The Fe-based WC composite coatings were clad on Q235 steel by double-pass plasma cladding method,in which the WC-Co(WC covered with cobalt:78wt%WC,12wt%Co)doping was about 10wt%,20wt%and 40wt%,respectively.The microst...The Fe-based WC composite coatings were clad on Q235 steel by double-pass plasma cladding method,in which the WC-Co(WC covered with cobalt:78wt%WC,12wt%Co)doping was about 10wt%,20wt%and 40wt%,respectively.The microstructure and wear performance of the composite coatings were investigated by X-ray diffraction(XRD),scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and ball-disc wear tests.The results show that the clad coatings contain mainly?-Fe,WC and carbides(Cr23C6,Fe3W3C-Fe4W2C)phases and the precipitation of carbides increases with the increase of WC-Co doping content.The WC-Co doping content has an obvious effect on the microstructure of the clad coatings.For the clad coatings with low WC-Co doping,the microstructure gradually transforms from planar crystal at the interface of substrate/coating to cell/dendritic crystal at the middle and the upper portion of the coatings.But there are a number of fishbone-like structure at the middle and the upper portion of clad coating with 40wt%WC-Co doping.The microstructure at the top is smaller than that at the bottom for all the coatings.The maximum of hardness of the clad coatings is 72.3HRC which is about 6.9 as much as the hardness of Q235 steel substrate.The composite coatings have good wear resistance due to the reinforcement of carbide particles and the strong bonding between carbide particles and ferroalloy.The suitable increase of WC-Co doping content can improve the wear resistance of the composite coatings.展开更多
研究了不同含量富 Ce 混合稀土(Re)在不同烧结温度下对含有质量分数为2%的 TiH_2和不含 TiH_2的铁基胎体显微组织和力学性能的影响.实验结果表明:铁基胎体的抗弯强度和硬度随混合稀土含量的增加而增加,抗弯强度增加的幅度比硬度增加的...研究了不同含量富 Ce 混合稀土(Re)在不同烧结温度下对含有质量分数为2%的 TiH_2和不含 TiH_2的铁基胎体显微组织和力学性能的影响.实验结果表明:铁基胎体的抗弯强度和硬度随混合稀土含量的增加而增加,抗弯强度增加的幅度比硬度增加的幅度大,同时稀土元素在不含 TiH_2的 Fe 基胎体中的作用比在含有 TiH_2的Fe 基胎体中的作用显著.在含 TiH_2的 Fe 基胎体中,当稀土质量分数为0.5%时,胎体的抗弯强度达到最大值,抗弯强度的最大值增幅为12.4%;在不含2%(质量分数)TiH_2的 Fe 基胎体中,当稀土质量分数为1.1%时,胎体的抗弯强度达到最大值,抗弯强度的最大增幅为35.1%.不含 TiH_2的铁基胎体的抗弯强度高于含有2%(质量分数)TiH_2的铁基胎体,而且两种胎体抗弯强度的差距随着稀土含量的增加而不断增大,二者之间抗弯强度的最大差值约230 MPa.添加微量的稀土使铁基胎体的孔隙率降低,晶粒细化,而添加 TiH_2使铁基胎体的孔隙率增加,并在组织中出现粗大的脆性相.展开更多
Fe-based coatings reinforced by spherical WC particles were produced on the 304 stainless steel by plasma transferred arc(PTA) to enhance the surface wear properties. Three different Fe/WC composite powder mixtures co...Fe-based coatings reinforced by spherical WC particles were produced on the 304 stainless steel by plasma transferred arc(PTA) to enhance the surface wear properties. Three different Fe/WC composite powder mixtures containing 0 wt%, 30 wt%, and 60 wt% of WC were investigated. The microstructure and phase composition of the Fe/WC composite PTA coatings were evaluated systemically by using scanning electron microscope(SEM) and X-ray diffraction(XRD). The wear properties of the three fabricated PTA coatings were investigated on a BRUKER UMT TriboLab. The morphologies of the worn tracks and wear debris were characterized by using SEM and 3 D non-contract profiler. The experimental results reveal that the microhardness on the cross-section and the wear resistance of the fabricated coatings increase dramatically with the increasing adding WC contents. The coating containing 60 wt% of WC possesses excellent wear resistance validated by the lower coefficients of friction(COF), narrower and shallower wear tracks and smaller wear rate. In the pure Fe-based coating, the main wear mechanism is the combination of adhesion and oxidative wear. Adhesive and two-body abrasive wear are predominated in the coating containing 30 wt% of WC, whereas threebody abrasion wear mechanism is predominated in the coating containing 60 wt% of WC.展开更多
基金Fundamental Research Funds for the Central Universities(2009B16214)China Postdoctoral Science Foundation funded project(20100481079)Scientific Research Start-up Fund Project of Hohai University(20080403)
文摘The Fe-based WC composite coatings were clad on Q235 steel by double-pass plasma cladding method,in which the WC-Co(WC covered with cobalt:78wt%WC,12wt%Co)doping was about 10wt%,20wt%and 40wt%,respectively.The microstructure and wear performance of the composite coatings were investigated by X-ray diffraction(XRD),scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and ball-disc wear tests.The results show that the clad coatings contain mainly?-Fe,WC and carbides(Cr23C6,Fe3W3C-Fe4W2C)phases and the precipitation of carbides increases with the increase of WC-Co doping content.The WC-Co doping content has an obvious effect on the microstructure of the clad coatings.For the clad coatings with low WC-Co doping,the microstructure gradually transforms from planar crystal at the interface of substrate/coating to cell/dendritic crystal at the middle and the upper portion of the coatings.But there are a number of fishbone-like structure at the middle and the upper portion of clad coating with 40wt%WC-Co doping.The microstructure at the top is smaller than that at the bottom for all the coatings.The maximum of hardness of the clad coatings is 72.3HRC which is about 6.9 as much as the hardness of Q235 steel substrate.The composite coatings have good wear resistance due to the reinforcement of carbide particles and the strong bonding between carbide particles and ferroalloy.The suitable increase of WC-Co doping content can improve the wear resistance of the composite coatings.
文摘研究了不同含量富 Ce 混合稀土(Re)在不同烧结温度下对含有质量分数为2%的 TiH_2和不含 TiH_2的铁基胎体显微组织和力学性能的影响.实验结果表明:铁基胎体的抗弯强度和硬度随混合稀土含量的增加而增加,抗弯强度增加的幅度比硬度增加的幅度大,同时稀土元素在不含 TiH_2的 Fe 基胎体中的作用比在含有 TiH_2的Fe 基胎体中的作用显著.在含 TiH_2的 Fe 基胎体中,当稀土质量分数为0.5%时,胎体的抗弯强度达到最大值,抗弯强度的最大值增幅为12.4%;在不含2%(质量分数)TiH_2的 Fe 基胎体中,当稀土质量分数为1.1%时,胎体的抗弯强度达到最大值,抗弯强度的最大增幅为35.1%.不含 TiH_2的铁基胎体的抗弯强度高于含有2%(质量分数)TiH_2的铁基胎体,而且两种胎体抗弯强度的差距随着稀土含量的增加而不断增大,二者之间抗弯强度的最大差值约230 MPa.添加微量的稀土使铁基胎体的孔隙率降低,晶粒细化,而添加 TiH_2使铁基胎体的孔隙率增加,并在组织中出现粗大的脆性相.
基金Funded by the Ocean Public Science and Technology Research Fund Projects of China(No.201405013-3)the National Natural Science Foundation of China(No.51609133)+1 种基金the China Postdoctoral Science Foundation(No.2017M620153)the Science&Technology Program of Shanghai Maritime University(No.20130448)
文摘Fe-based coatings reinforced by spherical WC particles were produced on the 304 stainless steel by plasma transferred arc(PTA) to enhance the surface wear properties. Three different Fe/WC composite powder mixtures containing 0 wt%, 30 wt%, and 60 wt% of WC were investigated. The microstructure and phase composition of the Fe/WC composite PTA coatings were evaluated systemically by using scanning electron microscope(SEM) and X-ray diffraction(XRD). The wear properties of the three fabricated PTA coatings were investigated on a BRUKER UMT TriboLab. The morphologies of the worn tracks and wear debris were characterized by using SEM and 3 D non-contract profiler. The experimental results reveal that the microhardness on the cross-section and the wear resistance of the fabricated coatings increase dramatically with the increasing adding WC contents. The coating containing 60 wt% of WC possesses excellent wear resistance validated by the lower coefficients of friction(COF), narrower and shallower wear tracks and smaller wear rate. In the pure Fe-based coating, the main wear mechanism is the combination of adhesion and oxidative wear. Adhesive and two-body abrasive wear are predominated in the coating containing 30 wt% of WC, whereas threebody abrasion wear mechanism is predominated in the coating containing 60 wt% of WC.
