Formation of Cr-Zr gradient layer by magnetron sputtering and ion mixing

The gradient Cr-Zr layer was formed onto Zr-1Nb substrate by magnetron sputtering of chromium and zirconium targets and ion mixing (Ar+ with 25 keV). The distribution of Cr and Zr elements in the deposited coatings was measured by using a glow discharge optical emission spectroscopy. The optimal ion fluence onto the substrate was 8×1019 ion/m2. At higher ion dose, the intensive sputtering of the deposited coating was observed

Magnetron Deposition of Cr Coatings with RF-ICP Assistance

The article describes a comparative analysis of chromium coatings deposited by magnetron sputtering with and without ion assistance induced by a radiofrequency inductively coupled plasma (RF-ICP) source. Four series of 2 µm-thick Cr coatings were prepared, and then their cross-sectional microstructure, crystal structure and corrosion resistance were investigated by scanning and transmission electron microscopy, X-ray diffraction and a potentiodynamic polarization method. RF-ICP assistance led to significant enhancement (almost twofold) of ion current density in a substrate. The role of RF-ICP assistance in coating properties for planetary-rotated substrates was defined in terms of ion-to-atom ratio in particle flux entering a substrate. Calculations of particle and ion flux densities revealed an increase in ion-to-atom ratio from 0.18 to 1.43 and 0.11 to 0.84 in substrate positions distant from the magnetron sputtering systems depending on their design. RF-ICP assistance is beneficial for depositing dense Cr coatings with increased corrosion resistance in a 3.5 wt.% NaCl solution. The corrosion rate of AISI 321 steel can be decreased from 6.2 × 10−6 to 4.0 × 10−8 mm/year by deposition of the dense Cr coating

Electrospun VDF-TeFE Scaffolds Modified by Copper and Titanium in Magnetron Plasma and Their Antibacterial Activity against MRSA

Copolymer solution of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) was used for electrospinning of fluoropolymer scaffolds. Magnetron co-sputtering of titanium and copper targets in the argon atmosphere was used for VDF-TeFE scaffolds modification. Scanning electron microscopy (SEM) showed that scaffolds have a nonwoven structure with mean fiber diameter 0.77 ± 0.40 μm, mean porosity 58 ± 7%. The wetting angle of the original (unmodified) hydrophobic fluoropolymer scaffold after modification by titanium begins to possess hydrophilic properties. VDF-TeFE scaffold modification by titanium/copper leads to the appearance of strong antibacterial properties. The obtained fluoropolymer samples can be successfully used in tissue engineering

Deposition of Cr films by hot target magnetron sputtering on biased substrates

The Cr films were deposited by hot target magnetron sputtering on grounded and biased substrates. The deposition modes with low and high deposition rates (different by 4 times) were selected. The sublimation of hot Cr target decreased the re-sputtering effect of the growing films under ion bombardment and reduced the losses of deposition rate from 28.7 to 13.4% (for −40 V bias and 1.9 kW discharge power). The calculations of energy flux density on the substrate revealed that the major contribution has a target radiation (56.2…85.5%) and kinetic energy of deposited particles and ions (4.8…34.3%) become a significant only with substrate biasing. The XRD measurements showed cubic structured (110) Cr films with compressive stresses (0.48…0.90 GPa), which is non-dependent from bias voltage for high-rate deposition modes. The Cr films mainly had a columnar structure and columnar width increased from 50 to 450 nm with rise of discharge power (W). The substrate biasing and high deposition rate resulted in the formation of irregular microstructure of the Cr films along their thickness from porous to columnar state. The indentation tests showed the strong dependence of film hardness and toughness (H/E) from W and different behavior of the mechanical properties of the Cr films for the deposition on biased substrates with low and high deposition rates