Strontium aluminates activated by Eu, Dy 3+ ions has recently attracted more attention due to not only their bright luminescence and super long afterglow without radioactivity but also the extensive application. SrAl 2 O 4 :Eu, Dy coatings were prepared by low power plasma thermal spraying (2.5-4W). The optimum spraying conditions have been established with spray parameters. The effects of the plasma conditions on the porosity rate of the coatings were investigated by many techniques, respectively X-ray diffraction (XRD) and scanning electron microscopy (SEM). To better qualify the characteristics of these coatings prepared from spray-dried powders, luminescence characteristics were also studied.

Thermal spray processes are widely used to protect materials and components against wear, corrosion and oxidation. As commercial arc sprayed coatings have been used to a limited extent in applications involving erosion and abrasion wear, developing attractive wear resistance arc sprayed coatings has been found necessary. Abrasive wear testing was carried out on four Fe-based composite coatings containing varied contents of Cr 3 C 2 particles as hard phases. Scanning electron microscopy (SEM) was used for observing the surfaces of the composite coatings, and wear mechanisms of the coatings were discussed on the basis of the observation. The results obtained from MLS- 225 wet sand/rubber wheel test showed that the abrasive wear resistance of composite coatings with Cr 3 C 2 hard phase is about 28 times higher than that of Q235 mild steel. The coating method was proved effective in producing a uniform and dense lamellar structure. The excellent abrasive resistance of the composite coatings with Cr 3 C 2 particles were found to be related to three major factors: enhanced bulk hardness, compact lamellar structure and strong bonding between matrix and hard phase, as well as a load supporting system constructed by the hard phase structure.

Iron base composite coatings were deposited on mild steel substrates by arc spraying and cored wire with TiC ceramic powders. The abrasive wear resistance properties were examined on the MLS-225 wet sand/rubber wheel tester. The microstructure, phase compositions and worn surface morphologies of the coatings were observed by means of optical, scanning electron microscopy and X-ray diffraction. The results showed that composite coatings with TiC ceramic hard phases were reinforced by the TiC hard particles distributed in the iron-based coating. The average micro hardness of the coatings is about 1137 HV0.1. The coatings have the excellent abrasive wear resistance which is 6 times higher than that of the Q235 mild steel. Wear mechanisms of coatings was mainly micro-ploughing and brittle fracture.