Mechanical Studies on Pure and Fe3+ Doped Potassium Hydrogen Phthalate Single Crystals for Device Fabrications

Background/Objectives: Mechanical properties of the selected materials play an important role in device fabrications. Thus the perfect cleavage (010) plane of doped and un-doped Potassium Hydrogen Phthalate (KHP) crystal is subjected to Vicker’s micro hardness study. Methods/Statistical Analysis: Slow evaporation solution growth method is employed for the growth of Fe³⁺ doped and un-doped Potassium Hydrogen Phthalate (KHP) crystals. Here, 0.1 mol% of FeCl₃ used as dopant. Saturated solution of both doped and un-doped KHP solutions are prepared according to the solubility data (12.5g/100ml at 30°C). Findings: A well developed (010) plane of pure and un-doped crystals have been subjected to hardness studies with various loads. It is found that Vickers Hardness numbers (H_V) for undoped and doped KHP crystals varied for different loads. Meyer’s index or work hardening co-efficient (n) values are found to be greater than 1.6 which reveals that the grown crystals are belongs to soft material’s category. i.e., for pure KHP the value of ‘n’ is 3.68 and for Fe doped KHP, it is 3.46. The minimum load indentation (W) to initiate the plastic deformation on the surface of the crystals are calculated based on Hays and Kendall’s theory. The value of W for KHP and doped KHP are found to be 1.965 and 4.368 respectively. The hardness related constants like materials constant (k₁) and load dependent constant (A₁) for the pure and un-doped KHP crystals have been estimated. The Elastic stiffness constant (C₁₁) are also calculated from Vickers micro hardness values. Applications/Improvements: Potassium Hydrogen Phthalate (KHP) is an efficient crystal analyzer material and is used in X-ray spectrometer. The improvement in hardness by dopant provides the use of materials for efficient optical device applications.