Research On The High Temperature Oxidation Behavior Of Ti(C, N)-based Cermet

In this work, research development and movement tendency of Ti(C,N)-based cermets and high temperature structural material were reviewed. Ti(C,N)-based cermets with the contents of 46%TiC-12%TiN-16%Ni-7%Mo2C-14%WC-5%TaC were prepared. By means of thermal gravity analysis(TGA), metal phase microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), sclerometer, TRS test, etc, the influence of oxidized time and temperature to the oxidization of Ti(C,N)-based cermets were studied. The microstructure of this material had been also investigated in present paper.The properties of the samples we prepared were perfect with the hardness reaching the level of HRA91.5, TRS 1600MPa.Along with the oxidized time and temperature, oxidation weight of Ti(C,N)-based cermets increased. It is found that when the sample is kept at different oxidized temperatures of 800℃, 1150℃and 1300℃for the same oxidized time(3h), the oxidation increased weight is 3.6g/m2, 253.1g/m², 421.3g/m² respectively. And when kept at for the same oxidized temperature (1150℃) for different time such as 3h, 24h, the oxidation increased weight is 253.1g/m², 421.3g/m² correspondly. It can be concluded that oxidation dynamic equation is W1.598 = 2638.6t from the curves of Ti (C,N)-based cermet under 1150℃conditions.It is indicated from the Microscopic analysis of the oxidized film that, when oxidized temperature is at 800℃,the oxidized film surface mainly is composed by granulated NiO and TiO₂, thickness is smaller than 10μm; when oxidized temperature is at 1150℃, the oxidized film can be divided into two layers: inner layer is composed by compact oxide film of NiO + TiO₂ and the outer layer is the oxide compound caused by the crack or other flaws, the thickness of the total oxide film is about 200μm; when oxidized temperature is at 1300℃, thickness of oxide film is 400 500μm.