以粘土合成β‘—Sialon粉料研究

以高岭土，叶腊石等为原料，利用碳热还原－氮化法合成β＇－Ｓｉａｌｏｎ粉料。研究了配方，合成温度，保温时间和氮气流量等对合成的影响。对合成粉料进行了ＸＲＤ，ＳＥＭ含氮量等检测。提供出实验室批量制备β＇－Ｓｉａｌｏｎ粉料的工艺条件。     

以粘土合成β′-Sialon粉料研究

以高岭土、叶腊石等为原料,利用碳热还原—氮化法合成β′-Sialon粉料。研究了配方、合成温度、保温时间和氮气流量等对合成的影响,对合成粉料进行了XRD、SEM含氮量等检测。提供出实验室批量制备β°-Sialon粉料的工艺条件。     

添加Sm_2O_3的β＇－12H复相sialon

在Ｓｉ－Ａｌ－Ｏ－Ｎ系统中，进行（β＇＋１２Ｈ）－ｓｉａｌｏｎ的成分设计，并以Ｓｍ￣２Ｏ￣３作为添加剂，用气压烧结（ＧＰＳ）制备了β＇＋１２Ｈ复相陶瓷。材料的相组成和微观结构研究表明：主晶相为β＇相和１２Ｈ相，纤维状的１２Ｈ与短柱状或等轴状的β＇交织排列形成致密组织。添加剂Ｓｍ￣２Ｏ￣３对复相ｓｉａｌｏｎ的致密化和结构性能有着较大影响，当添加量增加到５％（质量）时，材料达到理论密度为９９％，并显示较好的强度和韧性。另外，还对相同条件下制备的（β＇＋１２Ｈ）－ｓｉａｌｏｎ与β＇－ｓｉａｌｏｎ进行了比较，纤维状１２Ｈ相的引入，使裂纹扩展过程中产生偏转、分叉、桥接和１２Ｈ的拔出，对材料起到类似晶须的增韧补强效果。     

添加Sm2O3的β‘—12H复相sialon

在Ｓｉ－Ａｌ－Ｏ－Ｎ系统中，进行（β＇＋１２Ｈ）－ｓｉａｌｏｎ的成分设计，并以Ｓｍ２Ｏ３作为添加剂，用气压烧结（ＧＰＳ）制备了β＇＋１２Ｈ复相陶瓷。材料的相组成和微观结构研究表明：主晶相为β＇相和１２Ｈ相，纤维状的１２Ｈ与短柱状或等轴状的β＇交织排列形成致密组织。添加剂Ｓｍ２Ｏ３对复相ｓｉａｌｏｎ的致密化和结构性能有着较大影响，当添加量增加到５％（质量）时，材料达到理论密度为９９％，并显示较好的强     

粘土合成Sialon的研究进展及其添加剂的研究

本文全面地阐述了粘土合成Ｓｉａｌｏｎ的研究现状，对粘土合成Ｓｉａｌｏｎ的添加剂进行了详细的研究，除传统的Ｆｅ催化剂外，还可以利用碱金属或碱土金属氧化物添加剂合成高质量的β－Ｓｉａｌｏｎ粉末，为Ｓｉａｌｏｎ材料的应用与推广了新的技术途径。     

用不同粘土矿物合成Sialon粉末的研究

本文以高岭土、蒙脱石、叶腊石为原料，将粘土矿物与碳混合，加入适量的添加剂，在Ｎ２气氛１４００°Ｃ下，经４ｈ碳热还原氮化合成Ｓｉａｌｏｎ，产物经ＸＲＤ、ＸＰＳ、ＥＰＭＡ等分析，结果表明：用不同粘土矿物合成Ｓｉａｌｏｎ，矿物的Ａｌ／Ｓｉ比与碳的含量直接影响最终的合成产物，但主晶相仍为Ｚ＝３的β′－Ｓｉａｌｏｎ。     

纳米SiC—Ca—α—Sialon复相陶瓷的研究

研究了用表面活性剂有效地分散纳米ＳｉＣ粉体中的聚集体的实验过程，发现分散状态取于表面活性剂用量、ＰＨ值和浸 Ｓｉ３Ｎ４，ＡｌＮ，ＣａＣＯ３３和纳β－ＳｉＣ为原料粉料，用反应热压法制备了不同ＳｉＣ含量的纳米ＳｉＣ－Ｃａ－αｓｉａｌｏｎ复相陶瓷，并分别其相组成，力学性能和显微结构等进行了研究。     

交流阻抗谱法研究β‘—sialon结合SiC陶瓷材料的性能

采用交流阻抗谱法研究了β′－ｓｉａｌｏｎ结合ＳｉＣ陶瓷 显微组织，根据测得的阻抗谱ＸＲＤ数据及试样组成，提出了等效电路，用ＬＥＶＭ电化学软件对阻抗数据进行了拟合，获得该材料晶粒电导率σ０、晶界电导率σ１及颗粒边界电导率σ２与温度的关系。     

复相α—β—sialon陶瓷的微波反应烧结

微波烧地因具有极快的加热和烧结速度及内在性和体积性加热等特征使制品有潜力均匀地烧结，并获得较高的密度和均匀的微观结构通过适当的保温方式，名义组成为α：β＝２０：８０的复相α－β－ｓｉａｌｏｎ陶瓷在２．４５ＧＨｚ单模腔微波烧结系统于１６５０℃保温１０ｍｉｎ能完全反应，烧结致密，获得较高的密度和较小的晶粒尺寸及好的力学性能。     

非水解溶胶-凝胶碳热还原氮化法制备TiN粉体工艺研究

以四氯化钛和异丙醚为原料,二氯甲烷为溶剂,以非水解溶胶-凝胶法制备的Ti O2凝胶为钛源,选用分子量为1300000的聚乙烯吡咯烷酮(PVP)为碳源,采用碳热还原氮化法合成Ti N粉体。通过XRD和FE-SEM研究了PVP用量、合成温度及保温时间、氮气流量对Ti N粉体合成的影响。结果表明,适当增加PVP用量有助于Ti N的合成,但残余游离碳也相应增多;氮气流量一定时,升高合成温度及延长保温时间,有利于Ti N粉体纯度的提高,残余的游离碳变少,晶胞参数接近于标准值;当合成温度为1300℃,保温时间为5 h,氮气流量为40 m L/min时,制备出的Ti N粉体纯度高,晶粒发育良好,形状近似球形,粒径约为0.4μm。     

氮化铝粉末的制备及扩大实验研究

主要进行了碳热还原法制备氮化铝粉末扩大实验研究。研究了不同的铝源、碳源、氮化温度、保温时间、添加剂对合成氮化铝粉末的影响,并采用XRD、SEM、化学物理分析等手段对中试实验制备的氮化铝粉末进行分析。研究结果表明,采用经砂磨处理的铝源B（α-Al₂O₃）和3^#碳源（乙炔黑）为原料,有助于碳热还原反应;采用添加剂C可以降低反应活化能,提高氮化率;造粒工艺有助于扩大实验的碳热还原反应。     

Carbothermal reduction–nitridation of titania-bearing blast furnace slag

The synthesis of (Ca,Mg)α′-Sialon ((Ca,Mg)_xSi_12−3xAl_3xO_xN_16−x) powders using titania-bearing blast furnace slag as a starting material by carbothermal reduction–nitridation (CRN) was reported for the first time. The reaction processes were greatly affected by initial material and reaction parameters. With the compositions shifting range from x = 0.3 up to 2.0, the amount of (Ca,Mg)α′-Sialon, TiN and AlN, the solid solubility of Ca²⁺ and Mg²⁺, the unit cell parameters of the (Ca,Mg)α′-Sialon and the amount of elongated α′-Sialon grains increased, but β′-Sialon and SiC decreased. With the increase of synthesis temperature and holding time, the formation of (Ca,Mg)α′-Sialon in the products increased and the CRN reactions accelerated. The optimum synthesis conditions of (Ca,Mg)α′-Sialon were 1480 °C for 8 h, under which the crystalline phases of the products also included AlN, TiN and a small amount of SiC and β-CaSiO₃. The volatilization of SiO resulted in a mass loss of samples, which was enhanced with the increase of synthesis temperature and holding time.     

气氛对煤矸石中矿物质高温碳热还原反应的影响

利用煤矸石制备复合耐火材料是实现煤矸石高值利用的有效途径之一.以山西平朔煤矸石为研究对象,利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)分别研究了1200~1500 ℃氩气(Ar)和氮气(N2)气氛下煤矸石中矿物质的碳热还原反应情况,并通过变换两种气体通入次序,研究了气氛通入次序对矿物质碳热还原反应的影响.结果显示,只通入Ar时,高温样品中的莫来石在1300 ℃时开始发生碳热反应生成碳硅石(SiC);只通入N2时,莫来石在1300 ℃时发生碳热还原氮化反应生成β-Sialon相(Si5AlON7)和刚玉相(Al2O3);当先通入Ar并停留1 h后通入N2停留2 h时,样品中生成的碳硅石在通入N2后转化为β-Sialon相,而且中间体碳硅石的生成能够明显促进莫来石向β-Sialon相的转化.当煤矸石中碳含量较低时,热处理过程中难以同时生成SiC相和Sialon相.高温下煤矸石样品中β-Sialon相的生成使样品表面的棒状颗粒增多.     

Ultrafine-grained β-Sialon fabricated by two-stage sintering and study on diffusion toughening of Ti–22Al–25Nb

The ultrafine-grained β-Sialon ceramics were fabricated by spark plasma sintering at different temperatures with inorganic Al₂O₃–Y₂O₃ and Ti–22Al–25Nb intermetallic powder as composite additives. The research showed that β-Sialon ceramics achieve two-stage sintering densification. Al₂O₃–Y₂O₃ inorganic additives promoted the synthesis and densification of β-Sialon ceramics at 1125–1215°C. Ti–22Al–25Nb intermetallic powder diffused Ti and Nb elements at 1240–1425°C, thereby improving the fracture toughness of β-Sialon ceramics. The maximum fracture toughness (∼9.69 MPa m^1/2) under 19.6 N was obtained for β-Sialon ceramics sintered at 1600°C.     

COPNA树脂的热稳定性能及残炭率研究进展

COPNA树脂是一类新型热固性高分子材料,固化后的热稳定性非常高,其性能可与目前最耐热的聚酰亚胺树脂相媲美,并具有很高的残炭率,这为其合成耐高温耐摩擦材料奠定了基础.在树脂合成中,合成单体、交联剂、催化剂、反应时间温度、合适的分子结构键型、化学添加剂等因素都会影响其耐热性能及残炭率.本文主要从影响因素方面综述了近年来国内外有关COPNA树脂热稳定性及残炭率的研究进展状况.     

The Synthesis of β-Sialon Bonded Corundum Bricks from Al-Si Alloy

The paper presents a new method to synthesize β-Sialon bonded corundum brick(β-SBCB) from Al-Si alloy directly and easily under 1430℃,the volume expansion of reaction between Al powder and Nitrogen can help to establish the fast diffusion channel in Al-Si alloy;the suitable crystal seed of Si3N4 is helpful to the fast synthesis of β-Sialon.     

Synthesis of Calcium Hexaboride Powder via the Reaction of Calcium Carbonate with Boron Carbide and Carbon

The synthesis of calcium hexaboride (CaB₆) powder via the reaction of calcium carbonate (CaCO₃) with boron carbide (B₄C) and carbon has been investigated systematically in the present study. The influences of heating temperature and holding time on the reaction products have been studied using X-ray diffractometry, and the morphologies of CaB₆ obtained at various temperatures and holding times have been investigated via scanning electron microscopy. The interaction in the CaCO₃–B₄C–carbon system by which CaB₆ is formed is a solid-phase process that passes through the transition phases Ca₃B₂O₆ and CaB₂C₂. The optimal conditions for CaB₆ synthesis are a holding time of 2.5 h at a temperature of 1673 K, under vacuum (a pressure of 10⁻² Pa). CaB₆ powder has the same morphology as B₄C, and the properties and the shape of CaB₆ powders can be improved by choosing good-quality raw materials.     

β-Sialon对刚玉质耐火材料性能影响的研究

在刚玉质耐火材料的基质中引入硅粉和铝粉,通过原位氮化反应形成β-Sialon,并制备β-Sialon结合刚玉复相材料。研究了β-Sialon生成量对材料的物理性能、力学性能、热震稳定性等性能的影响。用XRD和SEM分析了材料的物相组成和显微结构。     

Zinc oxide obtained by the solvothermal method with high sensitivity and selectivity to nitrogen dioxide

The effect of heat treatment using [Zn(H₂O)(O₂C₅H₇)₂] precursor ethylene glycol solution (synthesis temperature 125–185 °C, holding time 2–6 h) on the characteristics of the obtained nanocrystalline zinc oxide powder was studied. Under all synthesis conditions crystalline ZnO was formed with a wurtzite structure and an average crystallite size of 8–37 nm. The thermal behaviour and microstructure of the nanostructured ZnO powder were studied. The sensory properties of the obtained films in terms of the detection of hydrogen, methane, carbon monoxide and nitrogen dioxide were studied. The high sensitivity and selectivity of a thick ZnO film (synthesis temperature 145°С, holding time 6 h) when detecting NO₂ was established. It was found, that humidity had almost no effect on response value for NO₂ detection.     

Preparation of submicron boron carbide powder through gas-solid reaction method

Boron carbide submicron powder was synthesized with boron oxide and graphene as starting materials by gas-solid reaction method using two different apparatuses. The effects of calcination temperature and holding time, apparatus type and B₂O₃/C ratio of the starting materials on the phase composition and morphology of the synthesized powders were evaluated. A newly formed residual carbon morphology distinct from original graphene were present in samples synthesized at a higher B₂O₃/C ratio or temperature. The synthesis temperature of ∼1500 °C was found to be more suitable to obtain boron carbide powder without the existence of residual carbon. The new type of apparatus enabled the synthesis of boron carbide phase at a relatively lower temperature, due to its more efficient use of B₂O₃ vapor.