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Influence Of Thermal Treatment On Relaxor Properties Of BaBi2Nb2O9 Ceramics

Adamczyk M., Pilch M., Pawełczyk M.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2A

545--550

EN

In the hereby paper the implications of thermal modification of BaBi2Nb2O9 ceramics in high vacuum (5×10−11 bar) at a temperature equal of 1173K are widely discussed. The mentioned modification caused changes in the ions concentration (confirmed by EDS and XPS analysis) and as a consequence an influence on the value of the unit cell parameters as well as on the dielectric and relaxor properties of described ceramics. The obtained results of EDS and XPS analysis of the sample before and after thermal treatment revealed bismuth ions diffusion to the surface of the sample (which was expected) and an almost complete the lack of barium ions on the modified surface. The comparison of EDS and XPS analysis results, suggested that they penetrated the interior of the sample and embedded into the crystal structure in place of bismuth. The hypothesis is in good agreement with the results of X-ray diffraction – the volume of the unit cell had an insignificant increase. The changes in the ions concentration influenced, also in a distinct manner, the dielectric and relaxor properties as well as on the shape of temperature characteristic of thermal stimulated depolarization current observed in BBN ceramics.

PL

W niniejszym artykule są szeroko dyskutowane konsekwencje obróbki termicznej ceramiki BaBi2Nb2O9 w warunkach wysokiej próżni (5×10−11 bar) w temperaturze 1173K. Wyniki analizy XPS wykonane zarówno przed jak i po obróbce cieplnej ujawniły dyfuzję jonów bizmutu ku powierzchni próbki (co było oczekiwane) i prawie całkowity brak jonów baru na modyfikowanej powierzchni. Porównanie wyników analizy EDS i XPS sugeruje, że jony baru dyfundują do wnętrza próbki i najprawdopodobniej wbudowują się w strukturę krystaliczną w miejsca bizmutu. Ta hipoteza pozostaje w dobrej zgodności z wynikami badań rentgenowskich – objętość komórki elementarnej. Zmiany w koncentracji jonów wpływają również na właściwości dielektryczne oraz zachowania charakterystyczne dla ferroelektrycznych relaksorów, a także kształt charakterystyk temperaturowych prądów termicznie stymulowanej depolaryzacji (TSDC) obserwowanych w ceramice BBN.

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Reliability estimation for manufacturing processes

Kostina M, Karaulova T., Sahno J., Maleki M.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 51, nr 1

7--13

EN

Purpose: of the current research is to develop a reliability assessment method with an extension of the existing ones and pooling them to a common framework. The system must identify the most unreliable parts of a production process and suggest the most efficient ways for the reliability improvement. Design/methodology/approach: FMEA is in the centre of the proposed framework,a reliability analysis type, the most widely used in enterprises. The current research suggests to extend the FMEA by introducing a classification of faults. In this procedure, Bayesian Belief Network is employed to analyze faults. Findings: An integrated modelling method based on a system modelling and complemented with a reliability evaluation mechanism has the capability to analyse and design manufacturing systems. The tool developed to analyse a production process, enables companies to analyse the process as a whole as well as its parts and achieve efficient prognosis for the production process reorganization. Research limitations/implications: The reliability analysis framework is developed for machinery manufacturing enterprises. Practical implications: The reliability assessment tool helps engineers quickly and with accurate estimate most unreliable places of production process and indicates ways of their elimination with great efficiency. Originality/value: Expansion of FMEA method, application of Bayesian Belief Network for process reliability estimation, usage of reliability estimation during production route creation.

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Biuro bezpieczeństwa nowoczesnego

Bartkiewicz Artur

Wiedza Obronna

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2006

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nr 2

48--54