共查询到18条相似文献,搜索用时 62 毫秒
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采用激光预置熔覆法,通过在FeCSiB合金粉末中添加一定比率的强碳化物形成元素Zr,在中碳钢基体上制备原位析出的颗粒增强铁基复合材料表层。利用光学显微镜、场发射电子扫描显微镜(能谱仪)和金相组织分析系统,对熔覆层显微组织、硬质颗粒的成分及其分布规律进行了观察与分析。其显微组织特征是树枝状的先共晶奥氏体分布在共晶基体上的亚共晶介稳组织;奥氏体在随后的冷却过程中转变为马氏体;熔覆层与基体成良好的冶金结合。熔覆层内析出的硬质颗粒是以ZrC为主的复合碳化物,主要分布在枝晶内与枝晶间;单道搭接熔覆层颗粒的体积分数分别为1.96%、2.2%~3.84%;显微硬度值在800HV0.2~1100HV0.2之间。 相似文献
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利用横流CO2激光器在38CrMOAl表面激光宽带熔覆NiCrBSi WC(重量百分比25%)复合涂层,用扫描电镜观察组织形貌,用X射线衍射仪进行物相分析,用磨擦磨损实验机进行耐磨性实验,并对多层熔覆工艺进行了初的探讨,结果显示,合金层与基体成良好的无裂纹气孔的冶金结合,表面耐磨性与工艺参数具有一定对应关系,且2.2kW时的耐磨性最高,为氧化工艺的2.9倍,多层熔覆试验能形成厚度可调的无裂纹熔覆层,对生产工件的修复具有实际意义。 相似文献
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利用YAG脉冲固体激光器, 在高纯氩气的保护下, 选取优化了的激光工艺参数在45#钢表面制备FeAlCrNiSiC六元高熵合金涂层。主要采用OM、SEM、EDS、XRD和显微硬度等分析手段, 对实验制备的合金涂层的形貌、组织结构、成分、相结构、硬度及相关机理进行了研究。实验结果表明: 优化的激光熔覆工艺参数为功率85 W, 激光扫描速度为5 mm/s, 能量密度47 J/mm2, 搭接率50%。采用此优化工艺参数成功制备了与基体形成良好冶金结合的FeAlCrNiSiC高熵合金涂层。制备涂层的硬度达到了800 HV, 涂层的内部结构由条状等轴晶及网状枝晶组成, 组分偏析得到了有效缓解。合金涂层具有FCC结构的γ-Fe和BCC结构的FeAlCrNiSiC固溶体的简单物相, 合金元素Al、Cr、Si、Ni、C固溶在两种多组元固溶体中, 增加了晶格畸变, 使涂层具有高的硬度。 相似文献
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《电子材料与电子技术》2010,(3):28-28
美国俄亥俄州的Battelle Momorial学院的新材料应用系的研究人员新近研究成功一种纳米材料涂层,用于金属表面能在金属出现腐蚀时会发出荧光。因此,这种纳米材料涂层能够在金属材料出现单凭肉眼不能发现的腐蚀时就能显示其腐蚀现象。这种功能纳米材料可以作为涂层的底层与表层的中间来应用,当金属材料刚一出现腐蚀时就能显示其腐蚀产物。 相似文献
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60号钢表面碳钨合金激光包覆的特性分析 总被引:5,自引:0,他引:5
本文叙述了用一台高功率二氧化碳激光器在60号钢表面所作的碳钨合金包覆实验。实验结果表明在低质钢材表面包覆一层碳钨合金层大大地提高了工件表面的耐磨性能;包层厚度与激光扫描速度的平方成反比。 相似文献
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The interfacial chemistry of InP/GaAs direct bonding with either 5% HF in water or HF:ethanol (1:9) chemical pretreatments
was investigated. Multiple internal transmission-Fourier transform infrared spectroscopy (MIT-FTIR) and atomic force microscopy
(AFM) were used to probe the bonding interface. The bond strength was measured as a function of annealing conditions and prebonding
chemical treatment. The HF-based pretreatments remove the initial native oxide, leaving an interfacial layer of either water
or ethanol. The initial room-temperature bond strength is primarily determined by the strength of hydrogen bonding, which,
in turn, is a function of the prebonding treatment. The removal of interfacial water and ethanol, and with the subsequent
formation of the oxide layer, leads to an increased bond strength. For ethanol-based HF treatments, ethanol appears to react
with the underlying interfacial oxide layer through a complex interaction with the absorbed water. After annealing, the bond
strength for all prebonding preparations can reach a high value, comparable to the fracture strength of the InP. The oxide
composition after thermal annealing shifts from In2O3 to the eventual thermodynamic equilibrium product, InPO4. 相似文献
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烧结工艺对PMS-PNN-PZT压电厚膜性能的影响 总被引:1,自引:1,他引:0
采用丝网印刷法制备了PMS-PNN-PZT四元系压电厚膜陶瓷材料。研究了压电厚膜的烧结温度、烧结气氛对其压电、介电等性能及微观结构的影响。用XRD和SEM分析材料的相组成、厚膜定位及显微结构,结果表明,在密封埋粉的PbO气氛中,烧结温度1060℃,保温时间2 h,制得一种性能良好的压电厚膜陶瓷材料。其中,该压电厚膜压电常数d33为240 pC/N,相对介电常数rε为1 112,机械品质因数Qm为1250,机电耦合系数kp为0.52。 相似文献
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Guohua Bai Junhong Liu Sateesh Bandaru Zhong Li Jiayi Sun Yanan Zhang Zhenhua Zhang Xiaolian Liu Hongxia Li Junfu Chen Xuefeng Zhang 《Advanced functional materials》2023,33(42):2303951
Soft magnetic composites (SMCs) are ungently demanded in high-frequency power electronics for their large magnetization and high electrical resistivity. However, traditional cold-pressed SMCs are faced with low mechanical strength and insulation instability, which severely restricts their applications. In this study, liquid-phase sintering techniques to prepare FeSiAl/MoO3 SMCs are orginally employed, where consolidation and insulation of metallic magnetic particles are achieved in one step. The redox reaction between FeSiAl and MoO3 melt greatly reduces the interfacial energy, facilitates fully wetting of FeSiAl particles by MoO3 melt, and promotes the densification process during sintering. In the final FeSiAl/MoO3 SMC, FeSiAl particles are bonded covalently and insulated electrically/magnetically by the resultant Al2O3 transition layer, endowing the SMC with high crushing strength of 250 MPa, cut-off frequency of 110 MHz, permeability of 35 (@1 MHz), and low power loss of 962 kW m−3 (5 MHz, 5 mT). This study provides alternative concept for designing new SMCs, and broadens the connotation and extension of liquid-phase sintering. 相似文献