The materials used for the synthesis of parent glass are 70% wt. metallurgical slag and 30% wt. industrial quartz sand. The initial batch is melted at and then quenched in water. The resulting glass frit is milled bellow 75 microns and pressed 1400 °C into “green” samples. In a next stage, they are heat treated at different temperatures with various heating rates and holding times. As a result, it is demonstrated the possibility for production variations, allowing the manufacture of three types of new materials by using the same pressed glass powders. We highlight the flexibility of the synthesis obtaining namely well densified glass-ceramics at about 950 °C, self-glazed glass-ceramics at about 1000 °C or glass-ceramic foams at approximately 1100 °C. The first set of materials is characterized by very well sintered structure combined with reasonable crystallinity; the second one—by smooth self-glazed surface with an attractive appearance and good properties and the third one—by 80–90% closed porosity and very good thermal stability above 1000 °C.
The investigation reported comprises an experimental study of the thermal and corrosion properties of electrodeposited nickel-phosphorus amorphous alloy layers. The structure of the species was determined by means of X-ray diffraction spectroscopy. Samples with hypo- and hyper-eutectic compositions were synthesised out of modified classical and customised electrolytic solutions on copper substrates. The composition of the samples was determined via energy dispersive spectroscopy. A short review of the development of the composition of existing plating baths for Ni–P electrodeposition has also been presented. Thermal treatment of the samples has been carried out to crystallise the amorphous structure and to compare the thermal and the corrosion properties of the species with both types of structure. Differential thermal measurements were used to examine the thermal effects in the Ni–P samples obtained. The corrosion parameters of initial as-plated and thermally treated binary Ni–P alloy coatings were determined from Tafel plot analysis.
In reported investigation we studied sintered glass-ceramics from a model diopside glass with moderate crystallization ability by in-situ optical dilatometeric experiments. The initial glass was ground and sieved below 75 μm. Then thus prepared powders were pressed with different pressures between 50 and 250 MPa. In this way were obtained samples out of pressed powders with different initial porosities determined with gas pycnometry. Then the samples were heat treated in a contactless horizontal optical dilatometer and their porosities were measured one more time. Both pressed green samples and synthesized glass-ceramics were analyzed further with X-Ray micro tomography.
This study investigates the potential of producing zero-clinker, alkali-activated binders and concrete entirely from industrial by-products—ladle furnace slag (LFS), coal ash (CA), and cement kiln dust (CKD). The incorporation of CKD enhanced the workability and compressive strength properties of the alkali-activated mixtures, with the highest mechanical properties at 20% CKD addition. XRD, FTIR, and SEM analyses confirmed the formation of hydrocalumite, indicating improved hydration and microstructural densification. Mortar and concrete produced using the eco-cement reached 28-day strengths of 34.5 MPa and 32.6 MPa, corresponding to concrete class C20/25. These findings demonstrate the feasibility of manufacturing 100% waste-based construction materials suitable for sustainable, non-reinforced applications.
This study presents the development of a one-part phosphate-activated geopolymer foam based on fayalite flotation residue from the copper industry. The solid activator consisted of triple superphosphate, enabling a dry-mix binder that requires only water addition prior to use. Foamed materials were characterized by XRD, FTIR, Mössbauer spectroscopy, DSC-TG, hot-stage microscopy, SEM-EDX and physical and mechanical testing. The foaming of the geopolymer reduced the densities between 0.753 and 2.15 g/cm3, relative porosities up to 73.6%, and compressive strengths ranging from 1.4 to 28.8 MPa. The foamed geopolymer maintained dimensional stability up to about 1000 °C. The thermal conductivity coefficient measured on large-sized specimen blocks was 0.099 W/mK at a density of 0.753 g/cm3. These results demonstrate that fayalite slag can be effectively utilized as a precursor for sustainable geopolymer foams combining low thermal conductivity, high thermal stability, and the utilization of industrial by-products.