Thermoanalytical studies of the ceramic-metal composites obtained by gel-centrifugal casting

Abstract

Composite material with a gradient concentration of the metallic phase was prepared by the novel gelcentrifugal casting method. This method combines the consolidation of powders by the centrifugal force with the reaction of radical polymerization of an organic monomer which simultaneously proceeds within the composite slurry. The combination of the centrifugal casting with gelcasting permits production of ceramic-metal composites, including materials with a gradient distribution of metallic particles in a ceramic matrix. Special attention was paid to the thermal analysis of the composite Al 2 O 3 -Ni green bodies and the binder used in the fabrication of the material. The experiments were performed on the simultaneous thermal analyzer coupled with the mass spectrometer. The measurements were carried out in air and the inert atmosphere (argon) what allowed to determine the effects characteristic for organic binder decomposition and type of gases released to the atmosphere during thermal treatment. The measurements allowed also to establish the sintering program of the green composite samples and evaluate whether harmful gases are released to the atmosphere. The thermal experiments were complemented with physical and structural measurements, including X-ray diffraction and scanning electron microscopy.

Performance Characteristics of Hot-dip and Plasma Spray Aluminide Coated Nickel-Based Superalloy 718 under Cyclic Oxidation in Water Vapour

“…9 b. Such voids in addition to presence of cracks within the coating layer acts as transport mechanism channel for oxidation of NiO and subsequent transformation into NiAl2O4 spinel as detected by EDS analysis [30]. The porous nature of NiAl2O4 spinel could further act as sites for internal oxidation and degradation of the aluminum layer as observed in Fig.…”

Thermal and physical properties of ZrO2–AlO(OH) nanopowders synthesised by microwave hydrothermal method

“…Transitions from RT up to approximately 450°C are associated with the H 2 O and CO 2 release (Fig. 10) [1,41,42], while the following endothermic transition is due to v-AlO(OH) transformation and water release [33]. The forth, weak endothermic event above 1000°C is related to particle growth and/or further (t ?…”

“…Obtained results from Scherrer equations are in agreement with particle size calculated using Eq. (1).…”

“…Chemical bonding of -OH groups and physisorption of H 2 O on the surface depend on material composition and its particle size. Their presence may influence densification and sintering processes [1]. Nanomaterials used in biomedical applications, especially the ones in implant and prosthetics applications area received a lot of attention in recent years [2].…”

Preparation of Porous Alumina/Nano-Nickel Composite by Gel Casting and Carbothermic Reduction

“…In recent years, the use of gel casting method for the production of various composites as well as porous products has been considered during various researches such as production of porous alumina composites containing nickel nanoparticles with nickel nitrate as a source of nickel and hydrogen gas as the reducing agent [5], porous alumina-nickel composite as a catalyst with nickel oxide as a source of supply of nickel and CO gas as a reducing agent [17], porous silicon carbide with carbon in resin as reducing agent and source of carbon and SiO as source of Si [17], alumina composite containing tungsten nanoparticles by gel casting method and tungsten in situ reduction [19], alumina-nickel composite with complex shapes by gel casting and using 3D printer technology [20], alumina-nickel composite by gel casting method and centrifugal method for fabrication of parts with high density and homogeneous properties [21], alumina-nickel layer composites by casting alumina gel between tungsten metal plates [22], making transparent alumina plates by gel casting with pressure control [23]. The study of the effect of thermal regime and atmosphere on the properties of alumina-nickel composite made of nickel powder by sol method was investigated by Zygmuntowicz et al [24]. In addition, magnesium aluminate spinel with alumina and magnesium oxide by gel casting method [25], use of presinter to improve the mechanical properties of alumina based composites made by gel casting [26], and recently, making high porosity alumina with suitable strength by gel casting method and optimizing the production process were invesitgated [27].…”