In the present work, a metal-polymer composite coating containing Al and ethylene-vinyl acetate copolymer (EVA) was prepared on the surface of a polymer matrix composite (PMC) using a detonation spraying process. The microstructure and bond strength of the as-prepared coatings were analyzed. The bonding mechanism of the coatings, especially the deposition behavior of the Al and EVA particles on the PMC surface is discussed. Results had shown that detonation spraying technique enables the deposition of metal-polymer coatings directly onto the PMC surface under precise process control. The preparation of metal-polymer composite coating on PMC via detonation spraying process presents promising application as an interlayer for the surface metallization of PMC.

Chromium oxide coatings are used in gas turbine engines in anti-wear applications. Ultrafine YPSZ and WC/Co feedstock powders have already been widely used to prepare the ultrafine structured YPSZ and WC/Co coatings, which exhibited improved mechanical properties when compared to those of conventional coatings. Ultrafine chromium oxide powders, prepared by the method of solution precipitation, can not be directly used as plasma spray feedstock powder, because of its low mass of individual ultrafine particle and not good flowability. In this paper, spray drying and heat treatment are used to reprocess the ultrafine chromium oxide powder. The chromium oxide coating is prepared by plasma spraying. X-ray diffraction (XRD) is used to analyze the phase constituents of the feedstock powder and coatings. Scanning electron microscopy (SEM) is used to observe the morphology and particle size of ultrafine powder feedstock powder as well as to examine the microstructure of the chromium oxide coating. In addition, loose density and flowability of the feedstock powder and hardness and bond strength of the ultrafine chromium oxide coating are measured. Experimental results show that the large agglomerated ultrafine chromium oxide feedstock powder after being reprocessed are spherical, have good flowability and high loose density, which are suitable for plasma spraying. The wear properties and microstructure of the ultrafine chromium oxide coatings are improved when compared to the ones of the conventional coatings.

With the incoming of HVOF, the coating properties and application extent of WC-Co type have been greatly improved, in the recent years, we found that the characteristics of WC-Co powder has some influence on its coating properties prepared by HVOF. In this paper, study has been prepared on powders made from aboard and Beijing General Research Institute of Mining & Metallurgy properties such as fluidity, aspect, profile of coating SEM and carbon content, also phase structure and properties analysis of HVOF coating has been made. Finally, influence of powder preparing technology and HVOF technology parameters of different powders for coating properties have been described.