava*
pages : 130-135
DOI : 10.1080/0371750X.2013.817602 |
| Abstract |
| Alumina and alumina matrix composites typically require sintering temperature in excess of 1550oC. Utilization of
aluminium phosphate bonding provides process flexibility and significantly lowers sintering temperature (500o to
1280oC). While phosphate bonded alumina (PBA) may have a lower sintering temperature, its limitations include
the presence of porosity in pressure less sintered samples leading to lowered strength and phase instability above
approximately 1200oC. The present study describes the effect of processing routes and binder concentration on
density, hardness, Young’s modulus and transverse rupture strength (TRS) of PBA. In this study, ultra fine Al2O3
(particle size 0.5 m) was reacted with H3PO4 to yield phosphate bond in a matrix of tabular Al2O3 (particle size
5 m) after final sintering at 1280oC for 6 h. Green samples were compacted at pressures in the range of 96-290
MPa. The effect of aluminium phosphate binder concentration on mechanical properties of the PBA samples was
measured at optimized pressure. The presence of different polymorphs of AlPO4 in the sintered product was
confirmed by XRD. |
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