Bogusław Rajchel

Low temperature Ti-Si-C thin film deposition by ion beam assisted methods

Thin, multiphase Ti-Si-C coatings were formed by IBSD or by IBAD methods on AISI 316L steel substrates in room temperature, using single Ti3SiC2 target. In those methods the TiXSiCY coatings were formed from the flux of energetic atoms and ions obtained by ion sputtering of the Ti3SiC2 compound sample. As sputtering beam the beam of Ar+ ions at energy of 15keV was applied. In the IBAD method the dynamically formed coatings were additionally bombarded by beam of Ar+ ions at energy of 15keV. The ion beams parameters were obtained by using Monte Carlo computer simulations. The morphology (SEM, TEM), chemical (EDS/EDX) and phase composition (XRD) examinations of formed coatings were provided as well as confocal Raman microspectroscopy. Analyzed coatings were relatively thin (150nm-1μm), flat and dense. XRD analysis indicated in amorphous TiSi, the traces of Ti5Si3 and other phases from Ti-Si-C system (TiSi, TiSi2,Ti3SiC2). For chemical bonds investigation, the laser beam with length of 532nm was used. Those analyses were performed in the low (LR) or in high (HR) resolution modes in room temperature and in 4000C. In the HR mode the spectral resolution was close to 2 cm−1. In Raman spectra peaks at: 152cm−1, 216cm−1, 278cm−1, 311 cm−1, 608cm−1, 691cm−1 were recorded. Nanoindentation tests were done on coated and uncoated substrates with diamond, Berkovich-type indenter. Vickers hardness HIT and reduced elastic modulus EIT were calculated using Olivier& Pharr method. HIT for coated substrates was in the range 2.7 to 5.3 GPa, EIT was 160 GPa.

On the wear of TiBx/TiSiyCz coatings deposited on 316L steel

Abstract Bilayer TiBx/TiSiyCz coatings were formed on AISI 316L steel substrates by dual beam ion beam assisted deposition from TiBx and TiSiyCz targets. Coated and uncoated substrates were subjected to nanoindentation, scratch and friction-wear tests. Scratch and ball-on-disc tests were conducted in non-lubricated sliding, using a diamond pin and 100Cr6 steel ball, respectively. Scanning electron microscopy and atomic force microscopy were used to examine the surfaces of coated samples, before and after tests. To investigate wear mechanisms in the coating–substrate systems, thin foils were prepared from worn areas for transmission electron microscopy observations. TiBx/TiSiyCz coatings proved to be well adherent to steel substrates. The main wear mechanism was of abrasive type. Intensive plastic deformation of steel substrate under critical loads was revealed.

Structure and properties of composite surface layers produced on NiTi shape memory alloy by a hybrid method

AbstractA hybrid process that combines oxidation under glow-discharge conditions with ion beam-assisted deposition (IBAD) has been applied to mechanically polished NiTi shape memory alloy in order to produce composite surface layers consisting of a TiO2 layer and an external carbon coating with an addition of silver. The produced surface layers a-C(Ag) + TiO2 type have shown increased surface roughness, improved corrosion resistance, altered wettability, and surface free energy, as well as reduced platelet adhesion, aggregation, and activation in comparison to NiTi alloy in initial state. Such characteristics can be of great benefit for cardiac applications.

Vibrational Spectroscopy of Binary Titanium Borides: First-Principles and Experimental Studies

Vibrational dynamics of binary titanium borides is studied from first-principles. Polarized and unpolarized Raman spectra of TiB, TiB2, and Ti3B4 are reported along with the experimental spectra of commercial powder and bulk TiB2 containing less than 1 wt.% of impurity phases. The X-ray diffraction spectroscopy, applied for phase composition examination of both bulk and powder materials, identifies only the TiB2 phase. The simulated Raman spectra together with literature data support interpretation and refinement of experimental spectra which reveal components arising from titanium dioxide (TiO2) and amorphous boron carbide (B4C) impurity phases as well as graphitic carbon. These contaminations are the by-products of synthesis, consolidation, and sintering aids employed to fabricate powder and bulk titanium diboride.

Introduction to Applications of the Raman Spectroscopy to Experimental Mechanics

In this work, the mechanical state of the material is considered in the form of the oscillation of the molecule. The analysis is carried out for material without an external load and for material under the action of the mechanical load. These two states are tested in a Raman spectroscope where oscillations of molecule with modulations are induced by laser light. One should expect that the results of these investigations will confirm the capability of Raman spectroscopy in analysis of molecular mechanical state of material.This research is carried out using photoelastic material, and an analogy to state of stress on the continuum level is presented by photoelastisity.

Investigation of TiO2 Thin Coatings for Medical Applications by X-Ray Diffraction and Raman Microspectroscopy

The titanium and titanium alloys endoprostheses surface may be improved by forming TiOx single layer or TiOx – hydroxyapatite multi – layer on their surface. Biocompatibility of TiOx layers depends highly on their microstructure, parameters of formation method and properties of substrate. Paper presents microstructure of the TiOx layer formed on titanium surface in fluidized bed reactor. In order to evaluate thickness, microstructure and Ti:O concentration ratio X-ray diffraction, Confocal Raman microspectroscopy methods are realized. Methods enables to define every type of TiOx structure simultaneously including rutile which dominates in investigated layers.

Ti–Si–C Films Formed by Dual Beam Ion Assisted Deposition

Ti–Si–C coatings were formed at room temperature on AISI 316L steel substrates by dual beam ion assisted deposition technique from single compound Ti3SiC2 target. Scanning and transmission electron microcopy method were used to examine as-deposited coatings. Their morphology was smooth and dense and their thickness were in the range from 100 nm to 1μm. Raman spectra of coated substrates were collected up with five peaks at the same positions as for Ti3SiC2 compound target. TEM and HRTEM examinations, accompanied by SAED analyses revealed that deposited films were amorphous. Nanoindentation tests were provided on coated and uncoated substrates and hardness HIT and reduced elastic modulus EIT were calculated using the Oliver & Pharr method.