Deposition and Properties of Doped Diamondlike Carbon Films Produced by Dual-Source Vacuum Arc Plasma Immersion

AbstractDiamond-like carbon films with mechanical properties approaching those of diamond have been consistently produced by cathodic vacuum arc based techniques. These films have been successfully used in applications where enhanced hardness and wear resistance are required Such DLC films have two major drawbacks that prevent their application in other areas: a high level of internal stresses, which promotes failure by spallation of thick films; and the loss of mechanical properties at temperatures higher than 300°C. In this paper we describe the effect of doping elements on the room-temperature mechanical properties and on the thermal stability of DLC films upon annealing in air. The effect of the presence of W and Ti was investigated and compared to pure DLC. The films were produced by dual-source metal plasma immersion ion implantation and deposition with magnetic filtering to remove macroparticles from the plasma; dopant content was controlled by varying the relative pulse duration of the two plasma sources. Microstructural and chemical characterization of the films are presented.

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Thermal stability and diffusion characteristics of ultrathin amorphous carbon films grown on crystalline and nitrogenated silicon substrates by filtered cathodic vacuum arc deposition

Scientific Reports ◽

10.1038/s41598-021-91903-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shengxi Wang ◽

Anurag Roy ◽

Kyriakos Komvopoulos

Keyword(s):

Thermal Stability ◽

Amorphous Carbon ◽

Silicon Substrate ◽

Elevated Temperatures ◽

Carbon Films ◽

Vacuum Arc ◽

Cross Sectional ◽

Prolonged Heating ◽

Filtered Cathodic Vacuum Arc ◽

Thermal Stability Of

AbstractAmorphous carbon (a-C) films are widely used as protective overcoats in many technology sectors, principally due to their excellent thermophysical properties and chemical inertness. The growth and thermal stability of sub-5-nm-thick a-C films synthesized by filtered cathodic vacuum arc on pure (crystalline) and nitrogenated (amorphous) silicon substrate surfaces were investigated in this study. Samples of a-C/Si and a-C/SiNx/Si stacks were thermally annealed for various durations and subsequently characterized by high-resolution transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The TEM images confirmed the continuity and uniformity of the a-C films and the 5-nm-thick SiNx underlayer formed by silicon nitrogenation using radio-frequency sputtering. The EELS analysis of cross-sectional samples revealed the thermal stability of the a-C films and the efficacy of the SiNx underlayer to prevent carbon migration into the silicon substrate, even after prolonged heating. The obtained results provide insight into the important attributes of an underlayer in heated multilayered media for preventing elemental intermixing with the substrate, while preserving the structural stability of the a-C film at the stack surface. An important contribution of this investigation is the establishment of an experimental framework for accurately assessing the thermal stability and elemental diffusion in layered microstructures exposed to elevated temperatures.

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Precision Coating of ta-C Films on Quartz Surfaces

JSME 2020 Conference on Leading Edge Manufacturing/Materials and Processing ◽

10.1115/lemp2020-8589 ◽

2020 ◽

Author(s):

Kotaro Kawai ◽

Yuki Hirata ◽

Hiroki Akasaka ◽

Naoto Ohtake

Keyword(s):

Cutting Tools ◽

Three Dimensional ◽

High Hardness ◽

Carbon Films ◽

Vacuum Arc ◽

High Wear Resistance ◽

Chemical Inertness ◽

Filtered Cathodic Vacuum Arc ◽

Surface Morphologies

Abstract Diamond-like carbon (DLC) films have excellent properties such as high hardness, low friction coefficient, high wear resistance, chemical inertness and so on. Because DLC film is considered as an effective coating material to improve their surface properties, this films are used in various applications such as parts for automobiles engines, hard disk surfaces, cutting tools and dies, and so on. DLC films consist of a mixture of sp2 bonded carbon atoms and sp3 bonded carbon atoms. Among them, ta-C film is known as the hardest and strongest film since it mainly consists of sp3 bonded carbon atoms. One of deposition methods to form ta-C is Filtered Cathodic Vacuum Arc (FCVA). The characteristic of this method is that it is possible to remove the droplets and form a high-quality film.. However, even though lots of mechanical components which require ta-C coating have three-dimensionally shapes, it is difficult to coat ta-C film three dimensionally by using FCVA process. At present, researches on 3D deposition of amorphous carbon films on three dimensional components is still insufficient, and investigation reports on the deposition mechanism and characterization of the deposited films are even more limited. In this study, we tried to deposit films on 3D components by the FCVA method and evaluated the microstructure and surface morphologies of films. Although films were coated successfully in the entire surfaces, different properties were showed depending on the location of components. These properties were investigated by Raman spectroscopy and laser microscope.

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Characterization of a Spray-Dried Soymilk Powder and Changes Observed During Storage

Food Science and Technology International ◽

10.1177/1082013209353236 ◽

2010 ◽

Vol 16 (2) ◽

pp. 169-178 ◽

Cited By ~ 11

Author(s):

G. Osthoff ◽

A. Hugo ◽

P. van Wyk ◽

M. de Wit ◽

S. Meyer

Keyword(s):

Unsaturated Fatty Acids ◽

Storage Temperature ◽

Chemical Properties ◽

Chemical Characterization ◽

Protein Composition ◽

Absorption Spectrometry ◽

Proximate Analysis ◽

Powder Particles ◽

High Level

Physical characterization of a soymilk powder was carried out by electron microscopy. Chemical characterization was analyzed by proximate analysis, mineral composition by atomic absorption spectrometry, fatty acid composition by gas chromatography and protein composition by electrophoresis. The powder consists of large granules of 60—80 μm, which may be hollow, with smaller granules of 10—20 μm attached to them. Powder particles are covered by a layer of fat. During storage at 25 °C fat is spreading over the surface, while at —12 °C the fat is contracting. This change affected chemical stability, resulting in high level of fat oxidation when stored at 4 °C or 25 °C as well as a decrease in unsaturated fatty acids. Storage also affected the chemical properties of the re-constituted soymilk; the pH of a 12% soy powder suspension increased from 6.68±0.05 to 7.06±0.08 after 12 months of storage. Storage temperature did not affect the pH of the suspension and this change could also not be ascribed to protein aggregation.

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Characterization of Microstructure and Mechanical Properties of 6060 Aluminum Alloy Processed by ECAP

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.275.81 ◽

2018 ◽

Vol 275 ◽

pp. 81-88

Author(s):

Monika Karoń ◽

Marcin Adamiak

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Plastic Deformation ◽

Aluminum Alloy ◽

Internal Stresses ◽

Refined Grains ◽

Angular Pressing ◽

Heat Treated ◽

Evolution Of Microstructure

The purpose of this paper is to present the microstructure and mechanical behavior of 6060 aluminum alloy after intense plastic deformation. Equal Channel Angular Pressing (ECAP) was used as a method of severe plastic deformation. Before ECAP part of the samples were heat treated to remove internal stresses in the commercially available aluminium alloy. The evolution of microstructure and tensile strength were tested after 1, 3, 6 and 9 ECAP passes in annealed and non annealed states. It was found that intensely plastically deformed refined grains were present in the tested samples and exhibited increased mechanical properties. Differences were noted between samples without and after heat treatment

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Mechanical properties of mortar produced with the replacement of natural sand by scheelite residue

Cerâmica ◽

10.1590/0366-69132019653752571 ◽

2019 ◽

Vol 65 (375) ◽

pp. 443-451 ◽

Cited By ~ 4

Author(s):

B. A. Medeiros ◽

G. A. Neves ◽

N. P. Barbosa ◽

R. R. Menezes ◽

H. C. Ferreira

Keyword(s):

Mechanical Properties ◽

Chemical Characterization ◽

Mechanical Tests ◽

Cement Type ◽

Natural Sand ◽

Physical And Chemical Characterization ◽

Water Absorption Test ◽

Treatment And Disposal ◽

Physical And Chemical

Abstract The residue generated by industrial activities represents a cost, since the generators are responsible for its management, transportation, treatment and disposal. Rio Grande do Norte State in Brazil is the greatest producer of scheelite residue. The aim of this research was to characterize this mining residue, identify its similarity with natural sand and produce a coating mortar with it. In the composition of mortar, a Brazilian Portland cement type CPII-F32 and an industrialized calcium hydroxide as a binder were used. Laser granulometry, bulk and relative density, EDX, XRD and thermal analysis were done to obtain a physical and chemical characterization of the residue. Mechanical tests (tensile bond strength and compressive strength), SEM and water absorption test were done to analyze the behavior of mortar. All tests confirmed that mechanical properties were according to standards for tile mortar.

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