真空吸气剂吸氢后样品的热解动力学及热重分析

Kinetic and Thermo-Gravimetric Analysis of PdO Getters after Hydrogen Adsorption

采用热重分析方法，以氮气为载气，对真空吸气剂吸氢后的样品进行了热解实验。含100％PdO的吸气剂吸氢后的热解分为PdO脱氢、Pd脱氢和PdO分解三个区域，对应的温度区间分别为202～284℃，593～780℃和800～900℃。PdO吸氢是物理吸附，Pd吸氢既有物理吸附也有化学吸附。热重分析的升温速率设定为20℃／min。A慰0分解与样品脱氢存在明显的协同作用，主要体现在593～780℃的热解区间。吸氢后样品的热解动力学采用3个一级反应来描述。在不同的升温速率和PdO含量的情况下，活化能和频率因子之间存在“动力学补偿效应”，其反应性能得到了很大的提高。在常压下，随着吸气剂中Ag2O含量的增加，其活化所需的最高温度明显下降。

The pyrolysis of PdO getter material after hydrogen adsorption was studied with kinetic calculation and thenno-gravimetric analysis at a heating rate of 20℃/min. Three distinctive stages： the dehydrogenation of PdO and Pd, and the decomposition of PdO, corresponding to the temperature ranges of 202- 284℃ ,593- 780℃, and 800- 900℃, respectively, can be identified in the pyrolysis of PdO with a purity of 100%. The PdO physically adsorbs hydrogen, whereas Pd physically and chemically adsorbs hydrogen. The Ag20 decomposition correlates to the hydrogen desorption, especially in the pyrolysis temperature range of 593℃ - 780℃. Three first-order reactions best describe the kinetics of the pyrolysis. Under the conditions of different heating rates and varying PdO contents, the kinetic compensation between the activation energy and the frequency factor boosts the pyrolysis. The highest activation temperature significantly decreases with an increase of the AgeO content of the PdO getter material.