金刚石与钛的原子热压扩散行为的分子动力学模拟

Molecular Dynamics Simulation of Atomic Diffusion Behavior of Diamond and Titanium under Hot Pressing Process

摘要:

应用分子动力学方法模拟了金刚石与钛在热压扩散过程中的原子扩散行为，模拟了不同扩散温度下金刚石与钛界面的原子扩散过程，得到了界面的原子浓度分布、扩散速度以及模拟扩散系数值；采用热压扩散法在金刚石表面镀覆钛层并测量界面的扩散带宽度。研究结果表明：在热压扩散过程中C原子的扩散速度大于Ti原子；随着扩散温度的升高，原子存在低速和快速两个扩散阶段。通过热压扩散的分子动力学模拟对模拟的扩散系数进行数据拟合，能够确定C和Ti原子的扩散因子和扩散激活能，从而简单、有效地确定原子的扩散系数计算公式。金刚石与钛扩散带宽度的计算值与实测值相近，应用分子动力学方法获得的原子扩散系数公式是可行的。

Abstract:

The molecular dynamics method was used to simulate the atomic diffusion behavior of diamond and titanium during the hot pressing diffusion process. The atomic diffusion process at the interface between diamond and titanium at different diffusion temperatures was simulated, and the atomic concentration distribution, diffusion velocity and simulated diffusion coefficient were obtained. The hot pressing diffusion method was used to coat a titanium layer on the diamond surface and the width of the diffusion band at the interface was measured. The research results show that the diffusion speed of C atoms is greater than that of Ti atoms during the diffusion process. With the increase of the diffusion temperature, there exist two stages of atom diffusion, low speed and fast stages. Data fitting of the simulated diffusion coefficients through the molecular dynamics simulation of hot pressing diffusion can be used to determine the diffusion factors and activation energy values of C and Ti atoms. The formula of atomic diffusion coefficient calculation can be determined through a simple and effective method. The calculated value of diamond and titanium diffusion band width is close to the measured value, which indicates that the formula of atom diffusion coefficient obtained by the molecular dynamics method is feasible.