Characteristics of various types of diamonds are summarized and selection of a diamond for a diamond anvil cell (DAC) is discussed. A diamond crystal with little internal strain and few crystal defects must be selected for generating ultra high pressure. The selection of a diamond is also based on other factors, such as a need for transparency in ultraviolet or infrared for optical studies or a need for low luminescence for Raman studies. Synthetic type II a diamond is most appropriate for diamond anvils, because it has a high crystalline quality, high transparency and low luminescence.
Fundamental techniques of polycrystalline x-ray diffraction measurement at high pressure using a diamond anvil cell are described. We point out several unusual conditions specific to a sample compressed in the DAC, give a detailed description of a laboratory x-ray diffractometer for high-pressure study and its performance, and briefly introduce a high-pressure synchrotron x-ray diffraction technique.
Diamond anvil, which is transparent in a wide wavelength region including visible, near infrared and infrared regions, is a most powerful tool to investigate optical properties of materials at high pressures beyond 100 GPa. Raman scattering and infrared absorption measurements with DACs and several techniques useful for producing high quality and reliable high-pressure spectra are reviewed in this article.
High temperature generation techniques used in diamond anvil cells and their application are reviewed. The configurations of internal heating, external heating and laser heating are described as common methods. The optics required in a laser heating system and the recent progress in heating quality are introduced in detail. The measurement and calibration of temperature, and pressure variation at high temperature are discussed for each method to realize stable experiments.
In this article, a diamond anvil cell system for optical studies at variable pressure and at low temperatures is described. A remotely controlled pneumatic driver unit, which consists of a pair of coaxial bellows, operates with helium gas. The setup and techniques for photoreflectance (PR) and time-resolved photoluminescence (TRPL) measurements with a diamond anvil cell are presented. Examples of the application to PR and TRPL in III-V semiconductor alloys under high pressure are shown.
In this paper, our 10-year developments and research for detecting superconductivity under high pressure in a DAC are described. With the progress of DAC technology to generate high pressure above100GPa, research for superconductivity as well as metallization of molecular solids of light elements became possible. The way of creating the low-temperature conditions and the high-pressure which is necessary for the superconducting research are explained in detail.
HIP is a powerful tool to produce functionally graded materials (FGMs) due to the heat treatment under isostatic gas pressure. PSZ/stainless steel, TiAI (α/α+γ), and W/Cu FGMs can combine incompatible functions of heat resistance and toughness in structural uses. In functional uses, the graded C/C composite for the heat receiver, the Ir/W/Ta emitter electrode for the thermionic converter, and one step formation of a graded thermoelectric conversion unit of SiGe with electrodes are developed using HIP. These recent developments of FGMs by HIP are reviewed.
The designing of threads for high-pressure equipment is described. We have formulated a computer program for the stress calculation at the first thread root based on the guidelines for high-pressure equipment proposed by the High Pressure Gas Safety Institution of Japan. A versatile method for lubrication to avoid seizure and scratching the threads is explained.