## 2 Materials and Methods
### Methods  
Mechanical testing was performed using a universal testing machine (Inspect 5 Table Blue, Hegewald & Peschke, Nossen, Germany). According to the standard DIN EN 196-1 [20], the three-point bending tests had to be performed on wet specimens. The testing device was set to a traverse speed of 5 mm/min until a pre-load of 1 N was reached. The traverse speed was then immediately lowered to 2 mm/min. The termination criterion was reached when the measured force decreased by 80%. All measurements were conducted with a 1 kN load cell.  
The density of the raw materials in powder form was determined using a helium pycnometer (AccuPycTMII 1340, Micromerities, Norcross, GA, USA). Before measurement, the chamber was flushed 10 times by helium gas. The filling pressure was set to 134.45 kPa, and the measurement started when equilibrium was reached (<0.0345 kPa/min). A series of 10 measurements for each powder was performed [21].  
The porosity of the cast specimens was measured using the Archimedes method. Before the measurement, the samples were stored in a drying chamber at 40 \({}^{\circ}\)C for at least 24 h. Then, the dry weight of the specimen was determined using a precision scale (AC 210 S, Satorius, Gottingen, Germany). The specimen was degassed inside a desiccator and evacuated for 30 min at a pressure of 10 mbar. Afterwards, deionized water with 50 ppm 2-octanol (Merck, Germany) was poured into the desiccator until the specimen was completely immersed. A cover with holes was placed above the specimen to prevent floating because the density of the specimen was expected to be lower than that of deionized water. After the addition of deionized water, the desiccator was evacuated for another 30 min before the lid was removed. The specimen was kept immersed at atmospheric pressure for at least 30 min. After infiltration, the buoyancy mass was determined. The weight of the wet sample was measured directly after removing the sample from the bath and blotting water with a wet towel.  
The pore network and microstructure were investigated by scanning electron microscopy (SEM, Sigma 300 VP, Zeiss, Oberkochen, Germany). The hydrated specimens were dried at 40 \({}^{\circ}\)C for at least 24 h before SEM analysis. Each specimen was sputtered with gold (Sputter Coater 108 Auto, Cressington, Watford, England) at 30 mA for 60 s. The SEM analysis was performed with an acceleration voltage of 5 kV.  
Phase analysis was carried out by X-ray diffractometry (XRD, D8 Discovery A25, Bruker, Billerica, MA, USA) with a copper radiation source (1.54060 A) operating at 40 kV and 40 mA. The diffractograms were recorded using a Lynveye detector. The measurement range of 2\(\Theta\) was set from 10\({}^{\circ}\) to 60\({}^{\circ}\) with a time step of 0.2 s. During the measurement, the sample was rotated at a speed of 15 rpm. Rietveld refinement and phase analysis were performed with the open-source software Profex (Version 4.3.5) [22].  
The thermal conductivity was measured using a surface and a needle probe (Isomet 2114, Applied Precision, Bratislava, Slovakia). Each specimen was dried in a drying chamber at 40 \({}^{\circ}\)C for 5 days before measurement. The measurement was conducted in an air-conditioned laboratory at 20 \({}^{\circ}\)C. Conductivity measurements were performed at three different spots on the large prisms.