Dissertation > Industrial Technology > Metallurgical Industry > Metallurgical Technology > Powder metallurgy (metal ceramic technology ) > Powder molding, sintering and post-processing > Sintering process

A Study on the Manufacture Process of Inorganic Oxide Lanthanum Chromite and the Properties after Sintered

Author HuangLing
Tutor ChenHong
School Hubei University of Technology
Course Materials Processing Engineering
Keywords Lanthanum Chromite Solid-phase method Vacuum sintering The doped Ca chromium lanthanum High - temperature conductivity
CLC TF124.5
Type Master's thesis
Year 2011
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Currently the preparation of lanthanum chromite materials exist high sintering temperature , low density and poor strength defects . This experiment will be to improve the solid phase method by optimizing existing processes prepared lanthanum chromite material defects , as well as to optimize its physical properties and the use of performance by the dopant compound , and further study the physical properties of the lanthanum chromite materials . Through Buried powder sintering method is commonly used volatile process chrome components existing improvement lanthanum chromite powder buried powder sintered powder requirements , the price is expensive , is not conducive to economic efficiency . The study found that not only can improve the sintering properties of the powder , but also to reduce the sintering temperature , i.e. in the 800 ° C synthesized under the lanthanum chromite powder can be sufficient solid phase reaction by vacuum sintering process . XRD analysis showed that the 1450 ° C synthesis chromic acid calcium -doped lanthanum ( La 0.9 Ca 0.1 < / sub > the CrO 3 < / sub >) Powder crystal structure is reasonable, superior powder synthesized at other temperatures , and synthesis in the temperature uniform particle size , is expected to be prepared in this study crystalline materials . Doped calcium lanthanum chromite crystal conductive study showed that the conductivity with temperature of the crystal was stable multi - linear change , namely: from room temperature to 330 ℃ linear resistance , 330 ° C to 720 ° C in a linear resistance , the more than 720 ° C constant resistance characteristic of the linear resistance, and the resistance increases with temperature drastically reduced , indicates that the crystal having a good conductive properties and stability at high temperatures , indicating that the material may be applied to the heating element in the oxidizing environment . Studies have shown that the resistance change of 330 ℃ and 720 ℃ La 0.9 Ca 0.1 CrO 3 crystal materials appear Cr volatile lead crystal lattice distortion phase change. Existing research shows that : 98MPa high-pressure molding at 1450 ℃ pressure vacuum sintering can be prepared by the crystal structure is reasonable, the performance of high-temperature conductive doped calcium lanthanum chromite crystal material , forming pressure increase will help improve the crystal density , add the appropriate molding agent conducive to crystal density is homogenized . The study also found that the the sintered La 0.9 Ca 0.1 CrO 3 crystal material body is collapsing , and its mechanism remains to be further studied .

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