抄録
Salt core for the high pressure die casting was investigated. Three alkali halides, i.e. sodium chloride NaCl (98%), potassium bromide KBr (99.7%) and sodium bromide NaBr (99.7%) were prepared as salt material. Aluminum borate whisker which is the best reinforcement for potassium chloride KCl was chosen for the reinforcement of the salt core. These salt materials were melted in an electric resistance furnace and poured into a permanent mold with 30K super-heat. 4point bending test was carried out to determine the strength.
The maximum whisker addition ratio of KBr and NaBr was about 10vol% and their strength increased linearly up to about 25MPa with increasing whisker addition. In contrast to these salts, NaCl could not be reinforced by aluminum borate whisker. SEM-EDX local analysis result shows that magnesium impurity could only be found near the agglomerated whisker in NaCl, suggesting that magnesium impurity in NaCl affects strength to some extent. High purity NaCl (99.5%) could actually be strengthened by aluminum borate whisker; the maximum whisker addition was about 7.6vol% and the maximum strength increased linearly with the addition of whiskers to about 20MPa.
