ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The halide-activated pack cementation method was utilized to deposit silicide coatings on amulticomponent Nb-Ti-Si based alloy. The siliconized temperature was 1150 °C and the holding timewas 10h. Both the specimens with siliconized coatings and without coatings were oxidized at 1250°Cfor 5, 10, 20, 50 and 100h respectively. The coating possessed a double layer structure with thecomposition of (Nb,X)Si2 (X represents Ti, Cr and Hf), and the outer layer was denser. The majorstructure in the outer layer was composed of columnar crystals perpendicular to the interface betweenthe coating and the substrate, and that in the inner layer was mainly composed of equiaxed crystals. Atransitional layer about 5μm thick was found between the coating and the substrate. After oxidation at1250°C, the major constituents in the scale were SiO2 and TiO2 and the mole ratio of these two phaseswas about 2:1. The thickness of the (Nb,X)Si2 layer decreased and that of transitional layer increasedas the oxidation time prolonged. The siliconized coating exhibited excellent oxidation-resistance at1250°C within 50 hours
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.371.pdf
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