This paper was to construct ensemble feature selection and random forest for the identification of ancient glass products via integrating the machine learning algorithm into the identification and analysis of ancient glass products and taking accuracy rate and AUC as the measurement indexes of classification performance. The results of different feature selection methods were analyzed, and the important chemical components were selected. The selected important features with random forest, k-nearest neighbor learning and naive Bayesian were investigated. The results show that lead oxide, barium oxide, and potassium oxide have an impact on the weathering of the glass surface by using ensemble feature selection. In high potassium glass, three components are closely related, the accuracy of classification by the random forest based on the k-fold cross validation for selected important features is great, and the model is stable. This method can provide a theoretical reference for the composition analysis and category identification of ancient glass products, and other glasses.

Solid oxide fuel cell (SOFC) is a high-efficiency, fuel-flexible, all-solid-state fuel cell, which is the focus of competing research and development around the world. It operates at a high temperature for a long time, and the material properties of the running components are quite different. The problems of component damage and failure caused by the inevitable internal thermal stress severely affect its commercial application. The thermal failure of SOFC has different manifestations and mechanisms in different scales. This review summarized recent work on the stack, single cell and electrode. The corresponding comments and suggestions in this field were given. This review could provide a guidance for studies on the thermal failure problems of SOFCs.

Amorphous carbon materials exhibit more advantages in mechanical, optical and thermal properties with the increasing concentration of sp³-hybridized bonds. High pressure, as an extreme physical condition, can effectively trigger sp² to sp³ bonding conversion in carbon materials. In this review, some recent achievements and progress on the synthesis of new superhard amorphous carbon materials under high pressure were introduced, mainly including the studies on the transformation of fullerene and glassy carbon into sp³ amorphous carbon material under high pressure and high temperature or high pressure with shear stress. These results deepen our understanding on the structural transition of covalently bonded amorphous materials and the relation between their microstructure and properties. Based on this, we also hold out some prospect for the future study of new superhard sp³ amorphous carbon materials under extreme conditions.

It is important to develop high emissivity infrared radiation materials for energy saving in high-temperature furnaces. In this work, Ni²⁺-doped MgCr₂O₄ materials were prepared by a high-temperature solid-phase reaction process. The effect of Ni²⁺ doping content on the infrared radiation properties of MgCr₂O₄ materials was investigated, and the mechanism of emissivity enhancement of MgCr₂O₄ materials was explored. The results show that Ni²⁺ ions can be doped into the lattice of MgCr₂O₄ materials, and the prepared Mg_1-xNi_xCr₂O₄ (0.1≤x≤0.5) materials produce the lattice distortion and a small amount of Ni²⁺ valence state transformation. Also, the concentration of oxygen vacancies increases, the forbidden band width decreases with the increase of Ni²+doping, thus improving the emissivity of the prepared materials in the near-mid-infrared band. The material with x of 0.5 (Mg_0.5Ni_0.5Cr₂O₄) has an average emissivity of 0.88 in the near infrared ref bands (i.e., 0.8-2.5 μm), which is 167% greater than that of the undoped specimens. Ni²⁺ ions doping enhances the lattice vibration absorption, free carrier absorption and impurity energy level absorption, and improves the infrared emissivity of MgCr₂O₄ materials in the near-mid-infrared band.

Porous aggregates are a key material for the lightweight refractory. Porous magnesia based composite spinel (Mg (Fe, Al)₂O₄) refractory aggregates were prepared by an in-situ decomposition synthesis method with calcined magnesite, Al(OH)₃ and iron oxide as raw materials. The influence of sintering temperature (i.e., 1 000-1 600 ℃) on the microstructures and strengths was investigated, and the synthesis mechanism of porous aggregates was analyzed. The results show that the pores in the samples are composed of the pores in the micron-sized particles and the pores among micron-sized particles as well as they have a few neck connections at the sintering temperatures of 1 000-1 300 ℃, and the pores in the micron-sized particles migrate to the gaps and the necks grow with a further increase of sintering temperature to 1 400-1 600 ℃, thus promoting the compressive strength of the samples. The formation of composite spinel (Mg (Fe, Al)₂O₄) in the samples involves that MgAl₂O₄ is formed on the surface of Al(OH)₃ pseudomorph and reacts with Fe³⁺ to form the composite spinel (Mg (Fe, Al)₂O₄) with a ring structure, and MgFe₂O₄ is formed in the position of MgO and reacts with Al³⁺ to form the composite spinel (Mg (Fe, Al)₂O₄) with the granular and strip structures. The porous magnesia based composite spinel (Mg (Fe, Al)₂O₄) refractory aggregates have the optimum performance (i.e., an apparent porosity of 24.4%, a median pore size of 25.89 μm, a thermal conductivity of 2.79 W/(m·K) at 1 000 ℃ and a compressive strength of 74.4 MPa) at the sintering temperature of 1 550 ℃. Meanwhile, compared with the existing sintered magnesia, the thermal conductivity of porous magnesia based composite spinel (Mg (Fe, Al)₂O₄) refractory aggregates synthesized can be reduced by 64.7%.

Al₂O₃-C refractories are important for the continuous casting process. It is essential for safe and effective steel making processes to enhance the strength and oxidation resistance of Al₂O₃-C refractories. A compound MAB phase Cr₂AlB₂ has attracted recent attention due to its high fracture toughness, high damage tolerance and excellent oxidation resistance. In this work, a ternary layered compound Cr₂AlB₂ was introduced into the Al₂O₃-C refractories. The structural evolution of Cr₂AlB₂ in Al₂O₃-C refractories after treated at different temperatures and its effect on the comprehensive properties of Al₂O₃-C refractories were analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results show that a gradual decomposition of Cr₂AlB₂ in Al₂O₃-C refractories generates a core-shell structure of CrB and Al₂O₃ covered with Al₂O₃, and catalyses the formation of carbon nanotubes and carbon fibers on the surface of the core-shell structure after thermal treatment at 800-1 200 ℃. Cr₃C₂ covered by BN structure is formed inside the core-shell structure after thermal treatment at 1 200-1 600 ℃. As a result, the densification of Al₂O₃-C refractories is facilitated, and the cold modulus of rupture and oxidation resistance is enhanced. The cold modulus of rupture after coking at 1 400-1 600 ℃ is increased by approximately 9%, and the oxide index after treated in air at 1 400 ℃ is reduced from 44% to 31%.

Corundum-Ti₂O₃ two-phase material is a by-product obtained via adjusting the smelting process of low-ferrotitanium alloy. Al₂O₃ and Ti₂O₃ exist independently in raw material, which can be used as a refractory raw material. According to the results by thermogravimetry-differential scanning calorimetry and thermodynamic analysis, the oxidation reaction of Ti₂O₃ in the raw material starts at 700 ℃, and the reaction between Al₂O₃ and TiO₂ starts at 1 263 ℃. The results by X-ray diffraction and scanning electron microscopy indicate that Ti₂O₃ completes the oxidation reaction at 800 ℃, which is affected by the decomposition reaction of Al₂TiO₅ at 1 300 ℃, only part of TiO₂ and Al₂O₃ reacts at the corundum junction to form flake Al₂TiO₅. As the sintering temperature is increased to 1 400 ℃ and 1 500 ℃, the reaction of Al₂O₃ and TiO₂ to form Al₂TiO₅ is gradually completed, and a typical columnar aluminum titanate is formed on the basis of flakes.

Silica bricks only used the combined mineralizer of calcium hydroxide and iron scale in the early domestic production. It is feasible and necessary to explore novel mineralizers to improve the performance of silica bricks. In this paper, novel silica bricks were prepared with ferrosilicon nitride and calcium carbonate as mineralizers instead of calcium hydroxide and iron scale. The prepared silica bricks have good properties, and the content of tridymite with 2% ferrosilicon nitride and calcium carbonate added reaches 62% and 65%, respectively. The effects of ferrosilicon nitride and calcium carbonate on the formation of tridymite in silica bricks were investigated by X-ray diffraction and scanning electron microscopy. The results show that in the silica brick with ferrosilicon nitride as mineralizer, Si₃N₄ network formed by the intertwined columnar Si₃N₄ in the sea urchin-like structure ferrosilicon nitride protects Fe and Fe₃Si through its oxidation reaction, thereby achieving a higher FeO/Fe₂O₃ ratio and a lower liquid formation temperature in the FeO-Fe₂O₃-SiO₂ ternary phase. The FeO/Fe₂O₃ ratio in the liquid phase fluctuates at a high temperature, and then the constant change of the solubility of tridymite in the saturated liquid phase promotes the crystallization of tridymite due to the reducibility of Fe, Fe₃Si and Si₃N₄. When calcium carbonate is used as a mineralizer of silicon brick, the formation temperature of the liquid phase in the brick is increased to 1 436 ℃. Before that, the reactions in the bricks are mainly the decomposition of calcium carbonate and the transformation from β-quartz to α-quartz and to metastable α-cristobalite. The increase of the formation temperature of the liquid phase does not reduce the content of tridymite in the brick, and the content of glass phase in the brick is less than that in the brick with iron mineralizer.

To improve the resistance to hydration, thermal shock and slag penetration of magnesia, a magnesia based composite was prepared via adding TiO₂ powder (i.e., 1% (in mass fraction), 2% and 3%) into a light burned magnesia powder. The effect of TiO₂ content on the sintering behavior, microstructure and properties of the composite was investigated. The results show that free CaO and some MgO transform into CaTiO₃ and Mg₂TiO₄ and the size of MgO grains increases as TiO₂ addition increases, leading to an improvement in the hydration resistance. The formed CaTiO₃ and Mg₂TiO₄ phases reduce the thermal expansion coefficient and induce the crack deflection as TiO₂ content increases, therefore improving the thermal shock resistance of the specimens. Besides, as 1% TiO₂ is added, the slag penetration resistance of the specimens is enhanced due to the increase in MgO grain size and the formation of high stable intergranular CaTiO₃ phase. However, the further increasing TiO₂ content reduces the slag penetration resistance due to the formation of low stable Mg₂TiO₄ phase at MgO grain boundaries.