Nickel–aluminide foams were synthesized from unalloyed nickel foams by using a two-step, high-activity pack-aluminizing process at 1273 K. After processing, the nickel–aluminide foams exhibited the original structure of the original nickel foams (open-cells with hollows struts and low density). Single-phase NiAl foams, with average composition within 1 wt.% of stoichiometry and with 92% open po...

The isothermal oxidation resistance of Al0.2Co1.5CrFeNi1.5Ti0.3 high-entropy alloy is analyzed and the microstructural evolution of the oxide layer is studied. The limited aluminum, about 3.6 at %, leads to the non-continuous alumina. The present alloy is insufficient for severe circumstances only due to chromium oxide that is 10 μm after 1173 K for 360 h. Thus, the aluminized high-entropy allo...

Mn2O3 has been selected to realize nanothermite membrane for the first time in the literature. Mn2O3/Al nanothermite has been synthesized by magnetron sputtering a layer of Al film onto three-dimensionally ordered macroporous (3DOM) Mn2O3 skeleton. The energy release is significantly enhanced owing to the unusual 3DOM structure, which ensures Al and Mn2O3 to integrate compactly in nanoscale and...

Pd+Zr and Pd+Hf co-doped aluminide coatings were deposited on the Mar-M247 nickel superalloy by palladium electroplating followed zirconizing-aluminizing or hafnizing-aluminizing processes. Both consisted of two zones, outer interdiffusion one build ?-(Ni,Pd)Al phase. Hafnium zirconium formed inclusions that precipitated at border zones close to surface (only in Zr+Pd modified coating). Oxidati...

In this work a pack cementation of germanium-doped aluminum and silicon coatings on low alloy steel type-T21 has been applied. This gives significant improvement in the oxidation. Steel-T21 was coated with germanium-doped aluminizing-siliconizing. Diffusion coating was carried out at 1050C for 6 h under an Ar atmosphere by simultaneous germanium-doped aluminizing-siliconzing process. Cyclic oxi...

in this research, aluminizing packs containing naf and nh4cl activators were used for aluminizing of pure titanium samples at 1100 ºc. the results showed that the layers of tial3, tial2, γ-tial, α2-ti3al, and α-solid solution are formed on titanium samples in both cases. however, the weight gain and the thickness of tial3 layer in treated samples with nh4cl activator are greater than those when...