Molybdenum zirconium titanium alloy sintering method
There are two sintering methods of molybdenum zirconium titanium alloy: hydrogen protected sintering and vacuum sintering.
First, hydrogen protection sintering: the so-called hydrogen protection sintering is carried out in the state of hydrogen.
Second, in the process of hydrogen protection sintering, due to the hydrogen reduction, oxide of molybdenum powder are hydrogen change, reduce oxygen content in the material below to dozens of mu g/g, but to add the active element such as titanium, zirconium, molybdenum alloys, as a result of the alloying elements highly active, can react with the impurity in the hydrogen gas generated oxide, nitride, hydride, etc. As a result, the impurity content of molybdenum zirconium titanium alloy remains high, which seriously affects its mechanical properties. Therefore, in general, molybdenum zirconium titanium alloy sintering is vacuum sintering.
Three, vacuum sintering: vacuum sintering is a method of sintering porcelain billet under vacuum conditions, its porosity is relatively small. Compared with hydrogen protected sintering, vacuum sintering can effectively reduce the content of oxygen, nitrogen and other impurities in molybdenum zirconium titanium alloy.
In the vacuum sintering process, a slightly excessive amount of carbon (relative to the given composition) is generally added to deoxidize metal oxides through the reduction of carbon. Among them, there are two main deoxidation mechanisms: metal oxide in carbon reduction system to metal carbide and? Copper and molybdenum dioxide disproportionate to form molybdenum metal and molybdenum trioxide under high vacuum temperature. In the disproportionation reaction of metal oxide and molybdenum dioxide in a carbon reduction system, the temperature at which the two reactions begin is related to the partial pressure of the product gas in the furnace. With the reduction of the partial pressure of the products in the furnace, the reaction temperature gradually decreases. Therefore, increasing the vacuum degree in the furnace and reducing the partial pressure of the product gas can reduce the temperature of deoxidation reaction, which is beneficial to deoxidation.
