P. Podolski

Influence of coatings obtained by PVD on the properties of aircraft compressor blades

Abstract In this paper, the results of investigations to increase aircraft compressor blade durability were presented. The blades were made of the martensitic steels. The coatings were obtained by the physical vapour deposition (PVD) method. TiN and (Ti, Al)N coatings on a titanium nitride base and CrN and CrCrN multilayer coatings on a chromium nitride base were used in the tests. Low corrosion resistance of the TiN coatings was shown in laboratory tests. The (Ti,Al)N coatings, particularly CrN and CrN modifications, behaved better. Coating density and chemical interaction of the coating and steel in the corrosive medium were shown to have an influence on the blade properties. A significant increase in the corrosion resistance was achieved by using the diffusion and chemical treatment of coatings obtained by the PVD method. Investigations of coatings in a humid atmosphere containing SO2 showed very low resistance of the steel. The resistance of the coatings was increased significantly by additional chemical treatment.

Erosion- and corrosion-resistant coatings for aircraft compressor blades

Abstract In this paper the comparative test results of protective properties of several coatings for aircraft engine compressor blades are presented. Erosion and corrosion tests for the base metals and coatings were carried out. Corrosion test for base materials and anodic coating was made in neutral salt spray. For cathodic coatings a modified corrosion test was performed. It has been determined that the coatings obtained by physical vapour deposition (PVD), particularly (Ti, Al) N and TiN(Pt) are the best in the erosion and corrosion test conditions. The electroplated Ni-Cd coatings do not show satisfactory erosion resistance, but they have good corrosion resistance. It seems that PVD coatings fulfil the requirements for the protection of aero engine compressor blades.

Corrosion Resistance of Zinc Coatings Obtained in High-Temperature Baths

We present the results of investigation of the technology of application of coatings in zinc baths at temperatures different from the standard temperatures of the process of galvanization. The corrosion resistance of the coatings is determined under the action of neutral salt mist and sulfur dioxide in the case of condensation of moisture. With the help of galvanization at elevated temperatures of 540–560°C, it is possible to obtain coatings of constant thickness with improved structure and higher corrosion resistance as compared with the coatings obtained at standard temperatures.