F.P.) 2 SVÚOM s.r.o., U Měšt'anského pivovaru 934/4, Abstract: This paper describes the structure and properties of an innovative Fe-Al-Si alloy with a reduced amount of silicon (5 wt. %) in order to avoid excessive brittleness. The alloy was produced by a combination of mechanical alloying and spark plasma sintering. Nickel and titanium were independently tested as the alloying elements for this alloy. It was found that wear resistance, which reached values comparable with tool steels, could be further improved by the addition of nickel. Nickel also improved the high-temperature oxidation behavior, because it lowers the liability of the oxide layers to spallation. Both nickel and titanium increased the hardness of the alloy. Titanium negatively influenced oxidation behavior and wear resistance because of the presence of titanium dioxide in the oxide layer and the brittle silicides that caused chipping wear, respectively. plasma sintering [16]. The alloys exhibited a very good oxidation resistance at high temperatures-much better than binary Fe-Al and Fe-Si alloys [17]. The improvement of oxidation resistance does not lie in the incorporation of silicon to the oxide layer in a significant amount; rather, it lies in the formation of large volume fraction of silicides under the oxide layer, when aluminum diffuse to the surface in order to form Al 2 O 3 . Additionally, it has been found that the presence of silicon reduces the amount of iron oxide in scales, causing their better adherence to a substrate due to a more favorable Pilling-Bedworth ratio [16]. However, the FeAl20Si20 alloy is very brittle. Powder metallurgy methods, including our high-energy mechanical alloying [18] and spark plasma sintering, allowed for an increase in the fracture toughness, but the values at room temperature still reached the parameters of brittle ceramics, i.e., approximately 3.5 MPa.m 1/2 [16]. Due to these parameters, the alloy could be applicable as a protective coating rather than as a bulk material.In recent research, we studied the high-temperature oxidation resistance of Fe-Al-Si alloys and its dependence on the Al:Si ratio, and we found that the 35:5 provided almost the same oxidation performance [17]. Since silicon is listed as a critical raw material in the EU [19], the minimization of its amount is reasonable. In a parallel research, our team studied Ti-Al alloys and proved that silicon also improves their oxidation behavior and reinforces the material by forming hard Ti 5 Si 3 silicides [20]. On the other hand, nickel is known to form stable aluminides rather than silicides [21].Therefore, this work aimed at a possible improvement of the properties of a lower-silicon FeAl35Si5 alloy by the addition of titanium as the expected silicide-forming element and nickel as the probable aluminide stabilizer. The tests were intended to study the high temperature oxidation behavior, basic mechanical properties, and tribological properties. Materials and Methods

A number of damage functions or dose-response equation, which are compared to the atmospheric corrosion of metals with environmental parameters, have been determined in field programs ISOCORRAG, UN ECE ICP Materials Exposure Programme and Multi-Assess. The all of these dose-response equations are derived on field exposure results performed during period 1986-1995 where the SO2 level was relative high at urban and very high at industrial test sites. Several exposure programmes, national and international, of structural metals’ atmospheric corrosion were conducted since the 1970s on Czech atmospheric test sites including on-site measurement of environmental data. All data from these exposure programs were compared with prediction models.

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