Reactive mechanical alloying(RMA)was carried out in a planetary ball mill for the synthesis of ternary hydride Mg2FeH6 for hydrogen storage.The formation mechanism of Mg2FeH6 in RMA process and the sorption properties of the products were investigated.The results show that Mg2FeH6 has a yield ratio around 80%,and a grain size below 10 nm in the powder synthesized by milling 3Mg+Fe mixture for 150 h under the hydrogen pressure of 1 MPa.The synthesized powder possesses a high hydrogen capacity and good sorption kinetics,and absorbs 4.42%(mass fraction)of hydrogen within 200 s at 623 K under the hydrogen pressure of 4.0 MPa.In releasing hydrogen at 653 K under 0.1 MPa,it desorbs 4.43%(mass fraction)of hydrogen within 2 000 s.The addition of Ti increases the hydrogen desorption rate of the complex in the initial 120 s of the desorption process.
The effects of oxidation temperature and thickness of thermally grown oxide (TGO) on thermal stress distribution in thermal barrier coatings (TBCs) system are studied in the present paper.A typical TBC system is used:air plasma sprayed (APS) Scandia,yttria-stabilized zirconia (ScYSZ) top coat (TC) and NiCrAlY bond coat (BC) deposited on the nickel super-alloy substrate.The behavior of BC oxidation was examined.Both the Numerical model and Finite Element (FE) method were used to analyze the stress distribution.The objective of this study is to provide important information for understanding the failure mechanism of TBCs at least in a qualitative way.
Liu Huaifei1,2,Li Qilian2,Li Songlin1,Li Yongming1 1State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China 2National Key Laboratory of Science and Technology on Power Beam Process,Beijing Aeronautical Manufacturing Technology Research Institute,Beijing 100024,China
