反応焼結法によるNi基高耐食耐摩耗合金の開発

概要

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A corrosion-and wear-resistant alloy for plastic shaping machines was developed by powder metallurgy including a HIP (Hot Isostatic Pressing) process. The results were obtained as follows: (1) The composition of the new alloy was Ni-17.5 mass%Cr-24.0 Mo-3.6 B-2.9 Si-1.0 Cu. A reaction sintering method was applied to produce the new alloy. Ni-Mo-Si-Cu alloy powder and CrB powder were reaction sintered by the HIP process. CrB particles were transformed into M3B2 particles during HIP. (2) The corrosion resistance of the new alloy was 6, 45 and 100 times superior to that of centrifugal cast alloy, respectively, and almost the same as that of Hastelloy C. It was concluded that the high corrosion resistance of the new alloy was due to the addition of Cu which inhibited the preferential corrosion of the matrix by a electrochemicalcell corrosion mechanism. (3) The wear resistance of the new alloy was 3 times superior to that of centrifugal cast alloy and 150 times superior to that of Hastelloy C. This high wear resistance of the new alloy was due to fine dispersion of M3B2 particles. (4) The new alloy was reaction sintered and bonded to the inner surface of steel cylinder body. This bimetallic cylinder can be used for plastic shaping machines.