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     

等离子喷涂Al2O3+TiO2复合陶瓷涂层的组织结构

利用ＳＥＭ,ＴＥＭ,ＥＤＡＸ及Ｘ射线等手段研究了Ａｌ２Ｏ３＋ＴｉＯ２／ＮｉＣｒＡｌＹ复合陶瓷等离子喷涂层的组织结构,涂层呈片层状,Ａｌ２Ｏ３＋ＴｉＯ２陶瓷涂层由γ－Ａｌ２Ｏ３,ＴｉＯ２及少量的α－Ａｌ２Ｏ３组成,由于喷涂层温度比较高,部分熔化的Ａｌ２Ｏ３和大部分熔化的ＴｉＯ２发生了一定程度的互熔,形成了Ａｌ２Ｏ３＋ＴｉＯ２共晶组织。片层内由Ｎｉ基固溶体及弥散分布其上的γ相（Ｎｉ３Ａｌ）组成,片间为     

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     

Mo—Ni／Al2O3催化剂的TPR特性与加氢脱硫性能

应用ＴＲＰ、ＸＰＳ及ＸＲＤ等技术研究了用浸渍法制备了的Ｎｉ／Ａｌ２Ｏ３、Ｍｏ／Ａｌ２Ｏ３和Ｍｏ－Ｎｉ／Ａｌ２Ｏ３３种催化剂的还原性能，并将Ｍｏ－Ｎｉ／Ａｌ２Ｏ３双金属催化剂与同类型的Ｍｏ－Ｃｏ／Ａｌ２Ｏ３和Ｗ－Ｎｉ／Ａｌ２Ｏ３催化剂进行了比较。结果表明：在Ｍｏ－Ｎｉ－Ａｌ２Ｏ３中，ＭｏＯ３呈高度分散状态，ＮｉＯ的加入减弱了Ｍｏ与载体间的强相互作用，并在催化剂表面形成了两种易还原的复合物，大大降低了     

Al_2O_3－Cr_2O_3－ZrO_2－SiO_2系列高温材料的研究

利用Ａｌ２Ｏ３－Ｃｒ２Ｏ３固溶体易形成直接结合和ＺｒＯ２的相变增韧效应，研究了Ａｌ２Ｏ３－Ｃｒ２Ｏ３－ＺｒＯ２－ＳｉＯ２系高级耐火材料，结果表明：在刚玉材料中．直接结合和增韧效应能改善材料的性能。     

添加Cr2O3对Al2O3-TiC陶瓷烧结及纳米结构形成的影响

研究了Ａｌ２Ｏ３－ＴｉＣ陶瓷材料中Ｃｉ２Ｏ３添加剂对该陶瓷材料烧结致密度和力学性能的影响。Ｃｒ２Ｏ３与ＴｉＣ在高度有化学反应发生,反应产物在高温产生的液相有助于陶瓷材料的烧结。Ｃｒ２Ｏ３与Ａｌ２Ｏ３形成的连续固溶体,使Ａ２ｌＯ３晶格的活化从而也促进了Ａｌ２Ｏ３－ＴｉＣ陶瓷材料的烧结。ＴＥＭ研究表明：Ｃｒ离子高温时在ＴｉＣ中具有较高的溶解度,降温后淀析出许多纳米级含Ｃｒ的颗粒,使Ａｌ２Ｏ３－ＴｉＣ陶     

SiCw／涂层／TZP陶瓷复合材料界面化学键的XPS和IR研究

本文用ＸＰＳ和ＩＲ测定了ＳｉＣｗ／（Ａｌ２Ｏ３，莫来石）涂层／ＴＺＰ陶瓷复合材料的界面化学键。结果表明ＳｉＣｗ／Ａｌ２Ｏ３、莫来石、ＴＺＰ界面为化学结合而Ａｌ２Ｏ３、莫来石／ＴＺＰ界面为物理结合。     

Al2O3—Cr2O3—ZrO2—SiO2系列高温材料的研究

利用Ａｌ２Ｏ３－Ｃｒ２Ｏ３固溶体易形成直接结合和ＺｒＯ２的相变增韧效应，研究了Ａｌ２Ｏ３－Ｃｒ２Ｏ３－ＺｒＯ２－ＳｉＯ２系高级耐火材料，结果表明：在刚玉材料中，直接结合和增韧效应能改善材料的性能。     

用量子化学方法计算3CaO.3Al2O3.SrSO4的水化活性

用新发展起来的计算量子化学－电荷自洽离散变分Ｘα方法（ＳＣＣ－ＤＶ－Ｘα）对水泥矿物３ＣａＯ．３Ａｌ２Ｏ３．ＳｒＳＯ４和３ＣａＯ．３Ａｌ２Ｏ３．ＣａＳＯ４进行了研究。通过分子轨道能级、键级及原子净电荷等信息的分析结果表明：在这两个矿物中Ｃａ，Ｓｒ原子对水化活性的贡献比Ａｌ重要。     

氯硅烷在M,oO2Br2催化体系引发丁二烯聚合反应中的作用

考察了在以ＭｏＯ２Ｂｒ２为主催化剂，Ａｌ（ｉ－Ｂｕ）２ＯＰｈＣＨ３为助催化剂的体系中添加第三组分氯硅烷系列组成的Ａｌ－Ｍｏ－Ｃｌ催化体系引发丁二烯的聚合。结果表明在适量氯硅烷范围内，随Ｃｌ／Ｍｏ上升，催化活性有所提高，聚合物分子量显著下降，但分子量分布以及１，２－链节含量变化较小。讨论了氯硅烷的作用     

Fe/Al2O3梯度涂层的制备与性能

采用喷涂法和溶胶-凝胶法相结合的工艺制备钢基Fe/Al2O3梯度涂层复合材料,并对其性能进行分析。结果表明：Fe/Al2O3梯度涂层与钢基体的界面结合强度较高,达21.2MPa;涂层与基体以及涂层与涂层之间没有明显的界面,实现了良好结合。涂层的表面硬度要比钢基体高4-5倍;Fe/Al2O3梯度涂层主要由α-Al2O3、AlFeO3、Al2Fe2O3和Al3Fe5O3物相组成。     

Effect of spraying parameter and injector angle on the properties of in-flight particles and alumina coatings on Al alloy with PA-HT

Bonding strength is one of the most important properties of plasma sprayed coatings, especially ceramic coatings on complexly shaped light alloys, which is mainly determined by the properties of in-flight particles and their flattening behaviors on substrate surface. Consequently, the influence of current, voltage, primary gas flow rate and injector angle on temperature and velocity of in-flight alumina particles and morphology of splats on Al alloy with plasma arc-heat treatment (PA-HT) were investigated in detail by DPV Evolution, optical microscope and 3D non-contact surface mapping profile. The bonding strength, hardness and wear behavior of corresponding alumina coatings were measured by universal testing machine, nano-indentation test and wear test. Results showed that particle temperature and velocity increased with increase of input current and voltage, while their trends were reverse with increasing primary gas flow rate. The droplets could melt Al alloy surface and penetrate into its interior that greatly affected the morphology and corresponding shape factor (SF) of splats. Moreover, reducing injector angle caused droplets to glide on substrate surface and then to form “sole-like” splats. The morphology change of these splats obviously influenced the interfacial bonding strength, compactness, hardness and wear resistance of alumina coatings.     

粉煤灰活性氩弧熔覆Al2O3-TiB2-TiC复合涂层组织和性能分析

以铁基合金粉末、Al、TiO2和B4 C粉末为涂覆材料,以高铝粉煤灰、SiO2、MgO、CaF2和CeO2为活性剂,采用活性氩弧熔覆技术在Q235钢表面原位合成Al2O3-TiB2-TiC颗粒增强铁基复合涂层.测试熔覆涂层的物相结构、金相组织、显微硬度和耐磨性能,并与未涂覆活性剂的常规熔覆涂层进行对比分析.结果表明,复合涂层由Al2O3、TiB2、TiC、FeSi2 Ti、FeB2和α-Fe相组成,其与基体界面无气孔、裂纹等缺陷,呈良好的冶金结合;复合涂层测试点的最高显微硬度为1283.4 HV0.2,其在室温干滑动磨损条件下耐磨性良好;粉煤灰复合活性剂的加入可以促进熔覆层与母材之间的良好熔合、增加涂层中新相种类和数目、提高氩弧熔覆效率,这对改善复合涂层的综合性能具有重要意义.     

镍基纳米SiC-Al2O3复合电刷镀层的组织及性能

在45#钢基体上制备了n-Al2O3/Ni和n-SiC–Al2O3/Ni复合刷镀层,采用能谱仪(EDS)、X射线衍射仪(XRD)、扫描电镜(SEM)和T-11球盘式磨损试验机等设备对比研究了2种复合刷镀层的组织及性能。EDS分析结果表明,n–Al2O3/Ni复合刷镀层中纳米颗粒特征元素Al的质量分数为5.65%,n-SiC–Al2O3/Ni复合刷镀层中纳米颗粒特征元素Al的质量分数为5.63%,Si元素的质量分数为4.86%。SEM分析结果表明,与n-Al2O3/Ni复合刷镀层相比,n-SiC–Al2O3/Ni复合刷镀层的表面更加平整,组织更加细化。n-SiC–Al2O3/Ni和n-Al2O3/Ni复合刷镀层的显微硬度分别为587HV和555HV,n-SiC–Al2O3/Ni复合刷镀层的耐磨性是n-Al2O3/Ni复合刷镀层的1.7倍。     

激光重熔NiCrAlY涂层研究

采用空气等离子喷涂技术(APS)将NiCrAlY粉末作为粘结层材料喷涂在IN718镍基合金上,再用5 kW CO2连续激光器对其进行激光重熔处理,利用扫描电镜(SEM)、能谱分析(EDX)和X射线衍射(XRD)等手段对等离子喷涂层和激光重熔层的微观组织与成分进行了比较分析.结果表明:应用优化激光重熔工艺进行重熔后,涂层...     

Titanium carbide/duplex stainless steel (DSS) metal matrix composite coatings prepared by the plasma transferred arc (PTA) technique: microstructure and wear properties

The present investigation focuses on the microstructure and the tribological properties of TiC/steel composite coatings obtained on 2205 duplex stainless steel (DSS) substrate, by using the plasma transferred arc technique. Two different plasma and shielding gas mixtures have been used, namely (a) 100% Ar and (b) 95% Ar + 5%N₂. The coatings obtained are defect-free and their thickness is 1.50 ± 0.05 mm. Both coatings consist of a dispersion of TiC _x N _y particles, with a volume fraction of about 18–22%, in an austenite–ferrite matrix. The austenite-to-ferrite volume fraction is 35/65% for the Ar coatings and it is found to increase to 40/60%, when nitrogen is used in the plasma and shielding gas. The hardness of the composite coatings is improved significantly (630–650HV on average) compared to the hardness of the substrate (250HV). The friction coefficient produced against an Al₂O₃ counterbody has decreased considerably to 0.2–0.3 from 0.5 for the 2205/Al₂O₃ pair and the wear rate was reduced at least by one order of magnitude with respect to the value of the 2205 DSS substrate.     

激光重熔处理等离子喷涂陶瓷涂层的研究现状及展望

本文介绍了激光重熔等离子喷涂陶瓷涂层的研究进展,并对其进行了展望。激光重熔使等离子喷涂涂层致密性提高,涂层与基体的结合方式由机械结合为主改为冶金结合为主,层状组织变化为柱状组织;激光重熔使等离子喷涂涂层的热疲劳抗力、耐蚀性、耐磨性、抗高温氧化性等性能提高。指出了激光重熔等离子喷涂陶瓷涂层目前存在的问题,探讨了激光重熔等离子喷涂陶瓷涂层易产生裂纹,甚至发生涂层剥落等问题的原因,提出了激光重熔技术的研究方向。     

电沉积Cu-Ni-Sn-Al_2O_3复合镀层及其性能的研究

采用电沉积方法在45~#钢表面制备出Cu-Ni-Sn-Al_2O_3复合镀层。研究了镀液中Al_2O_3的质量浓度对镀层的硬度、耐磨性及结合力的影响,并分别用SEM和XRD表征了镀层的表面形貌和结构。结果表明:当镀液中Al_2O_3的质量浓度为15g/L时,镀层具有较好的耐磨性。     

Wear behavior of graded Cr-CrN-Cr(1−x)Al(x)N coatings synthesized by closed-field unbalanced magnetron sputtering for advanced machining operations

Graded Cr-CrN-Cr_(1?x)Al_(x)N coatings were synthesized onto M42 HSS substrates used in advanced machining operations by closed-field unbalanced magnetron sputtering (CFUBMS). The tribological behavior of these graded coatings was explored in detail by advanced electron microscopy, confocal laser scanning microscopy, nanoindentation and dry sliding wear tests. The presence and magnitude of residual stresses in these coatings were determined by the XRD – sin²ψ method, which revealed increasing compressive stresses with increasing Al content. The coating surface morphology, mechanical properties were determined prior to dry sliding wear by atomic force microscopy (AFM) and nanoindentation methods, which yielded decreasing surface roughness (R_a) as well as enhancement of hardness and modulus along with increase in H/E and H³/E² ratios with increasing Al content. Tribological investigation was performed with a pin-on-disc arrangement by keeping the sliding velocity (0.2?ms^?1) and normal axial load (10?N) constant and varying the sliding distance. Specific wear rates of the order ~ 10^–17 m³ N^?1 m^?1 were encountered for all coatings with the wear rates increasing as the Al content increased implying a decrease of wear resistance of the coatings. Abrasive wear has been found to be the dominant wear mechanism during dry sliding wear. Increasing modulus mismatch between coating and substrate can be mainly attributed to a decrease in wear resistance of the coatings.     

Influence of Al content and post-annealing on synthesis and mechanical properties of plasma sprayed Cr–Al–C composite coatings

Due to ultra-high temperature and short reaction time, it was very challenging to produce high purity MAX phase by plasma spraying. In this study, Cr–Al-graphite agglomerated powders with different Al additions (x = 0.2–1.5) was used to prepare Cr–Al–C composite coatings by atmospheric plasma spraying followed with annealing. Results showed that the as-sprayed coatings displayed typical lamellar structure, mainly composed of Cr–C binary carbides (Cr₇C₃ and Cr₂₃C₆) and residual Al. After annealing at 700 °C, the newly formed Cr₂AlC phase increased significantly in the coatings. The higher addition of Al, the more Cr₂AlC phase formed after annealing. The enhanced atomic diffusion, sufficient Al source and existence of (Cr, Al)C_x contributed to the formation of Cr₂AlC under annealing. Annealing treatment improved the hardness of the coating, but with the increase of Cr₂AlC phase content, the hardness decreased slightly. The Al content and post-annealing had a synergistic effect on the formation of Cr₂AlC phase in the sprayed coatings. This provided an effective route to control the Cr₂AlC content in sprayed Cr–Al–C composite coatings.