共查询到20条相似文献,搜索用时 15 毫秒
1.
将Al2O3-TiC陶瓷材料与具有固体润滑特性的Al2O3-TiC-CaF2陶瓷材料进行叠层, 通过真空热压烧结制备Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料。在环盘式摩擦磨损试验机上进行摩擦磨损实验, 研究该材料在不同载荷、 转速条件下的摩擦系数和磨损率, 分别用SEM及EDS观察材料磨损前后的微观形貌和分析其成分组成, 研究其磨损机制。结果表明: 在相同载荷条件下, Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料的摩擦系数和磨损率随着转速的升高而下降, 在相同转速条件下, 其摩擦系数和磨损率随着载荷的增加而下降; Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料的磨损机制主要是磨粒磨损和黏着磨损。 相似文献
2.
采用往复式滑动摩擦磨损(SRV)试验机研究了高铬铸铁及三维网络结构Al2O3陶瓷增强高铬铸铁复合材料的干摩擦磨损性能,测量了高铬铸铁和Al2O3陶瓷/高铬铸铁复合材料在不同摩擦频率及载荷下的摩擦系数和磨损率;用扫描电镜观察磨损表面形貌,并分析了三维网络Al2O3陶瓷对复合材料磨损机制的影响。结果表明:陶瓷Al2O3与高铬铸铁基体之间具有良好的界面结合,复合材料的摩擦系数随摩擦频率和载荷的变化保持稳定,耐磨性远优于高铬铸铁,而且随着摩擦频率和载荷的增加,Al2O3陶瓷/高铬铸铁复合材料的抗磨损性能明显提高,这是由于复合材料中Al2O3与高铬铸铁相之间三维空间结构和良好的界面结合有利于摩擦载荷的传递;三维Al2O3陶瓷骨架在磨损表面形成硬的网络突体并起承载作用,能有效保护金属基体;磨损机制为氧化磨损及磨粒磨损共同作用。 相似文献
3.
研究了25%(质量分数)玻璃纤维增强PA66复合材料(25%GF/PA66)在干摩擦和水润滑条件下与Al2O3陶瓷之间的摩擦磨损行为。采用激光共聚焦扫描显微镜、 扫描电子显微镜、 傅里叶变换红外光谱仪和X射线光电子能谱分析仪对25%GF/PA66的组织、 磨损形貌和磨损表面的化学结构变化进行分析。结果表明: 相同实验载荷时,润滑条件下25%GF/PA66的摩擦系数小于干摩擦条件下的摩擦系数,但磨损体积却远远大于干摩擦条件下的磨损体积。在有水存在的条件下,机械微切削作用持续发生,温度的升高使25%GF/PA66试样变形,同时引起酰胺基团发生水解,C—C键大量断裂,导致磨损体积增加。采用扩展表面一般导热模型计算本实验所用材料的热软化温度为105.9℃。 相似文献
4.
5.
采用3种不同形貌的Al2O3原料对注凝成型制备ZrO2/Al2O3(ZTA)陶瓷工艺中悬浮体的流变性能进行了研究。以低毒的单体N,N-二甲基丙烯酰胺(DMAA)制备了ZrO2/Al2O3坯体和陶瓷。讨论了3种不同形貌的Al2O3原浆料的分散剂用量、球磨时间和固含量对浆料流变性的影响。Al2O3粉体呈扁平状有利于降低浆料的黏度,Al2O3粉体呈棒状对生坯强度的提高有利。制得的3种ZrO2/Al2O3坯体颗粒间结合紧密,抗弯强度分别达到21.45,19.87,25.90 MPa。Al2O3粉体呈颗粒状有利于最终陶瓷力学性能的提高,陶瓷的抗弯强度及断裂韧性分别为680 MPa和7.49 MPa·m1/2,453.1 MPa和6.8 MPa·m1/2,549.4 MPa和6.34 MPa·m1/2。 相似文献
6.
向SiO2基体粉料中添加Al2O3纤维,采用热压注法制备Al2O3/SiO2陶瓷型芯。分析Al2O3纤维含量对陶瓷型芯性能的影响。研究结果表明:Al2O3纤维含量对Al2O3/SiO2陶瓷型芯的线收缩率、体积密度和抗弯强度均有较大的影响。当Al2O3纤维含量大于1wt%时,Al2O3/SiO2陶瓷型芯的线收缩率大幅度降低,稳定在0.335%左右,体积密度随之降低,稳定在1.790 g · cm-3左右;当Al2O3纤维含量为1wt%时,陶瓷型芯抗弯强度达最大值20.48 MPa。分析了Al2O3纤维对Al2O3/SiO2陶瓷型芯烧结收缩的阻滞作用机制。 相似文献
7.
分别对灰铸铁样件进行磷化处理、磷化+纳米铁基离子表面处理、磷化+二硫化钼粘结固体涂层处理,在浸油润滑条件下,采用万能摩擦试验机,考察灰铸铁在不同表面处理下的摩擦磨损性能。试验结果表明,磷化+二硫化钼粘结固体涂层试件的摩擦系数最低,稳定在0.125左右,并出现少量的粘着磨损和磨粒磨损。 相似文献
8.
In order to clarify the effect of Al2O3 particle size on the arc erosion behavior of the ceramic-reinforced Al2O3/Cu composite, Al2O3/Cu composites with different sizes of Al2O3 particles were prepared by powder metallurgy, the effect of Al2O3 particle size on the characteristics of arc motion was studied, and the mechanism of arc erosion of Al2O3/Cu composites was discussed as well. The results show that with decrease in the size of Al2O3 particles, the erosion area increases significantly and the erosion pits become shallower. The vacuum breakdown is preferred to appear in the area between Al2O3 particle and the copper matrix. Based on the experimental results and theoretical analysis, a particle partition arc model is proposed. 相似文献
9.
N. Krishnamurthy M. S. Murali P. G. Mukunda M. R. Ramesh 《Journal of Materials Science》2010,45(3):850-858
Plasma spraying is one of the methods used for combating wear. Despite of its wide spread industrial use, little is known
about the basic friction behavior and mechanism by which such coatings wear. In this work, the abrasive wear resistance of
plasma-sprayed ceramic coatings on cast iron substrate has been investigated through pin-on-disc test. It was found that the
coefficient of friction and wear affected mainly by splats and porosity, surface roughness, and coating thickness. The coefficient
of friction is found to be more significantly affected by load than by other test parameters. This work also includes the
characterization of coatings. 相似文献
10.
激光表面加工是一种能够有效降低陶瓷材料表面粗糙度的方法,为了研究脉冲激光与陶瓷材料作用后表面形貌演变过程及激光工艺参数对表面粗糙度的影响,本文通过有限元法建立了瞬态二维轴对称数值模型,研究了单脉冲、多脉冲激光作用于氧化陶瓷表面形貌的演变过程及激光工艺参数对表面粗糙度的影响。结果表明:单脉冲激光对材料表面具有显著的平滑效果;多脉冲激光加工在脉冲2~3次时具有最好的平滑效果,继续增加脉冲数量,熔池内的表面轮廓开始向下凹陷,表面平滑效果减弱;采用不同工艺参数加工时,过大的频率、脉宽、激光功率都会导致材料表面粗糙度增加。当表面温度处于熔化温度与蒸发温度之间,熔池内流体以毛细力为主要驱动力,促使表面逐渐平滑;当表面温度超过蒸发温度时,熔池内流体受反冲压力挤压,促使表面粗糙。实验与模拟结果对比表明,该模型具有较高的准确性。 相似文献
11.
Indirect measuring of crack growth by means of a key-curve-method in pre-cracked Charpy specimens made of nodular cast iron 总被引:1,自引:0,他引:1
Andreas Emrich Uwe Michael Mühlich Meinhard Kuna Annette Ludwig Peter Trubitz 《International Journal of Fracture》2007,145(1):47-61
The determination of dynamic crack resistance curves from single specimen fracture tests requires information about the crack
advance during the experiment. Here, attention is focused on crack resistance curves for nodular cast iron based on experimental
data from instrumented Charpy tests. In order to estimate the actual crack length a key curve method (KCM) is employed. On
the other hand, the Charpy impact tests were realized numerically using finite element calculations in conjunction with a
continuum damage model (CDM) to simulate ductile crack growth. The parameters of the CDM model were determined from the experimental
data of single specimen fracture tests. Equivalence between the experimental and the numerical realization of a fracture test
was ensured by validating the predictions of the numerical simulations by means of low blow fracture tests. Comparison between
the crack advance predicted by the numerical simulations and the results obtained using the proposed KCM shows a sufficiently
well agreement with the actual crack length. Furthermore, crack resistance curves obtained from single specimen tests using
either standard estimation schemes in conjunction with the KCM or numerical simulations are compared with the predictions
based on low blow fracture tests. 相似文献
12.
以有机高分子化合物酒精和氢气为反应气体,用热丝CVD法在Al2O3陶瓷基片上沉积出金刚石薄膜,用拉曼光谱,X射线衍射等方法进行了表征,探索了碳源浓度、热丝温度、基片温度和预处理工艺对金刚石薄膜结构和性能的影响。并且得到了最佳的工艺条件。探讨了金刚石在Al2O3衬底上的成核和生长机理。 相似文献
13.
Meilin Gu Chuanzhen Huang Shourong Xiao Hanlian Liu 《Materials Science and Engineering: A》2008,486(1-2):167-170
TiB2–Al2O3 composites with Ni–Mo as sintering aid have been fabricated by a hot-press technique at a lower temperature of 1530 °C for 1 h, and the mechanical properties and microstructure were investigated. The microstructure consists of dispersed Al2O3 particles in a fine-grained TiB2 matrix. The addition of Al2O3 increases the fracture toughness up to 6.02 MPa m1/2 at an amount of 40 vol.% Al2O3 and the flexural strength up to 913.86 MPa at an amount of 10 vol.% Al2O3. The improved flexural strength of the composites is a result of higher density than that of monolithic TiB2. The increase of fracture toughness is a result of crack bridging by the metal grains on the boundaries, and crack deflection by weak grain boundaries due to the bad wetting characters between Ni–Mo and Al2O3. 相似文献
14.
将粒径为1~2 mm的ZrO2增韧Al2O3陶瓷颗粒(ZTAp)、高铬合金粉末和黏结剂混合真空烧结制备蜂窝状预制体,再浇注高铬铸铁液制备出ZTAp增强高铬铸铁基复合材料。采用SEM、EDS、XRD分析复合材料的界面微观结构和物相组成,通过三体磨损试验评价复合材料的耐磨性能。结果表明,烧结高铬铸铁基体在铸造过程中发生重熔,与铸造高铬铸铁基体呈冶金结合,ZTAp与金属基体界面结合致密,无裂纹、气孔等缺陷。复合材料三体耐磨性能达到高铬铸铁的3倍以上。将该复合材料应用于制备磨辊件,经过5 000 h服役,柱状区和复合区在磨辊半径方向上的磨损量分别为8.2 mm、5.9 mm,预计寿命可达到高铬铸铁磨辊的2倍以上。 相似文献
15.
为探索第三组元Y2O3添加对Al2O3/ZrO2共晶陶瓷显微组织与机械性能的影响,本文利用低温度梯度的高温熔凝法制备了直径为20 mm的Al2O3/ZrO2(Y2O3)共晶陶瓷块体,采用SEM、EDS及XRD技术对共晶陶瓷进行微结构分析,并利用维氏压痕法对其硬度和断裂韧性进行测试。SEM结果表明,凝固组织由群集的共晶团结构组成,随着Y2O3添加量的增加,共晶团形态由胞状转变为枝晶状,内部相间距在1~2 μm范围内变化。力学测试表明,Y2O3摩尔分数小于1.1%时,由于组织内部存在低硬度m-ZrO2及微裂纹缺陷,故陶瓷硬度较低,约为(9.53±0.22 )GPa;当Y2O3摩尔分数为1.1%时,陶瓷硬度最大,约为(18.05±0.27)GPa;当Y2O3的摩尔分数大于1.1%时,由于共晶团边界区内气孔缺陷及粗大组织增多,引起陶瓷硬度值略有下降。低Y2O3摩尔分数添加时,陶瓷断裂韧性相对较高,约为(6.30±0.16)MPa·m1/2,这与其内部存在大量微裂纹缺陷有关;随着Y2O3添加量的增加,陶瓷的微裂纹数量减少、边界区内缺陷增多,断裂韧性降低。 相似文献
16.
以CaO-B2O3-SiO2(CBS)玻璃粉体和Al2O3陶瓷粉体为原料,通过在CBS与Al2O3的质量比固定为50:50的玻璃-陶瓷复合材料中添加适量的Bi2O3作为烧结助熔剂,探讨了Bi2O3助熔剂对CBS/Al2O3复合材料的烧结性能、介电性能、抗弯强度和热膨胀系数的影响规律.研究表明:Bi2O3助熔剂能通过降低CBS玻璃的转变温度和黏度促进CBS/Al2O3复合材料的致密化进程,于880 ℃下烧结即能获得结构较致密、气孔较少的CBS/Al2O3复合材料.然而,过量添加Bi2O3将使玻璃的黏度过低,从而恶化CBS/Al2O3复合材料的烧结性能、介电性能及抗弯强度.当Bi2O3的添加量为CBS/Al2O3复合材料的1.5wt%时,于880 ℃下烧结即能获得最为致密的CBS/Al2O3复合材料,密度为2.82 g·cm-3,这一材料具有良好的介电性能(介电常数为7.21,介电损耗为1.06×10-3),抗弯强度为190.34 MPa,0~300 ℃的热膨胀系数为3.52×10-6 K-1. 相似文献
17.
郭生武 《理化检验(物理分册)》2001,37(3):103-105
采用宏观和微观分析方法对90Al2O3缸套内衬的微观结构进行了分析。结果表明,该缸套内衬为刚玉-镁铝尖晶石复合陶瓷,显微组织属A2O3-MO-SO2t S2O3-CO0-SiO2型结构,二次重结晶和玻璃相的存在及气 含量偏高,将导致韧性降低。 相似文献
18.
19.
Nanocomposite powders (Fe or Fe-Cr alloy)/-Al2O3 (75 and 85 vol.%) were obtained by room-temperature high-energy milling powder mixtures of hematite (and chromium oxide) with aluminum and alumina in a high-capacity mill for 8-10 h. The composition of iron and iron alloys was followed by Mössbauer spectroscopy, while the appearance of other phases was revealed by X-ray diffraction. The powder particles produced are assemblies of grains (10–20 nm in size) with a wide size distribution (from well below 1 μm up to several hundreds) and low porosity (fully dense particles). Both the metallic and ceramic phases have crystallite sizes below 15 nm for all the compositions investigated. Nano-nano type ceramic nanocomposites were, therefore, obtained. 相似文献
20.
采用刷涂法在Al2O3基多孔隔热材料表面制备Al2O3/MoSi2涂层,涂层以硅溶胶作为粘结剂,纳米Al2O3与Al2O3纤维作为耐高温组分,MoSi2为高发射率组分。通过SEM、XRD对Al2O3/MoSi2涂层微观表面结构、物相组成进行分析。研究纳米Al2O3与Al2O3纤维的质量比和MoSi2含量对Al2O3/MoSi2涂层耐温性能的影响,并对Al2O3/MoSi2涂层的抗热震性能、发射率进行表征。结果表明,当纳米Al2O3与Al2O3纤维的质量比小于1∶1时,热考核后Al2O3/MoSi2涂层表面无裂纹产生;当纳米Al2O3与Al2O3纤维的质量比在1∶2~1∶4之间时,Al2O3/MoSi2涂层中的纤维网络较完整。MoSi2的含量为20%时,Al2O3/MoSi2涂层抗热震实验循环25次后表面保持完好,热考核后在2.5~25 μm波段的平均发射率在0.85左右,具有较高的发射率。 相似文献