共查询到18条相似文献,搜索用时 828 毫秒
1.
2.
将表面不同镀覆(未镀、镀Ni和镀Ti)金刚石加入到铁基结合剂中进行热压烧结得到铁基结合剂金刚石节块,测试了节块的硬度和抗弯强度,用扫描电子显微镜对节块断口的微观形貌进行观测,用能谱仪对金刚石表面和金刚石脱落坑的成分进行了分析。结果表明,与表面未镀金刚石相比,加入镀Ni和镀Ti的金刚石,对节块的硬度影响不大,洛氏硬度(HRB)分别为109.4、112.4和112.3;但能使节块的抗弯强度有一定的提高,其值分别为641、658和695 MPa。SEM和EDS分析表明,镀覆金刚石表面镀层能使金刚石与铁基结合剂的结合更紧密,更牢固。 相似文献
3.
《超硬材料工程》2020,(3)
探究了金刚石镀覆工艺及镀覆金刚石热处理对提高金刚石在胎体中把持力的作用。结果表明:850°C真空镀铬的金刚石镀层中能检测到存在Cr_7C_3相,而化学镀铬的金刚石需经高温真空热处理后才能检测到Cr_7C_3,真空镀钛的金刚石热处理前后均没有检测到碳化物相。镀钛金刚石镀层改善了金刚石与金属胎体的浸润性,提高了金刚石的机械把持力,制备的组合绳锯切割寿命由3.44 m~2/m提高到了3.79 m~2/m。镀铬金刚石镀层改善浸润性提高机械包镶与Cr_7C_3相产生的化学结合力共同作用,提高了金刚石把持力;使用热处理真空镀铬金刚石的组合绳锯测试寿命提高到了3.95 m~2/m,而化学镀铬金刚石由于镀层过厚,在烧结中金刚石与镀层热膨胀差异导致结合层破裂,把持力减弱,组合绳锯寿命仅为3.50 m~2/m。 相似文献
4.
5.
6.
7.
8.
9.
10.
11.
12.
《Journal of the European Ceramic Society》2021,41(15):7525-7532
Porous SiC is a valuable membrane material for the microfiltration and ultrafiltration of various wastewaters because of its high hydrophilicity and low fouling tendency, but its preparation has been limited by the high sintering temperature. Here, a silica bonded silicon carbide membrane was prepared by the oxidation of SiC at low temperature. When the SiC substrates were sintered in the temperature range from 1200 to 1400℃, their porosity decreased from 45 % to 37 % while the flexural strength increased from 45 to 59 MPa. For the selective layers made from SiC particles with 0.5 μm in diameter, the average pore sizes that sintered at 1050 and 1150 ℃ were 0.34 and 0.26 μm, respectively, corresponding to the water fluxes of 1080 and 1240 L/(m2 h, respectively. Thus, this technique provided a cost-effective path to prepare ceramic membrane at low sintering temperature. 相似文献
13.
以Na2O-B2O3-Al2O3-SiO2系低温玻璃为基础结合剂烧制金刚石增强陶瓷基复合材料,利用扫描电子显微镜、X射线能谱、X射线光电子能谱、拉曼光谱及力学性能测试仪等对其界面结合强度、界面处元素分布及界面化学键进行了表征。结果表明,Na2O-B2O3-Al2O3-SiO2系陶瓷结合剂与金刚石颗粒界面结合强度高,790 ℃煅烧时试样抗折强度达到77.82 MPa。Si、B、Na、Zn各元素在界面位置发生扩散,而Al元素没有明显扩散,元素扩散提升了结合剂对金刚石的把持力。陶瓷结合剂与金刚石在界面处形成C-O、C=O和C-B键,化学成键进一步增进界面结合。另外,790 ℃煅烧的复合材料中金刚石颗粒保存完好,而850 ℃煅烧时金刚石出现石墨化迹象。 相似文献
14.
15.
耐高温电阻材料由于可调的表面阻抗使其兼具同向反射、损耗特性和宽频带等优异性能。本文通过刷涂法制备了含频率选择表面的耐高温吸波涂层,通过扫描电子显微镜和方阻测试仪表征分析了涂层的组分、微观结构和方阻的高温稳定性,通过矢量网络分析仪研究了涂层煅烧温度和煅烧时间对材料高温反射率的影响规律。结果表明,含频率选择表面耐高温陶瓷涂层经600 ℃长时间热处理后,表面形貌变化可控,表面方阻较为稳定,耐温性好。频率选择表面设计对制备耐高温宽频吸波涂层具有重要的指导意义。 相似文献
16.
为了提高陶瓷结合剂金刚石砂轮的性能,采用微波烧结技术,通过一系列试验,分析了陶瓷结合剂金刚石砂轮的微波烧结温度、陶瓷结合剂含量和金刚石磨料粒度对其性能的影响。结果表明:微波烧结温度是影响陶瓷结合剂金刚石砂轮性能的最主要因素,远超其余二者;陶瓷结合剂金刚石砂轮试样的洛氏硬度和抗弯强度在740 ℃时达到极大值且气孔率较小,此时洛氏硬度为66 HRB,抗弯强度为76.5 MPa,气孔率为17.8%;由微观组织观察可知陶瓷结合剂金刚石砂轮在740 ℃时可以实现陶瓷结合剂对金刚石磨料的均匀包裹,并且气孔较少。 相似文献
17.
《Ceramics International》2017,43(16):13133-13139
Electroless-plating and electro-plating have been used to deposit Cu-Ni-Au coating on diamond/Cu composites. Before electroless copper plating, pretreatment should be applied to the surface of composites by means of boiled HNO3 etching, sensitization with SnCl2 and activation with PdCl2. The influence of pre-treatment on the electroless copper plating and electroplating Ni/Au is studied in this paper. Scanning electronic microscope, energy dispersive spectroscopy and optical microscope are used to examine microstructure and morphologies of coatings. Results indicated that the uniform and tight bonded Cu/Ni/Au coating have been successfully deposited on the diamond/Cu composites. Meanwhile, high temperature baking, solder wetting and the polarization curve tests are used to evaluate the adhesion strength, solderability and corrosion resistance of Cu/Ni/Au coatings in detail. Investigated results indicated that diamond/Cu covered with Cu-Ni-Au coatings exhibited excellent solderability and mechanical properties. 相似文献
18.
通过分析磷石膏蒸压后样品的物相组成、相对结晶度、烘干抗压强度、微观形貌,研究了蒸压温度、保温时间、液固比、杂质等因素对磷石膏蒸压制备α-半水石膏的影响。结果表明:磷石膏蒸压后所得样品的烘干抗压强度与α-半水石膏晶体的相对结晶度呈正相关关系;在蒸压温度为130 ℃、保温时间为3~5 h、液固质量比为0.25条件下,所得α-半水石膏的相对结晶度高、烘干抗压强度大、晶体微观形貌完整且长径比小;磷石膏中的杂质会对蒸压样品的力学强度产生影响,将磷石膏水洗处理后,在蒸压温度为130 ℃、保温时间为3 h、液固质量比为0.25条件下,可制得2 h抗折强度为7.3 MPa、烘干抗压强度为32.8 MPa的α-半水石膏,该α-半水石膏符合JC/T 2038—2010《α型高强石膏》α30强度等级的要求。 相似文献