Wang Shenglai

Scattering centers caused by adding metaphosphate into KDP crystals

A mechanism for the formation of scattering centers in KDP crystals is reported. The crystals were grown from aqueous solution doped with a minute amount of sodium metaphosphate. From the observation using laser tomography, it was found that the density of the scatters rises with the increase of the concentration of the additive. The mother liquor macro inclusions also occur in the sector boundaries and pyramidal sectors when the dopant concentration is high enough. The scatters are proposed to be micro solution inclusions caused by the inhibition effect of metaphosphate on the growing faces.

Effects of impurities on growth habit of KDP crystal

The effects of metaphosphate, boric acid and quaternary ammonium cations with different concentration on the growth habit of KDP crystal are reported. The results are analyzed and discussed, which show that the effects of different impurities on the growth habit of KDP are not the same. It is due to the different adsorption mechanism of the impurities.

Effect of Pressure on Thermal Stability and Decomposition of KDP Crystal

Effect of pressure on thermal behavior of KDP crystals is investigated by using the in-situ infrared reflective spectra. Compared with that under normal atmosphere, the onset temperature of decomposition under pressure of 1 MPa is improved to from 210°C to 213°C, suggesting that the thermal stability of KDP is enhanced. Under pressure of 2 MPa, the thermal stability is deteriorated and KDP begins to decompose at 183°C. Under normal atmosphere KDP decomposes in route of translating to K4P2O7 firstly, and then to KPO3. Under pressures of 1 MPa and 2MPa, KDP translates to KPO3 directly without any other polymeric intermediates.