Abradable seal coatings are widely employed in the gas turbine of aero-engine, which not only strength enough to resist the impact of external particles and airflow, but also excellent wear resistance. In the current study, we concentrate on APS sprayed Aluminum Bronze Polyester abradable coating that can be used in turbo engines both for seals and clearance control. A composite thermal spray powder, substantially in the form of clad particles each of which has coarse polyester powders and sub-particles of Cu-Al alloy powders, was prepared using mechanically clad process. Abradable seal coating was prepared by atmospheric plasma spraying. The microstructure, hardness, bonding strength, thermal shock resistance and corrosion resistance of coatings were researched. Properties of the coating were able to meet the application requirements. The coating microstructures and phase compositions were evaluated via SEM. The corrosion mechanisms of the coating were compared by analyzing the cross-sectional and top surface microstructures of the as-sprayed and eroded coatings.

Abradable coatings are widely used in aerospace turbine engines to improve seal performance between rotating and stationary parts and thus the engine efficiency. As they are elaborated by thermal spraying of composite powders, these materials are highly heterogeneous. Their behaviour in working conditions is quite complex and not fully understood. This study contributes to a better knowledge of the mechanical behaviour of a range of abradable coatings. Finite Element calculations were derived from the analysis of micrographs and allowed to estimate the coefficients of an anisotropic elastic law of behaviour. Several models were investigated in the case of an AlSi-PE (Polyester) coating. As the PE % appeared to be a determinant factor, its influence was quantified ranging from 0% to 100%, using virtual micrographs deduced from the original ones. The computed Young's moduli Ex (in coating longitudinal direction) were quite consistent, considering the hypotheses made. An empirical relationship giving the variation law of Ex versus the PE % was suggested and applied to predict the modulus Ex of a real coating, which was close to the measured value.

Abradable seals are used in aerospace applications to control the overtip leakages between the blades of an engine rotor and its static parts. To achieve the combination of properties required, these seals have been developed with thermally sprayed coatings and are generally elaborated from a range of two or three phase powder mixtures. In the present study, the thermal conductivity of thermally sprayed AlSi/Polyester abradable coatings produced with Metco 601 NS and Durabrade 1605 powders was measured and investigated using finite element and finite difference methods based on two-dimensional structures obtained from micrographs. The computed values were compared to the experimental results.

The polyethylene terephtalate (PET) is widely utilized for high performance as a food and beverage container due to its excellent mechanical and chemical properties. The consumption of PET material is expected to increase more rapidly. Consequently, the recycling of waste PET is urgently needed to reduce environmental problems and economic costs. The purpose of this research is to endow waste PET materials with a new function by spraying of metal and ceramics such as Cu and TiO 2 . The recycled PET plate substrate for plasma spraying was prepared from waste PET bottles. It is found that Cu and TiO 2 powder could be sprayed on the surface of the recycled PET plate without heat damage and transformation of the substrate. In specific spray conditions, the implantation of melted Cu and TiO 2 particles, which retained their original shape, into the PET substrate was also observed and this is an unusual phenomenon in plasma spraying. In this research, the possibility of production of functional PET plates with electric conductivity and wear resistance was found by controlling the plasma spray conditions.

A CoNiCrAlY-hBN/Polyester material has recently been developed for clearance control applications in gas turbine compressors that use titanium alloy blades. While engine tests serve as the final evaluation of the coating performance, quality assurance laboratories and production shops would rely upon the more readily available coating hardness values to predict performance. This paper will focus on the reproducibility of coating macrohardness with a plasma spray process. It is shown that plasma spray parameters affect the hardness of CoNiCrAlY-hBN/Polyester coatings by changing the level of polyesters retained in the coating and the volume percentage of metallic matrix. The correlation between hardness, retained polyester level and microstructure of these coatings is captured in a coating hardness map from which desired microstructure and polyester entrapment are determined. Based on the understanding of the correlation between coating hardness and microstructural features, the use of additional criteria other than hardness such as retained polyester level and non-metallic portion of the coating is recommended in order to assure the quality of the coating more effectively.