共查询到19条相似文献,搜索用时 140 毫秒
1.
以NaAlO 2+NaOH为电解液体系,在恒压模式下对SiC体积分数为45%,粒径为5μm的SiCp/Al基复合材料表面进行微弧氧化处理,研究了占空比对SiCp/Al基复合材料微弧氧化膜层组织及性能的影响。用SEM分析微弧氧化膜层的形貌;用X射线衍射仪分析膜层的相组成;采用粗糙度仪、维氏硬度仪、划痕仪对膜层粗糙度、显微硬度及结合力进行了分析;用电化学工作站分析膜层的耐蚀性。结果表明:随着占空比的增大,微弧氧化膜层变得连续,厚度呈现增加趋势,粗糙度逐渐增加,孔隙率逐渐降低。占空比对微弧氧化膜层的物相有一定影响。SiCp/Al基复合材料微弧氧化膜层与基体的结合力随占空比的增加先增大后减小。不同占空比下制备的微弧氧化膜层均能提高SiCp/Al基复合材料的耐蚀性,占空比为70%时制备的微弧氧化膜层耐蚀性最好。 相似文献
2.
对SiC P/ 2024 铝基复合材料进行微弧氧化表面处理, 分析了陶瓷膜截面的显微组织、成分分布, 测量了其相组成和硬度分布, 并比较了氧化前后极化曲线的变化。结果表明, 在硅酸盐溶液中获得的陶瓷膜由莫来石、α-Al 2O 3 、γ-Al 2O 3 晶态相和SiO 2 非晶相组成, 残留的SiC 增强体很少, 膜与复合材料呈现良好的冶金结合。膜具有两层结构, 外层Si 含量较高并主要来自电解液, 而内层膜里莫来石的形成同SiC 增强体氧化密切相关。微弧氧化处理后, SiC P / 2024 铝基复合材料的抗腐蚀能力得到很大提高, 这归因于形成了一层完整连续的氧化膜。 相似文献
3.
在含有不同浓度氧化钕(Nd 2O 3)微粒的电解液中,利用微弧氧化技术在2A12铝合金表面制备膜层。研究不同浓度的Nd 2O 3微粒对微弧氧化膜层硬度、厚度以及膜基结合力的影响,为通过微弧氧化在2A12铝合金表面制备性能良好的膜层提供理论依据。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱(XPS)分析了膜层截面形貌和膜层的相组成,采用TT-230涡流测厚仪、HVS-1000数字维氏硬度仪和MFT-4000型多功能材料表面性能试验机分别对膜层厚度、硬度和膜基结合力进行测试。结果表明:膜层主要由α-Al 2O 3、γ-Al 2O 3和SiO 2相组成;随着Nd 2O 3微粒浓度的增加,膜层硬度、厚度和膜基结合力均呈现出先增加后减小的趋势,并且在Nd 2O 3微粒浓度为0.3 g/L时,膜层的显微硬度、厚度和膜... 相似文献
4.
在(NaPO 3) 6,Na 2SiO 3-NaOH和NaAlO 2-NaOH三种电解液中,采用微弧氧化技术在SiC p/Al基复合材料表面制备微弧氧化膜层。使用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、X射线衍射(XRD)对膜层组织结构及相组成进行表征,并通过摩擦磨损实验及电化学工作站分析基体及膜层的耐磨性和耐蚀性。结果表明:三种电解液中均能制备出均匀的微弧氧化膜层,NaAlO 2-NaOH中制备的膜层粗糙度和厚度最大。三种电解液中制备的膜层物相有差异。微弧氧化提高SiC p/Al基复合材料的显微硬度,其中NaAlO 2-NaOH中制备的膜层硬度达到1125HV。微弧氧化可降低SiC p/Al基复合材料的摩擦因数,综合摩擦因数及磨损情况,NaAlO 2-NaOH中制备的微弧氧化膜层的耐磨性较好。三种电解液中制备的微弧氧化膜层均能改善SiC p 相似文献
5.
采用微弧氧化方法在硅酸盐电解液里在2219铝合金搅拌摩擦焊接头表面均匀生长一层50 μm陶瓷膜, 分析了铝合金基体和焊缝区陶瓷膜的形貌、相组成和显微硬度分布, 探讨了合金显微组织和微弧氧化膜生长过程的相互影响. 结果表明, 铝合金显微组织对微弧氧化膜的生长影响较小, 铝合金基体和焊缝区的微弧氧化膜特性几乎相同, 陶瓷膜都是由α-Al 2O 3、γ-Al 2O 3和莫来石(3Al 2O 3·2SiO 2)相组成; 不同区域膜层的显微硬度相等, 其平均硬度约为HV 1500. 另外, 微弧放电高温过程对膜/基界面附近的铝合金显微组织没有影响. 相似文献
6.
为了提高铝合金的耐磨性,在六偏磷酸盐复合电解液中加入不同浓度氧化石墨烯(GO)对铝合金进行微弧氧化(MAO),利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、膜层测厚仪和显微硬度计分析GO对微弧氧化膜层的微观形貌、相组成、元素分布、厚度和显微硬度的影响,重点研究了不同GO浓度下的铝合金微弧氧化膜层的摩擦磨损性能。结果表明:电解液中添加GO纳米颗粒对微弧氧化膜层有显著的影响。Al 2O 3/GO膜层生长速率随GO含量增加而上升,其主要成分是α-Al 2O 3和γ-Al 2O 3。随着GO浓度的增加,微弧氧化膜层的显微硬度相较于纯2A12铝合金明显提高。由于电解氧化过程中C元素掺入膜层界面,Al 2O 3/GO膜层的表面变得致密且光滑,摩擦系数明显下降且耐磨性提高。该方法为强化铝合金表面耐磨提供了新思路,对拓展铝合金的应用具有重要意义。 相似文献
7.
针对Al 2O 3 / Al 复合材料中金属相Al 对其高温性能的不利影响, 本试验在高温下将铝合金熔体氧化渗透到注浆成型的SiC/ Ni 多孔预制体中, 制备了Al 2O 3 / SiC/ Ni/ Al-Si 多相陶瓷基复合材料。借助光学显微镜、电子显微镜(SEM) 、X 射线衍射仪(XRD) 、波谱仪( EDS) 等手段分析了预制体和复合材料的相组成、微观结构及界面特征。结果表明, 复合材料的主晶相为Al 2O 3 与SiC , 相间存在Al (Si) 复合氧化物、NiAl 2O 4 及Ni 与Al-Si 合金相, 各相界面处成分呈连续过渡变化趋势, 构筑了具有模糊界面特征的多相复合材料。 相似文献
8.
用电化学方法和腐蚀失重法研究了2024Al和SiCp/2024Al基复合材料在3.5%NaCl水溶液中的耐蚀性,用电化学交流阻抗技术对它们的硫酸阳极氧化膜的耐蚀性进行了研究。结果表明,SiCp/2024Al复合材料在3.5%NaCl水溶液中比相应的基体金属有较大的腐蚀敏感性。SiCp/2024Al的阳极氧化膜耐NaCl溶液腐蚀能力不如2024Al合金的阳极氧化膜,是氧化膜中SiC颗粒的存在破坏了氧化膜的完整性和均匀性。 相似文献
9.
采用微弧氧化技术在 TiC P/Ti6Al4V 复合材料表面制备陶瓷膜。在NaAlO 2和NaH 2PO 2两种溶液体系中通过添加不同添加剂 NaOH、C 10H 12CaNa 2N 2O 8·4H 2O和Na 2SiO 3, 研究电解液组分对陶瓷膜组织、耐蚀性和耐磨性的影响。结果表明: 在NaH 2PO 2电解液体系中生成的膜层由金红石型和锐钛矿型TiO 2相组成, 而在NaAlO 2体系中除了生成TiO 2外, 还生成了Al 2TiO 5和γ-Al 2O 3。添加NaOH可以加快微弧氧化反应速率, 添加NaAlO 2和Na 2SiO 3有利于提高膜层的硬度, NaH 2PO 2溶液体系中形成的膜层厚度是NaAlO 2溶液体系的2~3倍。 在NaAlO 2和NaH 2PO 2电解液体系中生成的膜层, 其耐腐蚀性能排序均为: Na 2SiO 3>C 10H 12CaNa 2N 2O 8·4H 2O>NaOH。在NaAlO 2电解液体系中生成的膜层的耐磨性能排序为: Na 2SiO 3>NaOH>C 10H 12CaNa 2N 2O 8·4H 2O, 而在NaH 2PO 2电解液体系中生成的膜层的耐磨性能排序为: Na 2SiO 3>C 10H 12CaNa 2N 2O 8·4H 2O>NaOH。TiC P/Ti6Al4V复合材料经过微弧氧化处理后, 耐磨性和耐蚀性均优于基体, 在NaH 2PO 2+Na 2SiO 3电解液中生成的微弧氧化膜的耐蚀性最好, 耐磨性也较好, 其腐蚀电流密度较钛基复合材料基体降低约2个数量级, 因此综合性能最好。 相似文献
10.
为提高7075铝合金表面的耐磨性能,在掺杂纳米BN颗粒的电解质溶液中通过微弧氧化技术构筑铝合金表面硬质陶瓷涂层。利用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、光电子能谱仪(XPS)、粗糙度仪、显微硬度计、摩擦磨损试验机等表征方法,研究了加入纳米BN颗粒对微弧氧化过程起弧电压及涂层的表面形貌、孔隙率、物相组成、厚度、粗糙度、显微硬度、摩擦磨损性能的影响。结果表明:涂层主要由α-Al 2O 3相和γ-Al 2O 3相组成;纳米BN颗粒提高了起弧电压,增加了涂层的厚度、粗糙度、硬度;当添加0.3 g/L纳米BN颗粒时,所得微弧氧化涂层的综合性能最佳。此时涂层中的微孔数量少、孔径小,致密度高,其表面孔隙率从未添加的6.617%降到3.518%;硬度达到最高值916.7 HV 10 N,厚度20μm,粗糙度2.38μm;摩擦系数降低至0.7,磨损率降低至7.84×10 -5 mm 3/(N·m)。 相似文献
11.
本研究利用小功率微弧氧化电源, 通过内充液式管状阴极的逐行扫描, 在2024铝合金样件表面生成微弧氧化陶瓷膜层, 对样件的局部受损部位进行了成功的修复, 从而突破了传统微弧氧化技术不能用于铝合金构件现场局部防护与修复的限制; 利用XRD、SEM、EDS等分析方法对陶瓷膜层的相组成与微观组织形貌进行了研究。利用纳米压痕仪测试了陶瓷膜层的纳米压痕硬度和弹性模量, 用动电位极化曲线测试陶瓷膜层的耐腐蚀性能。结果表明: 在恒电流模式下, 扫描式微弧氧化电压快速升高, 直接进入微弧放电阶段。其一次扫描成膜层厚度17 μm, 相对于传统微弧氧化具有很高的成膜效率。铝合金扫描式微弧氧化陶瓷膜层主要由α-Al 2O 3和γ-Al 2O 3组成, 膜层分为致密层和疏松层, 表面多微孔, 且有微裂纹; 纳米压痕测试结果表明, 陶瓷膜层纳米压痕硬度和弹性模量沿界面向外呈现先增加后减小的变化趋势。动电位极化曲线表明, 扫描式和传统微弧氧化陶瓷膜层都能够对基体起到有效的腐蚀防护作用, 传统微弧氧化陶瓷膜层的腐蚀防护作用高于扫描式。 相似文献
12.
研究了基体种类对SiC和石墨(Gr)颗粒混杂增强铝基复合材料的摩擦磨损性能的影响。各种铝基体的混杂复合材料的耐磨性有明显差异,纯铝基混杂复合材料具有最好的耐磨性,其次是A356,2024和6061为基体的混杂复合材料。 相似文献
13.
In the present study, the effect of aging behavior on the microstructure and mechanical properties of submicron SiC particulate-reinforced Al-Li composites was investigated, including the quenching sensitivity. The results showed that the age-hardening of AI-Li/SiCp composite was accelerated with an increase in the aging temperature and the amount of SiC particulates. Microstructural characterization studies revealed that the microstructurcs of aged Al-Li/ 10vol%SiCp composite consisted of T 1 T 2 phase, S 'phase, δ ' phase. The quenching sensitivity of solution-treated AI-Li/10vol%SiCp composite was low, and was independent of the cooling rate, while the sensitivity of T6-treated samples increased with a decrease in the cooling rate because of precipitation of the T 1 phase and T 2 phase. 相似文献
14.
The effect of size of silicon carbide particles on the dry sliding wear properties of composites with three different sized
SiC particles (19, 93, and 146 μm) has been studied. Wear behavior of Al6061/10 vol% SiC and Al6061/10 vol% SiC/5 vol% graphite
composites processed by in situ powder metallurgy technique has been investigated using a pin-on-disk wear tester. The debris
and wear surfaces of samples were identified using SEM. It was found that the porosity content and hardness of Al/10SiC composites
decreased by 5 vol% graphite addition. The increased SiC particle size reduced the porosity, hardness, volume loss, and coefficient
of friction of both types of composites. Moreover, the hybrid composites exhibited lower coefficient of friction and wear
rates. The wear mechanism changed from mostly adhesive and micro-cutting in the Al/10SiC composite containing fine SiC particles
to the prominently abrasive and delamination wear by increasing of SiC particle size. While the main wear mechanism for the
unreinforced alloy was adhesive wear, all the hybrid composites were worn mainly by abrasion and delamination mechanisms. 相似文献
15.
Wear behavior of Al/Al 2O 3/C hybrid metal matrix composites fabricated by squeeze casting method was characterized. The effects of volume fraction of carbon fiber on wear behavior of hybrid composites was investigated. Wear behavior of Al/Al 2O 3/C composites was characterized by the dry spindle wear test under various sliding speeds. The wear resistance of Al/Al2O3/C composites was remarkably improved over Al/Al2O3 composites by adding carbon fibers to Al/Al2O3/C composites. Specifically, at the intermediate sliding speed the wear resistance of Al/Al2O3/C composites containing 8 vol.% carbon fiber was found to be better than that of the rest of the carbon hybrid composites. From fractographic studies, damaged sections in wear surfaces of hybrid composites at intermediate sliding speed were not observed due to the formation of solid lubrication film. The solid lubrication film which was formed as a result of adding carbon fibers improved the wear resistance of carbon hybrid composites because this film reduced the high friction force between MMCs and counter material. 相似文献
16.
采用先进粉末冶金技术(放电等离子烧结+热挤压)制备了三种体积分数(3vol%、5vol%、7vol%)的微/纳B 4C增强6061Al复合材料,对不同制备阶段复合材料的微观组织(SEM、TEM、EBSD)进行观察分析,对复合材料的纳米压痕行为及拉伸性能进行测试。结果表明:烧结后B 4C颗粒在基体中呈“网状”分布;挤压变形后B 4C颗粒在基体实现弥散均匀分布。挤压变形后,纳米B 4C在晶内及晶界均有分布,纳米B 4C对位错的钉扎作用使得基体积累大量位错,提供驱动力并越过动态回复,使内部再结晶比例高达74%。当B 4C体积分数为3vol%时,挤压态B 4C/6061Al复合材料的抗拉强度、屈服强度及延伸率为219 MPa、88 MPa和22.5%,断裂形貌中呈现大量韧窝。 相似文献
17.
Fatigue-lifetime behaviour has been examined for extruded 6061 aluminium alloy composites reinforced with 15 vol% SiC and 10 vol% Al 2O 3 particles. The peak particle sizes are at about 4.5 and 6 μm. Within measured S- N curves the fatigue lifetime at given stress amplitudes of SiC p/AA6061 is superior to that of Al 2O 3p/AA6061 in the low-cycle fatigue region as well as in the high-cycle fatigue region. These results are discussed by consideration of theoretically evaluated crack propagation curves. 相似文献
18.
Al/Al 2O 3 composite coating was prepared by plasma spraying and characterized by XRD and SEM. Some thermal–mechanical properties of the composite coating including thermal diffusivity, microhardness, fracture toughness and sliding wear rate were measured. The results showed that the Al/Al 2O 3 composite coating, compared with Al 2O 3 coating, exhibits denser structure and developed splat interface. The coexistence of Al metal phase and Al 2O 3 ceramic phase effectively increased the fracture toughness and thermal diffusivity of composite coating, in spite of the slight decrease in microhardness. Furthermore, the wear resistance of Al/Al 2O 3 composite coating is superior to that of Al 2O 3 coating. 相似文献
19.
Thin films of CaCO 3 (calcite) have been grown with the atomic layer chemical vapour deposition (ALCVD) technique, using Ca(thd) 2 (Hthd=2,2,6,6-tetramethylheptan-3,5-dione), CO 2, and ozone as precursors. Pulse parameters for the ALCVD-type growth are found and self-limiting reaction conditions are established between 200 and 400 °C. Calcium carbonate films have been deposited on soda-lime glass, Si(100), -Al 2O 3(001), -Al 2O 3(012), -SiO 2(001), and MgO(100) substrates. The observed textures were: in-plane oriented films with [100](001)CaCO 3 [100](001)Al 2O 3 and [100](001)CaCO 3[110](001)Al 2O 3 on -Al 2O 3(001), amorphous films on -Al 2O 3(012) when grown at 250 °C, and columnar oriented films on soda-lime glass, Si(001), -SiO 2(001), and MgO(100) substrates with (00 l) and (104) parallel to the substrate plane at 250 and 350 °C, respectively. The film topography was studied by atomic force microscopy and AC impedance characteristics were measured on as-deposited films at room temperature. The films were found to be insulating with a dielectric constant ( r) typically approximately 8. Thin films of CaO were obtained by heat treatment of the carbonate films at 670 °C in a CO 2-free atmosphere, but the thermal decomposition led to a significant increase in surface roughness. 相似文献
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