Investigation of metallic multilayers coated graphite

مقدم أطروحة جامعية

Abd, Farah Amir

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم العلوم التطبيقية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2008

الملخص الإنجليزي

In the present work, a bulk graphite substrate was coated with nickel and multilayer of nickel-chrome using electroplating technology, the experimental equipment and facilities were locally designed and constructed.

After steps cutting, grinding and cleaning) of substrates and bath solution preparation, the electroplating process for preparing substrates was begun.

The deposition conditions (PM distance between electrodes, time of plating and current density) were varied during deposition process.

The heat treatment was carried ou or selected electrodeposited specimens at different temperatures for one hour.

The test and measurements (optical examination, thickness measurements, adhesion test and micro hardness test) of coated bulk graphite by layer of nickel and multilayer of nickel- chrome were carried ou.

The optical examination for morphologies of the coated surfaces showed that the variation in deposition conditions are influenced the microstructure of the electrodeposited layers.

From the microstructure analysis , it was found that the grain size tend to be smaller as the PH of solution, the current densities and distances between electrodes are increased and time decreased.

The effect of heat treatment on the microstructure showed an encouraged grain growth which was more at high treatment temperature.

The mechanical tests of electrodeposited layers results showed that the maximum value of adhesion strength was (13.75 MPa at t = 15 min, and PH = 3.5), but most samples show a perfect adhesion strength.

Adhesion strength is also enhanced by heat treatment effect due to the diffusion occurred between the coating layer and substrate.

The micro hardness value of graphite coated by layer of nickel showed to be increased to maximum values (5Z5 MPa at PH - 3.5and J= 6.5 A / dm2), and the maximum values of micro hardness of graphite coated by multilayer of nickel-chrome was 1325 MPa at t - 120 min.

and J = 32.6 A / dm2, but the micro hardness values decreased by the effect of heat treatment.

التخصصات الرئيسية

الفيزياء

الموضوعات

• الخواص الكهربائية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305011