Research And Designation On The TiN_0.3 Matrix PcBN Binder With Hign Toughness

Given the excellent performance of PcBN tool material on function, the development speed of PcBN is very fast, and the range of applications is extremely wide. One of the main factors which determine the performance of PcBN is its bond. This paper investigated the high quality PcBN in the industry. The results showed that the main component of binder is TiN and metals. With the increase of c BN content, the proportion of Co, Al and other metals in binder increases. In contrast to hardness,it also showed that binding agent additive metal PcBN’s microhardness was lower than vitrified PcBN hardness.Combining the research of PcBN, this paper took non-stoichiometric TiN_0.3 as the main component of binder, AlN and TaC as additives, then analysed and investigated the structure and the properties of the ceramic composite materials of TiN_0.3/AlN/TaC. The results showed that, under the condition of 5 GPa and 10 min’s hiolding time,when the ratio of TiN_0.3/AlN/TaC was 64%: 27%: 9%, with the increase of the temperature, the hardness of the binder maintained at about 22 GPa, and at 1500 ℃, the toughness value reached the maximum 8.59 MPa×m1/2. When the content of TaC was less than 16%, the hardness and toughness of the sintered body improved with the increase of TaC content. Besides, the addition of TaCcould inhibit the growth of TiN_0.3. The research found that, when the ratio of TiN_0.3/AlN was 8:2, the structure of the sintered body became loose and the performance was poor, whereas when the ratio of TiN_0.3/AlN was 7:3, the structure of the sintered bodywas compact and the performance was excellent.On the basis of the optimization of TiN_0.3/AlN/TaC ceramic composite binder, this paper chose the ratio of TiN_0.3/AlN/TaC which was 64%: 27%: 9%, took NbC as addictive and studied the effect of NbC on TiN/AlN/TaC/NbC ceramic composites.The results show that the addition of NbC reduces the performance of the sintered body. With the increase of NbC content, the microstructure of TiN_0.3 matrix composite ceramics was refined, and NbC could inhibit the growth of grain.