| 摘要 |
PURPOSE:To provide a titled material which solidifies at a high curing rate to enable production of a precise casting mold having high compressive strength by adding a curing accelerator such as hydrogencarbonate, etc. of alkali metals and an expansion accelerator of pulverous Al powder to aggregate consisting essentially of MgO. CONSTITUTION:Aggregate is formed by using MgO as an essential component and adding further SiO2, Na2O, Fe2O3 and Al2O3 thereto according to need. A self-curing mold material for casting Ti or Ti alloy is obtd. by adding >=1 kind among hydrogencarbonate, carbonate, phosphate, etc. of alkali metals or alkaline earth metals as a curing accelerator and pulverous Al powder as an expansion accelerator are added thereto. NaCHO3 or KH2PO4, etc. are more adequately usable as the above-mentioned self-curing mold material. The Mg(OH)2 yielded by the reaction between MgO and H2O and the curing accelerator reacts with each other to increase the solidifying rate and at the same time an insoluble salt or the like is formed to improve the compressive strength of the casting mold; moreover H2 is generated by the Al added to the material to accelerate the expansion of the mold by which precision casting of dental prosthesis, etc. consisting of Ti, etc. is made possible. |
