摘要
用肼与草酸作为添加剂制备了草酸钨酸肼复合盐 ,并以此作为前驱物制备黑色氧化钨 .热重分析的结果表明 ,在 50 0℃时热分解已经完成 .应用该复合盐在氮气保护下热分解制备了黑色氧化钨 .实验研究了肼与草酸添加量对产品性状的影响 .确定钨酸、肼、草酸的最佳比例 (物质的量比 )为 1 .0∶4.0∶0 .5.实验发现 ,热分解温度、热分解时间对产品性状有一定的影响 .采用最佳比例的前驱物热分解 ,温度为 650℃ ,时间为 30min时 ,所得典型产品呈黑色 .温度较高时 ,则产品略呈深棕色 ,表明此时产品主含WO2 相 .对黑色氧化钨中NH+4的质量分数亦进行了测定 ,实验表明 ,在所选择的条件下 ,氨钨青铜相可忽略不计 .典型产品的粉末X射线衍射 (XRD)图谱表明 ,产品主含W1 8O49相 ,WO2 相较少 .典型产品的比表面积 (BET法 )为 1 2m2 ·g- 1 ,团聚体粒度 (d50 )为 3.68μm .
Hydrazinium oxalate tungstate complicated salts were prepared by using hydrazine, oxalic acid and tungstic acid as raw materials, and tungsten black oxides were prepared by using these complicated salts as precursors under the protection of purified nitrogen. The result from thermogravimetry points out that the thermal decomposition of the precursor completes at about 500 ℃. The ingredient of raw materials composing the precursor affects some properties of the product. The optimal ratio of hydrazine, oxalic acid and tungstic acid was determined to be 1.0∶4.0∶0.5. Temperature and time of thermal decomposition were experimentally found to affect the properties of the product too. When the precursor with the optimal ratio is thermally decomposed at 650 ℃ and for 30 min, the product is typically black and called model product. The O/W index and content of ammonium ion were determined. The experimental result indicats that the O/W index is very close to that in W 18 O 49 and the ammonium tungsten bronze is not enough to account under the selected condition. The powder XRD pattern of model product reveals that the main phase is a W 18 O 49 one and the WO 2 phase takes a little. Of the model product, the specific surface area (BET method) was measured to be 12 m 2·g -1 and the agglomerate diameter ( d 50 ) 3.68 μm.
出处
《同济大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2000年第5期600-604,共5页
Journal of Tongji University:Natural Science
关键词
氧化钨
制备
热分解
tungsten oxide
preparation
thermal decomposition
