[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

High-entropy ceramics with five or more cations have recently attracted significant attention due to their superior properties for various structural and functional applications. Although the multi-component ceramics have been of interest for several decades, the concept of high-entropy ceramics was defined in 2004 by producing the first high-entropy nitride films. Following the introduction of the entropy stabilization concept, significant efforts were started to increase the entropy, minimize the Gibbs free energy and achieve stable single-phase high-entropy ceramics. High-entropy oxides, nitrides, carbides, borides and hydrides are currently the most popular high-entropy ceramics due to their potential for various applications, while the study of other ceramics, such as silicides, sulfides, fluorides, phosphides, phosphates, oxynitrides, carbonitrides and borocarbonitrides, is also growing fast. In this paper, the progress regarding high-entropy ceramics is reviewed from both experimental and theoretical points of view. Different aspects including the history, principles, compositions, crystal structure, theoretical/empirical design (via density functional theory, molecular dynamics simulation, machine learning, CALPHAD and descriptors), production methods and properties are thoroughly reviewed. The paper specifically attempts to answer how these materials with remarkable structures and properties can be used in future applications.

High-entropy ceramics: Review of principles, production and applications

Microstructure, mechanical and tribological characterization of CrN/DLC/Cr-DLC multilayer coating with improved adhesive wear resistance

Titanium alloys are widely used in aerospace, biomedical, and other engineering areas due to their superior properties. However, machining of titanium alloys has always been a challenge due to the high temperatures and tool wear rates. Dry machining has a limited range of permissible cutting conditions and is hence not suitable for industrial production. As a solution, flood cooling using cutting fluids is conventionally used to reduce the cutting temperatures. However, it is often discouraged in light of the associated environmental and health hazards. In order to achieve sustainable machining, different strategies for applying the cutting fluids are developed. Some of the prominent methods include minimum quantity lubrication (MQL), minimum quantity cooled lubrication (MQCL), and cryogenic cooling. This paper provides a comprehensive review of the available recent literature on such studies. Each of these techniques and results obtained in the studies has been discussed with emphasis on the advantages and limitations of each method. Major conclusions drawn are that coated carbides are better and machinability is greatly affected by the microstructure of the material. MQL certainly improved compared to other methods while cryogenic or super cooled cutting fluid application (MQCL) has been found to be better for specific situations. Use of nanofluids for titanium is not very popular among the researchers.

Application of cutting fluids in machining of titanium alloys—a review

In modern aerospace, nuclear energy, electric power and other high-tech industries, increasingly more requirements are put forward for the enhanced performance and functionality of lubricating materials. In recent years, intelligent lubricating materials and structures with properties on demand and bionic functions by imitating the life system have aroused great interest. The trigger and feedback behaviors of functional ingredients endow intelligent materials with the ability of controllable lubrication. However, there is still a lack of a review that outlines these encouraging results. In this review, the category and lubrication mechanism of the widely used solid lubricants are summarized, and then the novel intelligent lubricating technologies with micro/nanocontainers are comprehensively introduced, including the materials, sizes and synthetic methods of micro/nanocontainers. The stimuli-responsive behaviors and tribological properties of intelligent composites storing liquid lubricants are discussed. On the basis of four kinds of dual functional lubricating materials, the reported preparation strategies and the achieved performance are introduced, and potential functionalization methods are also presented. Finally, the review ends with a brief summary and some future perspectives.

Intelligent lubricating materials: A review

Relationship of microstructure, mechanical properties and titanium cutting performance of TiAlN/TiAlSiN composite coated tool

Doped graphite-like coating (GLC) has aroused great interest as one of the most promising protective materials in marine applications. However, there is a lack of systematic research on the tribocorrosion and antifouling performance of doped GLC coatings in harsh marine environments. Herein, a multifunctional (Cr, Cu)-GLC coating with combined antifouling and tribocorrosion properties was prepared via a magnetron sputtering method. The experimental results indicate that the resultant coatings changed from a dense structure to a loose columnar structure with the increment of Cr and Cu doping amount. At the same time, the hardness of the coating gradually decreases, but the contact angle between coating and seawater gradually increases. The algae adhesion test reveal that the algae density on the surface of the (Cr, Cu)-GLC coating decreases from about 565 to 70/mm2 as the amount of doping increased. However, on the contrary, the friction coefficient of the coating under OCP condition increases from 0.06 to...

Xudong Sui

Papers

Microstructure, mechanical and tribological characterization of CrN/DLC/Cr-DLC multilayer coating with improved adhesive wear resistance

Relationship of microstructure, mechanical properties and titanium cutting performance of TiAlN/TiAlSiN composite coated tool

Tailoring the Tribocorrosion and Antifouling Performance of (Cr, Cu)-GLC Coatings for Marine Application.

Improved toughness of layered architecture TiAlN/CrN coatings for titanium high speed cutting

Friction and wear properties of GLC and DLC coatings under ionic liquid lubrication