Silicon-boron alloys have been recently pointed out as novel ultra-high temperature phase change materials for applications in Latent Heat Thermal Energy Storage (LHTES) and conversion systems. One of the emerging challenges related to the development of such devices is a selection of refractories applicable to build a vessel for storing molten Si-B alloys at high temperatures and under consecutive melting/solidification conditions. Previously, it has been documented that hexagonal boron nitride (h-BN) is the only one ceramic showing a non-wettability and limited reactivity with Si-B alloys at temperatures up to 1750 • C, what makes it a good candidate of the first selection for the predicted application. Nevertheless, pure h-BN shows a rather low mechanical strength that could affect a durability of the LHTES vessel. Therefore, the main purpose of this work was to examine high temperature behavior of commercial high strength h-BN composite having a nominal composition of h-BN-24ZrO 2 -6SiC (vol.%) in contact with a solid/liquid eutectic Si-3.2B alloy. Two types of sessile drop experiments were carried out: a step-contact heating up to 1750 • C, and a thermocycling at 1300 − 1450 • C composed of 15 cycles of the alloy melting/solidification. The obtained results showed a lack of wettability in the examined system at temperatures up to 1750 • C. The Si-3.2B alloy presented good repeatability of melting/solidification temperatures in consecutive thermal cycles, which was not affected by the interaction with the h-BN composite. However, due to reactions taking place between the composite's components leading to structural degradation, it is not recommended to increase operational temperature of this material above 1450 • C. Keywords Silicon-boron alloys • Hexagonal boron nitride • Sessile drop method • Latent heat thermal energy storage • AMADEUS project Electronic supplementary material The online version of this article (
Biocompatible porous materials may find use in the manufacture of bone implant components to facilitate bonding of prostheses with bone tissues. The paper presentsa relatively simple method of producing a porous material from the Ti6Al4V alloy by high pressure hot isostatic pressing (HIP). The process was carried out in capsules made of superplastic alloy. The capsules were filled with a mixture of powdered titanium and a carefully selected salt crystals. The mixing ratios had been calculated from the crystal geometry of the components. The experimental verification of the calculation results defined the mixture component ratios, and the processing program was defined, including the temperature and pressure values for the processing stages. Following the HIP process the capsules were opened and the produced material was cleared of salt and examined to determine porosity, size and geometry of voids, and compressive strength.
This paper presents an assessment of the possibility of using digital image classifiers for tomographic images concerning ductile iron castings. The results of this work can help the development of an efficient system suggestion allowing for decision making regarding the qualitative assessment of the casting process parameters. Special attention should be focused on the fact that automatic classification in the case of ductile iron castings is difficult to perform. The biggest problem in this aspect is the high similarity of the void image, which may be a sign of a defect, and the nodular graphite image. Depending on the parameters, the tests on different photos may look similar. Presented in this article are test scenarios of the module analyzing two-dimensional tomographic images focused on the comprehensive assessment by convolutional neural network models, which are designed to classify the provided image. For the purposes of the tests, three such models were created, different from each other in terms of architecture and the number of hyperparameters and trainable parameters. The described study is a part of the decision-making system, supporting the process of qualitative analysis of the obtained cast iron castings.
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