OAM-RC

Abstract

New enamel refractory coatings were obtained at National Institute for Aerospace Research, Bucharest, Romania. The enamel was produced to protect the hot working surface of aircraft engines i.e. burning chamber, fire tube, volets etc. The enamels are designed to coat pieces made of supper alloys sheets as EI 435, EI 468 etc grades. To assess the thermal barrier effect (TBE) of the two new enamels, named NESA 1 and NESA 2, there were done measurements of thermal diffusivity, scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (EDP-XRFS). In this respect, the thermal diffusivity and thermal conductivity of coated and uncoated EI 435 samples were measured by Flash method using a FLASHLINE3000 Diffusivity system. The thermal barrier effect of NESA enamels were estimated by two parameters e.g. relative difference of thermal diffusivities and relative difference of time required for the back surface to reach half of the maximum temperature rise. The second parameter seems to be a more confident one from the direct meaning point of view. The SEM investigations were use to assess the morphology of enamel coat and of the interface between enamel and supper alloy that is essential for coating TBE and its lifetime. The EDP-XRFS analyses are most fitted to check the correlation among frite, barbotine and fired enamel chemical composition. A XEPOS SPECTRO EDP-XRFS were used for chemical analysis of NESA 1 and NESA 2 samples.

Keywords

Enamel, Thermal barrier effect, Thermal diffusivity, SEM investigation, EDP-XRFS analysis.

Citation

I. PENCEA, M. MICULESCU, M. PENCEA, C. E. SFAT, M. BRANZEI, V. MANOLIU, Thermal barrier effect estimation of a new refractory enamel, Optoelectronics and Advanced Materials - Rapid Communications, 3, 5, May 2009, pp.439-445 (2009).

Submitted at: Feb. 6, 2009

Accepted at: May 25, 2009