scholarly journals The Structure and Properties of Ceramics, Obtained from Mixtures of the System ZrO2–Al–C

2022 ◽  
Author(s):  
S.I. Dzhelialov
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
Physical And Mechanical Properties ◽  
Initial Mixture ◽  
Structure And Properties

Abstract. The paper presents the results of the analysis of the structures of materials obtained as a result of hot pressing of mixtures of the ZrO2(m) –Al – С system of various compositions. The nature of the change in the composition and physical and mechanical properties of the obtained materials was established depending on the concentration of aluminum and carbon in the initial mixture, as well as the parameters of hot pressing.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Contribution of the hybrid component to the structure and properties of ceramics based on metastable phases Al2O3

2021 ◽  
pp. 127-136
Author(s):  
A. V. Maletsky ◽  
T. E. Konstantinova ◽  
D. R. Belichko ◽  
G. K. Volkova ◽  
V. V. Burkhovetsky
Keyword(s):  
Mechanical Properties ◽  
Yttrium Aluminum Garnet ◽  
Metastable Phase ◽  
Physical And Mechanical Properties ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Mutual Inhibition ◽  
X Ray ◽  
Tetragonal Lattice ◽  
Yttrium Aluminum

The paper presents results of the study of the effect of doping with yttrium oxide on ceramics of the composition (γ + θ) Al2O3 + nY2O3 (n = 0, 1, 2, 3 wt%), sintered at 1550°C for 2 h, from powders of the specified composition annealed at temperatures of 500 , 800, 1000°С. X-ray diffraction analysis established the formation in ceramics of yttrium aluminum garnet Y3Al5O12 (YAG) and a metastable phase of the same composition with a tetragonal lattice type in powders at temperatures above 1200°C. The effect of YAG on the physical and mechanical properties was established: high properties were demonstrated by ceramics of the composition α-Al2O3 + 2wt% Y2O3, obtained from a powder annealed at 1000°C. In addition, high physical and mechanical properties were observed in ceramics of the composition α-Al2O3 + 0wt% Y2O3, obtained from a powder annealed at 800°C. The effect of the so-called “mutual protection against crystallization” was discovered, which consists in the mutual inhibition of crystallization processes in powders of the Al2O3 – Y2O3 system.

scholarly journals Environmentally-Friendly High-Density Polyethylene-Bonded Plywood Panels

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1166 ◽  
Author(s):  
Pavlo Bekhta ◽  
Ján Sedliačik
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
High Density Polyethylene ◽  
Phenol Formaldehyde ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Core Layer ◽  
High Density ◽  
Pressing Pressure ◽  
Pressing Time

Thermoplastic films exhibit good potential to be used as adhesives for the production of veneer-based composites. This work presents the first effort to develop and evaluate composites based on alder veneers and high-density polyethylene (HDPE) film. The effects of hot-pressing temperature (140, 160, and 180 °C), hot-pressing pressure (0.8, 1.2, and 1.6 MPa), hot-pressing time (1, 2, 3, and 5 min), and type of adhesives on the physical and mechanical properties of alder plywood panels were investigated. The effects of these variables on the core-layer temperature during the hot pressing of multiplywood panels using various adhesives were also studied. Three types of adhesives were used: urea–formaldehyde (UF), phenol–formaldehyde (PF), and HDPE film. UF and PF adhesives were used for the comparison. The findings of this work indicate that formaldehyde-free HDPE film adhesive gave values of mechanical properties of alder plywood panels that are comparable to those obtained with traditional UF and PF adhesives, even though the adhesive dosage and pressing pressure were lower than when UF and PF adhesives were used. The obtained bonding strength values of HDPE-bonded alder plywood panels ranged from 0.74 to 2.38 MPa and met the European Standard EN 314-2 for Class 1 plywood. The optimum conditions for the bonding of HDPE plywood were 160 °C, 0.8 MPa, and 3 min.

Preliminary Research on Manufacturing Technology of Thin Bamboo Veneer Consolidated Composite Floor

2012 ◽  
Vol 503-504 ◽  
pp. 74-77
Author(s):  
Nan Hu ◽  
Xian Jun Li ◽  
Yi Qiang Wu ◽  
Xin Gong Li ◽  
Zhi Cheng Xue
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Bond Strength ◽  
Hot Pressing ◽  
Physical And Mechanical Properties ◽  
Pressing Pressure ◽  
Pressing Temperature ◽  
Decorative Material ◽  
Preliminary Research ◽  
Surface Bond

In this paper, the new bamboo-based consolidated composite floors were fabricated with thin bamboo veneers which used as decoration layers, wear resistant layers, high density fiberboards and equilibrium layers through assembling and scuffing. The effect rules of the composite floor on properties were preliminarily studied by three factors: hot-pressing temperature, pressure and time. The results showed that the wear resistance and surface bond strength of the thin bamboo veneer consolidated composite floor significantly increased with the rise of hot-pressing temperature. In the scope of resources, the effect of hot-pressing pressure and time on properties of the floor is not significant. The optimizing technology is hot-pressing temperature 170°C, pressure 3MPa and time 40s/mm in this study. The thin bamboo veneer consolidated composite floor is an excellent floor decorative material, which has good physical and mechanical properties.

Evaluation of the Influence of Pre-Alloyed Powder Fe65Nb on the Production of Metal Matrices by Powder Metallurgy

2020 ◽  
Vol 1012 ◽  
pp. 3-8
Author(s):  
A.C.G. Silva ◽  
Hellen C.P. Oliveira ◽  
Thales Eduardo Leal ◽  
Paulo Santos Assis
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Chemical Composition ◽  
Solid State ◽  
Hot Pressing ◽  
Physical And Mechanical Properties ◽  
Toxic Element ◽  
Alloyed Powder ◽  
Eds Analysis ◽  
Porosity Measurements

The objective of this paper is to study Fe65Nb-Cu metal matrices, thus varying the content of the pre-alloyed Fe65Nb powder from 10% to 100%. Therefore, powders of Fe65Nb and Cu were used, innovating in the chemical composition of the commonly used matrices. The objective is to evaluate the substitution of Co (toxic element, commonly used) by Nb (98.2% of reserves are Brazilian). For the sintering of the samples it was used hot pressing technique. The parameters were set at: 850°C / 35MPa / 3min. The sintered bodies underwent SEM/EDS analysis and density and porosity measurements were performed. From the results it is possible to say that the compositions of (10% and 30% Fe65Nb) presented the best physical and mechanical properties. The relative density decreases for the compositions with 40%, 50% and 60% Fe65Nb is justified by the presence of fragile particles in metal matrices, since they require more energy in order to efficiently transport matter (diffusion) in a solid state.

Fabrication of Porous Polyethylene by Two-Stepped Heat Treatment and Powder Printing Technique

2010 ◽  
Vol 93-94 ◽  
pp. 165-168 ◽  
Author(s):  
Jintamai Suwanprateeb ◽  
Kitiya Wasoontararat ◽  
Waraporn Suvannapruk
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Density Polyethylene ◽  
Physical And Mechanical Properties ◽  
High Density ◽  
Processing Conditions ◽  
Structure And Properties ◽  
Porous Polyethylene ◽  
Printing Technique ◽  
The Relationship

In this study, a combination of powder printing technique and two-stepped heat treatment was utilized as a mean to prepare porous high density polyethylene structure. Physical and mechanical properties of the resulting structure were then characterized by porosity measurement and monotonic tensile test. It was found that the relationship between structure and properties was strongly influenced by processing conditions including compositions, treatment times and treatment temperatures. This process could increase the properties of porous high density polyethylene significantly over the single-stepped heat treatment without destroying porous structure. Porous high density polyethylene bodies having a porosity ranging from 46-58 percents with tensile strength up to approximately 4 MPa could be successfully prepared in this study.

Study on Physical and Mechanical Properties of Cu/MoS2 Composites

2013 ◽  
Vol 575-576 ◽  
pp. 156-159
Author(s):  
Dou Qin Ma ◽  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Ai Qin Wang ◽  
Wen Yan Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Diffraction Analysis ◽  
Electric Conductivity ◽  
Hot Pressing ◽  
Physical And Mechanical Properties ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vacuum Hot Pressing

Cu-3wt. %MoS2-7wt. %Mo and Cu-3wt. %MoS2 composites were prepared by repressing, re-sintering and vacuum hot pressing, respectively. Microstructures were characterized by optical metallographic microscope, EDS, SEM and X-ray diffraction analysis, respectively. The micro hardness, electric conductivity and density of samples were separately measured as well. Results show that the micro hardness of Cu-3wt. % MoS2-7wt. % Mo composites is about 33.3% higher than that of Cu-3wt. %MoS2 composites. The increase in micro hardness is attributed to the presence of Mo. The electric conductivity of Cu-3wt. %MoS2 and Cu-3wt. %MoS2-7wt. % Mo prepared by vacuum hot pressing were 80.6 % and 63.8% IACS, respectively, which is an increase compared with values of 80.2 % and 57.3% IACS of samples obtained by repressing and re-sintering.

scholarly journals SYNTHESIS OF STRUCTURES OF CELLULAR-CONCRETE COMPOSITES WITH NANOSIZED COMPONENTS

Vestnik MGSU ◽  
2017 ◽  
pp. 733-740
Author(s):  
Valentina Anatol'yevna Solonina ◽  
Galina Alexandrovna Zimakova ◽  
Dmitriy Sergeevich Baianov ◽  
Pavel Valer'evich Sharko ◽  
Marina Petrovna Zelig
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Pore Structure ◽  
Physical And Mechanical Properties ◽  
Structure And Properties ◽  
Integrated Research ◽  
High Calcium ◽  
Nanopore Structure ◽  
Matrix Stone ◽  
Cellular Concrete

The article reveals the results of one of the stages of the integrated research studying the influence of compounds and disperse characteristics of silica-containing materials on structure formation and qualities of cellular concrete. It has been indicated that the improvement of physical and mechanical properties of cellular concrete can be achieved through creating the best possible pore structure of the concrete and the structure of interporous frame as well as intensification of hydration and crystallization processes under hydrothermal treatment and, as a result, the increase in number and perfecting morphology of hydrated phases. Up-to-date knowledge about the structure and properties of cellular concrete shows potential capacities to enlarge strength characteristics through forming a nanopore structure of a matrix stone, the effective usage of power potential of multicomponent binding including Portland cement, high-calcium lime, activate silica components with grains of submicron and nanometer range.

scholarly journals Conversion of low-quality cotton to bioplastics

Cellulose ◽  
2021 ◽  
Author(s):  
Shaida S. Rumi ◽  
Sumedha Liyanage ◽  
Noureddine Abidi
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
Value Added ◽  
Physical And Mechanical Properties ◽  
Analytical Techniques ◽  
Solvent System ◽  
Cotton Fibers ◽  
Cellulose Films ◽  
Viable Solution ◽  
Amorphous Structures

AbstractThe use of eco-friendly bioplastics has become a viable solution to reduce the accumulation of petrochemical products in the biosphere and to decrease microplastic contamination. In this study, we used low-quality cotton fibers that lack textile applications to prepare bioplastics. We dissolved cotton fibers in N,N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system and converted cellulose solutions to strong, transparent, and flexible films through casting, gelation, regeneration, plasticization, and hot-pressing. Films were characterized using different analytical techniques to evaluate their physicochemical and mechanical properties. Compared to raw cotton cellulose, regenerated and hot-pressed cellulose films showed amorphous structures and excellent tensile characteristics. The physical and mechanical properties of cellulose films, such as deformation recovery, flexibility, homogeneity, elongation, and surface roughness, were significantly improved by means of plasticization and hot-pressing. Because glycerol plasticization increased the surface hydrophilicity of the films, plasma-induced surface grafting of oleic acid imparted hydrophobicity to cellulose films. This study presents a new avenue for using low-quality cotton fibers that are usually sold at a discounted price to produce value-added bioproducts for different applications. Graphic abstract

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