Hardness and Its Related Constants of Pure and Fe3+ Doped Potassium Hydrogen Phthalate Single Crystals for Optical Device Fabrications

Abstract

Single crystals of pure and Fe³⁺ doped Potassium Hydrogen Phthalate (KHP) single crystals were grown by slow evaporation technique. Variations of hardness on the (010) plane of pure and Fe³⁺ doped KHP crystals with various loads were studied. For both pure and doped KHP crystals, the Vickers Hardness values (Hv) were analyzed for varying loads. However, the dopant Fe³⁺ enhances the hardness of crystalline KHP. Hardness Meyer’s index (n) values of the pure and Fe³⁺ doped KHP crystals were found to be greater than 1.6 showing the soft materials category. Based on the Vickers micro hardness data, the Elastic stiffness constant (C₁₁) was determined. The results of hardness and the related parameters of the grown crystals are discussed and compared.