激光熔覆Al2O3+TiO2复合陶瓷涂层的微观结构

研究了４５＃钢表面Ａｌ２Ｏ３＋ＴｉＯ２复合陶瓷激光熔覆层的微观组织和相结构、Ａｌ２Ｏ３＋ＴｉＯ２复合陶瓷激光熔覆涂层由α－Ａｌ２Ｏ３,ＴｉＯ２,γ－ＴｉＯ２,γ－Ａｌ２Ｏ３及Ａｌ２ＴｉＯ５相组成,消除了等离子喷涂层的层状组织特征,形成了大致方向的柱状晶,晶内为溶入了Ｔｉ及少量底层元素的α－Ａｌ２Ｏ３;晶界为由ＴｉＯ２和Ａｌ２Ｏ３形成的Ａｌ２ＴｉＯ５相,溶有少量的Ｃｒ,Ｆｅ,Ｙ取代了Ａｌ２ＴｉＯ５     

W18Cr4V钢表面激光熔覆Al2O3陶瓷涂层的组织结构

研究了Ｗ１８Ｃｒ４Ｖ钢表面Ａｌ２Ｏ３／ＮｉＣｒＡｌ复合陶瓷涂层的组织结构、成分分布及界面组织特征。结果表明：Ａｌ２Ｏ３／ＮｉＣｒＡｌ复合陶瓷等离子喷涂层的组织呈层片状,面层由α－Ａｌ２Ｏ３和少量的γ－Ａｌ２Ｏ３组成,层间为机械结合界面,界面处成分变化梯度较大。经激光重熔后的面层组织为单一的α－Ａｌ２Ｏ３柱状晶,Ａｌ２Ｏ３与中间合金ＮｉＣｒＡｌ间存在明显的界面反应,且界面相增多,在ＮｉＣｒＡｌ与基体     

激光熔覆Ni包WC复合涂层的组织、耐磨和耐蚀性分析及应用

对45钢基体进行激光熔覆Ni包WC金属陶瓷涂层强化处理,通过X射线衍射(XRD)、扫描电子显微镜-能谱分析(SEM-EDX)和透射电子显微镜(TEM),研究了激光熔履Ni包WC涂层的显微组织和物相组成,并采用摩擦磨损试验和电化学测试系统研究了Ni包WC涂层的摩擦磨损性能和耐蚀性能.结果表明,在激光熔覆Ni包WC金属陶瓷...     

La_2O_3对激光熔覆生物陶瓷涂层显微组织结构的影响

采用梯度激光熔覆技术在钛合金(TC4)基体表面制备生物陶瓷涂层,研究不同含量稀土氧化物La2O3的加入对生物陶瓷涂层显微组织结构的影响。结果表明,La2O3对合成HA和β-TCP具有明显的催化作用,在生物陶瓷涂层表面形成了白色球形颗粒状的类珊瑚状结构,涂层与基体实现了良好的冶金结合。     

42CrMo钢表面激光熔覆复合涂层的显微组织与性能

为了研究超声波对激光熔覆过程的影响,在确定最优激光工艺参数的基础上,运用超声波辅助技术,该技术通过在42Cr Mo钢基体表面应用,成功制备了镍基合金复合熔覆层。随后,借助SEM、XRD、EDS以及显微硬度仪等精密仪器对涂层的性能进行了全面的检测与分析。通过与无超声振动的激光熔覆层进行比对,分析了两种方式下的涂层在组织与力学性能方面的差异。从而得出：在对比研究超声振动对激光熔覆涂层性能的影响中,无论是否引入超声振动,涂层的物相组成均包括固溶体γ-Ni（Fe）,金属间化合物Ni₃Fe,以及WC、Cr₂₃C₆、Fe₇C₃等;然而,超声振动显著细化了涂层晶粒,主要由树枝晶和细小枝晶组成,这一变化不仅提高了涂层的平均显微硬度至891.3 HV,相较于无超声振动涂层,提升了约27%;涂层的摩擦性能也得到了显著改善,摩擦因数降低至0.311,磨损量减少至9.17×10^-3 mm³,分别降低了约19%和25%。此外,涂层的磨损形式为轻微的磨粒磨损,进一步证实了超声振动对涂层性能的积极改善作用。     

激光熔覆原位合成TiC-TiB2/Ni基金属陶瓷涂层的组织和摩擦磨损性能

采用激光熔覆技术,以NiCrBSiC预合金粉末为原料,在TC4合金表面制备出以原位合成的TiC和TiB2颗粒为增强相的Ni基金属陶瓷涂层。测试了涂层的显微硬度。利用销-盘式摩擦磨损试验机,以YG8B硬质合金为对磨偶件(盘),评价了涂层的干滑动摩擦磨损性能。结果表明:涂层的硬度Hv为900～1100,摩擦系数为0.2～0.3,质量磨损率比TC4合金降低约1个数量级。     

钼含量对碳钢表面CoCrFeNiMo高熵合金激光熔覆涂层组织结构与耐磨性能的影响

采用激光熔覆技术在Q235钢表面制备了CoCrFeNiMox(x=0.1、0.2、0.3)高熵合金涂层,考察了钼含量对涂层性能的影响.通过扫描电镜、X射线衍射仪、能谱仪和硬度仪表征了涂层的相结构、微观形貌、组织结构、元素成分和显微硬度,并进行了摩擦磨损试验,研究了涂层的磨损机制.结果 表明,CoCrFeNiMo0.1、...     

Regulation mechanism of in-situ synthesized (Nb,Ta)C/Ni composite cladding coatings by laser shock peening: Microstructure evolution and electrochemical corrosion behavior

The surface microstructure of (Nb,Ta)C/Ni composite cladding coatings containing in-situ synthesized composite carbides (ISSCC-LCed coatings) was regulated by laser shock peening (LSP). The regulation mechanism of laser shock waves (LSW) on the microstructure evolution and electrochemical corrosion behavior of the ISSCC-LCed coatings was emphatically revealed. Correspondence between corrosion morphology and microstructure was established. Meanwhile, the phase evolution and residual stress variation laws were also tested and analyzed. The obtained results indicated that the LSW-induced surface structure exhibited interphase distribution characteristics of large and small grains through plastic deformation mechanisms such as extrusion, slip, folding, fracture, and cracking. Plastic deformation caused the relative movement of (Nb,Ta)C at the subsurface out of the surface, and the large (Nb,Ta)C fractured and extended over the entire carbide. Furthermore, element interdiffusion phenomenon existed between (Nb,Ta)C and Fe–Ni alloy. The coupling effect of LSW-induced surface fine grains and residual compressive stress inhibited corrosion propagation and improved electrochemical corrosion resistance.     

Effects of heat treatment on microstructure and mechanical properties of TiC/TiB composite bioinert ceramic coatings in-situ synthesized by laser cladding on Ti6Al4V

To improve the wear resistance of titanium alloy, in this work, TiC/TiB composite bioinert ceramic coatings were synthesized in-situ via laser cladding using Ti and B₄C mixed powders as precursor materials. And to decrease the impact of the excessive residual tensile stress generated by the uneven temperature distribution on the performance of coatings, the coatings were then subsequently heated for 3 h at different temperatures (400 °C, 600 °C, and 800 °C) and then air cooled. The effects of heat treatment on the microstructure, residual stress, micro-hardness, fracture toughness, and wear resistance of the coatings were investigated. The results showed that phase compositions and microstructure of the heat-treated coatings were virtually identical to that of the untreated coatings; however, the precipitation of acicular TiB enhanced mechanical properties of the heat-treated coatings. In addition, the average residual tensile stress values of the coatings decreased as the heat treatment temperature increased, which improved fracture toughness of the coatings from 3.95 to 4.68 MPa m^1/2. Moreover, wear resistance of the coatings was greatly enhanced by heat treatment; as the wear volume of the heat-treated coatings decreased by 50% at 800 °C compared with that of the untreated coatings. Lastly, the coatings showed good biocompatibility after being evaluated in vitro, and therefore had broad application prospects in the field of orthopedic implants.