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The effects of sintering temperature and manganese concentration on microstructure and electromechanical property were studied in [Pb0.9La0.1][Zr0.5Ti0.5]O3 piezoelectric ceramics with the substitution of the B-site by manganese by means of scanning electron microscope (SEM) and electron spin resonance (ESR). Grain growth is enhanced by increasing temperature but suppressed by manganese substitution. There was no relationship between Qm (inverse of mechanical vibration loss) and the grain size. Some part of manganese is considered to be reduced to Mn2+ ions during sintering. Qm is considered to be affected by the reduction of manganese ions because it was proportional to Mn2+ concentration, not to total manganese content.

Self diffusion coefficients of oxygen in PLZT ceramics were evaluated to estimate the vacancy structure by the oxygen-18 isotope exchange reaction and the iso tope analysis by the secondary ion mass spectroscopy (SIMS). In the piezoelectric composition of PLZT (10/ 50/50), the oxygen vacancy concentration was estimat ed as about one ppm/mol by means of oxygen diffusion measurements and it did not change by doping impuri ties except for manganese. It was considered that point defects existed at all sites of the perovskite struc ture of PLZT. On the other hand, the oxygen vacancy concentration increased to 100ppm/mol for man ganese doped samples, and the reason was considered that manganese ions were reduced during sintering and that the oxygen vacancies were created to compen sate the charge imbalance. In the transparent PLZT (9/ 65/35), the oxygen vacancy was ten times as much as that in PLZT (10/50/50). The increase in oxygen vacan cy was ascribed to volatilization of lead or variation of solubility of lanthanum in B site. All samples showed extraordinary oxygen diffusion at high temperatures near the surface, which was ascribed to the volatiliza tion of PbO.

The small punch creep (SPC) test is possible to predict residual creep life at a high accuracy. But, the results of SPC tests cannot be compared with uniaxial creep or internal pressure creep results directly. In this report, the relationship between SPC test results and uniaxial creep test results in ASME A335 P11 (1.25Cr-0.5Mo Steel) was studied. The obtained relationship between SPC load and equivalent uniaxial creep stress formed a simple linear equation under the wide range of test temperature and test period. Then, the SPC results can be compared with uniaxial results by converting SPC loads to the equivalent uniaxial creep stresses. The relationship between SPC test results and internal pressure creep tests results was also studied. The internal creep life of as-received P11 pipe was almost same as SPC result when the hoop stress was converted to the SPC load. The creep lives of internal pressure creep influenced materials also showed good correspondence with SPC results. Therefore SPC can estimate the residual life of internal pressure creep influenced materials.

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