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| 2. |
- Alami, Jones, et al.
(författare)
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Phase tailoring of Ta thin films by highly ionized pulsed magnetron sputtering
- 2007
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 515:7-8, s. 3434-3438
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Tidskriftsartikel (refereegranskat)abstract
- Ta thin films were grown on Si substrates at different inclination angles with respect to the sputter source using high power impulse magnetron sputtering (HIPIMS), an ionized physical vapor deposition technique. The ionization allowed for better control of the energy and directionality of the sputtered species, and consequently for improved properties of the deposited films. Depositions were made on Si substrates with the native oxide intact. The structure of the as deposited films was investigated using X-ray diffraction, while a four-point probe setup was used to measure the resistivity. A substrate bias process-window for growth of bcc-Ta was observed. However, the process-window position changed with changing inclination angles of the substrate. The formation of this low-resistivity bcc-phase could be understood in light of the high ion flux from the HIPIMS discharge.
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| 3. |
- Böhlmark, Johan, et al.
(författare)
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Guiding the deposition flux in an ionized magnetron discharge
- 2006
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Ingår i: Thin Solid Films. - Amsterdam, Netherlands : Elsevier. - 0040-6090 .- 1879-2731. ; 515:4, s. 1928-1931
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Tidskriftsartikel (refereegranskat)abstract
- A study of the ability to control the deposition flux in a high power impulse magnetron sputtering discharge using an external magnetic field is presented in this article. Pulses with peak power of 1.4 kWcm-2 were applied to a conventional planar magnetron equipped with an Al target. The high power creates a high degree of ionization of the sputtered material, which opens for an opportunity to control of the energy and direction of the deposition species. An external magnetic field was created with a current carrying coil placed in front of the target. To measure the distribution of deposition material samples were placed in an array surrounding the target and the depositions were made with and without the external magnetic field. The distribution is significantly changed when the magnetic field is present. An increase of 80 % in deposition rate is observed for the sample placed in the central position (right in front of the target center) and the deposition rate is strongly decreased on samples placed to the side of the target. The measurements were also performed on a conventional direct current magnetron discharge, but no major effect of the magnetic field was observed in that case.
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| 4. |
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| 5. |
- Böhlmark, Johan, et al.
(författare)
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Spatial electron density distribution in a high-power pulsed magnetron discharge
- 2005
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 33:2, s. 346-347
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Tidskriftsartikel (refereegranskat)abstract
- The spatial electron density distribution was measured as function of time in a high-power pulsed magnetron discharge. A Langmuir probe was positioned in various positions below the target and the electron density was mapped out. We recorded peak electron densities exceeding 1019 m-3 in a close vicinity of the target. The dynamics of the discharge showed a dense plasma expanding from the "race-track" axially into the vacuum chamber. We also record electrons trapped in a magnetic bottle where the magnetron magnetic field is zero, formed due to the unbalanced magnetron.
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| 6. |
- Böhlmark, Johan, et al.
(författare)
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The ion energy distributions and ion flux composition from a high power impulse magnetron sputtering discharge
- 2006
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 515:4, s. 1522-1526
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Tidskriftsartikel (refereegranskat)abstract
- The energy distribution of sputtered and ionized metal atoms as well as ions from the sputtering gas is reported for a high power impulse magnetron sputtering (HIPIMS) discharge. High power pulses were applied to a conventional planar circular magnetron Ti target. The peak power on the target surface was 1-2 kW/cm(2) with a duty factor of about 0.5%. Time resolved, and time averaged ion energy distributions were recorded with an energy resolving quadrupole mass spectrometer. The ion energy distributions recorded for the HIPIMS discharge are broader with maximum detected energy of 100 eV and contain a larger fraction of highly energetic ions (about 50% with E-i > 20 eV) as compared to a conventional direct current magnetron sputtering discharge. The composition of the ion flux was also determined, and reveals a high metal fraction. During the most intense moment of the discharge, the ionic flux consisted of approximately 50% Ti1+, 24% Ti2+, 23% Ar1+, and 3% Ar2+ ions.
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| 7. |
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| 8. |
- Edin, Emil, et al.
(författare)
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interfaceBuilder, a python tool for building and analyzing interfaces suitable for use in large screening applications
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Interfaces in materials are of importance in a large number of applications. In order to gain a better understanding of interfaces, their structures, their properties, and processes related to them and to be able to predict which interfaces are most likely to form, easy to use tools are needed for finding, constructing, storing and analyzing interfaces. Presented here is a free python package which allows for the finding and storing of the lowest strain interfaces between base structures at different relative rotations. Further, the package allows for fast and easy analysis of interface datasets by including standardized containers for interface properties and a large number of tools designed for visualization and analysis of geometric parameters as well as properties calculated using third party software and loaded back in to the original dataset. The package is well suited to be part of large scale screening searches of interface parameters which is demonstrated here by the calculation of the work of adhesion for 5000 interfaces, each with three different relative translations, in the interface system made up of the [100]/[110] surfaces of BCC W.
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| 9. |
- Edin, Emil, et al.
(författare)
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MD study of C diffusion in WC/W interfaces observed in cemented carbides
- 2019
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Ingår i: International journal of refractory metals & hard materials. - : ELSEVIER SCI LTD. - 0263-4368. ; 85
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Tidskriftsartikel (refereegranskat)abstract
- WC/Co tool used in the turning of Ti-alloys are subject to rapid crater wear due to chemical processes at the tool chip interface in the form of dissolution/diffusion. It has been observed that a thin layer of bcc W forms on the outermost WC grains in contact with the Ti workpiece meaning that C has diffused away from the WC. The rates involved in this process are of interest for formulating a theory of how wear progresses during turning of Ti-alloys. In this work we investigate the rates involved in this diffusion process by means of classical MD simulations on 6 different WC/W interfaces, 3 with a basal WC surface and 3 with a prismatic WC surface, as a function of C depletion in the outermost WC layer. The results show that all interfaces are stable and that principally no diffusion events of C occur at temperatures below 1373 K for C depletion levels below 30 at.%. At 50 at.% depletion, C diffusion starts occurring regularly and at 70 at.% depletion and above the majority of the C atoms are diffusing except at the lowest temperatures. Additionally, any difference in diffusion rate observed between the basal and prismatic interfaces in their pristine states have vanished at the point of 50 at.% depletion. This all points to a process which is initially slow for each layer of the WC but which increases in speed substantially as C atoms are removed.
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| 10. |
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