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41.
42.
真空渗硼预处理在CVD金刚石-硬质合金涂层工具中的应用 总被引:4,自引:0,他引:4
采用固体粉末真空渗硼工艺,研究了硬质合金工具表面真空渗硼预处理对金刚石涂层附着力的影响,研究结果表明,硬质合金工具通过固定粉末真空渗硼处理,表面生成具有较高稳定性的以CoWB、CoB为主的渗层,经过长时间的金刚石涂层后,硬质合金工具表面出现Co3B和W2Co21B6相,没有单质Co相出现,克服了金刚石沉积中硬质合金表面钴的不利影响,使标志金刚石涂层附着力的压痕测试的临界载荷达到了1500N,并且有着较好的重现性。 相似文献
43.
论述了用CVD和PVD方法制备硬涂层的若干进展,包括MT-CVD,PACVD,HVS及IBAD等,并介绍了超硬涂层发展的简况。 相似文献
44.
热铁盘法抛光CVD金刚石需要在800℃以上的真空环境下进行,抛光过程中金刚石的固定,常采用陶瓷胶粘结的方法,该法在实际使过程中经常出现陶瓷胶粘结不牢而导致金刚石脱落.据此设计出一套高温真空环境下使用的金刚石夹具,在抛光厚度0.7 mm的金刚石时,将其装夹在0.4 mm深的凹槽内,留出0.3 mm左右的高度以供抛光.加载方式可以实现加热过程中无载荷,抛光过程中施加载荷.实验表明,该夹具在抛光过程中,可以实现金刚石的完全固定,并能在273 mm/s的抛光速度条件下稳定工作.在温度800℃,速度273 mm/s,载荷2.54 kg,抛光30 min的条件下,金刚石表面粗糙度可由原始的Ra9.6 μm抛光至Ra0.16 μm. 相似文献
45.
WC基硬质合金CVD涂层的组织与性能 总被引:8,自引:2,他引:8
利用X射线衍射研究了CP3型硬质合金涂覆 5层 (TiC TiNC TiC TiCN TiN)硬质层的组织 ,用扫描电镜观察了涂层的断口形貌 ,用划痕法测定了涂层与基体的结合力 ,用三点弯曲方法测定了涂覆前后硬质合金的抗弯强度 ,并用Weibull统计方法对其进行了分析。结果表明 :涂层组织由TiC ,TiC0 .2 N0 .8和TiN组成 ,涂层中无发达的柱状晶 ,涂层与基体结合良好 ,涂覆后硬质合金的抗弯强度有所下降 ,但分散性却减小 相似文献
46.
用化学气相沉积(CVD)法在硬质合金模具上沉积TiC-Ti(CN)-TiN耐磨涂层,经工业试验表明,涂层具有硬度高,摩擦系数小,与基体结合良好,化学稳定性好和耐磨损等优良性能。有复合耐磨涂层模具比无复合涂层模具使用寿命高1 ̄10多倍。 相似文献
47.
Diamond deposition on a series of ferrous alloy substrates has been examined in a microwave plasma enhanced chemical vapor deposition reactor. The results show that the nucleation, growth, and adhesion properties of the diamond are strongly dependent on the types and relative concentrations of the alloy elements in the substrates. Along with high nucleation densities, continuous and adherent diamond films have been successfully fabricated on the Al-modified alloy substrates, even in the absence of inter-layers or nucleation enhancing surface pre-treatment. The mechanism is preliminarily clarified regarding the delicate competition and balance between the base metal and the alloying elements in terms of their activation and deactivation ability on catalyzing graphite formation during deposition process. 相似文献
48.
Hussein Yassine Chad R. Borges Matthew R. Schaab Dean Billheimer Craig Stump Peter Reaven Serrine S. Lau Randall Nelson 《Proteomics. Clinical applications》2013,7(7-8):528-540
Type 2 diabetes mellitus (T2DM) is an important risk factor for cardiovascular disease (CVD)—the leading cause of death in the United States. Yet not all subjects with T2DM are at equal risk for CVD complications; the challenge lies in identifying those at greatest risk. Therapies directed toward treating conventional risk factors have failed to significantly reduce this residual risk in T2DM patients. Thus newer targets and markers are needed for the development and testing of novel therapies. Herein we review two complementary MS-based approaches—mass spectrometric immunoassay (MSIA) and MS/MS as MRM—for the analysis of plasma proteins and PTMs of relevance to T2DM and CVD. Together, these complementary approaches allow for high-throughput monitoring of many PTMs and the absolute quantification of proteins near the low picomolar range. In this review article, we discuss the clinical relevance of the high density lipoprotein (HDL) proteome and Apolipoprotein A-I PTMs to T2DM and CVD as well as provide illustrative MSIA and MRM data on HDL proteins from T2DM patients to provide examples of how these MS approaches can be applied to gain new insight regarding cardiovascular risk factors. Also discussed are the reproducibility, interpretation, and limitations of each technique with an emphasis on their capacities to facilitate the translation of new biomarkers into clinical practice. 相似文献
49.
Hua Yu Zhengzhong Yang Luojun Du Jing Zhang Jinan Shi Wei Chen Peng Chen Mengzhou Liao Jing Zhao Jianling Meng Guole Wang Jianqi Zhu Rong Yang Dongxia Shi Lin Gu Guangyu Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
Control of the precise lattice alignment of monolayer molybdenum disulfide (MoS2) on hexagonal boron nitride (h‐BN) is important for both fundamental and applied studies of this heterostructure but remains elusive. The growth of precisely aligned MoS2 domains on the basal plane of h‐BN by a low‐pressure chemical vapor deposition technique is reported. Only relative rotation angles of 0° or 60° between MoS2 and h‐BN basal plane are present. Domains with same orientation stitch and form single‐crystal, domains with different orientations stitch and from mirror grain boundaries. In this way, the grain boundary is minimized and a continuous film stitched by these two types of domains with only mirror grain boundaries is obtained. This growth strategy is also applicable to other 2D materials growth. 相似文献
50.
We demonstrate a new approach to tune the electrical properties of graphene and functionalized graphene. Graphene was synthesized using thermal chemical vapour deposition(TCVD) method on copper foil using precursor gas acetylene and co-catalyst H2 gas. TCVD assisted graphene was successfully transferred onto a silicon wafer. Transferred graphene sheet was then functionalized to prepare graphene oxide(GO) and reduced graphene oxide(rGO). Different surface charge carbon nanoparticles, e.g. carbon nanoparticle with net positive charge and carbon nanoparticle with net negative charge were then immobilized on transferred graphene and functionalized graphene sheets. The functionalized graphene and charge mobilized functionalized graphene were characterized by Uv–vis spectroscopy,Fourier transformed infrared spectroscopy, scanning electron microscopy, and Raman spectroscopy. After immobilization of carbon nanomaterials, the ac electrical conductivity was found to increase due to enhancement of the surface charge, electron density, and mobility. It was observed that negative surface charge immobilized graphene and functionalized graphene show higher conductivity. Thus, the electrical property of graphene and functionalized graphene can be tuned by surface modification with different surface charge carbon nanomaterials. 相似文献