Due to respect for the environment and the search for more sustainable materials, scientists have started in recent decades to launch studies on bio-composite materials. It is well known that building materials are among the most commonly used materials and have an obvious negative impact on the environment. The development of environmentally friendly composites as insulating materials in buildings offers practical solutions to reduce energy consumption. Therefore, this work presents the use of a new bio-composite material composed of natural fibers, date palm fibers, cement, and sand. In addition, the study on the effect of adding date palm fibers on the thermo-mechanical characteristics of mortars assesses the thermal insulation properties as well as the water absorption and mechanical performance of this new bio-composite material to use it in the construction of buildings. The percentage by weight of date palm fiber in the test samples varied from 0% to 30% for a fiber size of length equal to 7 mm. The characteristics of these samples were determined experimentally in terms of resistance to bending and compression as well as thermal conductivity. The results show that while increasing the weight of date palm fiber, an obviously reduction in thermal conductivity, flexural, and compressive strength of the composite is observed. Hence, date palm fiber has a positive effect on the thermo-mechanical properties of the composite material. Therefore, it considerably improves the insulating capacity of the mortar.

The alumina-titania coatings produced by atmospheric plasma spraying are being developed for a wide variety of applications that require resistance to wear, erosion, cracking, and spallation. Consideration of parameters setting will develop reliable coatings with high performance properties for demanding coating application. Al2O3-3 wt% TiO2 was used as the main coating. Ni 20%Cr6Al powder was used as bond coat coating onto AISI 304 stainless steel substrate using Sulzer-Metco plasma spray system 9MC equipment. DOI: 10.12693/APhysPolA.132.538 PACS/topics: alumina-titania coatings, atmospheric plasma spraying, 304 stainless steel, process parameters, SEM, microstructure 1. Introduction Plasma-sprayed ceramic coatings are widely used for structural applications in order to improve resistances to wear, friction, corrosion, and oxidization [1,2]. In atmospheric plasma spraying (APS), one of many plasma spray methods [3], a coated layer is formed on a substrate surface by spraying melted powders onto a substrate at a high speed using a high-temperature plasma jet [4,5]. Powder grains are transported within a carrier gas at high temperature and high speed, injected into plasma jet. The melting powder is transferred to the substrate surface being coated and after impact; lamellar layer formation occurs [6][7][8]. Alumina (Al 2 O 3 ) and mixed alumina with titania are widely used in plasma sprayed as coating materials. The high hardness of alumina properties contributes to wear resistant coating and electrical insulation properties. Alumina is also highly thermal conductivity insulated for any substrate. Alumina with approximately 3 wt% titania is used extensively as wear resistance coating. The different coating microstructures and properties are depending on the spray technique, powder properties and spray parameters of the coating [9][10][11]. The coating conditions such as porosity, closed pores and unmelted particles are always the cause of defects in coatings. There are advanced tests or performance tests techniques of plasma sprayed ceramic coatings in order to determine the coating properties such as mechanical tests. A number of works for different purposes were also performed on different types of steel [12][13][14].In the present work, alumina-3 wt% titania coatings are deposited on AISI 304 stainless steel substrates with an intermediate bond coat of Ni20Cr6Al by atmospheric plasma spraying. The effects of the plasma variables setting such as the powder flow rate, current and standoff-distance on the microstructure and adhesion strength were investigated.

In this article, the relations between the formed shapes and process parameters had been studied for 3D laser forming of sheet metals. The investigation was performed on Stainless 1Cr18Ni9Ti sheet using a Nd:YAG laser source. The scanning strategies were being investigated to potentially achieve a more uniform temporal and spatial distribution of the laser energy, possibly leading to reduced part distortion, by scanning the beam across the sheet surface with both continuous and segmented irradiation geometries. The experimental results revealed that the cross spider scanning strategy could form square and circle sheets into spherical domes. And the radial lines scanning strategy could form rectangle sheets into saddle shapes. It was also apparent from the experimental results that the height of the center of the formed sheet increased with the increasing of the laser power and scanning numbers. The height of the formed square sheet firstly decreased with the laser scanning velocity increasing and began to decrease at a certain processing parameters by cross spider strategy, in which the circle sheet was opposite with the square sheet, and in which the rectangle sheet decreased with speed increasing.

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The present study has been conducted in order to obtaining chromium boride layers on carbon steel using a conversion processing comprising the following steps: boriding treatment in order to increase the amount of boron atoms in the steel surface, deposition of a thin layer of pure chromium using electrolytic method, and finally an annealing treatment for boron diffusion and formation of boride layer until complete transformation of chromium layer. Depending on the method used (chromium deposition followed by boriding or boriding followed by chromium deposition) and the holding time, the partial or complete conversion is obtained as a result of the diffusion process. The role of the annealing temperature on transformation rates of chromium into chromium boride films was investigated. It is shown that for 1 h at 900• C, the chromium layer is totally transformed. The scanning electron microscopy analysis and X-ray diffraction showed the presence of CrB and CrB2 chromium borides in addition of FeB and Fe2B iron borides.