专利类型:
相变材料专利导航
公开（公告）号:
DE4204173A1
申请日:
1992-02-13
申请局:
DE
摘要:
Prodn. of a single phase intermetallic phase, melting incongmently over a temperature range of 900-2000 K, and having a homogeneity of max 10 atm % at room temp., consists of calcio-thermally reducing a finely divided, homogeneous mixture of alloy components in which at least one is in oxide form. The exothermic is adjusted by the oxide content in the mixt. which in turn corresponds to the compsn. of the required single phase alloy. This temp. is given by Tm is more than Tr at least 0.9 Tm, where Tm is the melting temp. of the intermetallic phase and Tr the reaction temp. The reaction mixt. components except Ca, have an average particle size of not more than 75 microns. Following the exothermic reaction, the reaction prod. is tempered at at least 0.7 time Tm but below Tm for sufficient time to allow diffusion of the components. Finally the formed CaO and excess Ca is sepd., Provides single phased alloys such as Nd2Fe14B, SM2Fe17 and gamma TiAl., which have high hardness, thermal strength, corrosion resistance at high temps. super conductivity, permanent magnetism or magneto-optical properties
原始专利权人:
GOLDSCHMIDT AG TH
当前专利权人:
Evonik Operations GmbH