9 Processing and Application of Ceramics 2 [1] (2008) 9–12 * Corresponding author: tel: +375 17 284 11 64, fax: +375 17 2840 888, e-mail: kopylov@ifttp.bas-net.by High pressure sintering of TiB 2 ceramics at different temperatures Andrei V. Kapylou 1* , Vladimir S. Urbanovich 1 , Vladimir A. Kukareko 2 1 Laboratory of Refractory Ceramics and Nanomaterials, The Joint Institute of Solid State and Semiconduc- tor Physics, National Academy of Sciences of Belarus, 19 P. Brovka Street, Minsk BY-220072, Republic of Belarus 2 The Joint Institute of Mechanical Engineering, National Academy of Sciences of Belarus, 12 Akademich- naya Street, Minsk BY-220072, Republic of Belarus Received 30 August 2007; received in revised form 25 February 2008; accepted 30 March 2008 Abstract In this paper the effect of high-pressure sintering (HPS) temperature on the microstructure, physical and mechanical properties of TiB 2 ceramics has been investigated. Initial TiB 2 powder with the average particle size of 5 μm was sintered in a modified high-pressure anvil-type apparatus under static pressure of 4 GPa in the temperature range of 1400–1800°C. It is shown that HPS allows preparing full-dense TiB 2 ceramics with fine-grained structure. The density of samples rises with increasing the sintering temperature up to 1800°C while the maximal microhardness is observed on samples prepared in the temperature range of 1500–1600°C. XRD analysis has shown that this fact is connected with an increase of the level of internal stresses in these samples. Keywords: titanium diboride, high-pressure sintering I. Introduction Because of its properties (high melting point, high hardness, good corrosion resistance and excel- lent electric conductivity) TiB 2 ceramics is suitable for many applications including cutting tools, wear- resistant parts, armor materials and cathode materi- als for Hall–Heroult cells [1–3]. Bulk TiB 2 ceramics without additives is usually produced by hot press- ing [4,5]. However, up to now, the use of TiB 2 ceram- ics is rather limited due to the difficulties that exist in preparing a full-dense material. The high-pressure sintering processing (HPS) has been considered as an effective method for producing full-dense TiB 2 ce- ramics without any additives. The main features of HPS are a low sintering temperature and high sinter- ing rate. High pressure sintering kinetics of TiB 2 powder with a mean particle diameter of 60 μm was studied earlier [6]. It was shown that the densification process consists of two stages which proceed with different rates. On the first stage, densification rate is fast and the activation energy is low. It was assumed that the features of the first stage are caused by fragmentation and creep. On the second stage, densification is pro- vided by the afterflow and substitutional diffusion in the metallic sublattice. Structural transformations of titanium diboride un- der high pressures and temperatures were studied by Olejnik et al. [7]. It was shown that the plastic deforma- tion of TiB 2 under the pressure lower than 7.7 GPa and the temperature lower than 2200°C occurs by creep and intensive fragmentation of grains. The processes of pri- mary and collective recrystallization play an important role during the formation of the grain structure of TiB 2 ceramics under high pressures and temperatures. The aim of this study was to investigate the effect of the HPS temperature on microstructure and physical and mechanical properties of TiB 2 ceramics. The results about features of the sintering process, microstructure and mechanical properties are reported. II. Experimental TiB 2 powder produced by the “Donetsk Factory of Chemical Reagents” with the average particle size of 5 μm was used as a starting material in the present in-