Zhang Z.,Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education |
Zhang Z.,Tianjin Cement Industry Design and Research Institute Co. |
Li X.-L.,Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education |
Ji H.-M.,Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education |
Zhou Y.-G.,Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education
Cailiao Kexue yu Gongyi/Material Science and Technology | Year: 2010
In order to investigate the characteristics of oxide semiconductor materials to low concentration acetone gas, the spinel type ZnFe2O4 thin films were successfully prepared on Al2O3 substrate by sol-gel method using soluble inorganic salts as row materials. The synthesis process and the modality of thin films were characterized by DTA, TG, XRD and SEM. Using citric acid as chelating agent, sintered at 700°C, a compact and well-coated ZnFe2O4 thin film with crystal size of 100 nm would be obtained by inorganic sol-gel (ISG) method. The acetone-sensitive test shows that ZnFe2O4 thin films have a good sensitive characteristic to acetone, and the sensitivity is 8 at 550°C. Both the response time and the recover time are less than 5 s.
Lin Y.T.,Tianjin University |
Lin Y.T.,Tianjin Key Laboratory of Advanced Joining Technology |
Wang D.P.,Tianjin University |
Wang D.P.,Tianjin Key Laboratory of Advanced Joining Technology |
And 6 more authors.
Science and Technology of Welding and Joining | Year: 2016
The microstructures and mechanical properties of 2219 aluminium alloy joints welded by variable polarity TIG welding in four kinds of different heat treatment conditions, namely, with/without pre-/ post-weld heat treatment, were analysed and compared. The post-weld artificial aging treatment rendered fine dispersed precipitates (metastable θʹ phase) separate out of weld metal, which made the hardness of weld metal increase by ~20%. Meanwhile, the fracture location of joints during tensile test changed from weld zone to heat affected zone (HAZ). The pre-weld solution treatment reduced the overaging degree of HAZ and a large number of θʹ phase reprecipitated in HAZ after post-weld artificial aging treatment. Intermediate state welding, with pre-weld solution treatment and post-weld artificial aging treatment together, could increase 20% of the hardness of weld zone, increase 11.5% of the hardness of HAZ and increase 20.3% of the tensile strength of joint. © 2016 Institute of Materials, Minerals and Mining.