The nitriding diffusion layer has been considered wearing excessively during diamond turning due to its low nitrogen content in previous research. In this study, by increasing the gas flow rate during the cooling process, an extra needle-precipitates free phase sublayer with a thickness of 25 μm was formed beneath the compound layer, along with the traditional diffusion layer. The microstructure was analyzed and diamond turning test was carried out on each sublayer. After diamond turning all sublayers, no significant wear was observed on the diamond tool. The α-Fe(N) phase with supersaturated nitrogen atoms was found that it can inhibit the wear of the diamond tool. The needle-free precipitates phase sublayer had the lowest surface roughness value after diamond cutting, which was 6.10 nm.

由于先前的研究中氮化扩散层的氮含量较低，因此认为在金刚石车削过程中氮化层会过度磨损。在这项研究中，通过增加冷却过程中的气体流速，在化合物层下方与传统的扩散层一起形成了厚度为25μm的额外的针状沉淀自由相亚层。分析微观结构，并在每个子层上进行金刚石车削测试。金刚石车削所有子层后，在金刚石工具上未观察到明显的磨损。发现具有过饱和氮原子的α-Fe（N）相可以抑制金刚石工具的磨损。金刚石切割后，无针状沉淀相亚层的表面粗糙度最低，为6.10 nm。