The following article describes the approach and intermediate results of the highly interlinked research project InnoCrush. Within the project, innovations in the field of modern, low impact mining methods with a focus on small to medium sized, vein-like deposits are prepared. Such deposits currently are exploited only to a limited extend. In order to provide feasibility for the economic mining of such deposits an innovative process chain consisting of mechanical selective excavation in conjunction to near-face, dry, selective comminution is proposed. Within the project, six workgroups and cooperations with international partners, such as the Saint Petersburg Mining University are entwined. The workgroups combine experts and young scientists from the fields of Mineralogy, Mining, Processing, Geotechnics, Automation and for an holistic assessment, Economics.

X-ray computed microtomography has been applied to glass beads from the 18th century to study their shape and internal structure. This study is aimed to understand the history, manufacture technique and quality of glass beads. Only non-destructive methods have been required in this work considering the historical value of the artefacts. The elemental analyse has been made with energy dispersive X-ray spectroscopy and could indicates the presence of three main type of Glass: Lead glass, soda glass and high lime low alkali glass. This study focuses on the identification of the air bubbles in the glass and their shape and distribution in the different types of beads. Different types of bubbles are found in the beads. Long elongated bubbles, typical from the drawn bead manufacture and secondary bubble from the reboil effect. Bubbles can occur intentionally for making an optical translucent effect or due to a defect.

The results of experimental modeling of the arsenic transition from natural arsenides to mobile oxidized species in the near-surface environment are discussed. The experiment has been carried out with the samples collected from the dump of the Schlema-Alberoda deposit. Arsenides (safflorite, löllingite, nickeline, rammelsbergite) have been dissolved in acidic and near-neutral oxidative media for a month. As a result, the new data on arsenic leaching capability in order to form new phases (annabergite, scorodite, and iron hydroxides) have been obtained.

In a set of shock experiments under comparable porosities at pressures of about 35 GPa the melting behavior of porous copper was investigated. All experiments were performed with the impedance corrected sample recovery system and different degrees of decompression were used. It was possible to reduce the degree of molten metal in parts of the sample after sample recovery down to zero. The avoiding of melting was possible only by avoiding larger degrees of adiabatic decompression. This behavior implies a complete dependence of the melting on the release path for porous copper under the given conditions. The zones, where the melting processes are avoided, include also areas with intense micro jetting. Because also in these zones melting does not occur, it is possible that the melting curve of copper along the Hugoniot is not yet solved. The experiments have verified, that it is possible to use equation-of-state calculations for the solid state only, concerning the pressure area of currently commercial interest for the production of nitrides and diamond with copper-powder as pressure medium. Furthermore in this work the role of different parts of the sample recovery capsule is described to improve the comparability of shock wave synthesis experiments. On the other hand, the experimentally results given in this work show significant differences to data, obtained by a number of simulations.

The mechanical response of shock wave-prestrained high-alloy Cr16-Mn7-Ni6 TRIP steel was investigated under compressive and tensile loading at room temperature. Previous shock wave loading was carried out using a flyer-plate assembly with different amounts of explosives in order to achieve shock pressures of 0.3, 0.6, 0.9, and 1.2 Mbar. A significant increase in hardness and strength was observed as compared with the initial as-cast condition. In contrast, a slight decrease in strain hardening rates was measured together with a decrease in fracture elongation in the tensile test. Microstructural analyses of the shock-loaded samples were performed by light optical and scanning electron microscopy. The microstructure revealed a high density of deformation bands consisting of separated stacking faults, ε-martensite, or twins. Significant amounts of deformation-induced α′-martensite were only present at the highest shock pressure of 1.2 Mbar. The thickness of the deformation bands and the number of martensite nuclei at their intersections increased with increasing shock pressure. In all shock-loaded specimens, pronounced phase transformation occurred during subsequent mechanical testing. Consequently, the amount of the deformation-induced α′-martensite in the shock-loaded specimens was higher than in the unshocked as-cast samples.

The high pressure spinel-type γ-Si3N4 was prepared by using shock wave synthesis from amorphous precursors at the peak shock pressures around 34GPa. Due to the high liability of the precursor to oxidation, it is nearly impossible to obtain oxygen-free high-pressure material. The overall oxygen content varies between 7 and 12wt%. However, the X-ray and neutron diffraction experiments confirmed that the spinel-like phase dominates the samples. The neutron diffraction revealed that up to 5wt% of oxygen can be accommodated in the crystal structure of γ-Si3N4, where it replaces nitrogen. Additional oxygen seemed to increase the amount of an amorphous phase in the samples. The local chemical analysis in a transmission electron microscope proved that the amorphous phase contains more oxygen than the crystalline phase, thus the excess of oxygen was verified to be contained in the amorphous phase.

For the synthesis of high pressure phases from natural minerals and the shock wave treatment of fluid bearing phases a halide based method was developed. The experiments were performed in the pressure range between 25 and 162 GPa with a success rate for the new method of 100% for the new method. Based on the Impedance Corrected Sample Recovery Capsule under avoiding the adiabatic decompression a direct comparison between different loading paths and sample holder geometries is possible. The recovered samples show neither indications of melting in the case of kaolinite and very limited degassing in the case of carbonates. The recovery of amorphous water bearing Al-Si-phases with Aluminum in four-, five- and six-fold coordination was possible. The samples were analyzed with scanning electron microscopy, x-ray diffraction, nuclear-magnetic-resonance- and infra-red-spectroscopy and the results were directly compared.

Pressure-dependent thermodynamic properties of the ambient and high pressure phases of aluminum nitride (w-AlN and rs-AlN) were calculated from first principles in order to determine their phase boundary in the p- T phase diagram. These predictions were checked by static HP/HT experiments, using a multianvil press and an Al/N/H precursor with low decomposition temperature as educt. The experimental data show that at temperatures between 1000 and 2000K, the boundary line between the two phases is situated between 11 and 12GPa, which is similar to 1.3GPa lower than the theoretical result and generally lower than previously assumed. The hardness of rs-AlN - measured for the first time - is similar to 30GPa (Knoop indenter at loads of 25-50g), twice as hard as w-AlN. Shock wave recovery experiments on nano w-AlN allowed testing of the chemical and thermal stability of rs-AlN, and determination of its infrared absorption and Al-27 NMR data. The shock wave technique will eventually enable the synthesis of larger amounts of rs-AlN, making it available for technological use. Finally, implications on the high pressure stability of phases in the Si-Al-O-N system are discussed in the light of thermoelastic properties of AlN.

The high pressure phase of aluminium nitride with rocksalt structure (rs) is a ceramic with high potential and a challenging material to investigate. The rs-AlN was synthesised and recovered by shock wave experiments using the flyer-plate method with multiple reflections at peak pressures between 15 and 43 GPa. Successful syntheses were carried out using AlN nanopowder with ambient pressure wurtzite structure (w-AlN) as starting material. The high pressure modification could, however, not be obtained when starting from submicron w-AlN. The recovery of rs-AlN is sensitive to the synthesis conditions as these influence the reconversion of rs-AlN to w-AlN.

Aluminium nitride is a ceramic material with a high thermal conductivity, a small thermal expansion coefficient and good mechanical properties.Moreover AlN is a wide-bandgap semiconductor (E g = 6.2eV) and therefore high potential substrate material for high-power electronic applications [1].At pressure from 14-23GPa the wurtzitic aluminium nitride (wz) undergoes a phase transition to rocksalt structure (rs) at static experiments [2], [3], [4].A sinterbody of wz-AlN/rs-AlN show high hardness (>4000HV), high electric resistance and a thermal conductivity up to 600W/mK [5].Though the phase transition through shock waves were verified, shock experiments failed to quench the high-pressure phase so far [6].Currently rs-AlN were successfully synthesized from AlN nanopowder with shock wave synthesis via flyer-plate method at the Freiberg High-Pressure-Research-Centre (FHP).A 80mm metal plate were accelerated by high explosive to several km/s striking a steel container with the pure AlN sample powder.To obtain good conditions a flat shock wave were produced with a special plane-wavegenerator.The fine greyish powder (at the moment up to 2g per shot), which can be gathered from recovery container, shows up to 50% of the high-pressure AlN-phase.Caused by high oxygen content of the commercial AlN nanopowder, the synthesis product consist some percentage corundum and γ-AlON (up to 17%).At a given porosity of 1,68 at about 23GPa the highest yield can be achieved, while at higher pressures or major powder porosity, the post-shock-temperature is too high, so that the new high-pressure phase cannot be quenched and decomposes partly or complete to wz-AlN.First experiments show good chemical resistance of rs-AlN to acids and bases and a thermal stability higher than 1100°C in air.Further analysis (FTIR, 27Al MAS-NMR, neutron diffraction and insitu HT-XRD) are in progress.Fig 1: X-ray diffraction of (a) commercial nano-AlN-powder and (b) sample shocked at 22GPa with 50% rs-AlN yield.