激光熔覆原位合成Nb(C,N)陶瓷颗粒增强铁基金属涂层

采用预涂粉末激光熔覆技术，在42CrMo基体上制备出原位合成Nb(C, N)颗粒增强的铁基复合涂层。X射线及扫描电镜分析结果表明:激光熔覆获得的涂层基体为耐氧化、耐蚀性良好的Fe-Cr细晶组织及少量的-Fe相，原位合成的Nb（C, N）呈块状弥散分布在基体上。进一步的磨损试验表明:这些颗粒增强相极大增强了抗磨损性能，与未熔覆的母材相比，其磨损失重仅为母材的1/9左右; 涂层在750 ℃恒温氧化条件下具有较好的抗氧化性能，氧化层主要由NbO1.1，Cr2O3相组成; 母材的氧化产物为Fe2O3，容易脱落，保护性能较差; 激光熔覆涂层的氧化膜厚度仅为未涂层的1/5。

In-situ synthesis of Nb(C,N) ceramic particulates reinforced Fe-based composite coatings by laser cladding

The Nb(C,N) ceramic particulates reinforced Fe-based composite coatings have been successfully synthesized in situ by prior pasting laser cladding on steel 42CrMo. The phase constituents and microstructure of the composite coatings were investigated using X-ray diffraction, and scanning electron micrography. The results indicate that the coatings consist mainly of Fe-Cr fine phases with good resistance to oxidation and corrosion and a few of γ-Fe phases. In-situ synthesized Nb(C,N) particulates are uniformly distributed with blocky morphology in the composite coatings. The wear test shows that these reinforcement particulates improves wear resistance of the coatings significantly. The wear mass loss of the substrate with coating is about one ninth of that of the substrate without coatings. The coatings have better oxidation resistance through 750 ℃ constant temperature oxidation, and the oxide scale mainly consists of NbO1.1 and Cr2O3. The oxidation products of the substrate are Fe2O3 , and easy to spall off, resulting in a poor effect in substrate protection. The oxide scale of the coatings is one fifth as thick as that of raw substrate.