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The effect of ligand structure on the catalytic activity of amine-bis(phenolate) chromium(III) complexes in the ring-opening copolymerization of phthalic anhydride and a series epoxides was studied. Eight complexes differing in the donor-pendant group (R1) and substituents (R2) in phenolate units were examined as catalysts of the model reaction between phthalic anhydride and cyclohexane oxide in toluene. They were used individually or as a part of the binary catalytic systems with nucleophilic co-catalysts. The co-catalyst was selected from the following organic bases: PPh3, DMAP, 1-butylimidazole, or DBU. The binary catalytic systems turned out to be more active than the complexes used individually, and DMAP proved to be the best choice as a co-catalyst. When the molar ratio of [PA]:[epoxide]:[Cr]:[DMAP] = 250:250:1:1 was applied, the most active complex (R1-X = CH2NMe2, R2 = F) allowed to copolymerize phthalic anhydride with differently substituted epoxides (cyclohexene oxide, 4-vinylcyclohexene oxide, styrene oxide, phenyl glycidyl ether, propylene oxide, butylene oxide, and epichlorohydrin) within 240 min at 110 °C. The resulting polyesters were characterized by Mn up to 20.6 kg mol−1 and narrow dispersity, and they did not contain polyether units.

Orthophosphoric acid solutions of sodium orthovanadate, sodium tungstate, and sodium molybdate are tested as potential corrosion inhibitors of the Al 2 Cu intermetallic phase. Corrosion inhibition is observed for 0.2 M solutions of Na 3 VO 4 and Na 2 WO 4 by increasing the pH to > 2. When the pH is < 2, the aforementioned salts increase the corrosion rate of the intermetallic phase. A 0.2 M solution of Na 3 VO 4 causes the precipitation of vanadium phosphate on the surface of the Al 2 Cu phase at pH = 1.

In this paper, the structure of newly developed modified aluminide coatings is characterized. The platinum and palladium coatings were obtained by an electroplating process. The Pt and Pd electroplated samples were aluminized and also modified by zirconium doping during the CVD (Chemical Vapour Deposition) low-activity process. Aluminide coatings were deposited using industrial CVD system. In the paper, the process parameters are described as well as the results of the microstructural analysis. The chemical and microstructure analysis was conducted using electron microscopes equipped with an energy dispersive spectrometer attachment. The phase composition analysis was performed using an X-ray diffractometer and showed that the aluminide coatings (Pt-Zr and Pd-Zr modified) obtained by CVD low-activity aluminizing comprised β-NiAl phase grains enriched in platinum (max. approx. 16 at.% of Pt) or palladium (max. approx. 21 at.% of Pd). The coatings consisted of two or three zones. The first outer zone was a single phase-(Ni,Pt/Pd)Al type. The aluminium-content of the outer zone of the platinum modified aluminide coating was approx. 45 at.%, while aluminiumcontent in the outer zone of the palladium modified aluminide coatings was approx. 52 at.%. The results showed that the total thickness of aluminide coatings was an average of about 50 µm while the average thickness of the outer β-NiAl zone was about 35 µm. These types of aluminide coating are applied to the thermal barrier coatings with a ceramic outer layer produced by EB-PVD (electron beam physical vapour deposition) or hybrid LPPS PS-PVD

Yttria-stabilized zirconia (YSZ) is one of the most common materials used for a ceramic top coat in the thermal barrier coating (TBC). The high operating temperature used in the gas turbine engines causes the stress between the top coat and the bond coat. The stress relaxation can be assured by modifications of YSZ. Hence, studies on how to modify the chemical and phase composition of these coatings are still conducted. The laser flash analysis was used to determine the thermal diffusivity of composite mixture of 8 mol% yttria-stabilized zirconia with a-Al 2 O 3 in the range of temperatures between 20 and 1100°C. The powders were prepared with 5 and 25 mass% Al 2 O 3 addition to 8YSZ. The particle size distribution was done for each powder to analyse the grain size after milling of the a-Al 2 O 3 with 8YSZ in the ball mill. The density of each powder was measured in the helium pycnometer. The disc-shaped samples were produced by pressing using an isostatic press and then sintered at various temperatures: 1000, 1200, 1400 and 1600°C.

The gel type microscopic polymer beads bearing epoxy functionalities were modified using the two-stage procedures in order to decorate their surface with the moieties of the zeroth order PAMAM type dendrimer and different heterocyclic aldehydes (2-pyridinecarboxaldehyde, 2-pyrrolidinecarboxaldehyde, furfural or 2-thiophenecarboxaldehyde). The polymeric supports provided in this manner were then used for the immobilization of copper(II) ions. The resulting materials were characterized using different instrumental techniques (optical microscopy, SEM, FTIR microscopy, DR UV–Vis, ICP-OES, and thermal analysis). They were also used as catalysts in the model A3 coupling reaction of benzaldehyde, morpholine and phenylacetylene. The best catalytic activity was found for the polymeric catalyst bearing 2-pyridinecarboxaldehyde moieties. It turned out to be effective in the A3 coupling reactions included different benzaldehyde, alkyne, and secondary amine derivatives, as well. It could also be recycled several times without a significant decrease in its activity in the model A3 coupling reaction. Graphic Abstract