Microstructure and mechanical properties of ZrC coating on zirconium fabricated by interstitial carburization
Microstructure and mechanical properties of ZrC coating on zirconium fabricated by interstitial carburization
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DOI：
10.1016/j.jallcom.2020.155110
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发表时间：
2020-09
影响因子：
6.2
通讯作者：
Ziyuan Zhao;Fuyuan Liu;Qin Wang;Jun-ming Li;L. Zhong;Yunhua Xu;Pengfei Hui;Jianlei Zhu;
中科院分区：
文献类型：
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作者：
Ziyuan Zhao;Fuyuan Liu;Qin Wang;Jun-ming Li;L. Zhong;Yunhua Xu;Pengfei Hui;Jianlei Zhu;
本文采用间隙渗碳法在纯锆表面制备了ZrC涂层。选择高碳钢作为碳源，以提供间隙碳原子，并在1150 ° C和2MPa的单轴压力下与锆基体热压。间隙碳原子扩散到Zr表面形成ZrC涂层。采用X射线衍射（XRD）、扫描电子显微镜（SEM）和电子背散射衍射（EBSD）对涂层的微观结构进行了表征。所获得的涂层是完全致密的纯陶瓷，由单一ZrC相组成，体积分数为100%。ZrC颗粒的直径在180 nm~5.9 μ m范围内呈梯度分布。涂层厚度与渗碳时间的平方根成正比，遵循经典的抛物线规律，渗碳10 h后涂层厚度为7.2 μ m。在涂层表面上测试的显微硬度达到1500 HV，在ZrC涂层的横截面上测量的纳米硬度达到27 GPa，与锆基底（192 HV和3.6 GPa）相比显示出显著的改善。通过维氏压痕测量的ZrC涂层的平均断裂韧性为1.9 MPa·m1 ⁄ 2。响应于划痕载荷从0至100 N线性增加的划痕，涂层表现出与基材的优异粘附性。根据所获得的结果，我们期望间隙渗碳方法也可以应用于各种Zr基合金。
Herein, ZrC coating was fabricated on the surface of zirconium via interstitial carburization. High-carbon steel was selected as the carbon source to supply the interstitial carbon atoms and was hot-pressed with zirconium substrate at 1150 °C and uniaxial pressure of 2 MPa. The interstitial carbon atoms diffused into the surface of Zr forming a ZrC coating. The microstructure of the coating was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD). The obtained coating was completely dense and pure ceramic, consisting of a single ZrC phase with a volume fraction of 100%. The diameter of ZrC grains exhibited a gradient distribution with a range of 180 nm to 5.9 μm. The thickness of the coating was proportional to the square root of the carburizing time, following the classical parabolic law, reaching a coating thickness of 7.2 μm after carburizing for 10 h. The microhardness tested on the coating surface reached 1500 HV and nanohardness measured on the cross-section of the ZrC coating reached 27 GPa, displaying a remarkable improvement compared to the zirconium substrate (192 HV and 3.6 GPa). The average fracture toughness of ZrC coating measured via Vickers indentation was 1.9 MPa·m1⁄2. In response to a scratch where the scratch load increased linearly from 0 to 100 N, the coating demonstrated excellent adhesion with the substrate. As per the obtained results, we expect that the interstitial carburization method can also be applied to various Zr-based alloys.