Support materials for PEMFC and DMFC electrocatalysts—A review

Boron carbide is characterized by a unique combination of properties that make it a material of choice for a wide range of engineering applications. Boron carbide is used in refractory applications due to its high melting point and thermal stability; it is used as abrasive powders and coatings due to its extreme abrasion resistance; it excels in ballistic performance due to its high hardness and low density; and it is commonly used in nuclear applications as neutron radiation absorbent. In addition, boron carbide is a high temperature semiconductor that can potentially be used for novel electronic applications. This paper provides a comprehensive review of the recent advances in understanding of structural and chemical variations in boron carbide and their influence on electronic, optical, vibrational, mechanical, and ballistic properties. Structural instability of boron carbide under high stresses associated with external loading and the nature of the resulting disordered phase are also discussed.

Boron Carbide: Structure, Properties, and Stability under Stress

Noncarbon support materials for polymer electrolyte membrane fuel cell electrocatalysts.

Boron carbide is a strategic material, finding applications in nuclear industry, armour for personnel and vehicle safety, rocket propellant, etc. Its high hardness makes it suitable for grinding and cutting tools, ceramic bearing, wire drawing dies, etc. Boron carbide is commercially produced either by carbothermic reduction of boric acid in electric furnaces or by magnesiothermy in presence of carbon. Since many specialty applications of boron carbide require dense bodies, its densification is of great importance. Hot pressing and hot isostatic pressing are the main processes employed for densification. In the recent past, various researchers have made attempts to improve the existing methods and also invent new processes for synthesis and consolidation of boron carbide. All the techniques on synthesis and consolidation of boron carbide are discussed in detail and critically reviewed.

Synthesis and consolidation of boron carbide: a review

Chemistry of Diglycolamides: Promising Extractants for Actinide Partitioning

Titanium diboride (TiB2) based materials have received wide attention because of their high hardness and elastic modulus, good abrasion resistance, and superior thermal and electrical conductivity. Potential applications include high temperature structural materials, cutting tools, armour, electrodes in metal smelting and wear parts. Despite its useful properties, the application of monolithic TiB2 is limited by poor sinterability, exaggerated grain growth at high temperature and poor oxidation resistance above 1000°C. Pure TiB2 can be densified only at high temperatures (∼2000°C), with an applied pressure generally being necessary during sintering. However, these high sintering temperatures cause abnormal grain growth and microcracks, which are detrimental to the mechanical properties. Various sinter additives are commonly added to obtain dense TiB2 with optimised mechanical properties at lower sintering temperature. The present review surveys the current state of knowledge on development of bulk...

Processing and properties of monolithic TiB2 based materials

Pressureless sintering of boron carbide

Zirconium diboride is a strategic material, finding applications as thermal protection system in reentry vehicles, high temperature electrode, thermowell tubes, etc. Solid state reactions require high temperature and thus result in coarse powders which are difficult to sinter. Densification of ZrB2 is extremely difficult due to its refractory nature. Sinter additives help in densification but deteriorate the high temperature properties. In the recent past, various researchers have made attempts to improve the existing methods and also invented new processes for synthesis of pure and fine powders as well as for densification of ZrB2. All the techniques on synthesis and consolidation of ZrB2 are discussed in detail and critically reviewed in this article.

Synthesis and consolidation of zirconium diboride: review

Titanium diboride (TiB2) is one of the candidate materials for high temperature structural applications and also for control rod elements in high temperature nuclear reactors. This paper presents the experimental data on the synthesis, consolidation to dense pellets and property evaluation of TiB2 carried out in laboratory scale. TiB2 powder was prepared by the reduction of titanium oxide with boron carbide and carbon, purified by high temperature – high vacuum treatment and milled to obtain micron sized particles. The powders were characterized by XRD, chemical analysis and laser particle size analyzer. The reduction process was optimized for the production of titanium boride of ∼1 μm size median dia with oxygen, carbon and nitrogen contents close to 0.5% each. Studies on densification of TiB2 powders by hot pressing were conducted. Pellets with a high density of 97.56% ρth were prepared by hot pressing at 1800 °C. Hardness of this sample was measured as 26 GPa, fracture toughness as 5.3 MPa m1/2 and thermal conductivity as 59.44 W/m/K at 500 °C.

A.K. Suri

Papers

Synthesis and consolidation of boron carbide: a review

Processing and properties of monolithic TiB2 based materials

Pressureless sintering of boron carbide

Synthesis and consolidation of zirconium diboride: review

Synthesis and consolidation of titanium diboride