Keywords : Nano Particles
Studying the Effect of Nano Additives and Coating on Some Properties of Cement Mortar Mixes
Engineering and Technology Journal,
2016, Volume 34, Issue 3, Pages 553-566
The experimental work is divided in two parts, in the first part was prepared the mortar samples and mixing proportions cementsand (1:3)they were mixing these samples with nano scale ceramic powders (ZrO2 and TiO2) respectively the percentages by weight are taken from cement ratio (0.1, 1, 2.5, 5, and 10%) at particle size (50nm) and curing time (28day). The second part has included the preparation of mortar samples and then coated with a mixture of methanol alcohol, cement and ceramic nano-powders by cold spray technique by using compressed air at room temperature with pressure (8bar) and the spray distance (20Cm) and heating of the samples at (75C°), and then study mechanical thermal physical and structural properties for prepared samples.
The results of mechanical and physical tests showed large and significant improvement for all mixed and coated samples with nanoparticles, and that the highest value of the mechanical and physical properties obtained from cement coated samples with (%5ZrO2), reaching the rate of increase in values of Vickers hardness by (%54), and wear resistance increased by (%66), while reaching the rate of decrease in values of total water absorption by (%79), The porosity has decreased at a rate of (%65), With regard to the dry density has increased at a rate of (%2.3). The higher values for the mixed samples reaching the rate of increase in values of Vickers hardness by (%38), and wear resistance increased by (%58), while reaching the rate of decrease in values of total water absorption by (%67), The porosity has decreased at a rate of (%51.68), With regard to the dry density has increased at a rate of (%1.9).
The thermal conductivity test results have shown that there is a marked decrease in values conductivity for all mixed and coated samples with nanoparticles and that the minimum value of conductivity obtained from coated and mixed samples with (%5TiO2) as the value decreases conductivity for coated samples by (%64), while the lowest value for conductivity to the mixed samples by (%49). Results of Characterizations tests showed images of all of (SEM and AFM) Mortar reference sample that a high roughness as well as having to structure Ca(OH)2 a needle shaped structures with the presence of large pores, while after adding and coating by nanoparticles shows the disappearance of structures needle and produce a homogeneous structure of compounds (C-S-H) and the disappearance of the pores and gaps further decrease in surface roughness this explains the clear improvement in the properties.
Preparation and Characterization of Teo2 Nan particles by Pulsed Laser Ablation in Water
Engineering and Technology Journal,
2014, Volume 32, Issue 3, Pages 396-405
Tellurium dioxide (TeO2) nanoparticles were synthesized directly by pulsed laser ablation using Nd:YAG, λ=1064nm laser in pure water. The AFM and XRD measurements, in combination with FTIR and UV–Vis spectroscopy have been employed for the characterization of the prepared samples. The effects of operating parameters on nanoparticles composition, production rate and size were also studied. The XRD measurements revealed crystallization structure of TeO2 nanoparticles. The particle diameter by use of Scherer's equation was calculated to be about 28. nm and confirmed by AFM measurements. The UV–vis spectrum of the colloidal nanoparticles shows maximum absorbance around the UV region, indicating the formation of TeO2 nanoparticles, which confirmed by FTIR.