Methods of polydispersed material surface layer agglomeration

The aim of the work was evaluation of electrochemical properties of Co-based alloys (Remanium GM 800+ and Biosil F) and Ni-based alloys (Heraenium NA and Remanium G-Soft) commonly used on frameworks for porcelain faced cast partial dentures. First stage of the work was evaluation of surface roughness by means of direct linear contact measurement (SURTRONIC 3+ profiler, Taylor/Hobson) of samples after casting and surface treatment. Electrochemical properties of surface were assessed by means of potentiodynamic and impedance methods. In potentiodynamic tests, in order to evaluate pitting corrosion resistance of the analyzed alloys, anodic polarization curves were recorded. The VoltaLab® PGP 201 system was applied in corrosion tests. Moreover, in order to evaluate structure and properties of the surface layer the electrochemical impedance spectroscopy (EIS) was applied. Selection of this method enabled to determine the impedance of the material – surface layer – solution interface with the use of approximation of impedance data by means of equivalent electric circuit model. The EIS tests were carried out with the use of the AutoLab PGSTAT 302N system equipped with the FRA2 Faraday impedance module. Electrochemical tests were carried out in artificial saliva at the temperature of 37°C and pH = 7,0±0,1.

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Nitrogen Effect on Mechanical and Tribological Properties of STN 41 5230 Steel Surface Layer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1059.11 ◽

2014 ◽

Vol 1059 ◽

pp. 11-17

Author(s):

Ivan Kováč ◽

Rastislav Mikuš ◽

Jozef Žarnovský ◽

Juraj Ružbarský

Keyword(s):

Surface Layer ◽

Diffusion Processes ◽

Base Material ◽

Material Surface ◽

Surface Layers ◽

Mechanical And Tribological Properties ◽

Nitrogen Effect ◽

A Tig Welding ◽

The Subject ◽

Hardness Values

The subject-matter of this article is using diffusion processes to obtain chemically stable compounds with a low reactivity and higher mechanical properties in material surface layer. These processes were implemented by remelting the surface of a given material in arc process using a TIG welding method. Nitrogen was used as an alloying element in experiments. The experiment assumed that the dissociation and ionization of gases, enabling the ionization of diffusion processes in the surface layer of remelted steel, will be achieved by means of electric arc. Conditions for the formation of hard and stable structures with required properties should have been created by enriching the surface layer. The STN 41 5230 steel was used in experiments. After remelting, samples were examined on hardness and relative abrasive wear resistance, which are crucial in terms of required properties of given surface layers. In addition to hardness values in the surface layer, also its behaviour inwards the material up to thermally unaffected base material was determined. When remelting in the environment containing nitrogen, the values of examined quantities increased.

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Investigations of Graphite Particle Interaction with Metallic Surfaces

Metals ◽

10.3390/met10010140 ◽

2020 ◽

Vol 10 (1) ◽

pp. 140

Author(s):

Andreas Andris ◽

Felix Fischer ◽

Marion Herrmann ◽

Wolfgang Lippmann ◽

Antonio Hurtado

Keyword(s):

Surface Layer ◽

Structural Change ◽

Particle Interaction ◽

Test Facility ◽

Primary Circuit ◽

Material Surface ◽

Alloy 800H ◽

Gaseous Reaction ◽

Near Surface ◽

Graphite Particles

Previous studies on the safety of gas-cooled high-temperature reactors (HTR) have analyzed the corrosion and oxidation behavior of the primary circuit components under normal and accident conditions. Through the use of graphite components, graphite particles can be formed by mechanical and chemical means whose influence on the structural change of metal surfaces must be analyzed in a comprehensive manner. The dust resuspension and deposition in tank geometry (DRESDEN-TANK) test facility was set up to thermally anneal metallic samples (Alloy 800H, Inconel 617) loaded with graphite particles under typical HTR conditions (helium, 750 °C, 6 MPa) for the investigation of interactions over a long-term range. In addition to the carrying out of a description of the processes occurring on the material surface, the gaseous reaction products have been analyzed. The results show that the presence of graphite particles in the near-surface layer has a significant impact on corrosion processes due to thermally-induced interactions. In this case iron and chromium are degraded in the metallic alloys, which leads to a structural change in the near-surface layer. Furthermore, the graphite particles significantly influence the formation of the oxide layers on the alloys; for example, they influence the formation speed of the layer and the layer height. The originally deposited particles thus exhibit a chemically-altered composition and a different geometric shape.

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INVESTIGATION OF CHANGES IN THE MODULUS OF ELASTICITY OF THE SURFACE LAYER MATERIAL DURING FRETTING WEAR

Tribologia ◽

10.5604/01.3001.0014.0834 ◽

2020 ◽

Vol 289 (1) ◽

pp. 13-19

Author(s):

Vyacheslav F. BEZJAZYCHNYI ◽

Marian SZCZEREK ◽

Roman V. LYUBIMOV

Keyword(s):

Surface Layer ◽

Modulus Of Elasticity ◽

Fretting Wear ◽

Material Surface ◽

Research Results ◽

Layer Material

The method, the equipment used, and the results of the study are described in relation to the regularity of changes in the modulus of elasticity of the part material surface layer during operation when the part is under conditions of fretting wear of the contacting surfaces. Recommendations for the practical use of the research results are given.

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Perspectives of Using Ultrasonic surface hardening in Machine Part Manufacturing

MATEC Web of Conferences ◽

10.1051/matecconf/201929705009 ◽

2019 ◽

Vol 297 ◽

pp. 05009 ◽

Cited By ~ 1

Author(s):

Yulia Semenova ◽

Semen Mazhuga

Keyword(s):

Surface Layer ◽

Surface Topography ◽

Ultrasonic Vibration ◽

Thermal Processing ◽

Machine Part ◽

Surface Hardening ◽

Vibration Energy ◽

Material Surface ◽

Scientific Schools ◽

Wide Range

The paper under consideration presents the review of the research results of different scientific schools on applying ultrasonic vibration energy. The effect of ultrasonic vibration energy on changes in the structure of surface layer material, surface topography and other characteristics are presented. A wide range of possibilities of using ultrasonic surface hardening in preparing surfaces before the chemical-thermal processing, for coating and as a finishing processing is presented. The possibilities of applying the method in the combination with other methods of affecting the material are considered. The possibilities of reducing the price of the machine part manufacturing because of implementing the operation of ultrasonic surface hardening in the technological process are shown.

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Micro-Alloying and Surface Texturing of Ti-6Al-4V Alloy by Embedding Nanoparticles Using Gas Tungsten Arc Welding

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp4020029 ◽

2020 ◽

Vol 4 (2) ◽

pp. 29

Author(s):

Kavian Omar Cooke ◽

Muhammad Ali Shar ◽

Suleman Hussain

Keyword(s):

Surface Layer ◽

Arc Welding ◽

Surface Hardness ◽

Welding Current ◽

Surface Melting ◽

Gas Tungsten Arc Welding ◽

Material Surface ◽

Micro Hardness ◽

Gas Tungsten Arc ◽

Gas Tungsten

Titanium alloy Ti-6Al-4V is known for both its excellent mechanical properties and its low surface hardness. This study explores a two-step process for depositing a hard nanocrystalline coating onto the surface of the Ti-alloy, followed by surface melting, which embeds hard nanoparticles into a thin surface layer of the alloy. The treated surface layer was studied using X-ray diffraction, scanning electron microscopy, and Vicker’s micro-hardness testing. The results of the study show that the surface of the Ti-6Al-4V alloy can be successfully hardened by embedding nanosized Al2O3 particles into the surface using gas tungsten arc welding to melt the surface of the material. Surface melting the Ti-6Al-4V alloy with a 50A welding current produced the maximum microhardness of 701 HV0.2kg. The micro-hardness of the treated surface layer decreased with the increasing size of the nanoparticles, while the roughness of the surface increased with the increasing welding current. The heat input into the surface during the surface melting process resulted in the formation of various intermetallic compounds capable of further increasing the hardness of the Ti-6Al-4V surface.

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