scholarly journals The Effect of the Metal Phase on the Compressive and Tensile Stresses Reduction in the Superhard Nitride Coatings

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 798
Author(s):  
Alexey O. Volkhonsky ◽  
Igor V. Blinkov ◽  
Dmitry S. Belov
Keyword(s):  
Crack Resistance ◽  
High Hardness ◽  
Scratch Test ◽  
Vacuum Arc ◽  
Nitride Phase ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Cutting Inserts ◽  
Evaporation Apparatus ◽  
Arc Evaporation

The influence of the compressive and tensile stresses forming in the nanostructured Ti–Al–N coatings during deposition on their physical-mechanical properties was studied. The modifying influence of metal components (Ni and Cu) introduction into Ti–Al–N coatings, which do not interact with nitrogen and have limited solubility with the nitride phase, was also under research. Coatings were deposited on WC–(6 wt.%)Co carbide cutting inserts with an arc-PVD method using a cathodic vacuum arc evaporation apparatus. The introduction of Ni and Cu to the composition leads to the reduction of nitride phases grain size in both investigated coatings from 120 to 10–12 nm for Ti–Al–Cu–N and to 15–18 nm for Ti–Al–Ni–N. Thus, the hardness increases from 29 to 43 and 51 GPa for the mentioned above coatings, respectively. Meanwhile, Ti–Al–Cu–N and Ti–Al–Ni–N coatings are characterized by tensile stresses about 0.12–0.32 MPa against the much higher value of compressive stresses in Ti–Al–N coatings (4.29–5.31 GPa). The modification of Ti–Al–N coatings also leads to the changing of their destruction mechanism during the scratch-test. The critical loads characterizing the emergence of the first cracks in the coatings and complete abrasion of the coating (Lc1 and Lc3) were determined. They had the value of 20; 22 N (Lc1) and 64; 57 N (Lc3) for Ti–Al–Ni–N; Ti–Al–Cu–N coatings, respectively. The Lc1 parameter for Ti–Al–N coatings was much lower and was equal to 11 N. Along with those, Ti–Al–N coatings destructed according to the adhesion mechanism when the critical load was 35 N. In addition, the decreasing level of compressive stresses in Ti–Al–Cu–N and Ti–Al–Ni–N coatings as compared to that in the Ti–Al–N coating, their crack resistance during multi-cycle shock-dynamic impact test was significantly higher. The results can indicate that high hardness and crack resistance of the coatings is to a greater extent determined by coatings nanostructuring, not the stresses value. In addition, it confirms the possibility to obtain coatings with low stresses value while maintaining their superhardness.

Precision Coating of ta-C Films on Quartz Surfaces

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.

Correlation of Residual Stresses in the Fatigue Strength of Axles

1942 ◽  
Vol 9 (2) ◽  
pp. A85-A90
Author(s):  
O. J. Horger ◽  
H. R. Neifert
Keyword(s):  
Heat Treatment ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
High Surface ◽  
Full Size ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Actual Service

Abstract The object of this paper is to present a correlation between residual stresses, obtained by heat-treatment, with fatigue values, determined from an investigation of full-size railroad axles. The axles tested were of both solid and tubular design and represent members which could be used under a car in actual service. It was found from these tests that high axle fatigue strength is associated with high surface residual compressive stresses, and lowest axle strength values with surface residual tensile stresses.

Indentation Creep of Molybdenum: Comparison Between Thin Film and Bulk Material

1994 ◽  
Vol 356 ◽  
Author(s):  
K. B. Yoder ◽  
D. S. Stone ◽  
J. C. Lin ◽  
R. A. Hoffmann
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Room Temperature ◽  
Bulk Material ◽  
High Hardness ◽  
Rate Sensitivity ◽  
Indentation Creep ◽  
Creep Properties ◽  
Measurement Path ◽  
Arc Evaporation

AbstractIndentation creep, load relaxation, and rate-change experiments probe room temperature and 80°C creep properties of a 1.3 μm-thick molybdenum film on silicon. The film, with 0.51 GPa compressive stress, 8 GPa hardness and estimated 40 nm grain size, was deposited using steered-arc evaporation at -17V bias. Despite its small grain size and high hardness, the thin film behaves like bulk molybdenum does: the rate sensitivity of the hardness is only weakly-dependent on measurement path (as with bulk material), and activation volumes calculated based on strain rate sensitivity are consistent with those of bulk molybdenum We suspect deformation mechanisms are similar to those in bulk molybdenum under similar conditions.

Influence of Plasma Assistance on Arc Deposited MoN Coatings

2016 ◽  
Vol 712 ◽  
pp. 9-14 ◽  
Author(s):  
Olga Krysina ◽  
Vladimir V. Shugurov ◽  
Nikolay Koval ◽  
Nikita Prokopenko
Keyword(s):  
High Hardness ◽  
Ion Current ◽  
Vacuum Arc ◽  
High Wear Resistance ◽  
Molybdenum Nitride ◽  
Coating Properties ◽  
Current Ratio ◽  
Gas Plasma ◽  
Vacuum Arc Deposition ◽  
Arc Deposition

The paper reports on a study to optimize the modes of plasma-assisted vacuum arc deposition of molybdenum nitride (MoN) coatings. It is shown that the parameters of plasma assistance influence the coating properties and that varying the ion current ratio in the metal-gas plasma makes possible MoN coatings with high hardness and high wear resistance.

Nanomultilayer Coatings Based on Vanadium Nitride

2015 ◽  
Vol 237 ◽  
pp. 15-20 ◽  
Author(s):  
Jerzy Smolik ◽  
Adam Mazurkiewicz ◽  
Zbigniew Słomka ◽  
Jan Bujak ◽  
Joanna Kacprzyńska-Gołacka ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
Composite Coatings ◽  
Multilayer Coating ◽  
High Hardness ◽  
Scratch Test ◽  
Test Method ◽  
Vanadium Nitride ◽  
Material Solution

Based on the analysis of the research directions in the field of coatings and layers with special operating properties, the production technologies of composite coatings, including the gradient, multi-layer, and multi-component coatings, should be distinct. The paper presents the results of material properties tests of a multi-layer coating Ti / TiN / TiAlNgradient / (TiAlN/VN)multinano obtained on hot working steel EN X32CrMoV3.3. The preparation of the multilayer coating was specially designed to increase the durability of forging dies in the brass forging process. The authors discuss the results of the microstructure tests for the obtained coatings (STEM+FIB) and present the hardness and Young's modulus as a function of the distance from the surface (nanoHardness Tester CSM) and the results of adhesion tests carried out using a scratch-test method. The obtained multilayer coatings were also subject to a tribological test using a tribometer tester by DUCOM. The authors indicate that the coatings based on vanadium nitride have very high hardness and Young's modulus (HV = 32–35 GPa, E = 420–450 GPa), a much lower coefficient of friction in combination with brass than steel, and a lower stability of these parameters at elevated temperatures. According to the authors, the coating represents an interesting material solution to increase the durability of forging dies in the process of brass forging.

scholarly journals Investigations in Anti-Impact Performance of TiN Coatings Prepared by Filtered Cathodic Vacuum Arc Method under Different Substrate Temperatures

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 840
Author(s):  
Da Huang ◽  
Weifeng He ◽  
Xin Cao ◽  
Yang Jiao
Keyword(s):  
Substrate Temperature ◽  
Internal Stress ◽  
Adhesion Strength ◽  
Great Influence ◽  
High Hardness ◽  
Underlying Mechanism ◽  
Vacuum Arc ◽  
Impact Performance ◽  
Tin Coatings ◽  
Substrate Temperatures

In this study, the anti-impact performance of the TiN coatings prepared under various substrate temperatures (35, 200, 400, and 600 °C) were evaluated using a cyclic impact tester under 104 cycles. Moreover, the microstructure and anti-impact performance-related mechanical properties (adhesion strength and nano-hardness) were investigated to reveal the underlying mechanism of how the substrate temperature affects the anti-impact performance of the coatings. The results showed that the substrate temperature has a great influence on the internal stress, nano-hardness, and adhesion strength as well as the anti-impact performance of TiN coatings, and the coatings prepared under 400 °C exhibit the best impact resistance. The small internal stress, strong adhesion strength as well as high hardness and H3/E2 value for the 400 °C prepared coatings are the main contributes.

scholarly journals Phase Evolution and Microstructure Analysis of CoCrFeNiMo High-Entropy Alloy for Electro-Spark-Deposited Coatings for Geothermal Environment

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 406 ◽  
Author(s):  
Sigrun N. Karlsdottir ◽  
Laura E. Geambazu ◽  
Ioana Csaki ◽  
Andri I. Thorhallsson ◽  
Radu Stefanoiu ◽  
...  
Keyword(s):  
Bulk Material ◽  
Microstructural Analysis ◽  
Electrochemical Corrosion ◽  
High Hardness ◽  
Phase Evolution ◽  
Vacuum Arc ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Σ Phase ◽  
High Entropy

In this work, a CoCrFeNiMo high-entropy alloy (HEA) material was prepared by the vacuum arc melting (VAM) method and used for electro-spark deposition (ESD). The purpose of this study was to investigate the phase evolution and microstructure of the CoCrFeNiMo HEA as as-cast and electro-spark-deposited (ESD) coating to assess its suitability for corrosvie environments encountered in geothermal energy production. The composition, morphology, and structure of the bulk material and the coating were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The hardness of the bulk material was measured to access the mechanical properties when preselecting the composition to be pursued for the ESD coating technique. For the same purpose, electrochemical corrosion tests were performed in a 3.5 wt.% NaCl solution on the bulk material. The results showed the VAM CoCrFeNiMo HEA material had high hardness (593 HV) and low corrosion rates (0.0072 mm/year), which is promising for the high wear and corrosion resistance needed in the harsh geothermal environment. The results from the phase evolution, chemical composition, and microstructural analysis showed an adherent and dense coating with the ESD technique, but with some variance in the distribution of elements in the coating. The crystal structure of the as-cast electrode CoCrFeNiMo material was identified as face centered cubic with XRD, but additional BCC and potentially σ phase was formed for the CoCrFeNiMo coating.

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