On the causes of certain defects in the rod and belt materials of the Ni-38%Cu-2%Mn alloy with components of the electrovacuum devices

Based on analyzing the possible impurities, the paper establishes connection between the Ni-38%Cu-2%Mn nickel-copper alloy chemical purity and characteristic defects in rods and belts produced from it. It shows that the cause of pores and delaminations appearing in the finished rods and belts could be the impurities of bismuth, selenium and tellurium, which are poorly soluble in nickel and copper and at the same time fusible. These impurities not only worsen the resulting material vacuum density, but also, due to their tendency to sublimation, could cause contamination of the electric vacuum device working area and its failure. The paper shows disadvantages in the current regulatory documentation for rods and belts made of the Ni-38%Cu-2%Mn alloy in terms of requirements to the material chemical purity, which could become critical in manufacture of parts for the electrovacuum devices working area. Certain technological methods are described aimed at purifying the ingot material from harmful impurities, in particular at the required minimum duration of initial melt exposure to remove undesirable impurities bound in deoxidation and modification from it into the slag.
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