Abstract

Lattice dilation of metallic nickel film deposited by plasma-spraying on a ceramic layer that is also prepared by plasma-spraying, has been investigated by high resolution terahertz imaging and sequential zooming of the images to quantify the lattice parameter by graphical analysis. A metallic nickel sample was first imaged, and its measured lattice constant was found to be in agreement with the known value. Subsequently, four additional samples containing plasma-sprayed nickel film have also been imaged via an identical procedure. The lattice images of all samples were used for graphical analysis and quantification of the respective lattice parameters. Four samples, viz., 77, 81, 129 and 111 have been analyzed and their lattice dilation was investigated. It was found that the lattice distance (d) of these samples is in the order as, d₇₇ < d₈₁ < d₁₂₉ < d₁₁ and higher than the value of metallic nickel. Unit cell volume and density were also calculated for each sample from the measured lattice parameter. The density was found in the decreasing order for the 4 samples; i.e., ρ₇₇ > ρ₈₁ > ρ₁₂₉ > ρ₁₁ and the density values are significantly lower than the value for nickel. To our knowledge, this is the first direct evidence of the lattice dilation of plasma-sprayed metallic nickel measured via the terahertz lattice imaging, without requiring an electron microscope. Thus, the results presented herein establish an exciting extension of camera-less, reconstructive terahertz imaging technique that produces such a clear lattice image of nickel and allows to quantify the lattice parameter. The technique, however, is a general one, applicable to any material.

Keywords: Agriculture; Industry; Social; Marketing chain