Nickel sulphate hexahydrate (NSH) and potassium magnesium nickel sulphate hexahydrate (KMNSH) single crystals were grown by slow evaporation method. The grown NSH crystal was found to crystallize in tetragonal system with space group P41 21 2 and KMNSH in monoclinic system with space group P121/c. The optical band gap energies of the grown crystals using UV-Vis spectral results for the doped and undoped NSH crystals were calculated. The presence of various functional groups in the crystal was identified by FTIR analysis. The thermal behaviour of the grown crystal has been studied by TGA/DTA analysis. 1. Introduction Ultraviolet (UV) light filters are used in missile approach warning systems which locate and track UV energy emitting sources and are used as sensors for helicopters or transport aircraft. Commercially available nickel sulphate hexahydrate crystals are widely used as sensors. The biggest problem for these sensors arises due to low thermal stability of nickel sulphate crystals which is 76°C. The potassium nickel sulphate hexahydrate (KNSH) crystals which have higher thermal stability as 97°C are used in missile approach warning systems and as sensors in spaceships [1, 2]. Several other crystals such as cesium nickel sulphate hexahydrate (CNSH) [3], iron nickel sulphate twelvehydrate (FNSH) [4], rubidium nickel sulphate hexahydrate (RNSH) [5], and ammonium cobalt nickel sulphate hexahydrate (ACNSH) [6] are also reported as UV filter materials. Similar research work carried out on potassium sulphate [7, 8], potassium cobalt nickel sulphate hexahydrate (KCNSH) [9, 10], bis thiourea magnesium sulphate (BTMS) [11], and magnesium sulphate heptahydrate [12] crystals is also reported. In the search of newer crystalline materials with better filter transmission property and higher thermal stability, the growth of potassium magnesium nickel sulphate crystal has been carried out in this research work. 2. Experimental Procedure NiSO4·6H2O, K2SO4, and MgSO4·7H2O of AR grade (purity > 98.0%) were used. Approximate molar ratio of materials was taken using digital balance and dissolved in double distilled water. The solution of pH value 5 was stirred for nearly 2 hourswith magnetic stirrer to ensure homogeneity. Heating the solution to 60°C is carried out to promote the reaction and then is cooled to 40°C slowly. An abduction is formed according to the reaction given as follows: The homogenised solution was filtered twice using Whatman filter paper number 1 and then allowed to evaporate at 40°C temperature using a constant temperature bath. Then the solution
References
[1]
N. B. Singh, W. D. Partlow, S. Strauch, A. M. Stewart, J. F. Jackovitz, and D. W. Coffey, “Crystals for ultraviolet light filters,” U. S. Patent 5788765, 1998.
[2]
Y. He, J. Chen, G. Su, X. Zhuang, G. Lee, and R. Jiang, “Growth of potassium nickel sulfate hexahydrate (KNSH) crystal and its characterization,” Journal of Crystal Growth, vol. 233, no. 4, pp. 809–812, 2001.
[3]
E. B. Rudneva, V. L. Mamomenova, L. F. Malakhova, A. é. Voloshin, and T. N. Smirnova, “Cs2Ni(SO4)2 · 6H2O (CNSH) crystal: growth and some properties,” Crystallography Reports, vol. 51, no. 2, pp. 344–347, 2006.
[4]
G. Su, X. Zhuang, Y. He et al., “A new single crystal of iron nickel sulfate twelvehydrate (FNSH) used as optical bandpass filters,” Journal of Crystal Growth, vol. 243, no. 2, pp. 238–242, 2002.
[5]
X. Wang, X. Zhuang, G. Su, and Y. He, “A new ultraviolet filter: Rb2Ni (SO4)2· 6H2O (RNSH) single crystal,” Optical Materials, vol. 31, no. 2, pp. 233–236, 2008.
[6]
G. Su, X. Zhuang, Y. He, and G. Zheng, “A new crystal of ammonium cobalt nickel sulfate hexahydrate for UV light band-pass filter,” Optical Materials, vol. 30, no. 6, pp. 916–919, 2008.
[7]
S. Radhika, C. M. Padma, S. Ramalingom, and T. Chithambara Thanu, “Growth, optical, thermal, mechanical and dielectric studies of potassium sulphate crystals doped with urea,” Archives of Physics Research, vol. 4, no. 1, pp. 49–59, 2013.
[8]
S. Bin Anooz, R. Bertram, and D. Klimm, “The solid state phase transformation of potassium sulfate,” Solid State Communications, vol. 141, no. 9, pp. 497–501, 2007.
[9]
X. X. Zhang, G. B. Su, Y. P. He, and G. Z. Zheng, “Growth and characterisation of potassium cobalt nickel sulfate hexahydrate for UV light filters,” Crystal Research and Technology, vol. 41, no. 10, pp. 1031–1035, 2006.
[10]
I. Polovynko, S. Rykhlyuk, I. Karbovnyk, et al., “A new method of growing mixed crystals and their spectral investigation,” Journal of Crystal Growth, vol. 311, no. 23-24, pp. 4704–4707, 2009.
[11]
V. Krishnakumar, C. Ramachandraraja, and R. S. Sundararajan, “Crystal growth and vibrational spectroscopic studies of the semiorganic non-linear optical crystal—bisthiourea magnesium sulphate,” Spectrochimica Acta—Part A: Molecular and Biomolecular Spectroscopy, vol. 68, no. 1, pp. 113–116, 2007.
[12]
S. Karan and S. P. S. Gupta, “Vickers microhardness studies on solution-grown single crystals of magnesium sulphate hepta-hydrate,” Materials Science and Engineering A, vol. 398, no. 1-2, pp. 198–203, 2005.
[13]
D. Vanitha, S. Asath Bahadur, and Athimoolam, “Crystal growth and characterization of potassium magnesium nickel sulphate hexahydrate as UV filter,” Archives of Applied Science Research, vol. 4, no. 6, pp. 2378–2381, 2012.
[14]
A. Ruby and A. C. Raj, “Growth and characterization of a new metal-organic nonlinear optical thiourea potassium magnesium sulphate single crystals,” Archives of Physics Research, vol. 3, no. 2, pp. 130–137, 2012.
[15]
G. Sivanesan, P. Kolandaivel, and S. Selvasekarapaandian, “Laser Raman and FT-IR studies of pure and Zn-doped TGS,” Materials Chemistry and Physics, vol. 34, no. 1, pp. 73–77, 1993.
[16]
Y. He, J. Chen, G. Su, X. Zhuang, G. Lee, and R. Jiang, “Growth of potassium nickel sulfate hexahydrate (KNSH) crystal and its characterization,” Journal of Crystal Growth, vol. 233, no. 4, pp. 809–812, 2001.
