| 1. |
- Wang, Tiegang, et al.
(författare)
-
Influence of residual stress on the adhesive behavior of detonation gun sprayed WC-Co coatings
- 2012
-
Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 12, s. 59-62
-
Tidskriftsartikel (refereegranskat)abstract
- The residual stresses generated during D-Gun spraying process act as pre-existing stresses and seriously affect the various types of coating performance. To produce a reliable coating, it is necessary to know the influence of residual stress on the adhesive behavior of coating/substrate system. Based on the residual stress formula for thick coatings and accurate curvature measurements, the residual stresses of D-Gun sprayed WC-Co coatings were obtained. And a strong link was built between the residual stress and the adhesive strength of the coating, namely, the compressive stress in the coating could significantly improve the adhesion, whereas the tensile stress weakened the adhesion. The larger compressive residual stress is in the coating, the stronger adhesion between the coating and substrate. (C) 2012 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Wang, Tiegang, et al.
(författare)
-
Study on nanocrystalline Cr2O3 films deposited by arc ion plating: I. composition, morphology, and microstructure analysis
- 2012
-
Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972. ; 206:10, s. 2629-2637
-
Tidskriftsartikel (refereegranskat)abstract
- Nanocrystalline Cr2O3 thin films were deposited on silicon wafers with (100) orientation by arc ion plating (AIP) technique at various negative bias voltages. By virtue of X-ray diffraction analysis, scanning electron microscope, and high-resolution transmission electron microscope, the influence of substrate bias voltage on the film growth process, microstructure, and characteristics was investigated systematically, including the phase constituents, grain size, lattice constant, chemical compositions, as well as surface and cross-section morphologies. With increasing the bias voltage, the grain size and lattice constant of AIP Cr2O3 films first decreased slightly, and then increased gradually again. Both reached the minimum (35 nm and 13.57 angstrom) when the bias voltage was - 100 V. However, the bias voltage had little effect on the phase constituents and chemical compositions of AIP Cr2O3 films. During the film growth process, the surfaces of Cr2O3 films were getting smoother with the negative bias voltage increase, in the meantime, their microstructures evolved from coarse columnar grains to fine columnar grains, short columnar recrystallized grains, and fine columnar grains again. (C) 2011 Elsevier B.V. All rights reserved.
|
|
| 3. |
- Wang, Tiegang, et al.
(författare)
-
Study on nanocrystalline Cr2O3 films deposited by arc ion plating: II. Mechanical and tribological properties
- 2012
-
Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972. ; 206:10, s. 2638-2644
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, the influence of substrate bias voltage on the microhardness, adhesive strength, friction coefficient, and wear rate of AIP Cr2O3 films deposited on AISI 304 stainless steel substrates was investigated systematically. In the meantime, the wear failure mechanism of AIP Cr2O3 films in dry sliding contact was also analyzed and discussed. The results showed that the mechanical properties, adhesive behaviors, and tribological performance of AIP Cr2O3 films were greatly altered by applying a negative bias voltage. With increasing the bias voltage, the hardness, critical load, and tribological performance of AIP Cr2O3 films first were improved gradually, and then were impaired slightly again. When the bias voltage is - 100 V. the Cr2O3 film possessed the highest hardness, the strongest adhesion, and the best wear resistance. The essence of above phenomena was attributed to the variations of microstructure and defect density in the films induced by the substrate bias voltage increase. The main wear failure mechanism of AIP Cr2O3 films is crack initiation and propagation under the high contact stresses, inducing the local film with small area to flake off gradually, and eventually leading to the formation of a wear scar. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
|
|
| 4. |
- Geng, Dongsen, et al.
(författare)
-
An investigation on microstructure and milling performance of arc-evaporated TiSin/AlTiN film
- 2020
-
Ingår i: Thin Solid Films. - : ELSEVIER SCIENCE SA. - 0040-6090 .- 1879-2731. ; 709
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, TiSiN/AlTiN multilayer film was deposited on cemented-carbide solid end mill tools by cathodic arc evaporation. The multilayer consisted of CrN buffer layer, Al(0.6)7Ti(0.33)N adhesion layer, Ti0.9Si0.1N/Al(0.6)7Ti(0.33)N alternate layer, and Ti0.9Si0.1N outlayer. An investigation on microstructure, mechanical properties, high-temperature wear rate, and milling performance of TiSiN/AlTiN multilayer film was conducted. The results indicate that the as-deposited TiSiN/AlTiN film exhibits a mixture phase of fcc-TiN and fcc-(Ti, Al)N. The hardness and elastic modulus of the TiSiN/AlTiN film are 41.7 +/- 1.6 GPa and 340 +/- 17 GPa, respectively. The wear rate of TiSiN/AlTiN film changes slightly when the experiment temperature is below 400 degrees C, and then increases with the temperature increases to 600 degrees C. Indentation hardness of TiSiN/AlTiN changes can be maintained above 40 GPa upon annealing to 800 degrees C. However, the hardness of the film decreases from above 40 GPa to similar to 30.6 GPa when the annealing temperature increases to 1000 degrees C. During dry milling, the TiSiN/AlTiN film reduces the adhesion between the coated tool and machined material SKD 11, leading to a low cutting force and cutting temperature.
|
|
| 5. |
- Geng, Dongsen, et al.
(författare)
-
Impact of Si addition on oxidation resistance of Zr-Si-N nanocomposite films
- 2021
-
Ingår i: Vacuum. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0042-207X .- 1879-2715. ; 183
-
Tidskriftsartikel (refereegranskat)abstract
- Incorporating Si element into nitride films is known to enhance mechanical properties and oxidation resistance. Here, we reported the nanocomposite films of Zr-Si-N deposited using a hybrid deposited system combining rf magnetron sputtering from a Si3N4 target with dc magnetron sputtering from Zr target. Microstructure and oxidation resistance of Zr-Si-N nanocomposite films with 0-20.9 at.% Si content were investigated. The results indicated that the binary Zr-N film exhibits a typical columnar structure and the Zr-Si-N films become denser as the elevated Si content. The cross-section of film transforms to a dense and glassy structure when increasing the Si concentrations. The oxide scales of the Zr-Si-N films consist of ZrO2 nanograins and amorphous SiNx tissue. The introduction of the Si element significantly improves the oxidation resistance of the Zr-Si-N films due to the amorphous SiNx tissue phase suppresses both the inward diffusion of the oxygen and cracking in oxide scale caused by the phase transition from t-ZrO2 to m-ZrO2.
|
|
| 6. |
- Li, Xu, et al.
(författare)
-
Diamond-like/graphite-like carbon composite films deposited by high-power impulse magnetron sputtering
- 2020
-
Ingår i: Diamond and related materials. - : ELSEVIER SCIENCE SA. - 0925-9635 .- 1879-0062. ; 106
-
Tidskriftsartikel (refereegranskat)abstract
- Diamond-like carbon (DLC)/graphite-like carbon (GLC) composite films were prepared with high-power impulse magnetron sputtering (HiPIMS) using a mixture of Ar and Ne as the sputtering gas. The effect of the Ne fraction in the sputtering gas on the surface morphology, carbon bonding structure, microstructure, mechanical properties, residual stress, and tribological performance of the deposited films were characterized using laser scanning confocal microscopy, Raman spectroscopy, nano-indentation, residual stress tester, and friction and wear testing using a ball-on- plate tribometer, respectively. The films have a composite surface structure consisting of sp(2)-rich GLC microparticles embedded in an sp(3)-rich DLC matrix. Both components can be controlled to some degree by varying the Ne fraction. Specifically, as the Ne fraction is increased, both the number and size of the GLC microparticles decreases, while the sp(3) content increases. The GLC microparticles in the film can reduce the real contact area in friction testing, decreasing the friction coefficient, while the sp(3)-rich DLC phase enables the high hardness and wear resistance of the films. By adjusting the Ne fraction during the HiPIMS process, DLC/GLC composite films with low friction and high wear resistance can be generated.
|
|
| 7. |
- Wu, Zhengtao, et al.
(författare)
-
A comparative investigation on structure evolution of ZrN and CrN coatings against ion irradiation
- 2019
-
Ingår i: Heliyon. - : ELSEVIER SCI LTD. - 2405-8440. ; 5:3
-
Tidskriftsartikel (refereegranskat)abstract
- Binary ZrN and CrN nanostructured coatings deposited by magnetron sputtering were irradiated with 600 keV Kr3+ at room temperature. The ion irradiation fluences varied from 0 to 1 x 10(17) Kr3+/cm(-2). The results indicate the microstructure of the CrN illustrates higher stability during the Kr3+ ion irradiation compared to that of the ZrN. The ion irradiation produces surface etching of the CrN coating. However, the etching transfers to recrystallization and grain coarsening on the ZrN coating surface as the Kr3+ fluence increases.
|
|
| 8. |
- Wu, Zhengtao, et al.
(författare)
-
Cubic-structure Al-rich TiAlSiN thin films grown by hybrid high-power impulse magnetron co-sputtering with synchronized Al+ irradiation
- 2020
-
Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 385
-
Tidskriftsartikel (refereegranskat)abstract
- Adding Si into transition-metal nitride hard coatings is known to enhance mechanical properties and oxidation resistance. At the same time, however, Si promotes precipitation of wurtzite-structure AlN in Ti1-xAlxN during deposition by magnetron sputtering or cathodic-arc-evaporation, resulting in a decrease in layer hardness. Here, we report nanocomposite films of metastable cubic NaCl-structure TiAlSiN deposited using a hybrid approach combining high-power impulse magnetron sputtering (HiPIMS) from an Al target with DC magnetron sputtering (DCMS) from TiSi targets (Al-HiPIMS/TiSi-DCMS) in which a substrate bias is synchronized to the metal-rich portion of each HiPIMS pulse. The Al/(Al + Ti) ratio is varied from 0.26 to 0.77 by adjusting the TiSi target power, while the Si content ranges from 7.6 to 10.3 at.%. Cubic-structure TiAlSiN solid solutions are obtained with a maximum Al/(Al + Ti) atomic ratio of 0.59 and 9.4 at.% Si. Excess Si segregates to grain boundaries to form a SiNx-rich tissue phase. The hardness H and elastic modulus E of cubic TiAlSiN films increase from H = 19.4 +/- 1.7 and E = 322 +/- 12 for TiAlSiN layer with Al/(Al + Ti) = 0.26 to H = 37.3 +/- 1.3 and E = 388 +/- 12 GPa for TiAlSiN layer with Al/(Al + Ti) = 0.59. The TiAlSiN films also exhibit a low intrinsic stress (-0.55 to 0.62 GPa), resulting in a combination of properties: superior hardness and low stress.
|
|
| 9. |
- Wu, Zhengtao, et al.
(författare)
-
In situ nanoindentation measurements of arc-evaporated Cr0.49Al0.51N, Al0.66Ti0.34N, and Al0.65Ti0.33Y0.02N films up to 800 degrees C
- 2020
-
Ingår i: Journal of Vacuum Science and Technology B. - : A V S AMER INST PHYSICS. - 2166-2746 .- 2166-2754. ; 38:2
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, the in situ hardness and elastic modulus measurements of arc-evaporated Cr0.49Al0.51N, Al0.66Ti0.34N, and Al0.65Ti0.33Y0.02N films are investigated using a high-temperature nanoindentation tester. It is found that the hardness of Cr0.49Al0.51N initially increases from 30.2 +/- 2.3GPa at room temperature (RT) and reaches a maximum of 33.2 +/- 2.4GPa at 600 degrees C before decreasing to 27.9 +/- 2.1GPa at 800 degrees C. However, the results for elastic modulus versus temperature follow a degraded trend, with 405 +/- 23GPa for RT, decreasing to 280 +/- 18GPa at 800 degrees C. Increases in the hardness and the elastic modulus can be achieved for both Al0.66Ti0.34N and Al0.65Ti0.33Y0.02N films as their temperatures increase. The addition of Y effectively promotes the hardness and the elastic modulus of Al0.66Ti0.34N at RT-300 degrees C. However, both hardness and elastic modulus change slightly as Y is incorporated at 300-800 degrees C.
|
|
| 10. |
- Wu, Zhengtao, et al.
(författare)
-
Investigation on plastic deformation of arc-evaporated AlCrSiN and AlCrSiON nanocomposite films by indentation
- 2022
-
Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 441
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoindentation produced plastic deformation of arc-evaporated AlCrSiN and AlCrSiON nanocomposite films deposited on cemented-carbide substrates was investigated. The nanoindentation tests have the maximum penetration depth of 250 nm. Microstructure evolution in the indents was indicated by focused-ion-beam cutting and transmission-electron-microscopy observation. The results indicate that both the AlCrSiN and the AlCrSiON nanocomposite films exhibit excellent plasticity without the occurrence of microcrack initiation and propagation in the indents and grain boundaries. The prominent pile-up phenomenon produced by plastic flow was observed in the indent of the AlCrSiON film. Incorporating O into the AlCrSiN reduces both hardness and toughness of the film. This produces the pile-up in the AlCrSiON film when exposed to a nanoindenter. Rotation of the (Cr, Al)N nanograins and deflection of self-organized multilayer interface contribute to the plastic deformation of the AlCrSiN. However, shear band, interface deflection, and grain rotation contribute to the nanoindentationinduced plastic deformation of the AlCrSiON film.
|
|
