High Temperature Sliding Wear of NiAl-based Coatings Reinforced by Borides

  • Oleksandr UMANSKYI Frantsevich Institute for Problems of Material Science, Kyiv
  • Olena POLIARUS Frantsevich Institute for Problems of Material Science, Kyiv
  • Maksym UKRAINETS Frantsevich Institute for Problems of Material Science, Kyiv
  • Maksim ANTONOV Tallinn University of Technology, Tallinn
  • Irina HUSSAINOVA Tallinn University of Technology, Tallinn
Keywords: diboride, metallide, composite material, coating, high temperature oxidation, tribosynthesis, solid lubricant, wear resistance

Abstract

The development of composite materials (CM) in the systems “metal-refractory compound” is one of the up-to-date trends in design of novel materials aimed at operating under the conditions of significant loads at high temperature. To design such material, NiAl, which is widely used for deposition of protective coatings on parts of gas-turbine engines, was selected for a matrix. To strengthen a NiAl under the conditions of intense wear and a broad temperature range (up to 1000 °C), it is reasonable to add refractory inclusions. Introduction of refractory borides into matrix leads to a marked increase in metal wear resistance. In order to research the behavior of the designed composites at high temperatures and to study the influence of oxides on the friction processes, the authors carried out high temperature oxidation of CM of the above systems at 1000 °С for 90 min. It was determined that all of the composites were oxidized selectively and that the thickness of oxide layers formed on the boride inclusions is 37 times that on the oxides formed on the NiAl matrix. The mechanism of wear of gas-thermal coatings of the NiAlМеB2 systems was studied for conditions of high temperature tribotests using the «pin-on-disc» technique. The obtained results indicate that introduction of TiB2, CrB2 and ZrB2 leads to their more intense oxidation during high temperature tribotests as compared to the matrix. The oxides formed on refractory borides act as solid lubricants, which promote a decrease in wear of the contact friction pairs. For more detailed investigation of the effect of tribo-oxidation products on the friction processes, tribotests were conducted for prior oxidized (at 900 °С) coatings NiAl15 wt.% CrB2 (TiB2, ZrB2).

DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8093

Author Biographies

Oleksandr UMANSKYI, Frantsevich Institute for Problems of Material Science, Kyiv
D.Sc., Head of Material Science and Surface Engineering Department
Olena POLIARUS, Frantsevich Institute for Problems of Material Science, Kyiv
Ph. D., Material Science and Surface Engineering Department
Maksym UKRAINETS, Frantsevich Institute for Problems of Material Science, Kyiv
Material Science and Surface Engineering Department
Maksim ANTONOV, Tallinn University of Technology, Tallinn
Ph. D., Senior Researcher, Head of Tribology Laboratory, Department of Materials Engineering
Irina HUSSAINOVA, Tallinn University of Technology, Tallinn
D.Sc., Department of Materials Engineering
Published
2016-01-21
Section
METALS, ALLOYS, COATINGS