金刚石柔性磨带对接工艺的研究

文章主要研究了热压压力、温度和保温时间三种因素对金刚石柔性磨带对接接头质量的影响。结果表明：当热压压力为8MPa、上压头和下压头温度为50℃、保温时间为60s时,拉伸实验中对接接头胶带沿正弦波裁切线规整断裂,接头强度达到2420.70N/5cm,经水浸泡处理1小时后,拉伸强度仍有2127.24N/5cm,完全能够满足金刚石柔性磨带重力磨削要求。     

金刚石镀Ti对金刚石锯片性能的影响研究

研制了一套简单易行的镀膜工艺,并将镀膜金刚石应用于胎体配方中制得金刚石锯片,并与相同胎体配方含未镀金刚石的锯片作比较,考察其对锯片性能的影响,并从金刚石和胎体间的界面反应对界面粘结强度的影响及金刚石的损伤程度上对其机理进行了微观分析。     

Ni-P-纳米金刚石化学复合镀研究

采用纳米金刚石分散混合液配制碱性化学复合镀N i-P-纳米金刚石镀液。研究了镀液中纳米金刚石的体积分数、搅拌强度对镀层成分、结合力、形貌、显微组织的影响。结果表明:镀层中金刚石的质量分数最高可达12%~24%,镀速可达11μm/h。镀层与基体的结合力与镀液中金刚石的体积分数关系不大,其结合力符合GB2933-86标准。搅拌强度为200 r/m in时,可获得纳米金刚石含量较高、表面形貌好的镀层。     

化学镀Ni对金刚石性能的影响

采用ＤＴＡ，ＸＲＤ和ＳＥＭ等方法研究了在金刚石表面化学镀Ｎｉ对金刚石性能的影响。结果表明，该镀Ｎ层可提高金刚石强度，最大提高４７％。提高金刚石的氧化温度，最大提高１７０℃。还能提高金刚石的热稳定性。     

ABS塑料电镀中影响结合力的因素

ABS塑料再电镀的过程之中存在诸多的因素对其结合力产生一定的影响,深入研究影响结合力的因素,并针对性的采取控制的策略,能够显著的提升ABS塑料的电镀质量,为该类材料后期的使用奠定良好的基础。本文从ABS塑料自身的物理化学性质角度和电镀工艺的实施角度出发,分析对ABS塑料电镀时结合力造成影响的因素,并以此为基础论述了提升ABS电镀质量的具体策略。     

预处理对钼基片镀钌层结合力的影响

常用的钼基片镀钌前预处理工艺包括碱洗除油、阳极浸蚀、酸洗、活化、预镀冲击镍.讨论了预处理工艺中碱洗工艺方案、阳极浸蚀的电流密度和时间,以及预镀冲击镍的电流波形对钌镀层结合力的影响.在65℃的50 g/L氢氧化钠溶液中以阳极电流密度16 A/dm<'2>处理2 min,在体积分数为200 mL/L的硫酸溶液中以阳极电流密...     

镀液组成对铬-金刚石复合电沉积的影响

以紫铜片为基体,采用电沉积法在三价铬镀液中制备了铬-金刚石复合镀层。在pH=1.0、电流密度12A/dm2、搅拌速率150r/min、温度30°C及施镀时间15min的条件下,研究了镀液中主要组分的质量浓度对铬-金刚石复合镀层厚度和外观的影响,得到较好的镀液配方为:CrCl3·6H2O170g/L,HCOOK60g/L,KCl20g/L,CH3COONa·3H2O20g/L,NH4Cl60g/L,超细金刚石25g/L。采用该配方制备的Cr-金刚石复合镀层表面平整、裂纹细小,金刚石颗粒均匀镶嵌在铬镀层中,显微硬度高达1292.6HV,综合性能优于纯铬镀层。     

电刷镀技术在金属表面防磨耐蚀中的应用研究与探讨

论述电刷镀技术在金属表面耐磨和耐蚀方面的应用研究结果以及一些应用实例。     

CVD金刚石薄膜与硬质合金的结合力的改善途径

化学气相沉积金刚石涂层硬质合金工具综合了金刚石和硬质合金的优异性能,可广泛应用于难加工材料的切削、电子工业等诸多领域.制造金刚石薄膜涂层工具的关键在于增强金刚石膜与硬质合金基体间的结合力.文章综述了增强化学气相沉积金刚石膜与硬质合金基体结合力的多种措施.     

金刚石电镀砂带的特点及应用

金刚石电镀砂带具有超硬材料“硬”和涂附磨具“柔”的双重特性,其工作层表面有序排布磨削小单元之间的缝隙形成了较大的容屑空间,有利于散热,并提高了加工质量、砂带柔韧性及排屑能力,在使用过程中同时具有粉尘少、噪音小的环保优势,因此广泛应用于玻璃、石材、陶瓷、复合材料、水晶、航空航天、硅材料等硬脆材料的磨抛加工.同时,由于镍镀层对磨料有较强的把特力,使电镀砂带拓展于cBN领域成为可能,相对金刚石磨料,cBN砂带可应用于钢铁、铁合金等含铁族元素难加工材料的磨抛.随着国家高效高精加工要求的提高,以及环境保护的迫切需要,金刚石/cBN电镀砂带将有广阔的应用空间和发展前景.     

Effect of WC-Co substrates pre-treatment and microstructure on the adhesive toughness of CVD diamond

Well separated diamond particles were nucleated and grown by hot filament chemical vapor deposition (HFCVD) onto Co-cemented tungsten carbide (WC-Co). Two carbide grades were prepared. The former one was a ISO grade K10 carbide having a 1-μm average WC grain size, 5.8 wt.% Co and 0.2 wt.% VC. The latter one had a 6-μm average WC grain size, with 6 wt.% Co. Prior to deposition the substrates were submitted to two different pretreatments. The adhesive strength of deposited diamond crystallites was quantitatively determined in terms of interface toughness by directly applying an external load to the CVD diamond particles in the scanning electron microscope (SEM). The adhesive toughness was determined from the measurement of the maximum load required to scratch off the diamond crystallites. The variation of adhesive toughness was correlated to both the microstructure and the pretreatments of the substrate.     

Influences of NH3 pre-treatment and radicals on the growth of carbon nanotubes

A triple-layered catalyst (Al/Fe/Mo) undergoes considerable restructuring of surface morphology during NH₃ annealing prior to carbon nanotube (CNT) growth. The diameter (or density) of Al_xO_y–Fe clusters formed during the annealing is found to be dependent on the concentration ratio of NH₃ to H₂O present inside the chamber, which is confirmed by in-situ mass spectroscopy. The different diameter clusters then affect the types of CNTs (i.e. single or multi-walled CNTs) during the growth. Here, a growth model is also presented, where hydrocarbon radicals (C₅H₉, C₆H₉, and C₆H₁₃) generated from C₂H₂ pyrolysis (~ 800 °C) can be used as effective precursors to synthesize CNTs.     

水热预处理对剩余污泥有机物释放的影响

针对剩余污泥中有机能源利用率低的问题,研究了水热预处理对剩余污泥有机物释放及污泥厌氧消化过程中累积产气量的影响。结果表明:水热处理是一种有效的污泥预处理方法,当水热温度为200℃、水热时间为1 h时,污泥减量度达76.56%,污泥SCOD为原泥的34倍,大大减少了污泥固相有机物含量。经水热处理后,污泥厌氧消化最大产气量为2 950 m L,较原泥提高了69%;厌氧消化后,水热预处理污泥SCOD减少量为原泥的30倍。     

Adhesive bonding of CFRP: a comparison of different surface pre-treatment strategies and their effect on the bonding shear strength

A promising joining technology for thermoset CFRP is adhesive bonding. However, the mechanical performance is influenced negatively by contaminants, like release agents, as well as an excess of matrix in the top layer. In order to generate most suitable surface qualities prior to the bonding process, carbon fibre reinforced plastics are treated with different – UV (355 nm) and IR (1064 nm) – lasers. The results are compared to commonly applied grinding surface preparation. The preliminary results on surface properties, e.g. energy and topography point towards high levels of free surface energy, as well as new originated surface structures. After the bonding process mechanical tests are subsequently carried out in Mode II, to characterize the final joint by its tensile shear strength. Finally, the individual fracture behaviour is examined in post mortem analysis. The results indicate that it is possible to increase the tensile shear strength of the joints to a maximum, which equals the interlaminar shear strength of the CFRP-laminate. Therefore, ultrashort pulsed IR-laser techniques show the best reproducibility and the highest tensile shear strength. In addition, IR-laser treatment is expected to have the highest potential for later applications.     

金刚石生长的驱动力

籽晶方法生长金刚石采用温度梯度技术,金刚石晶体生长驱动力来源于腔体内构造的温度梯度。工业上采用自发成核生长金刚石技术,金刚石生长的驱动力来源于金刚石晶体与石墨温度差。     

底涂剂对聚氨酯密封剂粘接性能的影响

以异氰酸酯(TDI)和聚醚多元醇(如N-220、N-330和EP-330N等)为主要原料,合成了高性能双组分PU(聚氨酯)密封剂。采用不同底涂剂对水泥基材进行表面涂敷,以增强PU密封剂/水泥基材胶接件的粘接性能。结果表明:当D1[环氧树脂(EP)类底涂剂]作为PU密封剂/水泥基材胶接用底涂剂时,其粘接效果低于D2(PU类底涂剂);用硅烷偶联剂改性D1,可有效增强EP/PU间的界面结合力,提高PU密封剂/水泥基材胶接件的耐水性和耐热性;在D3(由EP、KH-550硅烷偶联剂和二乙烯三胺组成)未干时浇铸PU密封剂,则PU密封剂/水泥基材胶接件的性能满足JC/T 976—2005标准要求。     

Wafer bonding of highly oriented diamond to silicon

Polished, highly oriented diamond (HOD) with an RMS roughness of less than 3 nm was bonded to single-side polished silicon wafers in ultra-high vacuum (UHV) at 32 MPa of applied uniaxial pressure. Successful fusion of HOD to silicon was achieved at temperatures above 850 °C. Fusion resulted in the formation of an abrupt interface between the wafers in the areas away from diamond grain boundaries. Voids, partially filled with amorphous material, were observed at the fused interface near the diamond grain boundaries. Preferential diamond polishing, potential out-diffusion of hydrogen from diamond and oxygen from silicon are believed to have contributed to the observed non-uniformity of the bonded interface.     

固化体系对脲醛树脂粘接强度的影响

UF(脲醛树脂)胶粘剂在木材工业中应用广泛,但其在生产和使用过程中会持续释放出危害环境和人体健康的游离甲醛。采用降低n(甲醛)/n(尿素)比例和使用传统固化剂氯化铵时,虽可降低UF胶粘剂的游离甲醛含量,但其固化速率较小、粘接强度较低。以过硫酸铵、多官能团物质(G)、甲酸、氯化铵及其不同复合物等分别作为UF的固化剂,采用单因素试验法优选出制备改性UF胶粘剂的最佳工艺条件。研究结果表明:当p H=5.5、w(氯化铵)=3%和w(G)=0.6%(均相对于UF质量而言)时,改性UF胶粘剂的粘接强度(为1.95 MPa)相对最大、适用期(为8 h)相对较长且游离甲醛含量相对较低。