Additives On The Kdp Crystal Growth And Structure

In this paper,the growth mechanism of KDP crystal with the temperature reducing method in solution was introduced.The state of the research on the effect of different additives on the structure and optical properties of KDP crystal was detailed expatiated. The mechanism of the effect of the additives was summarized.By means of traditional temperature reducing method,we grew KDP crystals from solutions with different concentration of additives,and the additives were EDTA and KCI, metallic cations of Ce³⁺ and organic dyes(acidic fuchsin and methylene blue) respectively.The light scatter of KDP crystals was observed,and the transmittance of samples of the prismatic section was measured,tt indicated that EDTA and KCI with low concentration(0.01mol%EDTA,KCl＜1.5mol%) in solution can improve the transmittance of crystals,while high concentration(0.01mol%EDTA,2.0mol%KCl) doping may aggravate the light scatter and reduce the transmittance of crystals.The KCI doping with the concentration of 2.5mol%could restrain the crystal growth and induce the crystal defects.We measured the content of impurities(Fe³⁺,Cr³⁺,Cl^-) in KDP crystals,and it shew that the total content of trivalent metal ions(Fe³⁺,Cr³⁺) decreased with increase of doping concentration.The complexation of EDTA on the trivalent metal ions was confirmed.But the Chlorine element was not found in the KDP Crystals.As to the KDP crystal doped with organic dyes,the molecules of acidic fuchsin and methylene blue did not enter into the KDP crystal lattice due to the difference of the atomic structure between them and the KDP crystal.The impurities of Na⁺ entered the lattice of KDP crystal grown from the solution with acidic fuchsin by means of substituting the K⁺,and this was confirmed by the measurement of the content of the impurities.The investigation of the microhardness indicated that the hardness of the KDP crystal grown from the solution with low concentration of organic dyes increased greatly. The results of the elemental analysis to the KDP crystal doped Ce(NO₃)₃ revealed that Ce³⁺ can enter the crystal lattice of KDP.And the the KDP crystals doped Ce(NO₃)₃ exhibited good crystalline perfection and high microhardness.