Solid State Phenomena Vol. 225

Abstract: Cavitation attack in liquids generated a various states of stresses in surface layers of metals. Differences in stress state effects on hydrogen absorption activated by the cavitation implosion. Results of XRD investigation and FEM modeling shows on inhomogenity of process.

Abstract: The work shows the results of the tests of 9Cr-1Mo steel, which was for 10 years operated in the CCR platforming unit in Group Lotos SA in Gdańsk, and then in the laboratory was sulphidised during 166 h at a temperature of 600 °C. Sulphidation was performed in a mixture of H₂-H₂S gases at the vapour pressure of sulphur 4.1·10^-14 atm, so the order of magnitude of vapour pressure was less than that of the dissociation pressure of FeS. Although sulphidising took place in conditions which preclude any iron sulphide formation, research results have demonstrated that after 166 hour exposure in reaction mixture in 9Cr-1Mo steel produces iron and chromium sulfides. Sulphide precipitates form under a layer of fine carbides, located directly on the surface of steel. Formation of scale sulphide here is most likely caused by the penetration of hydrogen sulphide through the porous layer of carbides that increases the pressure of hydrogen sulphide. Thus the vapour of sulphur in apertures and narrow passages occurs between the layer of carbides and the rest of oversaturated carbon layer top, until its pressure value is reached allowing the formation of sulphide scaling.

Abstract: The article presents the phenomenology of problems of cell guides container ships wear processes. In the paper the issues of tribological and nontribological types of wear processes. Presented problems regard to the analysis of exposures that cause wear in the carriage by sea and in the process of containers handling at the maritime port.

Abstract: The aim of the study was to examine the effect of surface treatment of titanium elements on the bond strength to zirconium dioxide. Forty cylindrical titanium discs (Tritan CpTi 1) were divided into four groups (n=10) that were subject to: grinding (Group A), grinding and acid-etching with 5% HF (Group B), sandblasting with 60μm alumina particles (Group C) and sandblasting with 60μm alumina particles and acid-etching with 5% HF (Group D). Prepared materials were bonded to cylindrical discs made of zirconium dioxide (Ceramill Zi) by composite cement (Panavia F 2.0). The specimens were tested for the shear bond strength. The load was applied to the moment of the bond failure. Than the debonded specimens were vertically sectioned and the fractographic analysis of interfacial fractures under SEM as well as the analysis of chemical composition of the obtained fractures using radiographic spectrum were performed. The results were subject to the statistical analysis by using the analysis of variance. The highest values of bond strength were obtained for specimens whose surface was sandblasted and abraded. Fractographic investigation and the analysis of chemical composition of the cross-sections of the interfacial fractures revealed that the fracture occurred at the titanium-resin cement interface. Air abrasion treatment considerably improves the titanium and composite cement bonding and should be recommended for cementation of prosthodontic restorations constructed on titanium implants.

Abstract: Article presents results of measurements of vital parameters of PVD coatings of potential application in medicine (joint replacements or medical tools). The phase identification, level of residual stresses and texture were determined for various coatings by X-ray diffraction method. Chemical composition of coatings was verified by means of XRF. A set of measurements reveled the existence of advantageous compressive stresses in coatings, the texture determination showed undesirable fiber texture in TiN coating and advantageous uniformity of TiCN ones. XRF analysis pointed out the necessity of careful preparation of samples during PVD process during which phenomena of inhomogeneity in chemical can be present as it is presented in the paper.