Thermal decomposition of monosaccharides derivatives applied in ceramic gelcasting process investigated by the coupled DTA/TG/MS analysis

This paper focused on the characterization of the composites containing nickel aluminate spinel from Al 2 O 3 /NiO and Al 2 O 3 /Ni systems. The composites were prepared by die pressing of powders and subsequent sintering of green bodies in air atmosphere. Composites were characterized by XRD, SEM, EDS and DTA/TG/MS analyses. The physical properties of the composites were measured by Archimedes method. Quantitative description of the composites microstructure was made on the basis of SEM images using computer image analysis. The XRD studies and SEM observations of composites confirmed the presence of two phases Al 2 O 3 and NiAl 2 O 4 in the whole volume of samples from both systems. Spinel phase was evenly distributed throughout the volume of the material. Morphology of NiAl 2 O 4 obtained from both systems was characterized by the presence of voids. The DTA/TG/MS measurements showed the characteristics of organic binder decomposition and type of gases released to the atmosphere during thermal treatment. Moreover, the DTA/TG analysis showed the temperature of spinel-phase formation for both systems. It was found that the spinel-phase NiAl 2 O 4 formation retards the process of densification. Therefore, it can be concluded that densification of samples with spinel phase depends mainly on the volume of spinel phase in composite material and does not depend on the substrates used to prepare spinel phase. The values of the selected properties of Al 2 O 3 -Ni-and Al 2 O 3 -NiO-based materials confirmed that the physical properties depend on the type of substrates used in the fabrication of composites. The type of powder influences the open porosity of samples. For composites produced using NiO powder, open porosity is lower than for samples formed with nickel powder.

Section: Resultssupporting

confidence: 53%

Characterization of composites containing NiAl2O4 spinel phase from Al2O3/NiO and Al2O3/Ni systems

Zygmuntowicz

Wiecińska

Miazga

et al. 2016

“…The first loss of mass is related to the evaporation of the water fraction of the solvent, and the next loss is related to the evaporation of the hydration water (100-230°C) [24,25]. The IR spectrum obtained at a temperature of 163°C is related to the release of water, which was confirmed by comparing this spectrum with the model IR spectrum for water (library spectrum) (Fig.…”

Section: Resultssupporting

confidence: 55%

Thermal analysis in foundry technology

Grabowska

Hodor²,

Kaczmarska

et al. 2017

In this study, a polymer composition of poly (acrylic acid) and dextrin (PAA/D) cross-linked with microwave radiation, belonging to the new BioCo group of environmentally friendly foundry binders, was subjected to thermal analysis (TG-DTG-DSC, TG-MS, TG-IR) in a temperature range of 20-600°C. A thermal analysis of PAA/D compositions enables the determination of a temperature range at which the composition is not susceptible to thermal degradation and thus does not lose its binding properties. The study showed that the process of thermal degradation of PAA/D is complex and multi-stage (TG-DTG-DSC). Within a temperature range of 20-250°C, physical and chemical changes take place associated with the evaporation of the water fraction of the solvent (20-100°C), next with the evaporation of the water hydration and finally with intermolecular dehydration reactions (100-250°C). Above a temperature of 300°C, the decomposition of the polymer chains takes places, and thereafter, the intensive degradation of PAA/D occurs together the creation of gaseous substances, primarily low molecular weight inorganic (CO 2 , H 2 O, CO) and organic compounds, including methane (TG-IR, TG-MS).

“…It results from the fact that the mass of the sample taken to the analysis was ca. 0.3 g according to the capacity of the crucibles [18]. Mass loss starts at ca.…”

Section: Resultsmentioning

confidence: 99%

“…The important information from thermal analysis is the temperature at which decomposition of organics ends. Additionally, the coupling of DTA apparatus with mass spectrometry allows to observe type of gases released to the atmosphere during decomposition of any substances [17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Colloidal processing of Al2O3 and BST materials

Pietrzak

Wiecińska

Pawlikowska

et al. 2017

Self Cite

The paper presents the analysis of thermal stability and decomposition of Al 2 O 3 and (Ba,Sr)TiO 3 green bodies as well as commercially available organic additives which are used in shaping of ceramics by colloidal processing. The first analyzed ceramic material was Al 2 O 3 green body obtained by gelcasting. The second examined material was elastic ceramic-polymer composite based on ferroelectric powder Ba 0.8 Sr 0.2 TiO 3 with NiO obtained by tape casting method. This flexible and durable material is characterized by high value of dielectric constant and finds the application in devices operating at very high frequencies up to sub-THz. Most organic additives are indispensable just in forming step but must be then eliminated in order to obtain pure ceramic phase, additionally some of them have to be stable in a wide temperature range. The analyzed organic substances were as follows: 2-carboxyethyl acrylate, SYNTRAN 8250, DURAMAX D-3005, DURAMAX B-1000. The DTA/TG measurements coupled with mass spectrometry allowed to gain new knowledge concerning degradation of selected organic additives, thermal stability of ceramic-polymer composite and type of gases released from samples during thermal treatment.