Heating TiH2 and ZrH2 powder, Ti and Zr will break down form TiH2 and ZrH2 and add to Mo powder. Some Ti, Zr will react with matrix to form solid solution strengthening. Another Ti, Zr, will react with O, C to form carbide which is second phase and to produce second phase strengthening. Ti, Zr added by chemical reaction, so the size of Ti and Zr has reached the atomic or molecular level. The minimum fee's size of TiH2, ZrH2 can be purchased on the market is smaller than 10um and purity is about 96%.
During mixing powder, the lanthanum nitrate solution and stearic acid solution was added into mixed powder, instead of La2O3 and graphite powder, because solution can make powder mixed evenly. On the other hand, lanthanum nitrate can produce La2O3 during the sintering process, and stearic (C18H36O2) acid can be decomposed into C elements. These elements are produced by reaction, so that more uniform mixed in powder and finer, which is conducive to form solid solution strengthening and second phase strengthening. Further, stearic acid can act as a lubricant and release agent during pressing.
During mixing, using ethanol as a solid - liquid mixed media, can prevent and reduce powder oxidation. What’s more, stearic acid is insoluble in water, but it is soluble in alcohol.
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