[Kovove materialy - Metallic materials]
    Thu - March 28, 2024 - 10:27 No. of hits : 1736353 ISSN 1338-4252 (online) ISSN 0023-432X (printed)
© Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Bratislava, Slovak Republic

VOLUME 35 (1997), Issue 6

Two layered coating - surface roughness of NiAl and Al2O3 + 13%TiO2 layers
PALKA, V., POSTRKOVA, E., KRSEK, A., LIPA, Z.
vol. 35 (1997), no. 6, pp. 400 - 414

Abstract
Formation of a ceramic coating layer (Al2O3 + 13% TiO2) takes place by a gradual deposition (overlapping) of non-uniformly deformed particles irregularly distributed over the NiAl surface layer and then over the ceramic layer surfaces. This results in a layer with a rough surface and containing some microvoids (pores). This generally applies also to other types of metallic and ceramic layers (coatings). Surface roughness of a metallic or ceramic layer depends first of all on the powder granularity. Under the given conditions, the surface roughness is stabilized at values around Ra = 6-8 µm (NiAl) or Ra = 3-5 µm (Al2O3 + 13% TiO2). The effect of substrate surface roughness on surface roughness of the NiAl layer (and also the effect of metallic layer surface roughness on surface roughness of the ceramic layer) depends on the difference between the surface roughness of substrate surface (NiAl layer) and a stabilized surface roughness of the NiAl layer (Al2O3 + 13% TiO2 layer) as well as on the required layer thickness. The surface roughness of the ceramic layer (Ra = 3-5 µm) can be improved by polishing (Ra = 1-2 µm) or grinding (in the given conditions Ra = 0.8-0.9 µm). A better surface roughness can be achieved by altering the grinding conditions but mainly by the use of a diamond grinding wheel with smaller dimensions of abrasive grain size.

Key words
ceramic coating layer (Al2O3 + 13% TiO2)

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Full title of this journal is bilingual: Kovové materiály - Metallic Materials.
The official abbreviation in accordance with JCR ISI is Kovove Mater.


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