铁基高温耐磨堆焊焊条的研究

研究了Ｃｒ－Ｎｉ－Ｂ－Ｗ－Ｖ－Ｎｂ和Ｃｒ－Ｂ－Ｗ－Ｍｏ－Ｎｂ两种合金系统的高温耐磨堆焊合金焊条，其堆焊层组织分别为合金奥氏体＋骨架状共晶碳化物＋颗粒状共晶碳化物，隐晶马氏体＋块状硬质相，颗粒状硬质相，具有较高的高温硬度和高温耐磨性。     

颗粒增强复合镍基涂层耐磨性的研究

研究了４种不同涂层的耐磨性能,并对涂层形貌、组织、硬质相等进行了分析,结果表明：Ｎｉ６０中添加价格较低的ＦｅＯ５粉末后,涂层耐蚀磨损性能得到改善;随ＷＣ含量的增加,涂层的耐冲蚀磨损的性能也得到提高;而加入硬质颗粒后,其合金粉末涂层的耐磨性却不一定提高．     

铬硼钨钼铌钒系高温抗磨料磨损堆焊焊条的研究

研究出了Ｃｒ－Ｂ－Ｗ－Ｍｏ－Ｎｂ－Ｖ合金系统的高温抗磨堆焊合金焊条，其堆焊层组织为隐晶马氏体十块状硬质相十颗粒状硬质相，使其具有较高的高温硬度和高温耐磨性。     

铬硼及硬质相形态在高温耐磨堆焊合金中作用

通过高温硬度、高温磨损试验，系统地研究了合金元素铬、硼对Ｃｒ－Ｂ－Ｗ－Ｖ系高温耐磨料磨损等离子弧堆焊合金的红硬性影响规律．硬质相Ｃｒ７Ｃ３条束轴向垂直于磨损面时，堆焊合金的耐磨性最好．     

大型石材切割锯片刀头的金相分析及选用

通过对大型石材切割锯片刀头的使用状况、材料选择、金相组织、性能有寿命的研究分析，认为可以用Cu、Co作为胶结相来改善对碳化钨固溶相的润湿性及合金的烧结性能，同时还可添加少量的Fe、Ni作胶结相进一步改善性能。合金基体上均匀分布的细小碳化钨和合理分布的、颗粒大小约为25μm的金刚砂作为硬质相，可提高硬工及抗磨损能力。这些硬质相与柔韧性的基体结合，会使刀头的强韧性、耐磨性得到进一步提高。     

用正交试验法研究高温冲蚀磨损

介绍了正交试验法在高温冲蚀试验中的应用，通过正交试验法分析得出：对于等离子涂层来说，ＮｉＣｒＡｌ涂层最好，Ｘ４０（０．３）涂层其次；对于激光重熔层来说，４００℃时，Ｃｒ２Ｏ３涂层最好，ＷＴｉＣ２／ＮｉＣｒ涂层其次；７００℃时，Ｃｒ３Ｃ２／ＮｉＣｒ涂层最好，Ｘ４０（０．３）涂层其次。     

电沉积非晶态Ni—P合金的研究

讨论了电沉积的工艺条件（ｐＨ值，Ｈ３ＰＯ３的含量，电流密度）对沉积层组成的影响，热处理对Ｎｉ－Ｐ合金层结构的影响，以及合金层组成和结构与耐蚀性的关系，结果表明，随ｐＨ值的升，Ｈ３ＰＯ３含量的升高，电流密度的降低，沉积层中的Ｐ含量逐渐增大，高含Ｐ量的合金层的在３５０℃左右时，差热曲线上出现一尖锐的放热峰，即合金层开始晶化，析出Ｎｉ３Ｐ相；Ｎｉ－Ｐ合金随含Ｐ量的升高，耐蚀性增强。热处理后的合金层耐蚀性     

Ni—P化学镀层配方影响抗冲蚀性能的研究

研究了在含ＨＣｌ与不含ＨＣｌ的介质中，三种不同配方的Ｎｉ－Ｐ化学镀层的抗冲蚀行为，并与不锈钢１Ｃｒ１８Ｎｉ９Ｔｉ和２Ｃｒ１３作了对比。试验在自制试验机上进行。结果表明，Ｎｉ－Ｐ镀层的冲蚀机理主要表现为片状剥落和微切削。而在含ＨＣｌ介质的冲蚀浆体中其抗冲蚀腐蚀性能要优于无ＨＣｌ介质的浆体中的情况。在Ｃｌ＾－与Ｈ＾＋构成的腐蚀介质中，Ｎｉ－Ｐ化学镀层冲蚀抗力要优于１Ｃｒ１８Ｎｉ９Ｔｉ与２Ｃｒ１３。     

大型石材切割锯片刀头的金相分析及选用

通过对大型石材切割锯片刀头的使用状况、材料选择、金相组织、性能及寿命的研究分析,认为可以用Cu、Co作为胶结相来改善对碳化钨固溶相的润湿性及合金的烧结性能,同时还可添加少量的Fe、Ni作胶结相进一步改善性能.合金基体上均匀分布的细小碳化钨和合理分布的、颗粒大小约为25μm的金刚砂作为硬质相,可提高硬度及抗磨损能力.这些硬质相与柔韧性的基体结合,会使刀头的强韧性、耐磨性得到进一步提高.     

激光熔覆（WC＋SiC）／Ni基复合涂层中合金元素的分布

利用２ＫＷ的ＣＯ２激光器的１６Ｍｎ钢表面激光熔覆（ＷＣ＋ＳｉＣ）／Ｎｉ基复合涂层，经ＳＥＭ及ＥＤＸ能谱分析表明，基体与涂层呈良好的冶金结合。承着凝固过程的进行，γ－Ｎｉ固溶体的形貌由平面晶发展为树枝晶，且γ－Ｎｉ固沉吟体间合金元素的含量及平面晶的厚度均随机扫描的变化而变化。     

Microstructures and properties of WC-20Co-1Y_2O_3 cemented carbide by hot-press and liquid phase sintering

1　INTRODUCTIONInRef .[1],averyinterestingandinexplicablefindingwasreportedthataspecialwhisker likeWCgrainstructure ,mostintherangeof 10 0 2 0 0nmindiameterand 1 2mminlength ,wasformedinWC 2 0Co 1Y2 O3cementedcarbidepreparedbyhot pressbelowtheeutectictemperature .ItwasmentionedinthepaperthatWCpowderwithFisherSubsiereSizer(FSSS)of 1μm ,ultrafineCopowder ,andY2 O3powderof 1μmwereusedastherawmaterialsofWC 8Cocementedcarbide .However ,whetherthesamerawmaterialswereusedinWC 2 0Co …     

Corrosion Behavior of Plasma Transferred Arc Fe-based Coating Reinforced by Spherical Tungsten Carbide in Hydrochloric Acid Solutions

Fe-based coatings reinforced by spherical tungsten carbide were deposited on 304 stainless steel using plasma transferred arc(PTA) technology.The composition and phase microstructure of the coatings were evaluated using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS) and X-ray diffraction(XRD).The corrosion behaviors of the coatings in 0.5 mol/L HCl solution were studied using polarization curve and electrochemical impedance spectroscopy(EIS) measurements.The experimental results shows that the tungsten carbide improves the corrosion resistance of the Fe-based alloy coating,but increase in the mass fraction of tungsten carbide leads to increasing amount of defects of holes and cracks,which results in an adverse effect on the corrosion resistance.The defects are mainly present on the tungsten carbide but also extend to the Fe-based matrix.The tungsten carbide,acting as a cathode,and binding material of Fe-based alloy,acting as an anode,create a galvanic corrosion cell.The binding material is preferentially corroded and causes the degradation of the coating.     

Wear-resistance Performance of Spray-welding Coating by Plasma Weld-surfacing

Alloy powders including Ni60, WC, Cr_3C_2, and TiC with different mass ratios were deposited on medium carbon low alloy steel by plasma welding. Through the experiments, the optimal alloy powder reinforcing cutter tool surface properties were discovered. The wear resistance properties were investigated on the impact abrasive wear tester. The experimental results show that in terms of microstructure, there exists the shape of herringbone, spider mesh, broken flower structures in coatings. In addition, fusion area of four specimens surfacing welding layer displays a large number of acicular martensite with a small amount of austenite. The coating mainly consists of Ni-Cr-Fe austenitic phase and the other precipitates. TiC density is smaller, its content is less in alloy powder, in the process of surfacing welding, TiC is melted fully, which is mainly distributed in surface layer and middle layer of hard facing layer. The content of TiC gradually reduces from surface layer of hard facing layer to the fusion area. Compared to TiC, the density of tungsten carbide and chromium carbide is larger, there exist tungsten carbide and chromium carbide particles, which are not completely melted near the fusion area. The micro-hardness presents gradient change from the fusion area to the surface layer of hard facing layer, and the hardness of the middle layer is slightly lower than that of the fusion area, and the hardness increases near the surface layer.     

稀土元素镧和锶对镍基钎焊料焊接性能的影响

碳化钨(WC)复合涂层是一种高温下使用的有效耐磨蚀保护涂层.在BNi-2钎料粉末中添加稀土粉末,用机械合金化技术制备了改进的BNi-2钎料粉末,并在Q235钢基体上制备了碳化钨复合涂层;采用SEM观察了涂层显微组织,分析了稀土元素La和Ce对钎料焊接性能的影响规律.结果表明,在BNi-2合金中分别加入0.1 Wt.%稀土元素La,0.05 Wt.%稀土元素Ce,并采用机械合金化制备的粉状镍基焊料,与母材润湿性良好,焊接性能有所提高.采用此焊料及渗透钎焊技术可以制备出界面结合良好的WC复合涂层.     

镁合金化学镀Ni-W-P合金

将AZ91D镁合金无铬处理后,以硫酸镍和钨酸钠为主盐,柠檬酸钠和碳酸钠为复合络合剂,在碱性镀液中通过调整镀液组成,得到W含量较高的Ni-W-P合金镀层。此镀层中W及P的质量分数分别为4.50%和4.84%。通过孔隙率和极化曲线测量了此镀层的耐蚀性能,表明该镀层能够很好地提高AZ91D镁合金的耐蚀性。     

Microstructures and properties of WC-2OCo-1Y2O3 cemented carbide by hot-press and liquid phase sintering

Ultrafine tungsten carbide and fine cobalt as well as nano yttrium oxide powders were used as the raw materials. The effects of hot-press below the eutectic temperature and conventional liquid phase sintering on the structures and properties of WC-20Co-1Y2O3 cemented carbide were studied. It is shown that hot-pressed alloy has the character of isotropic properties and microstructure with homogeneous and ultrafine WC grains. However, the ultrafine and fully-densified structure is developed at the cost of the presence of large amount of cobalt-lake (uneven-ly distributed binder phase), and thus lower strength. Yttrium oxide in the alloy cannot play the role of grain growth inhibitor fully when cemented carbide with high content of cobalt and ultrafine raw materials is sintered at high liquid phase sintering temperature. Peculiar platelet-enhanced bi-model structure is formed in WC-20Co-1Y2 O3 cemented carbide by conventional liquid phase sintering, which points out that yttrium oxide in the alloy facilitates the formation of plate-like WC grain.     

钻头齿面堆焊用硬质合金耐磨性试验

为了选择更合适的钻头齿面强化材料,对多种粒度的球状烧结碳化钨和粒状铸造碳化钨堆焊层分别作了磨料磨损试验,以评价其抗磨性能。用 Ｎｉ 基合金作钎料,在高真空度下将硬质合金颗粒焊至２０ Ｎｉ４ Ｍｏ 表面。试验采用多种冲击能量,磨料介质为石英砂、水和少量悬浮剂,用天平称出磨损失重。结果表明：球状烧结碳化钨或不同类型和粒度混合的碳化钨堆焊层都比现行采用的粒状铸造碳化钨具有更好的抗冲击磨料磨损能力。用球状烧结碳化钨代替粒状铸造碳化钨作钢齿钻头齿面堆焊材料是提高齿面强化效果的有效途径。     

PREPARATION OF NANOSTRUCTURED TUNGSTEN POWDERS

The preparation of nanostructured tungstenpowders has been studied by using the characteristics of high-er temperature, higher chemical reactivity and quenchingtechnology of hydrogen plasma,in which WO_3 solid particlesserved as raw materials. The reduction mechanism of WO_3 athigh temperature has been also discussed. The composition,particle size distribution and morphology of nanostructuredtungsten powders have been measured by X-ray diffraction,small angle X-ray scatter and TEM. Tungsten powders ofmean particle size of 40 nanometer,and specific surface areaof 3×10~4m~2/kg have been prepared. The shape of nanostruc-tuted tungsten powders is sphere.     

可调轴流式锅炉引风机动叶片磨损失效分析

通过理化分析和磨损形貌观察，探讨了火焰喷焊动叶片的磨损机理。结果表明，动叶片的磨损主要是低角度冲蚀磨损，碳化钨等金属化合物的磨损机理是疲劳脆断，镍基奥氏体的磨损机理是微切削，提出了从喷焊材料和工艺方面提高耐磨性的措施。     

Purity of SiC powders fabricated by coat-mix

Silicon carbide powders were synthesized by the coat-mix process, with phenolic resin and silicon powders as starting materials.The effects of synthetic conditions, including sintering temperature and the molar ratio of resin-derived carbon to silicon on the composition and the purity of the resultant powders were investigated.The results show that a higher sintering temperature and an appropriate molar ratio of resin-derived carbon to silicon are favorable for producing high purity silicon carbide powders.It is found that the silicon carbide content increases slightly with increasing the sintering temperature during the solid-solid reaction.The temperature gradient plays an important role on this trend.When the sintering temperature is raised up to 1500℃, the formation of silicon carbide is based on the liquid-solid reaction, and high purity (99.8wt%) silicon carbide powders can easily be obtained.It can also be fotmd that the optimum molar ratio of resin-derived carbon to silicon is 1:1.