Modification of plasma-generated SiC nanoparticles by heat treatment under air atmosphere

2021 ◽  
pp. 163507
Author(s):  
Cheng Wang ◽  
Jiawen Zhou ◽  
Ming Song ◽  
Xianhui Chen ◽  
Yan Zheng ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Sic Nanoparticles ◽  
Air Atmosphere

Reduction of Gd6UO12 for the Synthesis of Gd6UO11

2013 ◽  
Vol 1514 ◽  
pp. 151-156
Author(s):  
Darío Pieck ◽  
Lionel Desgranges ◽  
Yves Pontillon ◽  
Pierre Matheron
Keyword(s):  
Heat Treatment ◽  
Xrd Analysis ◽  
Decomposition Products ◽  
Air Atmosphere ◽  
Reducing Conditions ◽  
Reducing Environment

ABSTRACTIn the present work, we focus on δ-Gd6UO12 phase and its stability under reducing conditions. This later point is interesting regarding reducing environment that could exist in some nuclear storage sites and that could possibly degrade δ–compounds. A polycrystalline δ-Gd6UO12 sample was prepared by sintering cubic-Gd2O3 and UO2 mixed powders under an air atmosphere. The resulting pellets were then characterized and reduced by heat treatment under an Ar with H2 5% atmosphere. XRD analysis of the sample after reduction did not confirm the reduction into Gd6UO11 but a decomposition of the δ-compound. Preliminary characterizations of these decomposition products are presented.

scholarly journals Influence of Heat Treatment on the Corrosion Resistance of Aluminum-Copper Coating

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 966
Author(s):  
Mieczyslaw Scendo ◽  
Slawomir Spadlo ◽  
Katarzyna Staszewska-Samson ◽  
Piotr Mlynarczyk
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Corrosion ◽  
X Ray Diffraction ◽  
Air Atmosphere ◽  
Cu Alloy ◽  
Acidic Chloride Solution ◽  
Acidic Chloride ◽  
Electrical Discharge Alloying

Influence of heat treatment on the corrosion resistance of the aluminum-copper (Al-Cu) coating on the aluminum substrate was investigated. The coating was produced by the electrical discharge alloying (EDA) method. The surface and microstructure of the specimens were observed by a scanning electron microscope (SEM). The phase analysis of the composite materials by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) indicated that intermetallic compounds (i.e., CuAl2 and Cu9Al4) were formed through reactions between Al and Cu. during the EDA process. A significant increase in the hardness of the Al-Cu coating was affected by the improvement of the alloy structure. The heat treatment of materials was carried out at 400 °C or 600 °C in the air atmosphere. A corrosion test of materials was carried out by using electrochemical methods. The corrosive environment was acidic chloride solution. After heat treatment at 400 °C the mechanical properties of the Al/Cu alloy increased significantly and the oxide layer protect of the alloy surface against corrosion. However, after heat treatment at elevated temperature, i.e., 600 °C it was found that the (Al2O3)ads and (CuO)ads coatings were destroyed. The mechanical properties of the Al/Cu alloy decreased, and its surface has undergone deep electrochemical corrosion.

Degradation of Mechanical and Structural Properties of Steel T23

2007 ◽  
Vol 567-568 ◽  
pp. 389-392 ◽  
Author(s):  
Marie Svobodová ◽  
Jindřich Douda ◽  
Jiří Kudrman
Keyword(s):  
Heat Treatment ◽  
Structural Properties ◽  
High Temperatures ◽  
Base Material ◽  
Experimental Results ◽  
Air Atmosphere ◽  
Mechanical And Structural Properties ◽  
Long Time ◽  
Initial Heat ◽  
Initial Heat Treatment

This paper deals with changes in mechanical and structural properties of Steel T23 during long-time annealing at high temperatures. The research is focused on the degradation of the base material (steel T23), where the samples of steel, after the initial heat treatment, were annealed at temperatures of 600, 650 and 700 °C for 10 to 10 000 hours in a furnace with air atmosphere. This contribution summarizes the experimental results of mechanical and structural measurements and gives the relations between them.

Preparation of ZrB2 Powders with Different Morphologies by Pressureless Reactions

2016 ◽  
Vol 697 ◽  
pp. 39-43
Author(s):  
Wan Xiu Hai ◽  
Yi Hui Huang ◽  
Yong Jiang ◽  
Zhen Bang Wei
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Raw Materials ◽  
Reaction System ◽  
Muffle Furnace ◽  
Reaction Systems ◽  
Air Atmosphere ◽  
Chemical Reaction System ◽  
Particle Size And Morphology ◽  
Size And Morphology

The ZrB2 powders with different morphology were prepared by pressureless reactions, using ZrO2, B2O3, B4C, and graphite as raw materials. Three kinds of chemical reaction system were employed. The ratio of raw materials and reaction temperature were adjusted to prepare ZrB2 powders of different morphology and particle size. The phase composition and purity of the as-prepared powders were analyzed by XRD, while the morphology and particle size were analyzed by SEM. The ZrB2 powders were purified by removing impurities at 600 °C in a muffle furnace in air atmosphere. The results showed that in the reaction systems of ZrO2-B2O3-C and ZrO2-B4C-C, the ZrB2 could be generated at 1500 °C. The morphology of the as-prepared ZrB2 powders were particles, rod-like or near spherical for ZrO2-B2O3-C system and particles for ZrO2-B4C-C system. In the reaction system of ZrO2, B2O3, B4C, and C with a mole ratio of 3:2:1:8, the ZrB2 powders with high purity could be produced at 1700 °C. The ZrB2 powder was near spherical. After heat treatment, the particle size and morphology changed to some extent.

Change in Residual Stress of TiN Coating Material during Heat Treatment in an Air Atmosphere

2015 ◽  
Vol 1110 ◽  
pp. 125-129
Author(s):  
Tatsuya Matsue ◽  
Masayuki Nishida ◽  
Takao Hanabusa
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Bias Voltage ◽  
Heating Temperature ◽  
Cutting Tools ◽  
Tin Films ◽  
Air Atmosphere ◽  
Tin Film ◽  
Temperature State ◽  
High Bias

TiN films are widely used as strengthening coatings for cutting tools. In a previous study, the crystal structure of TiN films deposited by arc ion plating was found to be strongly influenced by the bias voltage during deposition. The TiN films deposited under a high bias voltage were found to have a high compressive residual stress of-9.5 GPa. The residual stresses of the TiN films relaxed to thermal stress levels upon annealing. In the present study, the authors investigate the relaxation of the residual stress during heat treatment in atmosphere for TiN films with different initial residual stress values. The surface layer of the TiN films is oxidized by heat treatment in an air atmosphere. However, the crystalline state of the TiN films is hardly affected. So far, the residual stress of the TiN film hardly changes in a temperature state lower than the heating temperature when it is relaxed by heat treatment.

Effect of Heat-Treatment on the Properties of PBO Fibers

2017 ◽  
Vol 898 ◽  
pp. 2107-2117 ◽  
Author(s):  
Xiao Lin Zhu ◽  
Wei Hua Zhong ◽  
Zi Ming Jin ◽  
Peng Zhang ◽  
Zhong Ren Guo ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Nitrogen Atmosphere ◽  
High Modulus ◽  
Air Atmosphere ◽  
Process Route ◽  
High Tension ◽  
Resident Time ◽  
Pbo Fiber ◽  
Time Required

PBO fiber is a kind of super fibers which has both high tension strength and high modulus. After the heat-treatment procedure, the PBO fiber would present more perfect mechanical properties. The process route of heat-treatment on as-spun fibers (PBO-AS fibers) was optimized, and the obtained high modulus fibers (PBO-HM fibers) were tested and characterized by SEM, XRD, XPS, FT-IR and Universal material machine. The higher the temperature is, the shorter the heat treatment time required for the same heat treatment. And the most preferred procedure in the air atmosphere of heat-treatment was 550°C with the resident time of 32 s and the pre-stress of 2.35 cN/dtex. After the heat-treatment, the modulus of PBO-HM grew up to 229.4 GPa (1487.78 cN/dtex). The tensile strength would not be greatly decreased, if the fiber could be kept in the nitrogen atmosphere. Besides, the XRD data and the XPS data proved that after the heat-treatment, the crystal size and the crystallinity would have a huge growth and the content of phosphorus element on the surface of PBO-HM fibers would fall sharply.

Centrifugal Casting Practice and Microstructure and Mechanical Properties of a 2205 Duplex Stainless Steel

2005 ◽  
Vol 475-479 ◽  
pp. 2527-2532 ◽  
Author(s):  
Sang Mok Lee ◽  
S. Yang ◽  
S.T. Kim ◽  
Y.S. Park ◽  
B.M. Moon
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cooling Rate ◽  
Centrifugal Casting ◽  
Corrosion Properties ◽  
Σ Phase ◽  
Air Atmosphere ◽  
Treatment Conditions

Microstructural features, mechanical properties, and corrosion properties of a SAF2205 duplex stainless steel (DSS) were systematically investigated as functions of cooling rate during casting and heat treatment conditions. The choice of a duplex stainless steel was a SAF2205 alloy, of which composition is 0.03C, 21~23Cr, 4.5~6.5Ni, 2.5~3.5Mo, 0.08~0.2N, 1.0Si, and 2.0Mn with remaining Fe. A 5-stepped sand mold and the permanent Y-block mold were used to check the effect of cooling rate during solidification. The microstructural characteristics, such as grain size, the d/γ ratio, the existence of the carbides and σ phase has been noticed to greatly change with the variation of cooling rate during the casting procedure. Various heat treatment conditions were also examined to achieve the optimized mechanical properties of DSS. Based on the preliminary examination, the feasibility study of utilization of centrifugal casting has been carried out for the production of better quality DSS pipe components. Melting and casting practices of DSS during centrifugal casting in an air atmosphere were systematically investigated in order to obtain the optimized process parameters.

scholarly journals Peculiarities of ion-exchange in poled glasses

2021 ◽  
Vol 2086 (1) ◽  
pp. 012152
Author(s):  
E A Lubyankina ◽  
D V Raskhodchikov ◽  
E S Babich ◽  
V P Kaasik ◽  
A A Lipovskii
Keyword(s):  
Heat Treatment ◽  
Ion Exchange ◽  
Subsurface Layer ◽  
Silver Ions ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Air Atmosphere ◽  
Corona Poling ◽  
Thermally Poled ◽  
First Time

Abstract We demonstrate for the first time that the results of ion exchange processing of thermally poled soda-lime glass essentially depend on the poling conditions. In particular, the processing of vacuum-poled soda-lime glass in silver-sodium nitrate melt results in the diffusion and reduction of silver ions followed by clustering silver nanoparticles in the subsurface layer of the glass after either ion-exchange or additional heat treatment of the ion-exchanged samples. Poling in air atmosphere with deposited gold film anode prevents silver ions penetration in the glass, but electric field stimulated diffusion of gold in this configuration leads to the formation of gold nanoparticles in the glass after heat treatment. It is also shown that corona poling of the glass in air atmosphere does not completely block silver penetration.

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