Institute of Fundamental Technological Research

The presented paper concerns the technological aspects of the interface evolution in the nickel-silicon carbide composite during the sintering process. The goal of our investigation was to analyse the material changes occurring due to the violent reaction between nickel and silicon carbide at elevated temperatures. The nickel matrix composite with 20 vol pct SiC particles as the reinforcing phase was fabricated by the spark plasma sintering technique. The sintering tests were conducted with variable process conditions (temperature, time, and pressure). It was revealed that the strong interaction between the individual components and the scale of the observed changes depends on the sintering parameters. To identify the microstructural evolution, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy were used. The silicon carbide decomposition process progresses with the extension of the sintering time. As the final product of the observed reaction, new phases from the Ni-Si system and free carbon were detected. The step-by-step materials evolution allowed us to reveal the course of the reaction and the creation of the new structure, especially in the reaction zone. The detailed analysis of the SiC decomposition and formation of new components was the main achievement of the presented paper.

The laser spallation technique was applied for measurement of residual stress and adhesion of thin films. Two films of different properties, ductile and soft Ti, and hard and brittle TiN, were studied. The films were produced on 304 steel substrate by PVD method. The residual stress value obtained by laser spallation technique LST were compared with stress value from X-ray diffraction method. Good agreement of stress values measured by both methods was attained. Additionally, the interface strength of the films was tested by laser adhesion spallation technique LASAT with use of VISAR system. It was shown that shock wave induced by a nanosecond laser pulse adequately determines properties of PVD thin films on metal substrate

Laser spallation technique, Residual stress, Adhesion, Thin layer, PVD, VISAR system

The characteristics of hydroxyapatite (Ca10(PO4)6(OH)2) thin films deposited by the pulsed laser deposition technique have been describrd. The laser used was a Nd:YAG, operating at the wavelength of 355 nm. All films were deposited at room temperature, either in ambient water vapour or in vacuum, and were annealed, after deposition in air, at 600 °C. Next, they were examined with the use of an X-ray diffractometer, Fourier transform infrared spectrometer, atomic force microscope, micro scratch tester and scanning electron microscope. The analyses showed that crystalline films exhibiting very strong
adhesion to the substrate have been obtained.

pulsed laser deposition, hydroxyapatite, biomaterials