Advances in Laser Drilling of Structural Ceramics

The high-quality, high-efficiency micro-hole drilling of structural ceramics to improve the thermal conductivity of hot-end parts or achieve high-density electronic packaging is still a technical challenge for conventional processing techniques. Recently, the laser drilling method (LDM) has become the preferred processing tool for structural ceramics, and it plays an irreplaceable role in the industrialized processing of group holes on structural ceramic surfaces. A variety of LDMs such as long pulsed laser drilling, short pulsed laser drilling, ultrafast pulsed laser drilling, liquid-assisted laser drilling, combined pulse laser drilling have been developed to achieved high-quality and high-efficiency micro-hole drilling through controlling the laser–matter interaction. This article reviews the characteristics of different LDMs and systematically compares the morphology, diameter, circularity, taper angle, cross-section, heat affect zone, recast layer, cracks, roughness, micro–nano structure, photothermal effect and photochemical reaction of the drilling. Additionally, exactly what processing parameters and ambient environments are optimal for precise and efficient laser drilling and their recent advancements were analyzed. Finally, a summary and outlook of the LDM technology are also highlighted.

Innovative research carried out at the nanocenter of the NRC “Kurchatov Institute” – CRISM “Prometey”

This article presents the results of comprehensive innovative research carried out over the past 15 years at the Nanocenter of the NRC “Kurchatov Institute” – CRISM “Prometey” in the following areas: the creation of coatings based on quasicrystals of the Al-Cu-Fe system, laser synthesis technologies, systems electromagnetic protection of technical equipment and biological objects, structural ceramics and composite materials, technologies for surface modification and magnetron sputtering, obtaining powders by melt spraying, hydrogen and alternative energy.

Progress and challenges towards additive manufacturing of SiC ceramic

Silicon carbide (SiC) ceramic and related materials are widely used in various military and engineering fields. The emergence of additive manufacturing (AM) technologies provides a new approach for the fabrication of SiC ceramic products. This article systematically reviews the additive manufacturing technologies of SiC ceramic developed in recent years, including Indirect Additive Manufacturing (Indirect AM) and Direct Additive Manufacturing (Direct AM) technologies. This review also summarizes the key scientific and technological challenges for the additive manufacturing of SiC ceramic, and also forecasts its possible future opportunities. This paper aims to provide a helpful guidance for the additive manufacturing of SiC ceramic and other structural ceramics.

Standardization of the Laser Notching Method for Measuring Fracture Toughness in Structural Ceramics

The single-edge V-notched beam (SEVNB) method based on the laser notching approach can effectively overcome the shortcoming of time-consuming and avoid large errors in traditional fracture toughness measurement ways, nevertheless the laser notching method has not yet been standardized. Taking oxide (ZrO2 and Al2O3), carbide (SiC), nitride (Si3N4) and boride (ZrB2-based) ceramics as the research objects, this paper systematically discussed the effects of notch tip sharpness, notch depth and equivalent notch angle on the measured value of fracture toughness, thereby clearly defined the range of these parameters that required for measuring the fracture toughness accurately. Furthermore, in order to give full play to the advantages of the laser notching method, the feasibility of sample miniaturization was also discussed. This study could provide important data reference and theoretical basis for the standardization of laser method in the near future.

Use of Mining Tailings or Their Sedimentation and Flotation Fractions in a Mixture with Soil to Produce Structural Ceramics

The ceramic materials industry has vast potential for use of waste from industrial processes, such as iron mining tailings. The aim of this study was to test technological use of tailings samples from the dam rupture of the Samarco S.A. Company in 2015 to produce structural ceramics. Sedimentation and flotation processes were used to improve their characteristics, analyzing their chemical and mineralogical composition and granulometry. We produced 48 samples with a mixture of soil and residues in proportions of 10, 20, and 30 wt%, with sintering at 950 °C. The results showed that co-processing of iron mining tailings can be considered viable for improving certain aspects of some technological properties. The maximum amount of residue used was 30 wt% for any of the fractions used, as above this concentration the specimens lose important characteristics.

Temperature dependence of hardness prediction for high-temperature structural ceramics and their composites

Hardness is one of the important mechanical properties of high-temperature structural ceramics and their composites. In spite of the extensive use of the materials in high-temperature applications, there are few theoretical models for analyzing their temperature-dependent hardness. To fill this gap in the available literature, this work is focused on developing novel theoretical models for the temperature dependence of the hardness of the ceramics and their composites. The proposed model is just expressed in terms of some basic material parameters including Young’s modulus, melting points, and critical damage size corresponding to plastic deformation, which has no fitting parameters, thereby being simple for materials scientists and engineers to use in the material design. The model predictions for the temperature dependence of hardness of some oxide ceramics, non-oxide ceramics, ceramic–ceramic composites, diamond–ceramic composites, and ceramic-based cermet are presented, and excellent agreements with the experimental measurements are shown. Compared with the experimental measurements, the developed model can effectively save the cost when applied in the material design, which could be used to predict at any targeted temperature. Furthermore, the models could be used to determine the underlying control mechanisms of the temperature dependence of the hardness of the materials.