Ceramic coatings have been developed on AZ31B Mg alloys by micro arc oxidation (MAO) technique, using a mixture of sodium phosphate and sodium fluoride electrolytes. Further, MAO coatings were sealed by the conventional hot water immersion technique. The coatings were characterised by X-ray diffraction, potentiodynamic polarisation, mechanical as well as optical profilometry and nanoindentation techniques. The results showed that the surface roughness and related parameters were always higher after the corrosion test in comparison to as developed MAO coatings, the corrosion resistance of the sealed MAO coatings were enhanced in comparison to unsealed coatings and the MAO coatings had nanohardness ,10 times and Young's modulus about two times as high as those of the AZ31B Mg alloys. Further, the characteristic scatter in the data was treated by the application of Weibull statistical method. These results are discussed in terms changes in microstructure of the MAO coatings, especially after sealing.

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The analysis of the 13C NMR chemical shifts of 16 substituted 2‐phenylthiazolidines shows that the 1,3‐thiazolid‐2‐yl group exerts a deshielding effect at the ipso carbon (C‐1′) and shielding effects at the ortho and para positions of the benzene ring (C‐2′ and C‐4′), and that the transmission of the resonance effect from the substituents in the phenyl ring to the benzylic carbon (C‐2) in the thiazolidine heterocycle is diminished by the polarizable nitrogen and sulphur atoms.

The 'H NMR 270-MHz spectra of substituted 2-phenylthiazolidines were recorded and the substituent-induced chemical shifts (SCS) of the benzylic proton plotted against u, the correlation coefficient being 0.801 and --p = 10.29 Hz. Halogens show deviations in the SCS plots. When the halogen-substituted derivatives are omitted, the correlation with u is greatly improved. The applicability of dual-substituent correlations using Swin-Lupton parameters (F and R) and Taft's u, , up parameters has been studied.

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