Use of KBF4–Al Mixed Powder to Produce Boron-Bearing 6063 Aluminum Alloys
2018 Volume 59 Issue 1 Pages 104-109
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2018 Volume 59 Issue 1 Pages 104-109
In this study, a simple boron addition process for producing 6063 aluminum alloy containing 0.03% B was investigated. KBF4 (98.0 mass%) and commercial-purity aluminum powder (>99.7 mass%, particle size: 30 μm) were weighed, mixed, wrapped in aluminum foil, and placed in a phosphorizer. The phosphorizer was then immersed in a molten 6063 aluminum alloy at a temperature of 720, 760, 810, or 860℃. The boron recovery rate depends on the amount of aluminum powder in the mixture and the melt temperature. Optimizing these factors gives a 90% boron recovery rate. Excess aluminum powder in the mixture leads to an increase in the specific surface area of the KBF4 particles and promotes the reaction, 2KBF4 + 3Al → AlB2 + 2KAlF4. The AlB2 contained within the KAlF4 migrates into the melt as the KAlF4 evaporates. Therefore, a mixed powder of KBF4 and aluminum can be an effective means of adding boron to 6063 aluminum alloy if the amount of aluminum and the temperature are carefully controlled. For the present experimental conditions, it was difficult to find AlB2 in the alloy by EPMA, because only a small amount of boron was added. Boron seems to form a solid solution with aluminum without forming coarse intermetallic compounds.
This Paper was Originally Published in Japanese in J. JILM 67 (2017) 222–227.
