Diffuse reflectance infrared spectra and their relation to the thermal stability of aluminophosphate oxynitrides as a function of nitrogen content

摘要: Abstract Amorphous aluminophosphate oxynitrides (AlPON) solids with a variable nitrogen content (2.8, 3.6, 7.2, 11, 17.5 and 20%w/w) have been prepared by nitridation of AlPO4 using gaseous NH3. Their thermal stability below 500°C is investigated diffuse reflectance infrared spectroscopy mass spectrometry. Water ammonia, coming from AlPON surface hydrolysis upon exposure to air, are desorbed around 150°C sites involving Al–OH. At higher temperature (350°C) terminal –PNH2 groups attacked water produce NH3 additional P–OH in tetrahedral co-ordination. There simultaneous reaction between –PO generating P–OH(tet) but no Besides, highly nitrided samples suffers condensation 250°C yield process thermodynamically favoured controlled the coverage groups.