论文部分内容阅读
用氢轻度还原仲钨酸铵(APT)所得兰钨的组成随还原温度不同而变化。在275℃为非晶态铵钨青铜(ATB);在325℃为结晶态ATB;随着还原温度升高,ATB含量逐渐减少,在575℃的试样中不存在ATB。超过325℃时,出现W_(20)O_(58),其含量随温度升高而增加,在525℃达到最大值,然后随温度继续升高而迅速减少。在525℃至575℃之间,还原产物的相组成发生显著变化,由ATB和W_(20)O_(58)组成的物相迅速转变为由WO_2、β-W和α-W所组成的物相。本文给出了兰钨的相组成与APT还原温度的定量关系。与用氢还原WO_3相比,在APT的轻度氢还原过程中,β-W出现的温度范围广,且含量高。 在450℃用氢还原APT,当还原时间为5min时,产物是结晶态ATB;随着还原时间延长,将出现W_(20)_O_(58),并逐渐增多,而ATB的含量则逐渐减少。本文实验地研究了在450℃用氢还原APT时所得兰钨的相组成与还原时间的关系。
The composition of blue tungsten obtained by mild reduction of ammonium paratungstate (APT) with hydrogen will vary with the reduction temperature. It is amorphous ammonium tungsten bronze (ATB) at 275 ℃. It is crystalline ATB at 325 ℃. As the reduction temperature increases, the content of ATB gradually decreases. There is no ATB in the sample at 575 ℃. When it exceeds 325 ℃, the content of W_ (20) O_ (58) appears. The content of W_ (20) O_ (58) increases with the increase of temperature and reaches the maximum at 525 ℃, then decreases rapidly with the increase of temperature. The phase composition of the reduction products changed significantly from 525 ℃ to 575 ℃. The phase composed of ATB and W_ (20) O_ (58) rapidly changed into the phase consisting of WO_2, β-W and α-W phase. In this paper, the quantitative relationship between the phase composition of blue tungsten and the APT reduction temperature is given. Compared to the reduction of WO 3 with hydrogen, β-W appears to have a wide range of temperatures and high levels during mild hydrogen reduction of APT. The reduction of APT with hydrogen at 450 ° C showed that when the reduction time was 5 min, the product was crystalline ATB. With the reduction time prolonged, W_ (20) _O_ (58) appeared and gradually increased while the content of ATB gradually decreased. In this paper, the relationship between the phase composition and the reduction time of blue tungsten obtained by hydrogen reduction of APT at 450 ℃ was studied experimentally.