Heat protective coatings on niobium alloys
The article shows that during plasma-diffusion deposition, a multilayer coating was formed on the surface of the niobium alloy. A highly porous plasma-sprayed layer of molybdenum silicide has a significant spread in thickness (h=100...350 μm, Hμ20=6880 MPa). When studying the microstructure of sampl...
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| Format: | Article |
| Language: | English |
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National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute"
2020-12-01
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| Series: | Mechanics and Advanced Technologies |
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| Online Access: | http://journal.mmi.kpi.ua/article/view/219550 |
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| author | Vitaliy Babak Boris Lyashenko Vitaliy Shchepetov Sergei Kharchenko |
| author_facet | Vitaliy Babak Boris Lyashenko Vitaliy Shchepetov Sergei Kharchenko |
| author_sort | Vitaliy Babak |
| collection | DOAJ |
| description | The article shows that during plasma-diffusion deposition, a multilayer coating was formed on the surface of the niobium alloy. A highly porous plasma-sprayed layer of molybdenum silicide has a significant spread in thickness (h=100...350 μm, Hμ20=6880 MPa). When studying the microstructure of samples with a plasma-diffusion coating after testing, it was found that cracks in the coating originate in the process of creep, mostly at the interface between the plasma and diffusion layers of the coating. The source of their origin is individual discontinuities in the diffusion layer as delivered. Crack propagation occurs both into the plasma and diffusion layers of the coating. Crack growth in the plasma layer is inhibited due to the rounded nature of the pores and the increased plasticity of this layer. The growth of cracks deep into the sample is, as a rule, inhibited by a boride sublayer. The advantage of plasma-diffusion technology provided an increased plasticity of the coating, the presence of thin barrier sublayers, a discontinuous coating structure, the presence of low-melting compounds that contribute to the healing of defects in the coating, an increase in its corrosion resistance and resistance to thermal fatigue destruction. The combination of these properties made it possible to provide an increase in durability compared to silicide and borosilicide coatings under conditions of isothermal creep in air (1400°C, 50 MPa) 1.9...3.7 times and under conditions of thermal cyclic creep (1400-250°C, 50 MPa) in 6.8...8.5 times. It has been determined that the use of a discrete structure will increase the thickness of the coating layer and ensure an increase in their working properties. |
| format | Article |
| id | doaj-art-32533de7a41d4fcbb18e82d54e25c626 |
| institution | DOAJ |
| issn | 2521-1943 2522-4255 |
| language | English |
| publishDate | 2020-12-01 |
| publisher | National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute" |
| record_format | Article |
| series | Mechanics and Advanced Technologies |
| spelling | doaj-art-32533de7a41d4fcbb18e82d54e25c6262025-08-20T03:15:42ZengNational Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute"Mechanics and Advanced Technologies2521-19432522-42552020-12-013(90)10.20535/2521-1943.2020.0.219550Heat protective coatings on niobium alloysVitaliy Babak0Boris Lyashenko1Vitaliy Shchepetov2Sergei Kharchenko3Institute of Engineering Thermophysics of the National Academy of Sciences of UkraineG.S. Pisarenko Institute for Problems of Strength of the National Academy of Sciences of UkraineInstitute of Engineering Thermophysics of the National Academy of Sciences of UkraineInstitute of Engineering Thermophysics of the National Academy of Sciences of UkraineThe article shows that during plasma-diffusion deposition, a multilayer coating was formed on the surface of the niobium alloy. A highly porous plasma-sprayed layer of molybdenum silicide has a significant spread in thickness (h=100...350 μm, Hμ20=6880 MPa). When studying the microstructure of samples with a plasma-diffusion coating after testing, it was found that cracks in the coating originate in the process of creep, mostly at the interface between the plasma and diffusion layers of the coating. The source of their origin is individual discontinuities in the diffusion layer as delivered. Crack propagation occurs both into the plasma and diffusion layers of the coating. Crack growth in the plasma layer is inhibited due to the rounded nature of the pores and the increased plasticity of this layer. The growth of cracks deep into the sample is, as a rule, inhibited by a boride sublayer. The advantage of plasma-diffusion technology provided an increased plasticity of the coating, the presence of thin barrier sublayers, a discontinuous coating structure, the presence of low-melting compounds that contribute to the healing of defects in the coating, an increase in its corrosion resistance and resistance to thermal fatigue destruction. The combination of these properties made it possible to provide an increase in durability compared to silicide and borosilicide coatings under conditions of isothermal creep in air (1400°C, 50 MPa) 1.9...3.7 times and under conditions of thermal cyclic creep (1400-250°C, 50 MPa) in 6.8...8.5 times. It has been determined that the use of a discrete structure will increase the thickness of the coating layer and ensure an increase in their working properties.http://journal.mmi.kpi.ua/article/view/219550alloymulticomponent coatingsplasma-diffusion coatingsheat strengthheat resistance |
| spellingShingle | Vitaliy Babak Boris Lyashenko Vitaliy Shchepetov Sergei Kharchenko Heat protective coatings on niobium alloys Mechanics and Advanced Technologies alloy multicomponent coatings plasma-diffusion coatings heat strength heat resistance |
| title | Heat protective coatings on niobium alloys |
| title_full | Heat protective coatings on niobium alloys |
| title_fullStr | Heat protective coatings on niobium alloys |
| title_full_unstemmed | Heat protective coatings on niobium alloys |
| title_short | Heat protective coatings on niobium alloys |
| title_sort | heat protective coatings on niobium alloys |
| topic | alloy multicomponent coatings plasma-diffusion coatings heat strength heat resistance |
| url | http://journal.mmi.kpi.ua/article/view/219550 |
| work_keys_str_mv | AT vitaliybabak heatprotectivecoatingsonniobiumalloys AT borislyashenko heatprotectivecoatingsonniobiumalloys AT vitaliyshchepetov heatprotectivecoatingsonniobiumalloys AT sergeikharchenko heatprotectivecoatingsonniobiumalloys |