Anodic Synthesis of α-PbO2-CeO2-TiO2 Composite Materials from Colloidal Electrolyte: Morphology, Composition and Structure of PbO2-Matrix Composites

2011 ◽  
Vol 308-310 ◽  
pp. 728-733
Author(s):  
Bu Ming Chen ◽  
Zhong Cheng Guo ◽  
Hui Huang
Keyword(s):  
Electrocatalytic Activity ◽  
Fine Particles ◽  
Surface Composition ◽  
Lead Dioxide ◽  
Solid Particles ◽  
Matrix Composites ◽  
Pure Lead ◽  
Surface Areas ◽  
The Matrix ◽  
Unit Cells

During electrodepositing pure lead dioxide, the electrocatalytic activity of PbO2 electrodes, as well as their stability, can often be considerably enhanced by the incorporation of some fine particles added to the electrodeposition. The morphology, crystal phase, surface composition, microstructure, of the electrode were characterized by means of SEM, XRD and EDS. SEM-EDS analysis showed the addition of solid particles could inhibit the growth of α-PbO2 unit cells, improving the specific surface areas of coating surface.Under all condition, the matrix was highly oriented α-PbO2. The electrocatalytic activity of the prepared materials has been tested in Zn2+ 50g L-1, H2SO4 150g L-1 solution. It showed that the electrocatalytic activity of the A1/conductive coating/α-PbO2-3.71 wt.% TiO2-2.12 wt.% CeO2 anode is the best.

A Review on In Situ Synthesis of Al/TiC and Al/SiC-Composites

2016 ◽  
Vol 684 ◽  
pp. 287-292 ◽  
Author(s):  
Hrusikesh Nath
Keyword(s):  
Fine Particles ◽  
Matrix Composites ◽  
Homogeneous Microstructure ◽  
Large Particles ◽  
The Matrix ◽  
Matrix Reinforcement ◽  
Sic Composites ◽  
Al Matrix Composites ◽  
Al Matrix

The in-situ synthesis of ceramic particles in Al-matrix composites gives an uniform and homogeneous microstructure. The matrix reinforcement interface is compatible with the matrix, interface is clean and provides good interface bonding. The evenly distributed sub micron sized reinforcement particles in Al-matrix enhances the strength and toughness of the composite. The formation of particle clusters and agglomerations are minimized or eliminated by suitably choosing the in-situ process parameters. Large particles and agglomerate are easily fractured where as evenly distributed fine particles are resistant to crack propagation and improves the strength of the composites. The problem encountered with the formation of secondary intermetallic Al3Ti and Al4C3 phases are addressed.

Mechanical Behavior of Reactively Hot-Pressed Aluminide Matrix Composites

1996 ◽  
Vol 460 ◽  
Author(s):  
M. Inoue ◽  
K. Suganuma ◽  
K. Niihara
Keyword(s):  
Fracture Toughness ◽  
Hot Pressing ◽  
Fine Particles ◽  
Relaxation Effect ◽  
Matrix Composites ◽  
Ambient Temperatures ◽  
Environmental Embrittlement ◽  
The Matrix ◽  
Al Matrix Composites ◽  
Al Matrix

ABSTRACTFeAl and Ni3Al matrix composites containing various fine particles were fabricated successfully by reactive hot-pressing. The strength and the fracture toughness of these composites at ambient temperatures were evaluated. The addition of β-SiC particles was effective for strengthening of the Fe-40at%Al matrix, however, an extreme decrease of fracture toughness occurred due to the suppression of stress relaxation effect by plastic deformation at a crack tip. The fracture toughness of the reactively hot pressed Fe-40at%Al and its composites was also affected by the environmental embrittlement effect. TiB2 and ZrB2 particles in the Fe-40at%Al matrix composites were clarified to play a role in the reduction of the environmental effect. For the Ni-25at%Al matrix, higher flexural strength was achieved by the addition of TiB2, TiC and TiN particles. TiB2 particles reacted with the matrix during hot-pressing. The Ni-25at%Al/TiB2 composite had a fracture strength of 1.5 GPa in spite of large grain size of the matrix. TiC and TiN were the best choices as effective reinforcing matrials for the Ni3Al matrix among the chemical compatible ones.

CONTRIBUTION OF THE INTERPHASE INTERACTION TO THE INTERNAL ENERGY AND THERMODYNAMIC PROPERTIES OF DISPERSED MATRIX COMPOSITES

2011 ◽  
Vol 25 (11) ◽  
pp. 781-799
Author(s):  
V. S. BORISOV
Keyword(s):  
Heat Capacity ◽  
Internal Energy ◽  
Solid Particles ◽  
Colloid Solution ◽  
Additional Contribution ◽  
Matrix Composites ◽  
Interphase Interaction ◽  
Proposed Model ◽  
The Matrix ◽  
Interphase Boundaries

This paper is devoted to the analysis of physical processes in composite matrix materials whose properties are greatly affected by the interphase interaction of the matrix and the modifier. Contribution of this interaction to thermodynamic and dielectric properties of such materials is investigated by the example of a model system which is a colloid solution of solid particles with charged surface in a polar liquid. Mechanisms underlying formation and stabilization of specific structures near the interphase boundaries of the examined system are discussed. Special attention is paid to the assessment of additional contribution to the internal energy and heat capacity related to the electric interaction of solid and liquid components. Results obtained within the proposed model show that for a certain concentration of liquid (about several percent) the interphase energy in a unit of volume magnificently increases to the values of about 107–108 J/m3 and therefore exceeds heat motion energy of polar molecules. Moreover it was revealed that the electrical part of heat capacity is comparable to self-capacity of the liquid matrix provided that the surface charge density of solid particles is high enough.

scholarly journals Characterization of Microstructure and Hardness of Aluminum Alloy Matrix Composites Reinforced with Boron Fiber (Coarse and Fine) Particles Prepared by Powder Metallurgy Technique

2019 ◽  
Vol 8 (12) ◽  
pp. 5437-5444
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Powder Metallurgy ◽  
Fine Particles ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Boron Fiber ◽  
The Matrix ◽  
Aluminum Alloy Matrix

Powder metallurgy is one of the best methods to achieve uniform distribution of reinforcement in to the matrix. In this Paper, characterization of microstructure and hardness of aluminum alloy matrix composites reinforced with boron fiber particles prepared by powder metallurgy technique are investigated. The effects of boron fiber (Coarse particles size of 120 µm and Fine particles size of 50 µm) on mechanical properties were studied. Increasing the reinforcement of boron fiber content with 5%, 10% and15% into the matrix improved the mechanical properties. The percentage of boron fiber reinforcement increasing the strength of the hardness number is also increasing simultaneously, the aluminum alloys and boron fiber particles on the microstructure and mechanical properties of the composites were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with Energy dispersive spectrum (EDS) analyses indicated. Analysis and observing microstructure of the composite is boron fiber particles are uniformly dispersed in the aluminum alloy matrix composites.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

Effect of graphene nano-platelets on mechanical and impact characteristics of carbon/Kevlar reinforced epoxy hybrid nanocomposites

2021 ◽  
pp. 095440622110168
Author(s):  
Mohamad Alsaadi ◽  
Bashar Younus ◽  
Ahmet Erklig ◽  
Mehmet Bulut ◽  
Omer Bozkurt ◽  
...  
Keyword(s):  
Impact Test ◽  
Charpy Impact ◽  
Hybrid Nanocomposites ◽  
Matrix Composites ◽  
Sem Images ◽  
The Matrix ◽  
Impact Characteristics ◽  
Positive Effect ◽  
Hybrid Carbon ◽  
Composite Samples

The influence of various graphene nano-platelets (GNPs) content on the tensile, flexural and Charpy impact characteristics of carbon, Kevlar and hybrid carbon/Kevlar fibers reinforced epoxy matrix composites was investigated. Both of composite configurations as carbon and Kevlar at outer and core skins were experimentally tested. The SEM images for flexural specimens were taken to observe the adhesion mechanism of GnPs particles with fiber/epoxy system. It is found that hybridization with Kevlar layers is contributed a positive effect on the hybrid carbon/Kevlar laminate structures in terms of tensile, flexural and impact behaviour. The incorporation of GnPs particles in hybrid and non-hybrid composite samples results in significant improvements in tensile, flexural and impact properties, and the greatest improvement occurs within the GnPs particle content of 0.1 and 0.25 wt%, indicating that the interfacial bonding between the matrix and the fibers is better due to the large surface area of the GnPs and the good entanglement between the GnPs layers and the matrix chains. The samples of impact test are experimented for edgewise and flatwise directions.

scholarly journals Characterization of the Structure, Mechanical Properties and Erosive Resistance of the Laser Cladded Inconel 625-Based Coatings Reinforced by TiC Particles

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2225
Author(s):  
Aleksandra Kotarska ◽  
Tomasz Poloczek ◽  
Damian Janicki
Keyword(s):  
Laser Cladding ◽  
Inconel 625 ◽  
Matrix Composites ◽  
Erosion Rates ◽  
Laser Cladding Process ◽  
Composition Variation ◽  
The Matrix ◽  
Reinforcing Material ◽  
Inconel 625 Superalloy

The article presents research in the field of laser cladding of metal-matrix composite (MMC) coatings. Nickel-based superalloys show attractive properties including high tensile strength, fatigue resistance, high-temperature corrosion resistance and toughness, which makes them widely used in the industry. Due to the insufficient wear resistance of nickel-based superalloys, many scientists are investigating the possibility of producing nickel-based superalloys matrix composites. For this study, the powder mixtures of Inconel 625 superalloy with 10, 20 and 40 vol.% of TiC particles were used to produce MMC coatings by laser cladding. The titanium carbides were chosen as reinforcing material due to high thermal stability and hardness. The multi-run coatings were tested using penetrant testing, macroscopic and microscopic observations, microhardness measurements and solid particle erosive test according to ASTM G76-04 standard. The TiC particles partially dissolved in the structure during the laser cladding process, which resulted in titanium and carbon enrichment of the matrix and the occurrence of precipitates formation in the structure. The process parameters and coatings chemical composition variation had an influence on coatings average hardness and erosion rates.

scholarly journals Prediction of Effective Thermal Conductivities of Four-Directional Carbon/Carbon Composites by Unit Cells with Different Sizes

2021 ◽  
Vol 11 (3) ◽  
pp. 1171
Author(s):  
Chang Xu ◽  
Zhihong Sun ◽  
Guowei Shao
Keyword(s):  
Carbon Fiber ◽  
Longitudinal Direction ◽  
Unit Cell ◽  
Carbon Composites ◽  
Temperature Boundary ◽  
The Matrix ◽  
Unit Cells ◽  
Experimental Values ◽  
Different Diameters ◽  
Thermal Conductivities

Two-unit cells developed to predict the effective thermal conductivities of four-directional carbon/carbon composites with the finite element method are proposed in this paper. The smaller-size unit cell is formulated from the larger-size unit cell by two 180° rotational transformations. The temperature boundary conditions corresponding to the two-unit cells are derived, and the validity is verified by the temperature and heat flux distributions at specific positions of the larger-size unit cell and the smaller-size unit cell. The thermal conductivities of the carbon fiber bundles and carbon fiber rods are measured firstly. Then, combined with the properties of the matrix, the effective thermal conductivities of the four-directional carbon/carbon composites are numerically predicted. The results in transverse direction predicted by the larger-size unit cell and the smaller-size unit cell are both higher than experimental values, which are 5.8 to 6.2% and 7.3 to 8.2%, respectively. In longitudinal direction, the calculated thermal conductivities of the larger-size unit cell and the smaller-size unit cell are 6.8% and 6.2% higher than the experimental results, respectively. In addition, carbon fiber rods with different diameters are set to clarify the influence on the effective thermal conductivities of the four-directional carbon/carbon composites.

Effect of temperature on matrix multicracking evolution of C/SiC fiber-reinforced ceramic-matrix composites

2020 ◽  
Vol 39 (1) ◽  
pp. 189-199
Author(s):  
Longbiao Li
Keyword(s):  
Strain Energy ◽  
Ceramic Matrix Composites ◽  
Critical Value ◽  
Matrix Cracking ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Temperature Dependent ◽  
Damage State ◽  
The Matrix ◽  
Sic Composites

AbstractIn this paper, the temperature-dependent matrix multicracking evolution of carbon-fiber-reinforced silicon carbide ceramic-matrix composites (C/SiC CMCs) is investigated. The temperature-dependent composite microstress field is obtained by combining the shear-lag model and temperature-dependent material properties and damage models. The critical matrix strain energy criterion assumes that the strain energy in the matrix has a critical value. With increasing applied stress, when the matrix strain energy is higher than the critical value, more matrix cracks and interface debonding occur to dissipate the additional energy. Based on the composite damage state, the temperature-dependent matrix strain energy and its critical value are obtained. The relationships among applied stress, matrix cracking state, interface damage state, and environmental temperature are established. The effects of interfacial properties, material properties, and environmental temperature on temperature-dependent matrix multiple fracture evolution of C/SiC composites are analyzed. The experimental evolution of matrix multiple fracture and fraction of the interface debonding of C/SiC composites at elevated temperatures are predicted. When the interface shear stress increases, the debonding resistance at the interface increases, leading to the decrease of the debonding fraction at the interface, and the stress transfer capacity between the fiber and the matrix increases, leading to the higher first matrix cracking stress, saturation matrix cracking stress, and saturation matrix cracking density.

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