用低品位硼矿石炼制的硼铸铁缸套材料性能

<正> 1 概述近年来的实践证明,硼铸铁是一种优良的减磨铸铁,同高磷铸铁相比其耐磨性可提高50％。一般来说,在冲天炉生产条件下大多从后炉加入硼铁合金来熔炼硼铸铁。硼铁合金具有密度大、吸收率高且稳定、加入工艺简单等优点,但这种加硼剂价格昂贵将使硼铸铁生产成本大幅度上升,为此需寻求实用价廉的加硼剂材料来降低硼铸铁生产成本,显然,硼矿石是硼铁合金的优良代用加硼剂,它具有实际经济效益。     

气缸套加硼的分析与应用

硼合金铸铁气缸套具有高的耐磨性,比高磷铸铁气缸套耐磨性提高30%～50%.因此目前绝大多数缸套厂家生产的气缸套,材质以硼合金铸铁为主.而加硼材料过去主要是硼铁合金,但由于资源短缺,价格上涨,大部分厂家纷纷采用价格低廉的硼矿石,但由于受B_2O_3含量和其它矿物组成的影响,以及各种气缸套不同硼量的工艺要求,使它在使用中受到限制,下面就本厂在各种加硼材料的开发、利用方面做一分析.     

硼铸铁气缸套加硼新工艺探讨

硼铸铁作为一种性能优良的耐磨材料,已被广泛地用于制造内燃机、机床等各种耐磨件。目前,硼铸铁的熔制多半采用炉内投入B—Fe合金的加硼工艺。由于B-Fe合金价格较贵,供应日趋困难,因此,生产硼铸铁铸件的厂家都在积极地探讨硼铸铁加硼工艺的新途径。我厂作为用B—Fe合金加硼工艺生产硼铸铁气缸套的厂家之一,也在不断地寻求新的加硼材料。 近年来,有关单位利用天然硼矿石熔制硼铸铁取得成功。虽然这种方法可以大幅度地降低铸件成本,但是,由于硼矿石是生产硼酸,硼砂等硼制品的主要原料,而且,这种硼矿石在开采、运输等方面还存在一些问题,故使硼石在铸造上的推广应用受到限制。 最近,国内市场出现了一种新材料──含硼生铁。来源丰富,价格较便宜。是制造硼铸铁的理想材料。为此,我们进行了应用试验。     

硼扩散设备若干难点问题的研究

随着针对n型太阳电池的投资提速，国内光伏企业积极开展TOPCon太阳电池布局，产业化进程得到加速，推进新技术落地。硼扩散设备作为TOPCon太阳电池技术的关键工艺设备之一，获得了市场极大的关注。针对硼扩散设备使用过程中遇到的不同类型硼源的问题，通过分析各种硼源的特性，提出了相应的硼源处理方案，并验证了硼源控制效果；针对副产物硼硅玻璃(BSG)粘连的问题，通过分析副产物的特点和危害，提出了斜率升降温功能；针对高能耗的问题，通过分析能耗的主要来源，提出了设备加热功率输出比功能。研究结果表明：所提出的这些方法能有效解决这几个难点问题，有助于提高硼扩散设备的稳定性。     

硼水浓度的测量及硼表的标定方法

以大亚湾核电站引进的硼表为例，介绍了硼表的测量原理，分析了测量中的影响因素，提出了硼表的实用标定方法，对有关工程人员在消化，吸收此项技术过程中将起到推进作用。     

降低渗硼消耗的有效途径——渗剂回收利用

本文介绍了不同添加剂对回收固体粉末渗硼剂渗硼效果的影响试验，结果表明在回收渗硼剂中加入适量不同添加剂，其渗硼效果可接近或超过原配渗硼剂的渗硼效果，而渗硼剂的成本却可大幅度降低，从而有效地降低了渗硼工艺的消耗。     

硼系耐磨铸铁的发展及应用

本文介绍了硼耐磨铸铁国内外概况，叙述了我国硼耐磨铸铁的生产现状及应用，由于含硼生铁－新加硼剂的问世，大大地降低了硼耐磨铸铁的生产成本，提高了经济效益，为硼耐靡无故的发展开拓了新途径。     

含硼再生铁在气缸套铸造中的应用

1 研制含硼再生铁的必要性 硼铸铁引进及在气缸套产品上的应用已用二十多年历史,由于其各项技术标准均已标定,国内在中小型内燃机气缸套上的产量已近2000万支,发展非常迅速和成功。 硼铸铁气缸套在国外其含量大体上可分为两档,一档为超硼铸铁(其含硼量大于0.08％),另一档为普通硼铸铁(其含硼量为0.035％～0.08％),目前国内应用最多的为后者。硼元素的加入经历了由硼砂、硼铁合金,发展至今多为应用含硼的矿石加入的方法。硼砂由于需经脱水处理后在铁水包中加入,其吸收率很不稳定,较难保证其成分要求,人们只是在试验过程中采用此方法,在投入批量试制中,则均以硼铁合金配入(硼铁合金硼量为24％)。但由于硼铁合金为生产硼钢用的铁合金,国内产量有限,而且由于电炉熔剂价格非常昂贵,各厂在开始生产后,均由含硼的矿石代替了硼铁合金。开始阶段各厂均用含硼量较高的青海产的柱硼镁石(B_2O_3含量达42.46％),但由于开采困难无法保障供应,进而改用湖南来阳产硼矿石(B_2O_3含量达11％),其氧化硼含量虽然较低且不均匀但仍能应用。进入九十年代需求量过猛,供求有难,这为各缸套生产厂带来了更大困难。作为货源的补充,一种含氧化镁接近40％。硼镁矿石开始应用,但含硼量低,且不均匀,B_2O_3含量在5％～17％间波动,用     

硼缸套铸造缺陷的产生和防止措施

1 硼铸铁气缸套铸造缺陷的产生当前国内中小型缸套普遍采用金属型厚涂料离心铸造工艺进行生产,硼铸铁在浇注缸套时,一般都要遇到两个问题,一是外表面容易激冷产生料硬白口,二是内孔容易产生疏松针孔.金属模离心铸造气缸套时,硼铸铁具有强烈的激冷倾向,在快冷的外表面极易产生白口、麻口组织,机加工难度很大.     

辽宁硼泥资源综合利用的探讨与对策

阐述了辽宁省硼泥资源及其资源浪费和污染环境等情况。探讨、研究如何对硼泥资源进行开发、有效治理和综合利用，使其充分发挥经济效益和广泛的社会效益。     

Boron as an Alternate Engine Fuel

Abstract

Boron fuel is made up of the element boron. Boron as a chemical fuel will be a promising engine fuel in the future. Cars in which boron fuel simply burns will be true zero emission vehicles. Total world production of boron minerals was approximately 4,270,000 tons in 2000. Turkey has the largest boron sources in the world. It is estimated that about 64% of the known reserves are in Turkey, which has a substantial boron extraction industry. The amount of this resource is about 2.5 million tons and has high tenor and quality.     

Boron Compounds as Hydrogen Storage Materials

Abstract

Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. Hence, hydrogen storage is very important for humans. Hydrogen storage in metal hydrides is considered as one of the most attractive methods. In the present work, the hydrogen absorption-desorption behavior of the boron compounds has been compared. We present recent developments in the search for hydrogen-storage capacity of boron. Boron compounds have a very high energy density, much better than that of liquid hydrogen and also a lot safer. LiBH₄ is a complex hydride that consists of 18 mass% of hydrogen. It has stability compared with other chemical hydrides and an easy conversion to H₂. Thus, there are a good many reasons that hydrogen-storage materials for LiBH₄ will be used in the future at many ranges for power sources. The future warrants further investigations of the B-H system from the viewpoint of hydrogen energy storage.     

采用双联熔炼含硼缸套注意要点

1　前言随着市场需求的不断更新 ,内燃机不断地向高转速、高寿命、低能耗和低排放的方向发展 ,这样势必对其主要零部件—缸套的技术含量提出更高的要求。缸套的机械性能必须在原来的基础上提高 2 0 %以上 ,抗拉强度要≥ 2 60 MPa。目前内燃机在使用寿命和抗磨损能力方面均已提出更高的指标 ,必须要达到 5 0万公里的指标 ;对缸套的几何尺寸、形位公差在原 IT7级的基础上提高到 IT6级 ;对平台网纹的质量要求越来越高。这样才能保证发动机尾气排放达标。总之 ,内燃机技术的发展 ,完全是建立在主要零部件性能和寿命的不断改进基础上的。缸套…     

Temperature Effect on Young's Modulus of Boron Nitride Sheets

In this article, based on the oscillations of atoms due to the thermal effects (i.e., thermal phonons), Young's modulus of a hexagonal boron nitride sheet at different environment temperatures is investigated. To this end, the density functional theory (DFT) and quasi-harmonic approximation (QHA) are applied to calculate the energies of electrons and phonons, respectively, and then to obtain the total energy of the system. Unlike graphene, Young's modulus of boron nitride sheets tends to considerably increase with the increase of temperature to a specific value about 800 K. For the temperatures greater than 800 K, variation of Young's modulus with temperature is not considerable so that it can be neglected at high temperatures. It is also discerned that when temperature is high, the effect of phonon energy on Young's modulus is negligible.     

比色法测定钢中微量硼的研究

试样以酸溶解,在硫磷溶液介质中,加入氟化氨与硼生成氟硼络离子(BF-4),加入次甲基蓝与之生成蓝色络合物,用二氯乙烷萃取后,以光度法测定。测定范围:硼含量0.000 5~0.05%的碳钢、低合金钢、高合金钢。     

Boron and nitrogen co-doped porous carbon and its enhanced properties as supercapacitor

Boron and nitrogen co-doped porous carbons (BNCs) were prepared through a facile procedure using citric acid, boric acid and nitrogen as C, B and N precursors, respectively. The BNC samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen sorption at 77 K. Cyclic voltammetry and galvanostatic charge/discharge experiments were adopted to investigate their electrochemical behaviors. The BNC-9 and BNC-15 samples with high specific surface areas of 894 and 726 m² g⁻¹ showed the large specific capacitance up to 268 and 173 F g⁻¹, respectively, with the current of 0.1 A g⁻¹. When the current was set as 1 A g⁻¹, the energy densities were 3.8 and 3.0 Wh kg⁻¹ and the power densities were 165 and 201 W kg⁻¹ for BNC-9 and BNC-15, respectively. Thus, BNC-15 is more suitable to apply in high-power-demanded occasion, while BNC-9 tends to store more energy.     

Boron substitution effect on adsorption of H2 molecules on organometallic complexes

Hydrogen adsorption properties of Be/Sc doped pentalene complexes are investigated using second ordered Møller-Plesset method (MP2). In order to study the boron substitution effect, pentalene is further modified by substituting two and four boron atoms for carbon atoms at different positions and named as TBP1 and TBP2 for two boron atom substituted structures and FBP1 and FBP2 for four boron atom substituted structures. Two H₂ molecules get adsorbed on each Be doped complex and having 3.25, 3.31, 3.31, 3.38 and 3.38 wt% H₂ uptake capacity for C₈H₆Be₂, TBP1Be₂, TBP2Be₂, FBP1Be₂ and FBP2Be₂ complexes respectively. All Sc doped pentalene and boron substituted pentalene complexes can interact with nine H₂ molecules except TBP2Sc₂ complex. The TBP2Sc₂ complex can adsorb eight H₂ molecules. The H₂ uptake capacity is found to be 8.63, 8.73, 7.84, 8.83 and 8.83 wt% for C₈H₆Sc₂, TBP1Sc₂, TBP2Sc₂, FBP1Sc₂ and FBP2Sc₂ complexes respectively. Gibbs free energy corrected adsorption energy plots show that the H₂ adsorption on all Be doped complexes is possible at all temperatures and pressures considered here. The TBP1Sc₂ complex seems to be more promising hydrogen storage material among all Sc doped complexes over a wide range of temperature and pressure. The H₂ desorption temperatures obtained for the Be doped complexes are higher than the Sc doped complexes. Stability of the complexes is predicted with the help of the gap between the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals.     

Thermophysical Properties of Zirconia Toughened Alumina Ceramics with Boron Nitride Nanotubes Addition

Abstract

The demand for high thermal conductivity substrates with electrically insulating materials are increasing with the emerging markets in power electronics and mobile telecommunication device packages. Effective heat transfer in those packages is important to provide high performance and reliability of the product. This paper mainly presents the thermophysical properties of zirconia toughened alumina ceramics with the addition of small amount of boron nitride nanotubes (BNNTs). The effects of the boron nanotubes addition on the sintering behavior, the microstructure and the thermal properties of the yttria-stabilized zirconia toughened alumina (YZTA), nanocomposite ceramics are investigated. The addition of 0.3?wt% boron nitride nanotubes into the YZTA matrix enhanced the thermal diffusivity as well as a mechanical strength. Above all, the addition of boron nitride nanotubes greatly decreased the coefficient of thermal expansion (CTE) of the composites in which the CTE of pure alumina increases with increasing temperatures. Moreover, the BNNTs added YZTA composites revealed a drastic decrease in CTE at high temperature range, 400–800?°C. This enhanced thermal stability of YZTA–BNNT composites may have a potential application to the high temperature structural ceramics and high power semiconductor packaging substrate.     

Boron substituted carbon nanotubes—How appropriate are they for hydrogen storage?

The storage of hydrogen in carbon nanotubes requires appropriate chemical activators in suitable geometry. In this study, the role of boron substitution in carbon nanotubes is demonstrated for activation and storage of hydrogen.