SANS investigation of potassium morphology in bubble inclusions of sintered tungsten

According to the theoretical expectations, the potassium content in bubbles of sintered tungsten covers the internal surface, forming a solid or liquid shell. Depending on the temperature, this coverage becomes thinner and thinner by raising the temperature, as more and more potassium from the shell evaporates into the gas phase in the center of the bubble. Small angle neutron scattering investigations were made on annealed samples, varying the temperature between 300 K and 1023 K. The scattering intensity at 1020 K has been chosen as a reference state and the differences of the scattering intensities, in comparison with this reference state, were analysed by using the model of a hollow sphere. The results of the experiment correspond to the theoretical expectations.