A master’s student, Heba M. Abdelkader, defended her thesis “Synthesis of Bio-Medical Materials Using Electroless Deposition Technique” on Tuesday, January 14^th, at the conference room (C), Department of Materials Engineering, University of Technology. The Committee members included:

The dissertation was scientifically evaluated by Ass. Prof. Dr. Mazhir T. Mohamed, University of Diyala, College of Engineering, Materials Engineering Department, and linguistically by Ass. Prof. Dr. Samir A. Ameen, Mechanical Engineering Department, University of Technology.

The discussion was conducted in a scientific atmosphere and a master's degree with grade of pass was awarded to the student after the completion of all the corrections that have been decided by the examiners.

Abstract

In this work, the Ni-based nanocomposite coatingmetal matrix)                       nanocomposite coating) by electroless deposition technique on a stainless steel (316L) substrate was prepared, where this coating technique is representing an alternative technique to obtain coatings on various substrates. However, the effect of the bath composition on the phase structure, microhardness and corrosion rate is very important, therefore the present work will compare the effects of incorporation of (Al2O3, ZrO2 and MWCNTs) at different concentrations (1.25% wt, 2.25% wt and 4.25% wt) g/L to pure nickel path coating and preparation of the (Ni–Al2O3, Ni–ZrO2 and Ni– MWCNTs) nanocomposites coatings on the phase microstructure,  the mechanical property (microhardness), chemical properties (corrosion rate and ion release) and structural analysis (XRD, SEM and EDS) were studied for the all types of nanocomposite coatings specimens. The results of microhardness tests showed a significant improvement in the hardness property of (Ni-Al2O3), (Ni-MWCNTs), and (Ni- ZrO2) nanocomposites coatings were prepared by electroless deposition technique at the concentration (4.25%wt) were (Hv 521.6, Hv 495.3, and Hv 397.4) , respectively. Where nanocmoposite coating above recorded the highest values compared with that for base coating of pure nickel (395.2Hv). The corrosion rate of the coated specimen (Ni-Al2O) nanocomposites coating was improved with excellent at of different concentrations of alumina nanoparticles by the electroless deposition technique at the concentrations. (4.25 and 1.25 g / l) which the corrosion rate (81.9 mpy and 94.4 mpy), respectively. It is lower than the corrosion rate of the Ni- pure coated sample (254.8 mpy) The corrosion rate of the coated specimen (Ni–MWCNT) nanocomposites coating was enhanced at concentration (4.25%wt and 1.25%wt) and the corrosion rate results (117.5 mpy and 152mpy) respectively. For (Ni- ZrO2) nanocomposites coating at concentrations (4.25%wt and 1.25%wt), the corrosion rate of coating was improved (143mpy and 190 mpy),respectively. Regarding the results of the ions release for the substrate coated by electroless (Ni-Al2O3, ZrO2) nanocomposites coating, the results of the coating analysis of elements (Ni, Fe, Al, and Zr) for the added concentrations (1.25% wt, 2.25% wt, and 4.25% wt). Showed the presence of ions release in the immersion tests for ( 3 and 7 ) days in Ranger’s solution was found within the permissible limit according to the quantity of nickel with the amount of iron allowed to exist within the human body.  Concerning the ions release for different embedded concentrations (1.25%wt, 2.25%wtand 4.25%wt) for MWCNTs, it was observed that the carbon ions release in the immersion tests for (3 and 7) days in Ranger’s solution increased with increasing concentration of MWCNTs and with the increase of immersion time. These amounts of carbon ions release cause toxicity inside the body.