Oxidation of boron silicide and materials based on it

Boron silicide and compounds based on it containing titanium, chromium, nickel, and yttrium and scandium oxides are studied for their oxidation in air from room temperature to 1300°C. It is shown that chromium boride markedly improves the heat resistance of B₄Si over a wide temperature range (700–1300°C) probably as a result chromium-oxide dissolution in borosilicate glass and alteration of its structure. A favorable effect of yttrium and scandium oxides as well of nickel silicide appears at above 100°C as a result of forming complex oxide compounds in the scale.     

硼和铬对多晶Fe83Ga17合金磁致伸缩和室温力学性能的影响

研究了添加B和Cr对多晶Fe₈₃Ga₁₇合金磁致伸缩和拉伸力学性能的影响.结果表明:在Fe₈₃Ga₁₇合金中添加原子分数1%的B,不仅提高了合金的磁致伸缩性能,而且还大幅提高了合金的室温力学性能,抗拉强度达到548MPa,延伸率达到3.56%.B元素以Fe₂B相的形式偏聚在晶界,细化了合金晶粒,增加了合金晶界结合力,抑制了沿晶脆断.添加原子分数2%的Cr,Cr固溶在Fe₈₃Ga₁₇合金中,同时提高了合金的磁致伸缩性能和室温力学性能,(Fe₈₃Ga₁₇)₉₈Cr₂合金最大磁致伸缩系数达到7×10^-5,延伸率也较Fe₈₃Ga₁₇合金有所增加,达到0.6%.     

高铬铸铁抗磨、耐热、耐蚀性能的研究

分析了高铬铸铁具有的抗磨、耐热、耐蚀性机理。通过对化学成分(碳、铬、和锰、钼、铜等合金元素及稀土元素)的含量在此3类铸铁中的影响研究,提出了相关设计参数。     

Adsorption-chemical activity of finely-dispersed amorphous powders of brown and black boron used in synthesizing metal borides

Kinetic features of adsorption-desorption processes for a nitrogen and oxygen mixture of gases, nitrogen and water vapor at the surface of finely-dispersed amorphous powders of brown and black boron used to synthesize metal borides are studied. The different adsorption-chemical activity of amorphous brown and black boron powders towards the main components of an air atmosphere is determined. It is shown that the original boron, apart from hard impurity compounds, may carry at the surface gaseous constituents with a capacity to change the physicochemical parameters of the system in the reaction zone, and to affect the phase composition and quality of the product obtained. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(449), pp. 79–84, May–June, 2006.     

粒径对超细空心镍球光吸收性能的影响

用自催化还原法制备不同粒径的超细窄心镍球,用场发射扫描电镜和透射电镜观察空心镍球的形貌,并通过粒度分析仪和X-Ray衍射仪等对其粒径对光吸收性能的影响进行研究.结果表明,在紫外一近红外区,随着粒径减小,镍球的光吸收性能明显增强;纳米尺寸的镍球在紫外光区的吸收特性与大粒径镍球明显不同,前者在375 am处产生一个吸收峰;而在中红外区域,空心镍球具有很弱的光吸收能力.经过氧气气氛下热处理后,空心镍球的晶粒尺寸变大,其在紫外一近红外区域的光吸收减弱,纳米级的空心镍球,原来在375 nm的吸收峰移到了440 nm,这可能是由于晶粒尺寸增大所致.     

硼和钛对低碳铝镇静钢组织和性能的影响

 研究了低碳铝镇静钢08Al中单独添加硼、钛和同时添加硼、钛对其组织和力学性能的影响,结果显示,在相同控轧控冷工艺条件下,单独添加微量硼对盘条的屈服强度和抗拉强度影响不大,单独添加质量分数0.057%的钛可使盘条屈服强度和抗拉强度升高约20 MPa,同时添加质量分数为0.004 8%的硼和质量分数为0.07%的钛可使盘条屈服强度和抗拉强度显著提高,试验中,屈服强度由260升高到316 MPa,提高了56 MPa,抗拉强度由363升高到463 MPa,提高了100 MPa。同时添加硼和钛使强度提高的原因主要是由于获得了具有高位错密度的不规则的准多边形铁素体,同时细片层珠光体相变强化对该钢强度的升高也有一定贡献。     

碳化硼陶瓷力学性能及其影响因素

碳化硼的力学性能与其他陶瓷材料一样,对结构十分敏感.在工艺控制过程上看,不可能制得结构完全相同的材料,文献报道的计算式和数据亦非常分散.作者测定了用热压方法制得的碳化硼陶瓷(表现密度为2.1～2.3g/cm~3,晶粒度为12μm)的抗弯强度、抗压强度、弹性(弯曲)模量和泊松比.同时,通过文献检索,搜集了各种公式和数据,并对本实验结果进行了综合分析,得出了有关的计算式和性能值.     

Structure and high-temperature strength of composite materials based on boron nitride

The structure and physicomechanical properties of composite materials based on boron nitride within which new phases (mullite and sialon) form during hot compaction are studied. It is established that the microstructure of composites is specified by their texture formation caused by the crystal morphology of boron nitride particles and it is almost independent of composite phase composition. It is shown that the main factor that affects strength is porosity. The dependence of strength on porosity is exponential in character. The strength of boron nitride-mullite and boron nitride-sialon composites is 110–140 MPa and at 20–1200°C it is almost unchanged. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(449), pp. 33–39, May–June, 2006.     

Compaction, structure formation, and properties of materials based on boron carbide

The effect of adding aluminum and titanium on the compactibility kinetics, structure, and properties of materials in the systems B₄C-Al and B₄C-(Ti-Al) is studied. The micromechanical properties (microhardness, microbrittleness, microstrength, and crack resistance factor (K_1c) of composite materials are determined. The influence of high pressure on the compactibility, structure, and properties of B₄C-based materials with additions of titanium and aluminum is investigated.     

硼对低碳铝镇静钢酸洗钢板性能的影响

在宝钢工业生产中,通过对薄规格酸洗低碳铝镇静钢中添加（10～30）×10-4%硼合金的研究,分析了硼对钢力学性能、金相组织及表面质量的影响。结果表明,钢中添加（10～30）×10-4%的硼合金可使钢的屈服强度降低20 MPa,延伸率提高1.5%,屈强比降低5.7%;回归出屈服强度和延伸率与终轧温度、C含量、Mn含量、B含量的关系。添加适当硼合金有利于生产高表面质量低碳铝镇静钢酸洗板。     

低碳微合金化含硼冷镦钢的力学性能研究

实验室试制了低碳Nb、V微合金化含硼冷镦钢,并对试验钢的组织和性能进行了对比研究.结果表明:钢中添加适当的Nb、V细化了含硼钢的铁素体晶粒,显著提高了含硼钢的抗拉强度,其中,Nb、V复合微合金化含硼钢的效果最好,其次是含钒硼钢和含铌硼钢.分析表明,Nb、V复合微合金化在含硼钢中的主要作用在于细化晶粒和沉淀强化.     

立方氮化硼超硬刀具材料的合成与性能研究

以CBN微粉、WC粉和Co粉为原料,在六面顶压机上合成PCBN复合片。研究了立方氮化硼超硬刀具材料（PCBN复合片）的合成规律,对PCBN复合片的微观结构和性能进行了分析。研究发现,当烧结温度为1 750℃时,WC/Co结合剂对CBN颗粒的结合力增强,此时样品的磨耗比最大,为7 750。将1 750℃烧结出的PCBN复合片做成刀具,连续切削球墨铸铁,切削里程为20 km时,PCBN刀具后刀面磨损量（VB）最小,为0.272 mm。随着温度升高,样品中的颜色偏差越来越少,厚度分布越来越均匀,平整度逐渐变好,说明提高烧结温度有助于提高复合片中CBN聚晶层的平整度。     

低温燃烧法合成纳米二氧化钛粉体研究

采用一种简便、快速、低温的溶胶凝胶自蔓延燃烧法制备了纳米TiO₂粉体颗粒.从柠檬酸络合反应的机理阐释了纳米TiO₂粒子的形成过程.通过热综合分析、X射线衍射和透射电镜分析探讨了金属离子与柠檬酸的摩尔比和溶液杂质离子的存在对TiO₂粉体颗粒物相组成及粉末晶粒尺寸大小的影响.本实验制备了粒径为40~90 nm分散性较好的球形状TiO₂纳米颗粒.X射线衍射结果表明,当摩尔比为0.5时,自燃合成产物中金红石相的质量分数达到91%.     

Microstructure and optical absorption properties of Au/NiO thin films

Au nanoparticles dispersed NiO composite films were prepared by a chemical solution method.The phase structure,microstruclure,surface chemical state,and optical absorption properties of the films were characterized by X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,and Uv-vis spectrometer.The results indicate that Au particles with the average diameters of 35-42 nm are approximately spherical and disperse in the NiO matrix.The optical absorption peaks due to the surface plasmon resonance of Au particles shift to the shorter wavelength and intensify with the increase of Au content.The bandwidth narrows when the Au content increases from 8.4wt% to 45.2wt%,but widens by further increasing the Au content from 45.2wt% to 60.5wtolo.The band gap E_g increases with the increase of Au contents from 8.4wt% to 45.2wt%,but decreases by further increasing the Au content.     

石墨粒度对Cu-Fe基摩擦材料性能的影响

研究了石墨粒度对Cu-Fe基摩擦材料性能的影响,发现随着石墨粒度的细化,材料的硬度升高,强度降低,材料及对偶的磨损增大,对材料的摩擦因数也有所影响。     

碳包覆CdS纳米颗粒的光学性能研究

采用水热法制备了核壳结构的碳包覆CdS纳米颗粒(CdS@C),利用X射线衍射、高分辨透射电子显微镜和光谱仪研究了碳包覆层对CdS@C的微观结构与光学性能影响.结果表明,碳包覆CdS纳米颗粒具有明显的核壳结构,内核为六方纤锌矿结构CdS,外壳为碳层.颗粒形貌主要为球形或椭球形结构,粒度均匀,分散性良好,粒径分布在20～6...     

钨粉粒度对电极用钨铜合金组织和性能的影响

钨粉粒度是影响钨铜合金组织和性能的主要因素之一,采用不同粒度(2.65 μm、4 μm、8 μm)的钨粉用熔渗法制备钨铜合金,通过性能检测和组织分析研究了钨粉粒度对该合金密度、硬度和电导率的影响.实验结果表明:钨粉粒度越细,钨铜合金的密度和硬度越大;但是由细钨粉制备的W-Cu合金闭孔较多,均匀性较差,电导率较小.钨粉粒度为4μm时所得产品综合性能最好,W-30Cu合金密度为14.44 g/cm3、硬度为HB 212、电导率为24.2 MS/m.W-20Cu合金密度为15.38 g/cm3,硬度为HB225,电导率为22.6 MS/m.     

腐蚀条件对氧化铝纳米线制备的影响

采用阳极氧化法制备多孔阳极氧化铝(AAO)模板,研究磷酸溶液中氧化铝纳米线的化学刻蚀合成.分析磷酸溶液的浓度和反应温度对氧化铝陶瓷纳米线生长的影响,探讨化学腐蚀法制备氧化铝陶瓷纳米线的反应温度区间和溶液的浓度范围.实验结果表明,腐蚀溶液的反应温度愈高或腐蚀溶液浓度愈高,纳米线出现时间愈早,生长速率愈快,最终纳米线长度愈长.氧化铝纳米线的制备与腐蚀溶液的浓度和反应温度密切相关.在浓度为4%-10%的磷酸溶液和35-60℃的温度范围内都形成氧化铝陶瓷纳米线.     

热等静压法制备大尺寸铝基碳化硼复合材料及性能研究

采用热等静压法制备铝基碳化硼复合材料(Al-B4C)板材,测试板材的密度和抗拉强度,并观察复合材料的微观组织和拉伸断口形貌。结果表明,Al-31%B4C(质量分数)板材的尺寸为3 mm×200 mm×5000 mm;Al-31%B4C复合材料的相对密度大于99.69%,抗拉强度大于300 MPa,断后延伸率大于3%,B4C颗粒均匀分布在基体中,并与基体紧密结合;Al-B4C复合材料板材的力学性能符合工程用中子吸收材料的要求。比较含不同质量分数B4C颗粒(10%、15%、20%、25%、30%、31%、35%、40%)的Al-B4C复合材料性能,当B4C质量分数为10%~40%时,随基体中B4C颗粒含量的增加,Al-B4C复合材料的密度和相对密度均逐渐降低;当B4C质量分数为10%~35%时,随基体中B4C颗粒含量的增加,Al-B4C复合材料的抗拉强度逐渐增大,断后延伸率逐渐降低。     

Synthesis and physicomechanical properties of B4C-VB2 composites

We have studied the properties of composites in the B₄C-VB₂-C system, obtained by reaction synthesis with hot pressing. We have established that the presence of free carbon and vanadium boride in the ceramic makes it possible to activate the sintering process and to obtain a dense, highly dispersed ceramic with good structural homogeneity parameters for lower isothermal holding temperatures. The composite ceramic has higher hardness and bending strength over a broad range of vanadium boride content than the monophase ceramic based on boron carbide. The strength properties of the composite ceramic containing up to 8 vol.% vanadium boride are improved by means of a mechanism involving propagating cracks bending around obstacles. When the VB₂ concentration increases further, the properties of the composite are determined by a microcracking mechanism. In this case, we observe relatively small changes in the elastic characteristics, which depend linearly on the composition of the ceramic. Introducing vanadium boride into the material is also accompanied by an increase in the contact and microstructural strengths. The results obtained indicate that the new composite material is promising for fabricating wear-resistant and shock-resistant components of various structures and machines. __________ Translated from Poroshkovaya Metallurgiya, Nos. 1–2(447), pp. 59–72, January–February, 2006.