Predictive study for optimum sintering parameters for oxide ceramics

مقدم أطروحة جامعية

Ibrahim, Ilham Abd al-Majid

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الإنتاج و المعادن

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2006

الملخص الإنجليزي

Powder technology (P / T) process includes compacting of fine powders followed by sintering process to get products of desired properties.

In this research sintering process analyzed theoretically by predicting unsteady-state mathematical model in order to give more description and understanding for the mechanism of this process, which includes mass transport that may occur via diffusion.

Material transport mechanisms involved surface diffusion, volume diffusion and grain boundary diffusion.

There are different techniques that have been used to solve the heat transfer equation.

Due to their time-dependency the techniques are usually employed in time domain.

Finite difference time domain (FDTD) method is most widely used for this purpose.

The spatial and temporal temperature profile with the solid medium has been determined by solving the unsteady state Fourier heat energy transport equation using the explicit finite difference nu Powder technology (P/T) process includes compacting of fine powders followed by sintering process to get products of desired properties.

In this research sintering process analyzed theoretically by predicting unsteady-state mathematical model in order to give more description and understanding for the mechanism of this process, which includes mass transport that may occur via diffusion.

Material transport mechanisms involved surface diffusion, volume diffusion and grain boundary diffusion.

There are different techniques that have been used to solve the heat transfer equation.

Due to their time-dependency the techniques are usually employed in time domain.

Finite difference time domain (FDTD) method is most widely used for this purpose.

The spatial and temporal temperature profile with the solid medium has been determined by solving the unsteady state Fourier heat energy transport equation using the explicit finite difference numerical method, which would minimize the solution errors, this leads to more realistic determination of temperature distribution within the work-piece.

Alumina and zinc oxide have been selected as targets to represent non-metallic materials of diverse physical and thermal properties.

The average grain size for two materials are 0.5 urn with initial compact density 2160 kg/m3 for alumina, and 2040 kg/m3 for zinc oxide.

These values gave a reliable approach to calculate the porosity and relative strength.

Several factors affected sintering; however, the most significant are time and temperature, with temperature being the most important single variable.

The model of the sintering process begins with a particle packing and developed to study the temperature distribution in a sintered part as a function of the grain size, density, porosity and relative strength.

These results lead to decrease the porosity and increase in relative strength.

At sintering temperature for target materials which were used (1610 °C, and 1328 °C) with sintering time (8100, and 7200 second), a good results have been got for the thermal and physic-chemical properties to these materials.

These results gave a good reliability and validation with experimental and theoretical work available.

However, there is no limitation in the present model which was built here.

It was given more generally used to calculate many properties for different materials type.

Medical method, which would minimize the solution errors, this leads to more realistic determination of temperature distribution within the work-piece.

Alumina and zinc oxide have been selected as targets to represent non-metallic materials of diverse physical and thermal properties.

The average grain size for two materials are 0.5 urn with initial compact density 2160 kg / m3 for alumina, and 2040 kg / m3 for zinc oxide.

These values gave a reliable approach to calculate the porosity and relative strength.

Several factors affected sintering; however, the most significant are time and temperature, with temperature being the most important single variable.

The model of the sintering process begins with a particle packing and developed to study the temperature distribution in a sintered part as a function of the grain size, density, porosity and relative strength.

These results lead to decrease the porosity and increase in relative strength.

At sintering temperature for target materials which were used (1610 °C, and 1328 °C) with sintering time (8100, and 7200 second), a good results have been got for the thermal and physic-chemical properties to these materials.

These results gave a good reliability and validation with experimental and theoretical work available.

However, there is no limitation in the present model which was built here.

It was given more generally used to calculate many properties for different materials type.

التخصصات الرئيسية

العلوم الهندسية والتكنولوجية (متداخلة التخصصات)

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305976