In order to investigate different pipe diffusion behaviors with different diffusing elements, diffusion behaviors of Cr and Ti were studied.
The results show that both oxidation at the coatings' surface and the elements' diffusion inside of the materials were temperature- and chemical-composition dependent.
The porosity appeared at the interface of matrix and Fe3Si layer in the CG sample due to Kirkendall effect, however, the bonding of the compound layer and matrix was tighter due to the promotion of the elements diffusion in the SMAT sample.
It is hypothesized that accelerated element diffusion, especially of aluminum, from coating to substrate is the main factor for these observations.
Element diffusion, the formation of reaction products, interface reactions and the failure mechanism of the coating during the cyclic oxidation and laser pulse heating in air were also discussed.
The use of novel crystallographic techniques in the present study lays the groundwork for the use of this technology in future investigations of mineral element diffusion phenomena in surface-ripened cheese.
Different from the electrodeposited chromium coating and tantalum coating (especially from the β-Ta coating), the main failure mechanism of NiCrAlY coating in gunpowder gas is the elements inter-diffusion of the coating and substrate for the thermal effect and the mechanical erosion of high temperature and pressure gunpowder gas.
All the elements of diffusion matrix were expressed in terms of derivatives of exchange chemical potentials of the components with respect to concentration and temperature.
The γ′ single phase interdiffusion in Ni3Al X (X=Cr, Fe, Nb and Ti) was studied in temperature interval 1173 1533 K. Elements of diffusion matrix, D̃ij(Ni), were estimated by a modification of Dayananda's method which enables evaluation of their concentration dependence using one couple only.
These three parameters have to be in accordance in order to obtain aluminum in the melted phase, avoid excessive substrate oxidation, promote fast diffusion of elements forming aluminides, and avoid diffusion of elements blocking the exothermic reaction that forms aluminides during the heat treatment.
