**2.1 Materials and mixture preparation**

The materials used in powder form were: tungsten carbide (WC), cobalt (Co), cerium oxide (CeO2), lanthanum oxide (La2O3), calcite (CaCO3), and graphite.

The tungsten carbide powder of high purity used was provided by Wolfram Bergbau-Und-GmbH, whose main characteristics are presented in Table 1. The cobalt powder of high purity was provided by Vetec Química Fina, whose grain size is < 400 mesh. The rare-earth oxides (> 99 %) were provided by Vetec Química Fina. The calcite and graphite were used in assembling the reactive cell in the high-pressure experiments. The graphite powder of high purity was provided by Nacional Grafite.


Table 1. Characteristics of the WC powder.

Several WC10wt.%Co mixtures containing up to 2 wt.% of La2O3 and CeO2 of the cobalt phase were prepared (Table 2). The samples of dry powders were mixed and homogenized in a laboratory mixer during 1 h.

sintered under various conditions. The processes commonly used are pressing/sintering, hot pressing, and sinter/hot isostatic pressing (HIP) (North et al., 1991; White, 1998). Recently, an unusual process for the production of cemented carbide using a high pressure technique has been investigated (Rodrigues et al., 2006). On the other hand, the effect of the rare-earth elements addition on the sintering behavior of cemented carbide has also been investigated. In particular, the beneficial effects of the rare-earth elements on the mechanical properties, microstructure and cutting performance have been extensively investigated (Li et al., 1986; Yao et al., 1987; Liang et al., 1989; Shan, 1990; Luo, 1991; Liu et al., 1992; Chenguang, 1992; Pan, 1993; Yang et al., 1993; Deng, 1993; Li et al, 1993; He et al., 1994; Li et al, 1994; Yan et al., 1995; Cheng and Yu, 1995; Yuan et al., 1995; Li, 1996; He, 1996; Ji et al., 1996; Xu et al., 2001; Gomes, 2004). However, the production of cemented carbide doped with rare-earth elements using a high pressure technique is still

This chapter focuses on the possibility of production of WC-10wt.%Co doped with rareearth elements under high pressure and high temperature (HPHT) conditions. Emphasis is given on the effects of the rare-earth additions on the densification behavior and physical

The materials used in powder form were: tungsten carbide (WC), cobalt (Co), cerium oxide

The tungsten carbide powder of high purity used was provided by Wolfram Bergbau-Und-GmbH, whose main characteristics are presented in Table 1. The cobalt powder of high purity was provided by Vetec Química Fina, whose grain size is < 400 mesh. The rare-earth oxides (> 99 %) were provided by Vetec Química Fina. The calcite and graphite were used in assembling the reactive cell in the high-pressure experiments. The graphite powder of high

Characteristic Range

Several WC10wt.%Co mixtures containing up to 2 wt.% of La2O3 and CeO2 of the cobalt phase were prepared (Table 2). The samples of dry powders were mixed and homogenized

Total C, wt.% 6.15 Free C, wt.% 0.04 Density, g/cm3 15.65 Mean particle size, μm 1.07 Specific surface (BET), m2/g 0.42

to be investigated.

and mechanical properties of the end product.

**2.1 Materials and mixture preparation** 

purity was provided by Nacional Grafite.

Table 1. Characteristics of the WC powder.

in a laboratory mixer during 1 h.

**2. Preparation and testing of the cemented carbide** 

(CeO2), lanthanum oxide (La2O3), calcite (CaCO3), and graphite.


Table 2. Composition of the cemented carbides doped with rare-earths.
