Interface Stabilized Nanoscale Quasi-Liquid Films

A unique class of impurity-based quasi-liquid films has been widely observed at free surfaces, grain boundaries (GBs), and hetero-phase interfaces in ceramic and metallic materials (Figure 1). These nanometer-thick interfacial films can be alternatively understood to be: (a) quasi-liquid layers that adopt an “equilibrium” thickness in response to a balance of attractive and repulsive interfacial forces (in a high-temperature colloidal theory) or (b) multilayer adsorbates with thickness and average composition set by bulk dopant activities [1–2]. In several model binary systems, such quasi-liquid, interfacial films are found to be thermodynamically stable well below the bulk solidus lines, provoking analogies to the simpler interfacial phenomena of premelting in unary systems [3] and prewetting in binary de-mixed liquids [4]. These interfacial films exhibit structures and compositions that are neither observed nor stable as bulk phases, as well as transport, mechanical, and physical properties that are markedly different from bulk phases.

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Corrosion of metals and alloys. Test method for high temperature corrosion testing of metallic materials by embedding in salt, ash, or other solids

10.3403/30259851u ◽

2015 ◽

Keyword(s):

High Temperature ◽

High Temperature Corrosion ◽

Metals And Alloys ◽

Corrosion Testing ◽

Test Method ◽

Metallic Materials

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Interfacial Aspects of Metal Matrix Composites Prepared from Liquid Metals and Aqueous Solutions: A Review

Metals ◽

10.3390/met10101400 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1400

Author(s):

Peter Baumli

Keyword(s):

Aqueous Solutions ◽

Physical Properties ◽

Metal Matrix Composites ◽

Metal Matrix ◽

Liquid Metals ◽

Interfacial Phenomena ◽

Matrix Composites ◽

Good Adhesion ◽

Mechanical And Physical Properties ◽

The Matrix

The paper reviews the preparation of the different metallic nanocomposites. In the preparation of composites, especially in the case of nanocomposites, interfacial phenomena play an important role. This review summarizes the literature on various interfacial phenomena, such as wettability and reactivity in the case of casting techniques and colloidal behavior in the case of electrochemical and electroless methods. The main contribution of this work lies in the evaluation of collected interfacial phenomena and difficulties in the production of metal matrix composites, for both nano-sized and micro-sized reinforcements. This study can guide the composite maker in choosing the best criteria for producing metal matrix composites, which means a real interface with good adhesion between the matrix and the reinforcement. This criterion results in desirable mechanical and physical properties and homogenous dispersion of the reinforcement in the matrix.

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6H- AND 4H-SiC(0001) Si SURFACE RICHNESS DOSING BY HYDROGEN ETCHING: A WAY TO REDUCE THE FORMATION TEMPERATURE OF RECONSTRUCTIONS

Surface Review and Letters ◽

10.1142/s0218625x03004652 ◽

2003 ◽

Vol 10 (01) ◽

pp. 55-63 ◽

Cited By ~ 6

Author(s):

M. DIANI ◽

J. DIOURI ◽

L. KUBLER ◽

L. SIMON ◽

D. AUBEL ◽

...

Keyword(s):

High Temperature ◽

Atomic Hydrogen ◽

Room Temperature ◽

Binary Systems ◽

Temperature Treatment ◽

Heating Time ◽

High Temperature Treatment ◽

Formation Temperature ◽

Hydrogen Etching ◽

Chemical Surface

In 6H- or 4H-SiC(0001) surface technology, a Si-rich 3 × 3 reconstruction is usually first prepared by heating at 800°C under Si flux, and two other most stable [Formula: see text] or [Formula: see text] reconstructions are obtained by further extensive annealing at higher temperatures ranging between 900 and 1250°C. The 3 × 3 Si excess is thus progressively depleted up to a graphitized C-rich surface. By crystallographic (LEED) and chemical surface characterizations (XPS and UPS), we show that all these reconstructions can be obtained at a unique, low formation temperature of 800°C if the Si richness is controlled before annealing. This control is achieved by exposing the 3 × 3 surface to atomic hydrogen at room temperature. This procedure allows one to etch or partially deplete the (3 × 3)-associated Si excess, and make it more comparable to the final Si coverages, required to form the less Si-rich [Formula: see text] or [Formula: see text] reconstructions. After annealing at 800°C, the latter reconstructions are no longer determined by the heating time or temperature but only by the initial Si coverage set by the H doses inducing the low temperature etching. The high temperature treatment, required to remove by sublimation a significant Si amount associated with the Si-rich 3 × 3 reconstruction, is thus avoided. Such a methodology could be applied to other binary systems in the formation of reconstructions that depends on surface richness.

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High temperature abrasive wear of metallic materials

Wear ◽

10.1016/j.wear.2016.12.042 ◽

2017 ◽

Vol 376-377 ◽

pp. 443-451 ◽

Cited By ~ 22

Author(s):

M. Varga

Keyword(s):

High Temperature ◽

Abrasive Wear ◽

Metallic Materials

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An Experimental Study on the Properties of Recycled High-Density Polyethylene

International Polymer Processing ◽

10.1515/ipp-2020-4071 ◽

2021 ◽

Vol 36 (5) ◽

pp. 557-563

Author(s):

A. G. Toroslu

Keyword(s):

Physical Properties ◽

High Density Polyethylene ◽

Iron Alloy ◽

High Density ◽

Magnetic Method ◽

Metallic Materials ◽

Metallic Material ◽

Alloy Particles ◽

Plastic Materials ◽

Mechanical And Physical Properties

Abstract Recycling of plastic materials has become more environmentally important than recycling of other materials. The most important problem during recycling is the presence of oil, dirt, dust and metal particles that are mixed with plastic materials. These mixtures can change their its mechanical and physical properties and it is quite costly to remove them completely. Removing iron alloy particles from plastic is possible by using the magnetic method. However, removing non-metallic materials requires extra processing. In this study, the use of recycled High-Density Polyethylene (rHDPE) without an expensive cleaning processes has been investigated. Different amounts of aluminium oxide (Al2O3) were added to High Density Polyethylene (HDPE) to simulate the effect of non-metallic material involved. The effect of these contamination rates on the mechanical and physical properties of HDPE was examined in detail. For this purpose, recyclable materials were produced by mixing rHDPE with 1%, to 7% Al2O3 . The results show that up to 7% of the mixture has acceptable effects on the properties of HDPE. When the results of the experiments are examined, it is observed that there is a 3.74% change in the elastic modulus of the material. This means, that up to 7% non-metal contaminated rHDPE material can be used without any costly recycling process.

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Influence of Processing Parameters and Different Content of Tib2 Ceramics on the Properties of Composites Sintered by High Pressure -High Temperature (HP-HT) Method

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0033 ◽

2014 ◽

Vol 59 (1) ◽

pp. 205-209 ◽

Cited By ~ 17

Author(s):

I. Sulima ◽

L. Jaworska ◽

P. Figiel

Keyword(s):

High Pressure ◽

High Temperature ◽

Processing Parameters ◽

Structure Changes ◽

High Pressure High Temperature ◽

Mechanical And Physical Properties ◽

Temperature And Pressure ◽

Different Content ◽

Scanning Electron ◽

Properties Of Composites

Abstract In this paper the properties of the austenitic stainless steel reinforced with various volume fractions of TiB2 ceramics have been studied. The high pressure- high temperature (HP-HT) method of sintering was applied to the formation of composites. Samples were sintered at pressure of 5 and 7 ±0.2 GPa and temperatures of 1273 K and 1573 K. For the tested materials, the relative density, Young’s modulus and hardness were measured. In order to investigate the structure changes, the scanning electron microscope was used. The obtained results show that the temperature and pressure influence on the mechanical and physical properties of the investigated composites.

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