Additive-assisted synthesis of boride, carbide, and nitride micro/nanocrystals

Mechanical activation-assisted autoclave processing and sintering of HfB2-HfO2 ceramic powders

“…morphology (rod, cube, sheet, i.e.) of the particles [23,44]. Moreover, autoclave synthesis is considered as an environmentally friendly method because the process proceeds in a closed/isolated system and it saves energy by low synthesis temperature [22,45].…”

“…In a previous study in which HfB 2 powders were prepared by a reaction of HfCl 4 with NaBH 4 at 600 °C in an autoclave, it was stated that the powders had small particle size range of 20-30 nm [17]. In another study in which a chemical reaction in an autoclave were utilized for the synthesis of different borides such as TiB 2 and ZrB 2 from related oxides and amorphous B in the presence of elemental Na and S, particle size of the TiB 2 and ZrB 2 products were respectively reported as 100 and 500 nm after related washing and leaching treatments [23]. It can be said that the particle size of the boride products strongly depends on the decomposition or melting temperature of boron source.…”

“…On the other hand, there exist a limited number of researches on the solvothermal synthesis of boride compounds in an autoclave. Previously, a series of boride compounds such as ZrB 2 and TiB 2 were produced by the reactions of related oxides and amorphous B with the use of elemental Na and S in an autoclave (20 ml capacity) heated at 150 °C for 2 h [23]. Chen et al [11] prepared HfB 2 powders via a chemical reaction in a stainless steel autoclave from HfCl 4 (5 mmol)-NaBH 4 (30 mmol) mixtures at 600 °C.…”

“…there are some studies showing that boride compounds can be produced by autoclave synthesis route in different morphologies like rods, cubes or flakes[23,24,44]. Zhang et al…”

Microstructural Evaluation of ZrB₂/ZrO₂ Ceramic Powders Prepared by Milling-Assisted Magnesiothermic Reduction of Oxide Raw Materials

“…Chemical vapor deposition (CVD) technique has been applied to obtain ZrB 2 coatings by using ZrCl 4 , BCl 3 and H 2 gas mixtures (Gebhardt and Cree, 1965;Greenwood et al, 1966;Deng et al, 2012). In recent years, low-temperature synthesis in an autoclave (Chen et al, 2004;Chen et al, 2012) and self-propagating high-temperature synthesis (SHS) (Radev and Klissurski, 2001;Khanra et al, 2008) methods have been developed to achieve ZrB 2 or ZrB 2 -based ceramic powders. Synthesis of ZrB 2 powders by high-energy ball milling derived mechanochemical reaction has been examined by a group of researchers using the starting materials of ZrO 2 , B 2 O 3 and Mg (Setoudeh and Welham, 2006;Guo et al, 2011;Akgün et al, 2011;Jalaly et al, 2013Jalaly et al, , 2014.…”