The Zinc Story under High Pressure

Kenichi Takemura

doi:10.4236/jmmce.2019.75024

Abstract

A historical review is presented on the experimental and theoretical studies on Zn under high pressure. Based on our high-pressure powder x-ray diffraction experiments that have been done for nearly a decade, we describe the structural change of Zn up to 126 GPa at room temperature. Although several experimental and theoretical studies indicated an anomalous change of the c/a axial ratio with pressure, we found no such an anomaly within our experimental uncertainty. Our high-pressure low-temperature experiments up to 18 GPa at 40 K also gave no evidence of the c/a anomaly. We suspect that the pressure-transmitting media played an important role in producing the anomaly. The structural anisotropy of Zn is drastically reduced at high pressures, which would be a general trend for hexagonal close-packed (hcp) metals.

Highlights

Zinc is one of the elemental metals and used for many practical applications in industry [1]
Based on our high-pressure powder x-ray diffraction experiments that have been done for nearly a decade, we describe the structural change of Zn up to 126 GPa at room temperature
We have extensively studied the structural change of Zn under high pressure up to 126 GPa at room temperature (297 K) and to 18 GPa at low temperature (40 K) by using powder x-ray diffraction techniques

Summary

Introduction

Zinc is one of the elemental metals and used for many practical applications in industry [1]. It is an important constituent of various kinds of alloys such as brass and nickel silver. From a crystallographic point of view, zinc is unique among elemental metals. It takes hexagonal close-packed (hcp) structure, which is common for the crystal structure of metals. Since the axial ratio c/a of a hexagonal crystal with an ideal packing of rigid spheres is 1.633 ( 8 / 3 ), it follows that the arrangement of atoms is not “close-packed” in zinc. Due to the long c-axis, each zinc atom has six nearest neighbors in the c-plane and six nearest neighbors in the adjacent planes

Objectives

Discussion

Conclusion