Influence of porosity on the mechanical properties of lead zirconate--titanate ceramics

Technical Report · Wed Sep 01 00:00:00 EDT 1976

DOI:https://doi.org/10.2172/7110774· OSTI ID:7110774

Biswas, D R

Niobium doped lead zirconate-titanate (PNZT) was used to investigate the effect of porosity on the mechanical properties of a polycrystalline ceramic. Spherical and acicular pores (25 to 150 ..mu..m) were introduced by using organic materials and the grain size (2 to 5 ..mu..m) was constant throughout the study. The very fine pores (2 to 3 ..mu..m) were formed by varying the sintering conditions and the grain size was comparable to the pore size. The fracture strength of the ceramic was measured by simple 4-point bending. A sonic resonance technique was used to measure the elastic modulus and the double torsion method was used to measure the fracture toughness of the ceramic. The effect of porosity on the fracture strength was predicted quite well by Weibull's probabilistic approach. The elastic modulus showed a linear relationship with increase in porosity (110 to 150 ..mu..m) and showed a higher value for PNZT-fine pore (2 to 3 ..mu..m) ceramics at same volume percent porosity. A decrease in fracture toughness with increase in porosity (110 to 150 ..mu..m) was also observed. It has been found that the fine pores in PNZT polycrystalline ceramic gave higher strength, elastic modulus and fracture toughness compared to the PNZT-large pore ceramics at equivalent porosities. Fracture surface analysis by scanning electron microscopy showed that the fracture origin was at the tensile surface, at the edges of the specimen and just underneath the tensile surface.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7110774
• Report Number(s): LBL-5479
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALLOYS
CERAMICS
ELASTICITY
FRACTURE PROPERTIES
LEAD COMPOUNDS
MECHANICAL PROPERTIES
NIOBIUM ADDITIONS
NIOBIUM ALLOYS
OXYGEN COMPOUNDS
POROSITY
TENSILE PROPERTIES
TITANATES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONATES
ZIRCONIUM COMPOUNDS