Wyniki wyszukiwania - Biblioteka Nauki

1

Multiscaled analysis of wear mechanism of titanium and carbon basis multilayer coatings

100%

Major L. , Lackner J. M. , Major B.

Archives of Materials Science and Engineering

|

2013

|

tom Vol. 63, nr 2

53--57

EN

Purpose: The wear mechanisms of Ti/TiN and (TiN/Ti/a-C:H) multilayer coatings were investigated. Coatings were deposited using the hybrid Pulsed Laser Deposition technique (PLD) on austenitic stainless steel. The microstructure investigations were performed with the TECNAI G2 SuperTWIN FEG (200kV) transmission electron microscope. Ceramic TiN and a-C:H layers showed brittle cracking, while very thin metallic Ti layers were deformed plastically. The presence of metallic phase led to the cracking resistance and increased an energetic cost of propagating cracks. Design/methodology/approach: Ti/TiN and (TiN/Ti/a-C:H) multilayer coatings were deposited on austenitic stainless steel (316L) using the hybrid PLD (Pulsed Laser Deposition + magnetron sputtering) equipped with high purity titanium target (99.9% at. Ti) and carbon target. Microstructure was analyzed on thin foils prepared using the FEI Dual BeamTM FIB system equipped with an Omniprobe lift-out technique. Foils were cut perpendicularly both to coating surface and wear path. The microstructure observations were performed using TECNAI F20 SuperTWIN (200kV) transmission electron microscope. Findings: The wear mechanism of the multilayer coating was realized through brittle cracking of ceramic layers and plastic deformation of metallic ones. Research limitations/implications: Optimization of layer thickness and modulation; application of advanced deposition and diagnostic methods. Practical implications: Switching from mono- to multi-layered coatings allows changing the mechanism of wear from through-coating cracking leading to catastrophic delamination to more gradual layer-by-layer coating removal. The farther wear decrease should be sought at lower multilayer period. Originality/value: Design and fabrication of Ti/TiN and (TiN/Ti/a-C:H) multilayer coatings revealing an improved behavior in service systems subjected to wearing. Multiscale microstructure diagnostics of multilayer coatings.

2

Microscale interpretation of tribological phenomena in Ti/TiN soft-hard multilayer coatings on soft austenite steel substrates

100%

Lackner J. , Major L. , Kot M.

|

2011

|

tom Vol. 59, nr 3

343-355

EN

The mechanical and tribological behavior of physical vapor deposited coatings on soft substrate materials gains increasing interest due to economical and environmental aspects – e.g. substitution of steels by light-weight metals or polymers in transport vehicles. Nevertheless, such soft materials require surface protection against wear in tribological contacts. Single layer hard coatings deposited at room temperature are brittle with a relatively poor adhesion. Therefore, they should be better substituted by tough multilayer coatings of soft-hard material combinations. However, the mechanics of such multilayer coatings with several 10 nm thick bilayer periods is difficult and yet not well described. The presented work tries to fill the gap of knowledge by focusing both on mechanical investigations of hardness, adhesion, and wear and on microscopic elucidation of deformation mechanisms. In the paper 1 ěm thick Ti/TiN multilayer stacks were deposited by magnetron sputtering on soft austenitic steel substrates at room temperature to prevent distortion of functional components in future applications. High hardness was found for 8 and 16 bilayer films with modulation ratio Ti:TiN = 1:2 and 1:4. This was attributed (with use of transmission electron microscopy) to stopping the crack propagation in thin Ti layers of the multilayer systems by shear deformation combined with different fracture mechanisms in comparison with that for the TiN single layers (edge cracks at the border of the contact area and ring cracks outside, respectively).

3

Contribution of TiN/Ti/a-C:H multilayers architecture to biological and mechanical properties

88%

Major L. , Lackner J. M. , Kot M. , Janusz M. , Major B.

|

nr 3

4

Nanocrystalline Cr/CrN and Ti/TiN multilayer coatings produced by pulsed laser deposition at room temperature

75%

Lackner J. M. , Waldhauser W. , Major L. , Morgiel J. , Kot M. , Major B.

|

nr 2

5

Nanocrystalline Cr/CrN and Ti/TiN multilayer coatings produced by pulsed laser deposition at room temperature

75%

Lackner J. M. , Waldhauser W. , Major L. , Morgiel L. , Kot M. , Major B.

|

2006

|

tom Vol. 54, nr 2

175-180

EN

Mechanical components and tools in modem industry are facing increasing performance requirements leading to the growing need for advanced materials and thus, for modem frictional systems. In the last decades, the Pulsed Laser Deposition (PLD) has emerged as an unique tool to grow high quality mono- as well as multilayers surfaces in metal-lic/ceramic systems. Building up a knowledge base of tribological properties of indu-strially-scaled, room temperature deposited PLD hard coatings are the most important step for the application of these coatings in engineering design. Although single-layer coatings find a range of applications, there are an increasing number of applications where the properties of a single material are not sufficient. One way to surmount this problem is to use a multilayer coating. Application of metallic interlayers improves adhesion of nitride hard layer in multilayer systems, which has been used in PVD processes for many years, however, the PLD technique gives new possibilities to produce system comprising many bilayers at room temperature. Tribological coatings consisted of 2, 4 and 16 bilayers of Cr/CrN and Ti/TiN type were fabricated with the Pulsed Laser Deposition (PLD) technique in the presented work. It is found in transmission electron examinations on thin foils prepared from cross-section that both nitride-based multilayer structures studied are characterized by small columnar crystallite sizes and high defect density, what might rise their hardness but compromise coating adhesion. The intermediate metallic layers contained larger sized and less defective columnar structure compared to the nitride layers, which should improve the coatings toughness. Switching from single layer to multi-layer metal/nitride composition improved resistance to delamination.

6

Laser modification of the materials surface layer - a review paper

63%

Kusiński J. , Kac S. , Kopia A. , Radziszewska A. , Rozmus-Górnikowska M. , Major B. , Major L. , Marczak J. , Lisiecki A.

|

tom Vol. 60, nr 4

711-728

EN

The state of laser processing in surface materials modification in Poland is reported, based on own experience, coworkers and coauthors results, as well the literature review. The curriculum concerning historical development of lasers and laser technology in Poland, laser-matter interaction, as well basis of different laser techniques applied in materials surface engineering (solid state hardening, melting, alloying, cladding, ablation, shot peening, cleaning and texturing) are reviewed, and compared with results of coauthors, as well with a wide range of Polish authors papers. Finally, it is concluded that overall state of research on laser application in surface engineering in Poland is well developed and still growing industrial application is observed.