材料期刊网

为获得抗氧化性能更为优越的TiN/TiCN/Al2O3/TiN复合涂层,本文采用中温化学气相沉积(MT-CVD)在WC-Co硬质合金基体表面沉积不同厚度α-Al2O3层的TiN/TiCN/Al2O3/TiN多层涂层,并在1 000℃下对涂层试样进行氧化实验.通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)等手段研究α-Al2O3层厚度对TiN/TiCN/Al2O3/TiN涂层抗氧化性能的影响,确定可显著提高涂层抗氧化性能的α-Al2O3层厚度,同时探索涂层的抗氧化机理.结果表明:随着α-Al2O3层厚度的增加,TiN/TiCN/Al2O3/TiN多层涂层试样氧化后质量增量减少,涂层氧化增厚降低.当α-Al2O3层厚度为6.5 μm时,TiN/TiCN/Al2O3/TiN涂层的抗氧化性能显著提高.随着涂层厚度的增加,涂层阻止O向涂层内部扩散及Al、Ti向外部涂层扩散能力增强,抗氧化性能更优越.

In order to achieve superior oxidation resistant TiN/TiCN/Al2O3/TiN multilayer coatings,TiN/TiCN/Al2O3/TiN multilayer coatings with different thickness of oα-Al2O3 layer were deposited on WC-Co cemented carbide substrate by medium temperature chemical vapor deposition (MT-CVD),and then oxidized at 1 000 ℃ in this study.Effect of α-Al2O3 layer thickness on oxidation resistance of TiN/TiCN/Al2O3/TiN coatings was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The thickness of oα-Al2O3 layer which could enhance the oxidation resistance of the coatings significantly was identified and the oxidation resistance mechanism of coating was explored.The results show that with the increase of α-Al2O3 layer thickness,the oxidation mass gain and oxidation thickness of TiN/TiCN/Al2O3/TiN coating samples are reduced.The oxidation resistance of TiN/TiCN/Al2O3/TiN coating is enhanced significantly when the oα-Al2O3 layer thickness is 6.5 μm.With the increase of coating thickness,the oxygen-rich layer of TiN/TiCN/Al2O3/TiN coating is thicker,the oxygen content of oxygen-rich layer increases,the inward diffusion of oxygen and the outward diffusion of Al and Ti are prevented,and thus the oxidation resistance improves.