COBEM99

S19 Usinagem dos Materiais

Titulo:

SINGLE POINT DIAMOND MACHINING OF FERROELECTRIC MATERIALS

Resumo :

ABSTRACT: FERROLECTRIC CERAMICS AND SINGLE CRYSTALS HAVE ATTAINED AN ENORMOUS IMPORTANCE IN AN EVER-WIDENING RANGE OF APPLICATIONS. THEIR EXCEPTIONAL COMBINATION OF PROPERTIES INCLUDES STRONG PIEZOELECTRIC, PYROELECTRIC AND ELECTRO-OPTIC EFFECTS. ONE OF THE MOST IMPORTANT AND WIDELY-USED GROUPS IS THE LEAD ZIRCONATE TITANATE SOLID SOLUTION SERIES (PZT). THE CONTEMPORARY TECHNOLOGY THAT HAS BEEN USED TO MACHINE THESE MATERIALS HAS BEEN GRINDING AND DIAMOND SAWING FOLLOWED BY LAPPING AND POLISHING. THE OBJECTIVE OS THIS RESEARCH PROGRAM IS TO DEVELOP A HIGHLY EFFICIENT AND PRECISION MACHINING PROCESS FOR THIS GROUP OF CERAMIC MATERIALS REDUCING SUB-SURFACE DAMAGE AND THUS ELIMINATING THE NEED FOR LAPPING AND POLISHING, LEADING TO REDUCED COSTS OF PRODUCTION. THE RESULTS SHOW THAT "DUCTILE REGIME" MACHINING CAN BE ACHIEVED WITH THIS GROUP OF BRITTLE MATERIALS. THE PLASTICITY OBSERVED IN PZT IS APPARENTLY DEPENDENT ON THE POLING DIRECTION, WHICH HAS BEEN SHOWN TO DIRECTLY INFLUENCE THE DUCTILE REGIME MACHINING CONDITIONS. OTHER MATERIALS CHARACTERISTICS, SUCH AS POROSITY AND HARDNESS, ALSO INFLUENCE THIS BEHAVIOUR. THE RESEARCH IS HELPING IN THE UNDERSTANDING OF THE FERROELECTRIC MATERIAL MECHANICAL AND ELECTRICAL CHARACTERISTICS WHEN MACHINED AND ALSO IS BEING USED TO BUILD UP AN OPTIMISED PROCESS MODEL FOR THE DAMAGE FREE DIAMOND GRINDING OF PZT. KEYWORDS: LEAD ZIRCONATE TITANATE; PZT; X-RAY DIFFRACTION; SINGLE POINT DIAMOND TURNING; FRACTURE MECHANICS.

Autores :

Beltrão, Paulo A.
Corbett, John
Gee, Anthony E.
Whatmore, Roger W.

Trabalho Completo :