The invention relates to a composite oxide refractory material for titanium and titanium alloy melting crucible and a preparation method for crucible thereof. According to the thermodynamic calculation results, the crucible material is mainly composed of calcium oxide 20 ~ 50% and zirconia 45 ~ 75% refractory materials, supplemented with appropriate flux and additives. The material is made into crucible through pretreatment, molding, pre-sintering, sintering and other processes. The composite oxide crucible is used as a container for melting titanium alloy at a temperature range of 1500 ~ 1800℃ under vacuum environment; After melting, the inner and outer surfaces of the crucible are intact and there is no reaction with the titanium alloy, which ensures the purity and performance of the titanium alloy.
At present, consumable electric arc furnace combined with water-cooled copper crucible is commonly used as a device for smelting titanium alloy in industry. However, the water-cooled copper crucible takes away a large amount of heat, which seriously wastes energy, and causes the inhomogeneous thermal field, which makes the titanium alloy inhomogeneous structure and affects its service performance.
In addition, a crucible of oxide refractory material is used as a melting container. But the melting point of titanium metal is high, in the melting state, titanium chemical activity is large, under the current melting conditions, almost and all the commonly used refractory materials have different degrees of reaction, so ordinary refractory materials, alumina, magnesium oxide and silicon oxide, are not suitable for smelting titanium alloy crucible material.
Some people use graphite as a crucible material for smelting titanium and titanium alloy. After melting titanium alloy with graphite crucible, the titanium ingot carburized seriously, and the large scale brittle layer was formed, which reduced the performance of titanium alloy. And the use of calcium oxide crucible, but calcium oxide crucible on the one hand can not meet the titanium alloy on the oxygen content control requirements, on the other hand, calcium oxide crucible is not easy to sintering molding, and easy to hydrate in the air, not easy to preserve. It has been reported that yttrium oxide, as a refractory material for melting titanium alloy, has a small reaction with titanium alloy and can form an intermediate layer, which can effectively inhibit the further reaction between titanium alloy and refractory, and is an ideal refractory material for melting titanium alloy. But its price is too high, directly raising the cost of titanium alloy, is not suitable for large-scale use.
