Synthesis, Characterization, and Thermal Decomposition of Pure and Dysprosium Doped Yttrium Phosphate System

Table 3

Results of thermal decomposition for different temperature ranges with observed and calculated weight loss in the following cases.

(a) Yttrium phosphate (YP)

Stage	Temperature (°C)	Decomposition steps	Weight loss (%)
			Observed	Calculated
First	39–176	YPO4·H2O → YPO4 + H2O	7.9	8.9
Second	176–437	2[YPO4] → Y2O3 + P2O5(g)	37	38.7
Third	437–706	Y2O3 → YO + 0.5O2(g)	6	7

(b) Dysprosium doped yttrium phosphate (DyYP)

Stage	Temperature (°C)	Decomposition steps	Weight loss (%)
			Observed	Calculated
First	43–176	Dy0.02Y0.98PO4·2H2O → Dy0.02Y0.98PO4 + 2H2O	13.65	16.28
Second	176–519	3[Dy0.02Y0.98PO4] → (Dy0.02Y0.98)2P2O7 + PO3(g) + O2	19.04	19.95