Theoretical calculations show that, for the low reflectance coatings, losses due to light coupling into optical fibre cannot be omitted in the analysis of the experimental results.
The model has been applied to the estimation of the service life for aircraft coatings concerning loss of gloss.
The apparatus, together with the Service Life Prediction methodology, have already been successfully tested for the degradation of aircraft coatings regarding loss of gloss, where sulfuric acid aerosol was used to simulate the post-eruption stratosphere conditions.
Coatings also reduce loss of light by reflection in the desired rays.
The amount of non-recoverable strain was highest in the heat-treated coatings indicating a loss of strain tolerance of YSZ coatings during simulated service conditions.
Moreover, the resistivities of the samples were found to increase with N content due to a decrease in the number of metallic bonds in the coatings and a loss of oxide layer conductivity.
Dynamic mechanical thermal analysis revealed that decreasing the resistivity of ZnO Al coatings causes the loss factors of the composites to initially increase until the maximum value, before rapidly decreasing.
However, the coatings often suffered loss of adhesion with extended periods of immersion in H2SO4, either locally or generally, possibly associated with the presence of a thin oxide layer at the interface between the coating and the substrate.
For single-layer coatings, the reflection loss below −5 dB (over 70% microwave absorbing) can be obtained in the frequency range of 13 18 GHz for the composite with 50 wt% TiC and 7 15.2 GHz for the composite with 60 wt% TiC.
A detailed analysis of the coating showed that, the loss of coatings resistant to high temperature is due to oxidation, corrosion, erosion and inters diffusion of coating-substrate, which results in diffusion of alloy elements into the coating.
