(湖南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410082)
摘 要: TiH2常用作泡沫鋁和粉末冶金制品的原料，控制其脫氫進(jìn)度是生產(chǎn)中的關(guān)鍵步驟。利用XRD與DSC技術(shù)得到TiH2在氬氣氣氛中加熱分解分3步完成，即TiH2→TiH1.5→Ti(固溶)→Ti。用單個(gè)掃描速率法和多重掃描速率法對(duì)DSC/TG數(shù)據(jù)進(jìn)行計(jì)算，得到TiH2→TiH1.5的機(jī)理模式為球形對(duì)稱邊界反應(yīng)，TiH1.5→Ti(固溶)的機(jī)理模式為化學(xué)反應(yīng)，Ti(固溶)→Ti轉(zhuǎn)變機(jī)理為三維球形對(duì)稱擴(kuò)散，3步轉(zhuǎn)變的活化能分別為240、190和145 kJ/mol。因此，與單個(gè)掃描速率法相比，采用多重掃描速率法研究TiH2熱分解，其結(jié)果與實(shí)際情況更接近。
關(guān)鍵字: TiH2脫氫; 動(dòng)力學(xué)計(jì)算; 多重掃描速率法
（College of Materials Science and Engineering, Hunan University, Changsha 410082, China）
Abstract:Thermal dehydrogenation of TiH2 is a key step in the manufacture of foamed aluminum and other powders metallurgy (PM) parts when TiH2 powders are used as raw materials. With the test results of TiH2 thermal decomposition in argon atmosphere obtained by XRD and DSC techniques, its thermal dehydrogenation process can be divided into three steps, namely, TiH2 → TiH1.5 → Ti (with H in solution) → Ti. The thermal decomposition dynamics calculation of titanium hydrides was conducted by both individual scanning rate method and multiple scanning rate method. It is found that the transformation mechanism of TiH2 → TiH1.5, TiH1.5 → Ti (with H in solution) and Ti(with H in solution) → Ti are of spherical symmetric boundary reaction, chemical reaction and three-dimensional spherical symmetric diffusion, respectively, and their opposite dehydrogenation activation energies are 240, 190 and 145 kJ/mol, separately. Multiple scanning method was finally proposed in dynamics analysis of TiH2 thermal decomposition for more reasonable results fitted with reality in comparison with individually scanning rate method.
Key words: TiH2; dehydrogenation; dynamics calculation; multiple scanning rate method
