In Situ Synthesis of Ceramic Composite Materials in the Ti-B-C-N System by a Mechanically Induced Self-Sustaining Reaction

The synthesis of multicomponent ceramic materials in the titanium-diboride-carbide-nitride-carbonitride system by the mechanochemical process known as the mechanically induced self-sustaining reaction (MSR) was investigated. Ceramic composite powders containing TiB 2and TiC, TiN or TiC xN 1-xwere prepared from a blended mixture of the elements by exploiting the highly exothermic nature of the formation reactions. The…

Development of multicomponent-multiphase materials based on (Ti,Ta,Nb)CxN1-x carbonitride solid solutions

A set of powdered cermets based on (Ti,Ta,Nb)C xN 1-x carbonitride solid solutions were synthesized from mixtures of elemental powders by a mechanically induced self-sustaining reaction (MSR) method and subsequently sintered using a pressureless method. Differing nominal compositions of the hard phase were used, and the nature of the metallic-binder phase (Co, Ni, or Co-Ni)…

Spark plasma sintering of Ti yNb 1-yC xN 1-x monolithic ceramics obtained by mechanically induced self-sustaining reaction

Nanometer-sized titanium-niobium carbonitride powders (Ti yNb 1-yC xN 1-x) with different Ti/Nb atomic ratios were obtained by a mechanically induced self-sustaining reaction, and sintered by spark plasma sintering technique at 1500°C for 1min in a vacuum atmosphere. Mechanical properties such as hardness and Young’s modulus were determined by nanoindentation technique and friction and wear coefficients…

Nanoclay Nucleation Effect in the Thermal Stabilization of a Polymer Nanocomposite: A Kinetic Mechanism Change

The enhanced thermal stability of polymer-clay nanocomposites over the original polymers is one of their most interesting features, and it has been profusely studied within the last decades. Here, a thorough kinetic analysis of polystyrene and a montmorillonite-polystyrene nanocomposite has been performed making use of state-of-the-art kinetic procedures. It has been found that the degradation…

Room temperature mechanosynthesis of the La 1-xSr xMnO 3±δ (0≤x≤1) system and microstructural study

Monophase nanocrystalline powders belonging to the La1−xSrxMnO3±δ system (0≤x≤1) with a perovskite structure have been obtained by mechanochemistry synthesis using a planetary ball milling equipment from La2O3, SrO, and Mn2O3 mixtures. The solid state reaction was complete after one hour of milling treatment. For all the compositional range, the diffraction domain was very small and…

Nanostructured Spark Plasma Sintered Ce-TZP Ceramics

In this work, spark plasma sintering (SPS) of 10 mol% CeO 2-doped ZrO 2 nanocrystalline powders, obtained by a two-step synthesis procedure, allows the preparation of fully densified nanostructured ceramics. The CeO 2-ZrO 2 powders with particle size below 100 nm are obtained after CeO 2 deposition on hydrothermally synthesized ZrO 2 particles by the…

Inverse core-rim microstructure in (Ti,Ta)(C,N)-based cermets developed by a mechanically induced self-sustaining reaction

Cermets with a nominal composition (Tia(0.8)Ta(0.2)C(0.5)N(0.5)-20 wt.% Co) were synthesised by a mechanically induced self-sustaining reaction (MSR) process from stoichiometric elemental powder blends. The MSR allowed the production of a complex (Ti,Ta)(C,N) solid solution, which was the raw material used for the sintering process. The pressureless sintering process was performed at temperatures between 1400 degrees…

Thermal behaviour of ground and unground acid leached vermiculite

Acid leaching of vermiculite is an interesting procedure to prepare high surface area porous silica. Thermal behaviour of unground and ground vermiculite leached with HCl solutions has been studied by TG, DTA, ETA and high temperature XRD. Important differences have been observed in the thermal behaviour of unground and ground vermiculite after the acid treatments.…