The aim of this work is to improve the microstructure, the morphology, the mechanical and the corrosion behavior of Zn-Ni layers electrodeposited on low alloy carbon steel. Some factors such as the nickel concentration in the electrolyte, the electrolyte temperature and the current density are studied and optimized. The efficiency of the layers to protect the low alloy carbon steel against corrosion in HCl solution is also studied in this work. The electrodeposited Zn-Ni layers morphologies and microstructure were investigated by Scanning Electronic Microscopy (SEM) and X-ray diffraction (XRD) respectively. The best deposits of Zn-Ni layers are obtained with 50%-Ni in the electrolyte bath at a temperature of 40°C and a current density of j = 3 A dm-2. The XRD spectrum showed the coexistence of two phases: δ-phase (Ni3Zn22) and γ-phase (Ni5Zn21), and a pyramidal morphology is detected by SEM. The lost mass method results showed that the corrosion rate tacked a steady state between 10 and 50% of Ni, and it increased with the increase of Ni amount in the electrolyte bath.

The objective of this research is to study the influence of film thickness on the optical and electrical properties of prepared NiO thin films. Nickel oxide thin films have been prepared on the glass substrates by a spin coating technique using nickel nitrate hexahydrate (Ni(NO3)2.6H2O) as a source of materials. The coating process was repeated 11, 13, 15, and 17 layer times to obtain a good NiO thin film. The optical and electrical characterizations were observed to be dependent on each film thickness. The smaller layers have a high optical transmission (over 88%) in the visible range. The bandgap energy was found to be in the range of 3.94–4.06 eV depending on the film thickness. The lowest value of Urbach energy was 0.182 eV. The electrical measurements are investigated by the four-point method; the results show that good electrical conductivity was found for the sample with a thickness around 171 nm.

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

The aim of this research is to study four samples using the fluoroplastic scanning calorimeter which contain different concentrations of thermally extended graphite (GTD) in different dispersions. We noticed that the heating speed plays a very important role. Increasing the heating speed from 5 to 10 then 15 °C/min, changes the thermal behavior of an infinitesimally small compound regardless of the concentration and/or dispersion. All curves each contain an anomaly in the calorimetric curves. The shape of the latter, its energizing energy, and its intensity depend on the concentration and dispersion. The temperature of anomalies in the calorimeter curve changes from one sample to another. We have shown that nanomaterials that contain the smallest GTD concentration with high dispersion and heat up at the highest heating speed deteriorate at high temperatures. It is more resistant to thermal shocks. One of the interesting results of this work the introduction of an amount of GTD in to the polymer improves the thermal properties of the infinitesimal compound, and its use becomes possible in a wide range of temperature.

In this work, we have studied the Kaolin M1 and M2 by the X-ray diffraction method, and we have focused on mullite phase which is the main phase present in common in both products. An update of the program of the method of Stokes was carried out, it was necessary to the microstructural analysis. The completed version is less sensitive to the choice by excess of the number of coefficients of Fourier with regard to the effect of truncation and the office plurality of the errors. The determination of the symmetry of the cell of the principal phase (mullite) in the studied fritted Kaolins was carried out. In Kaolin M1, the size of crystallites of the dominant phase varies between 80 to 170 Å. In Kaolin M2, the size of the crystalline grains of mullite varies between 100 to 400 Å. The size of crystallites was confirmed by the joint method of Williamson-Hall. A distribution of sizes of crystallites was carried out. It shows a dominance of the size of approximately 140 Å for the principal phase of Kaolin M1 and a dominance of the size of approximately 230 Å for the same principal phase of Kaolin M2. By the study of the profiles of line by DRX, it appears very clearly that the principal phase of the various sintered Kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted not only at low temperature (1100℃) during 1 hour but also the case of the mixtures of the type ‘chamotte’ cooks with 1350℃ during very long times.