# High-pressure synthesis of superhard and ultrahard materials

## TL;DR

This paper reviews high-pressure synthesis techniques for creating superhard and ultrahard materials, highlighting promising chemical systems, exploration strategies, and recent experimental results on novel phases with exceptional hardness.

## Contribution

It provides a comprehensive overview of the current state, methodologies, and recent discoveries in high-pressure synthesis of superhard materials, emphasizing future research directions.

## Key findings

- Discovery of orthorhombic gamma-B28
- Synthesis of diamond-like BC5
- Development of cubic B-C-N phases

## Abstract

A brief overview on high-pressure synthesis of superhard and ultrahard materials is presented in this tutorial paper. Modern high-pressure chemistry represents a vast exciting area of research which can lead to new industrially important materials with exceptional mechanical properties. This field is only just beginning to realize its huge potential, and the image of "terra incognita" is not misused. We focus on three facets of this expanding research field by detailing: (i) the most promising chemical systems to explore (i.e. "where to search"); (ii) the various methodological strategies for exploring these systems (i.e. "how to explore"); (iii) the technological and conceptual tools to study the latter (i.e. "the research tools"). These three aspects that are crucial in this research are illustrated by examples of the recent results on high pressure - high temperature synthesis of novel super- and ultrahard phases (orthorhombic gamma-B28, diamond-like BC5, rhombohedral B13N2 and cubic ternary B-C-N phases). Finally, some perspectives of this research area are briefly reviewed.

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Source: https://tomesphere.com/paper/1904.00700