The invention relates to a growth method of a fluxing agent of
boron phosphate monocrystal, which comprises the steps of: 1) proportionally mixing a
boron phosphate compound and the fluxing agent, putting the mixture into
platinum crucible, and heating till completely fusing in a
crystal growing furnace; and then cooling to the temperature being 2 to 15 DEG C above a saturation temperature, thus obtaining a high temperature melt containing
boron phosphate and the fluxing agent; and 2) putting
seed crystal loaded on a seed rod into the high temperature melt, keeping constant temperature for 10 to 180 minutes, reducing the temperature to saturation temperature, and rotating the seed rod at the speed of 10 to 50 revolution / minute; and reducing the temperature at the speed of 0.1 to 2 DEG C / day, lifting the
crystal from the liquid surface after the
crystal grows up, and cooling to
room temperature at the speed of 20 to 50 DEG C / hour to obtain the
boron phosphate monocrystal. The fluxing agent used by the method can reduce the
viscosity of the high temperature melt, is beneficial to melt
mass transportation in the process of
crystal growth, avoids the formation of inclusions in the crystal, and can stably grow the transparent
boron phosphate monocrystal which has cm-level size, short
ultraviolet cutoff
wavelength and good mechanical
processing performance, is not easy to crack, does not absorb
moisture, and is easy to be stored.