Fabrication de carbure de titane par combustion auto-entretenue de titane et de carbone : initiation par diffusion à l'état solide

Self-propagating high temperature synthesis of titanium carbide from finely divided powders of Ti and C is initiated in the solid state by diffusion at the contacts between particles. In the model of concentric spheres of titanium and carbon, the formation of TiC has been computerized as a function of graphite particles radius r(m), time t(s) and absolute temperature T(K). The reaction rate α (moles of carbon reacted relative to the initial amount of carbon) can be expressed by the relationship : [MATH

Interaction of Graphite with a Ti–Al Melt during Self-Propagating High-Temperature Synthesis

International audienc

From nanoparticles to bulk crystalline solid: nucleation, growth kinetics and crystallisation of mixed oxide Zr x Ti 1−x O 2 nanoparticles

International audienceWe describe the preparation of mixed metal oxide nanoparticles of a desirable composition and their transformation to the crystalline solids Zr x Ti 1−x O 2 (0.0 ≤ x ≤ 1.0) after heat treatment

Ti-Al-C MAX phases by aluminothermic reduction process

International audienceA new approach to synthesis of Ti₂AlC-Ti₃AlC₂/Al₂O₃ compounds is developed based on thermite reaction in the TiO₂-Al-C system. The effect of Al excess is also discussed. XRD analysis has proved that this parameter can be used to improve the product purity, i.e., the amount of TiC in the final product. It has also been shown that, with increasing Al excess, the composition of a major MAX phase undergoes a change from Ti₂AlC to Ti₃AlC₂

SHS joining by thermal explosion in (Ni + Al)/Nb/(Ni + Al + Nb) sandwiches: Microstructure of transition zone

International audienc

Study on the Synthesis and Structural Characterization of the Cermets TiC/Fe by Self-Propagating-High-Temperature and by Thermal Explosion

International audienceA study of the TiC/Fe cermets produced by self-propagating high-temperature synthesis and by thermal explosion with various quantities of added iron was performed. It was established that both experimental and calculated adiabatic temperature of combustion and the propagation velocity of the reaction front decrease with the addition of iron in the reactants. The addition of iron was optimized at 30 wt % to ensure the stability of the propagation. The products were characterized by X-ray diffraction (XRD); the reaction seems to start at the surface of the solid titanium particle and to proceed by solid-state diffusion of iron and carbon to form TiFe and TiC/Fe cermets composite. The evolutions of the phases, size, and density of TiC grains during both kinetics reactions were highlighted by X-rays diffraction, optical and scanning electronic microscopy equipped with microindentation and energy-dispersive X-ray spectroscopy, respectively