Abstract Titanium dioxide coating can be deposited by many processes such as thermal spray, Sol-Gel, vapor deposition, and so on. Among those coating deposition methods, thermal spray process is characterized by rapid formation of coatings easily and flexibly compared with other coating depositing processes. It is reported that nano-structured materials such as aluminum oxide, manganese(III) oxide, and zirconium dioxide could be produced by thermal spraying process with liquid feedstocks. With the process using liquid feedstocks, it was reported previously that nano-structured anatase titanium dioxide can be synthesized and the deposit mainly consist of anatase phase. In this paper, the effects of spray parameters on the grain size and phase structure of titanium dioxide deposits are systematically studied using liquid flame spraying system with butyl titanate as a liquid precursor. Paper includes a German-language abstract.

Abstract Refractory borides are suitable for wear protection due to their excellent material properties. In addition to their high hardness, they have excellent corrosion resistance and very good wetting behavior of metals. In addition, the density of many borides, such as titanium diboride, is significantly lower than that of conventionally used toilets. In this paper, the investigations show, that mechanical alloying permits the production of nanostructured titanium diboride composite feedstock for thermal spray application. In order to prevent the formation of undesired secondary borides, a suitable Ni-based alloy is selected for production. A liquid fuel-operated HVOF system is used to prevent the fine microstructure of the composite powders from degrading during thermal spraying. The sprayed layers are characterized in terms of layer morphology and wear behavior and compared with conventional cermets. Paper includes a German-language abstract.

Abstract Nanostructured materials show great potential for a wide variety of technical applications. This paper investigates microstructures and properties of various nanocrystalline TiC-based coatings, which were processed by high velocity oxy-fuel (HVOF) spraying and vacuum plasma spray processes. It examines conditions on how nanocrystalline cermet powders based on TiC with different metallic matrices can be tailored for applications in thermal spraying using high-energy milling. In terms of commercial applications, the combination of high-energy milling and HVOF syringes, in particular, appears to have a great potential to produce inexpensive layers of nanocrystalline composite materials with better properties. Paper includes a German-language abstract.

Abstract The research work described in this paper is a collaborative study between the two universities (U.L.B. and U.T.B.M.) in the field of plasma sprayed ceramic coatings. The aim is to prepare nanostructured coatings with enhanced properties based on micrometric size titanium dioxide doped with synthesized silicon dioxide nanometric size particles. Nanoscalline powders made of silicon dioxide are first produced from the gas phase in high-frequency induction plasma reactors. The powders are then spray-dried in order to produce a homogeneous mixture of micro- and nano-crystalline oxide powders, which are suitable for DC plasma spraying. The layers are analyzed and characterized. The nanocrystalline particles are distributed homogeneously in the layer composite. An HF induction plasma system is used as the spray system. Results of aluminum oxide from conventional powders are discussed. Paper includes a German-language abstract.

Abstract Various processes are used to manufacture the nanostructured materials, such as the sol-gel process, the DC-MSIP process, and the HF-MSIP process. It is also possible that the nanostructures can also be produced in a short time using a thermally activated coating process. Zirconium oxide and aluminum oxide are the most important oxide ceramics. Both have a wide range of applications. In this paper, nanostructured layers of zirconium and aluminum oxide are produced with atmospheric plasma spraying. The layers are characterized with a scanning electron microscope, a transmission electron microscope, and an X-ray phase analyzer. Dense nano-structured oxide layers (zirconium oxides and aluminum oxides) with high microhardness are produced using the atmospheric plasma spray process. Paper includes a German-language abstract.

Abstract In this paper, mechanical parameters and wear parameters of plasma-sprayed aluminum oxide-13wt% titanium dioxide layers are investigated. Micro and nano powders are deposited on hot and cold substrates with different spray parameters using the atmospheric and vacuum plasma spraying method. The investigations of the layers include light microscopy and SEM. Mechanical properties and wear properties of the layers are also investigated. It is observed that the layer properties and characteristics were very dependent on the coating system, the powder form, and the spray parameters. The layers sprayed with nanostructured powder in a vacuum achieved the best results. Paper includes a German-language abstract.

Abstract FeAl iron-aluminide based materials with the ordered B2 structure are excellent candidates for use in high temperature applications because of the combination of good mechanical properties, low density, low cost and availability of raw materials, and improved oxidation resistance. The aim of this article is to produce an ultra-fine grained FeAl coating by HVOF thermal spraying of milled powders and characterize the fine scale features of its microstructure. Comparison is made with a more conventional coating obtained by projection of powders obtained by atomization. Starting powders and coatings were investigated using X-ray diffraction and transmission electron microscopy. It was observed that the coating obtained from milled powders had a microstructure essentially characterised by a nanometer grain size and the presence of a disordered FeAl phase.