钢基体表面WC/Al_2O_3/Co涂层的电接触强化研究

Investigation on Electrical Contact Strengthening WC/Al_2O_3/Co Adhesive Coating on Surface of Steel Substrate

以WC、Al2O3、Co为粉末原料,采用干磨混合、湿磨分散工艺,制备了分散均匀、稳定性好的WC-Al2O3-Co和WC-Co料浆。然后用常温喷涂法将该料浆喷涂在45钢基体表面形成预涂层,再对该预涂层进行电接触强化。对强化层进行金相观察、扫描电镜观察和X射线衍射分析,以及抗热震实验和显微硬度测试。结果表明:与热喷涂WC-Co强化层相比,用常温喷涂+电接触强化制备的WC-Al2O3-Co涂层和WC-Co涂层的显微硬度和抗热震性能都得到明显提高;用Al2O3代替部分Co形成的WC-Al2O3-Co涂层的显微硬度比WC-Co涂层略高,但抗热震性能略低。

WC, Al2O3, Co powders were mixed by dry grinding and then were dispersed into steady slurry through wet milling. Based on an air spraying method, WC-Al2O3-Co slurry was deposited on 45 steel surface. Then the electrical contact strengthened equipment was used to remelt the coatings and the enhancement layers were formed on surface of the substrate.Metallographic observation, SEM, XRD, thermal shock resistance and micro-hardness test were employed to analyze the microstructure, phase constitution and mechanical properties of the enhancement layers respectively. The results show that both WC- Al2O3-Co and WC-Co electrical contact strengthening layer have higher micro-hardness and more excellent performance of thermal shock resistance than WC-Co thermal spraying layer; replacing some Co with Al2O3 can enhance the micro-hardness, but has lower performance of thermal shock resistance than WC-Co electrical contact strengthening layer.