Bentonite-bonded molding sand is one of the most common mold materials used in metal casting. The high casting temperatures cause dehydration and alteration of the molding sand, thereby degrading its reusability. Neutron radiography and neutron diffraction were applied to study these processes by using pure bentonite-quartz-water mixtures in simulation casting experiments. The aim of the experiments was to compare the dehydration behavior of raw and recycled mold material in order to assess possible causes of the limited reusability of molding sands in industrial application. Neutron radiography provided quantitative data for the local water concentrations within the mold material as a function of time and temperature. Dehydration zones, condensation zones, and areas of pristine hydrated molding sand could be established clearly. The kinematics of the zones was quantified. Within four cycles of de- and rehydration, no significant differences in water kinematics were detected. The data, therefore, suggest that the industrial handling (molding-sand additives and the presence of metal melt) may have greater effects on molding-sand reusability than the intrinsic properties of the pure bentonite–quartz–water system.

The commissioning and operation of apparatus for neutron diffraction at simultaneous high temperatures and pressures is reported. The basic design is based on the Paris-Edinburgh cell using opposed anvils, with internal heating. Temperature is measured using neutron radiography. The apparatus has been shown in both on-line and off-line tests to operate to a pressure of 7 GPa and temperature of 1700°C. The apparatus has been used in a neutron diffraction study of the crystal structure of deuterated brucite, and results for 520°C and 5.15 GPa are presented. The diffraction data that can be obtained from the apparatus are of comparable quality to previous high-pressure studies at ambient temperatures, and are clearly good enough for Rietveld refinement analysis to give structural data of reasonable quality.

Since Roentgen's discovery of X rays in the late 1800s the use of penetrating radiation to form images has become a part of our everyday life as well as providing a useful tool for the scientific study of processes that have been previously impossible to measure. This can include the study of processes that are too deeply embedded in opaque materials for direct observation, or that occur on a length or time scale smaller than otherwise can be easily measured. As technologies to generate penetrating radiation and quickly collect images have matured, new techniques have emerged to measure processes that have been hidden for many years. One example is advances in flash radiography using charged particles as radiographic probes, including proton radiography and electron radiography. Recently the successful commissioning of proton microscope systems has provided remarkable improvements in spatial resolution. These techniques are being implemented for applications with electron radiography. With the evolution of these new techniques comes the opportunity to choose the probe that provides the maximum information for the desired measurement. This paper describes these new imaging techniques, predicts the capabilities of high-energy electron radiography, and provides a guide for identifying the optimal probe for a wide range of measurements.