| 摘要 |
PURPOSE:To improve dispersibility by preparing an aqueous solution of H[NbO2(O)2] by adding strong acid and H2O2 water into at least one kind of Nb compd. selected from Nb(OH)5, Nb2O5 and NbCl5, and maintaining the mixture at specified temp. CONSTITUTION:At least one kind of Nb compd. selected from Nb(OH)5, Nb2O5 and NbCl5, by one mol is mixed with 5 moles of strong acid such as HCl or HNO3, into which 4 moles of H2O2 water is added for oxidation to obtain an aqueous solution of H[NbO2(O)2]. This solution is maintained at 5-50 deg.C for specified time to obtain H<+>[NbO2(O)2]<-> sol. Ammonia water is added to this sol to control pH, and the sol is refined by filtering through an ultrafiltration membrane to remove impurity negative ions such as Cl<->. If the sol is to be stored before use, a stabilizer comprising water-soluble org. dibasic acid such as oxalic acid is added to the aqueous solution of H[NbO2(O)2] by the propor tion of one mol of the stabilizer to one mol of Nb to inhibit increase of sol ratio. On using the solution, ammonia water of the same equiv. to the stabilizer is added to decomposed the stabilizer and to change the solution into sol. |
