Papers by Author: Teppo Fält

Abstract: Special nanoreinforced ceramic composite coatings were produced. Dense nanostructured alumina and chromia coatings alloyed with various nanofraction elements such as Ni, NiO, ZrO2 and SiC were manufactured by HV2000 HVOF spraying. As a result coatings with nearly 100% improvements relative fracture toughness, were produced.

Abstract: Special mechanical properties have widely been demonstrated with bulk nanocrystalline materials. An increasing effort has been made to transfer such improvements also into thermal sprayed ceramic coatings. This paper focuses on such efforts in alumina-based ceramic coatings. The optimization of process conditions and effect of different process parameters on the mechanical performance of high velocity oxy-fuel (HVOF) sprayed ceramic coatings is discussed.

Abstract: HVOF thermal spraying has been developed to deposit dense Al2O3-coatings for improved protective properties. As compared to generally used plasma sprayed coatings HVOF coatings can be prepared much denser and thus are better suited for applications where protective properties of the coating are needed. In this paper we describe the development of HVOF spraying technologies for nanocrystalline Al2O3- and Al2O3-Ni-coatings. The microstructure and the mechanical properties of these novel coatings are reported and compared to a conventionally processed Al2O3-coating.