| 1. |
- Böhlmark, Johan, et al.
(författare)
-
The ion energy distributions and ion flux composition from a high power impulse magnetron sputtering discharge
- 2006
-
Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 515:4, s. 1522-1526
-
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.
|
|
| 2. |
|
|
| 3. |
- Ehiasarian, A. P., et al.
(författare)
-
Comparison of microstructure and mechanical properties of chromium nitride-based coatings deposited by high power impulse magnetron sputtering and by the combined steered cathodic arc/unbalanced magnetron technique
- 2004
-
Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 457:2, s. 270-277
-
Tidskriftsartikel (refereegranskat)abstract
- Sliding, abrasive, and impact wear tests were performed on chromium nitride (CrN)-based coatings deposited on mirror-polished M2 high speed steel substrates by the novel high power impulse magnetron sputtering (HIPIMS) utilising high peak cathode powers densities of 3000 W cm−2. The coatings were compared to single layer CrN and multilayer superlattice CrN/NbN coatings deposited by the arc bond sputtering (ABS) technique designed to improve the coating substrate adhesion by a combined steered cathodic arc/unbalanced magnetron (UBM) sputtering process. The substrates were metal ion etched using non-reactive HIPIMS or steered cathodic arc at a substrate bias voltage of −1200 V. Subsequently a 2- to 3-μm thick CrN or CrN/NbN coating was deposited by reactive HIPIMS or UBM. No bias was used during the HIPIMS deposition, while the bias during UBM growth was in the range 75–100 V. The ion saturation current measured by a flat electrostatic probe reached values of 50 mA cm−2 peak for HIPIMS and 1 mA cm−2 continuous during UBM deposition. The microstructure of the HIPIMS coatings observed by transmission electron microscopy was fully dense in contrast to the voided columnar structure observed in conventional UBM sputtered CrN and CrN/NbN. The sliding wear coefficients of the HIPIMS CrN films of 2.3×10−16 m3 N−1 m−1 were lower by a factor of 4 and the roughness of the wear track was significantly reduced compared to the UBM-deposited CrN. The abrasive wear coefficient of the HIPIMS coating was 2.2×10−13 m3 N−1 m−1 representing an improvement by a factor of 3 over UBM deposited CrN and a wear resistance comparable to that of the superlattice CrN/NbN. The adhesion of the HIPIMS deposited CrN was comparable to state-of-the-art ABS technology.
|
|
| 4. |
|
|
| 5. |
- Ehiasarian, A.P., et al.
(författare)
-
High power pulsed magnetron sputtered CrNx films
- 2003
-
Ingår i: Surface & Coatings Technology. - 0257-8972 .- 1879-3347. ; 163-164, s. 267-272
-
Tidskriftsartikel (refereegranskat)abstract
- Microstructure and macroscopic properties of droplet free CrN films deposited by the recently developed high power pulsed magnetron sputtering (HIPIMS) technique are presented. Magnetron glow discharges with peak power densities reaching 3000 W cm-2 were used to sputter Cr targets in both inert and reactive gas atmospheres. The flux arriving at the substrates consisted of neutrals and ions (approx. 70/30) of the sputtered metal and working gas atoms (Ar) with significantly elevated degree of ionization compared to conventional magnetron sputtering. The high-speed steel and stainless steel substrates were metal ion etched using a bias voltage of -1200 V prior to the deposition of CrN films. The film-to-substrate interfaces, observed by scanning transmission electron microscope cross-sections, were clean and contained no phases besides the film and substrate ones or recrystallized regions. CrN films were grown by reactive HIPIMS at floating potential reaching -160 V. Initial nucleation grains were large compared to conventional magnetron sputtered films, indicating a high adatom mobility in the present case. The films exhibited polycrystalline columnar growth morphology with evidence of renucleation. No intercolumnar voids were observed and the corrosion behavior of the film was superior to arc deposited CrNx. A high density of lattice defects was observed throughout the films due to the high floating potential. A residual compressive stress of 3 GPa and a hardness value of HK0.025=2600 were measured. A low friction coefficient of 0.4 and low wear rates against Al2O3 in these films are explained by the absence of droplets and voids known to contribute to extensive debris generation.
|
|
| 6. |
- Ehiasarian, A.P., et al.
(författare)
-
Influence of high power densities on the composition of pulsed magnetron plasmas
- 2002
-
Ingår i: Vacuum. - 0042-207X .- 1879-2715. ; 65:2, s. 147-154
-
Tidskriftsartikel (refereegranskat)abstract
- The application of high power pulses with peak voltage of -2 kV and peak power density of 3 kWcm-2 to magnetron plasma sources is a new development in sputtering technology. The high power is applied to ordinary magnetron cathodes in pulses with short duration of typically some tens of microseconds in order to avoid a glow-to-arc transition. High plasma densities are obtained which have been predicted to initiate self-sputtering. This study concerns Cr and Ti cathodes and presents evidence of multiply charged metal ions as well as of Ar ions in the dense plasma region of the high power pulsed magnetron discharge and a substantially increased metal ion production compared to continuous magnetron sputtering. The average degree of ionisation of the Cr metal deposition flux generated in the plasma source was 30% at a distance of 50 cm. Deposition rates were maintained comparable to conventional magnetron sputtering due to the low pressure of operation of the pulsed discharge - typically 0.4 Pa (3mTorr) of Ar pressure was used. Observations of the current-voltage characteristics of the discharge confirmed two modes of operation of the plasma source representing conventional pulsed sputtering at low powers (0.2 kWcm-2) and pulsed self-sputtering at higher powers (3 kWcm-2). The optical emission from the various species in the plasma showed an increase in metal ion-to-neutral ratio with increasing power. The time evolution within a pulse of the optical emission from Ar0, Cr0, Cr1+, and Cr2+ showed that at low powers Cr and Ar excitation develops simultaneously. However, at higher powers a distinct transition from Ar to Cr plasma within the duration of the pulse was observed. The time evolution of the discharge at higher powers is discussed. © 2002 Elsevier Science Ltd. All rights reserved.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Lattemann, Martina, et al.
(författare)
-
Investigation of high power impulse magnetron sputtering pretreated interfaces for adhesion enhancement of hard coatings on steel
- 2006
-
Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 200:22-23, s. 6495-6499
-
Tidskriftsartikel (refereegranskat)abstract
- In order to improve the adhesion of hard coatings such as CrN, a surface pretreatment by the novel high power impulse magnetron sputtering (HIPIMS) technique followed by reactive unbalanced d.c. magnetron sputtering deposition was performed using a Cr target. The HIPIMS plasma comprising a high metal ion-to-neutral ratio consisting of single- and double-charged metal species identified by mass spectrometry increased the metal ion flux to the substrate. When applying a negative substrate bias Ub the adhesion was enhanced due to sputter cleaning of the surface and metal ion intermixing in the interface region. This intermixing, resulting in a gradual change of the composition, is considered to enhance the adhesion of the hard coatings on steel substrates. The pretreatment was carried out in an inert gas atmosphere at a pressure of pAr = 1 mTorr, the duration was varied between 25 and 75 min, whereas the negative substrate bias was varied between 400 V and 1200 V. The adhesion was found to depend on the substrate bias as well as on the target power and, for low substrate bias, on the duration of the pretreatment. For CrN the critical load of failure determined by scratch test could be increased in comparison to the values reported for specimens pretreated by conventional Ar etching. The influence of the target peak voltage, the substrate bias as well as pretreatment time on the constitution and morphology of the interface after the pretreatment is discussed applying analytical transmission electron microscopy.
|
|
| 10. |
|
|
