Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Provided are materials for a formed body comprising hexagonal boron nitride and such formed bodies. Also provided are heat-treated formed body obtained by heat-treating the formed bodies. The invention further relates to processes for making the formed body and the heat-treated formed body.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al.sub.2O.sub.3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al.sub.2O.sub.3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

An electrostatic chuck device includes: a base having one principal surface which is a placing surface on which a plate-shaped sample is placed, wherein the base is made from a sintered compact of ceramic particles, which include silicon carbide particles and aluminum oxide particles, as a forming material; and an electrostatic attraction electrode which is provided on a surface of the base on the side opposite to the placing surface of the base, or in the interior of the base, in which the volume resistivity value of the sintered compact is 0.510.sup.15 cm or more in the entire range from 24 C. to 300 C., a graph which shows the relationship of the volume resistivity value of the sintered compact to a temperature at which the volume resistivity value of the sintered compact is measured has a maximum value in the range from 24 C. to 300 C., and the amount of metal impurities in the sintered compact other than aluminum and silicon in the sintered compact is 100 ppm or less.