This aim of this study is to assess the Tigris River sediments and utilize them as a new abrasive for the preparation of polished surface of magnetite ore to be studied under reflected light ore microscope. Such polishing process was tested using 250, 125, 71, 45, 25 and 18μm grain sizes of the river sediments. For the completion of the polishing and to obtain a glossy perfect polished surface, the 7 and 2.5 μm sized standard diamond pastes were used. After each polishing stage, the reflectance and roughness of these surfaces were measured as an evaluation step for the polishing efficiency. The reflectance values (R%) of the magnetite surface were found to be reversely proportioned to the abrasive grain size; while the surface roughness values (Ra) showed positive relationship with the grain size. The polished surface showed gradual improvement with decreasing grain size of the abrasive. The reflectance increased at a rate of 0, 0, 0.3, 1.2, 2.5, 3.7, 9.3, 20% with reducing grain sizes from 250, 125, 70, 45, 25, 18, 7 and 2.5 µm; at the same time, the roughness reduced at a rate of 72.2, 51.8, 23.7, 17.2, 10.9, 7.5, 6, 3.8 with reducing grain size. The 18 µm abrasive grain size of river sediments was found to be the best. Buffing by 2.5 µm diamond paste as the last stage, improved the polishing efficiency and resulted in 20% reflectance. Based on the obtained results, the Tigris sediments can be considered as fine-grained granules with the ability of preparing a flat, homogeneous surface with little roughness and reasonable degree of reflectivity.

Ore --- Abrasives --- Magnetite --- Reflectivity --- Surface roughness

Iron oxide(Fe3O4) nanoparticles of different sizes and shapes were synthesized by solve-hydrothermal reaction assisted by microwave irradiation using ferrous ammonium sulfate as a metal precursor, oleic acid as dispersing agent, ethanol as reducing agent and NaOH as precipitating agent at pH=12. The synthesized Fe3O4 nano particles were characterized by X-ray diffraction (XRD), FTIR and thermal analysis TG-DTG. Sizes and shapes of Fe3O4 nanoparticles were characterized by Scanning Electron Microscopy (SEM), and atomic force microscopy (AFM).

حضرت دقائق Fe3O4 النانوية من مختلف الأحجام والأشكال بطريقة المذيب-هيدروحرارية بواسطة إشعاع الميكروويف باستخدام كبريتات الأمونيوم الحديد كمصدر للفلز، وحامض الأولييك كعامل مشتت، والإيثانول كعامل مختزل وهيدروكسيد الصوديوم كعامل ترسيب في دالة الحموضة = 12. شخصت دقائق Fe3O4 النانوية من حيود الأشعة السينية (XRD)، تحليل الاشعة تحت الحمراءوالتحاليل الحرارية (TG-DTG). شخصت الحجوم والأشكال للدقائق النانوية Fe3O4 بواسطة المجهر الإلكتروني الماسح (SEM)، ومجهر القوة الذرية (AFM).

Magnetite --- microwave --- oleic acid --- SEM --- AFM --- مغناتايت، ميكروويف، حامض الأولييك،SEM، AFM.

Thin films of Magnetite have been deposited on Galvanized Steel (G-S) alloy using RF-reactive magnetron sputtering technique and protection efficiency of the corrosion of G-S. A Three-Electrodes Cell was used in saline water (3.5 % NaCl) solution at different temperatures (298, 308, 318 & 328K) using potentiostatic techniques with. Electrochemical Impedance Spectroscopy (EIS) and fitting impedance data via Frequency Response Analysis (FRA) were applied to G-S alloy with Fe3O4 and tested in 3.5 % NaCl solution at 298K.Results taken from Nyquist and Bode plots were analyzed using software provided with the instrument. The results obtained show that the rate of corrosion of G.S alloy increased with increasing the temperatures from 298 to 323K; and showed that deposition of Fe3O4 caused protection efficiency to reach 79.76% for G-S in 318K. In addition the enthalpy & entropy of activation were evaluated. Apparent energies of activation have been calculated for the corrosion process of uncoated and coated G.S alloy by sputtering technique in saline water (3.5 % NaCl). The morphological analysis was carried out using Scanning Electron Microscopy (SEM) technique.

تم في هذا البحث ترسيب غشاء رقيق من المغنتايت على سبيكة الحديد المغلون بأستخدام الموجات الراديويه – تقنية الترذيذ الماكتروني الفعال كطلاء حمايه,و درست كفاءة حماية التآكل للحديد المغلون في المياه المالحه (3.5% كلوريد الصوديوم)بأستخدام جهاز مقياس الجهد الساكن مع ثلاثة اقطاب, وبأستعمال جهاز قياس الممانعه الكهروكيميائيه الطيفي تم تحليل النتائج. أظهرت النتائج أن معدل سرعة التآكل للحديد المغلون بدون طلاء زاد بزيادة درجة الحراره (298-328) كلفن, و اظهرت النتائج أن ترسيب المغنتايت الناجم عن كفاءة حمايه بلغ 79.76% في درجة حراره 318 كلفن ,تم حساب قيم التغير في الانثالبي وطاقة التنشيط,حيث قدرت قيم الطاقات الظاهريه من التنشيط لعملية التآكل لسبيكة الحديد المغلون المطليه وغير المطليه في المياه المالحه (3.5% كلوريد الصوديوم), تم أجراء التحليل المورفولوجي بأستخدام تقنية المجهر الضوئي الالكتروني.

Corrosion protection --- Electrochemical Impedance --- Magnetite Nanoparticle --- Polarization --- Sputtering. --- حماية التآكل --- نانومغنتايت --- الترذيذ --- الأستقطاب --- مطيافية المعاوقه الكهروكيميائيه