B4C/SiCw陶瓷喷砂嘴的制备及其冲蚀磨损机理研究

采用热压烧结工艺制备了B4C/SiCw陶瓷喷砂嘴,研究了SiC晶须的含量对B4C/SiCw陶瓷材料性能的影响.以SiC和Al2O3磨料对B4C/SiCw陶瓷喷砂嘴进行冲蚀磨损试验,研究不同磨料对B4C/SiCw陶瓷喷砂嘴冲蚀磨损的影响,分析了其冲蚀磨损机理.结果表明:B4C/SiCw陶瓷喷砂嘴的冲蚀磨损机理主要表现为脆性断裂和磨料粒子对喷嘴的切入所造成的微观切削作用.磨料的硬度和粒度对陶瓷喷嘴的磨损有重要的影响,磨料的硬度和粒度越大,陶瓷喷嘴的磨损速度加快.     

氮化硅陶瓷水煤浆喷嘴的损坏机理

用热压烧结法制备了Si3N4/TiC和Al2O3/TiC陶瓷水煤浆喷嘴.测量了喷嘴的磨损质量损失,用扫描电子显微镜观察了喷嘴磨损后的表面形貌,研究了其磨损特性.结果表明:陶瓷水煤浆喷嘴材料的硬度和断裂韧性对其热冲蚀磨损有重要影响.在相同条件下,硬度较高的Al2O3/TiC陶瓷喷嘴的磨损率较低,而断裂韧性较高的Si3N4/TiC陶瓷喷嘴的热冲击损伤较小.陶瓷喷嘴磨损表面因区域不同而显示不同的特征,Si3N4/TiC陶瓷喷嘴的损坏机理主要表现为塑性变形、脆性断裂、研磨损伤、热裂纹和热崩.     

B4C(W,Ti)C陶瓷复合材料的制备及其性能

采用热压烧结工艺制备了B4C/(W,Ti)C陶瓷复合材料.研究表明:B4C/(W,Ti)C陶瓷材料烧结时将产生化学反应,反应产物为TiB2和W2B5.B4C/(W,Ti)C陶瓷材料的性能与(W,Ti)C的含量密切相关,随(W,Ti)C含量的增加,材料的致密度、抗弯强度和断裂韧性逐渐增加,硬度逐渐减小;当保温时间低于50min时,材料的致密度、抗弯强度和硬度显著降低;B4C/(W,Ti)C陶瓷复合材料的最佳性能参数为:抗弯强度693MPa,维氏硬度23.5GPa,断裂韧性3.9MPa·m1/2.磨损实验表明,B4C/(W,Ti)C陶瓷材料在低速小载荷的实验条件下,耐磨性能优异,在高速大载荷的实验条件下,磨损过程中局部点的高温导致试样表面发生氧化,加剧了材料的磨损.     

Al_2O_3–SiC复相陶瓷的摩擦磨损特性

用真空热压工艺制备了Al2O3-SiC复相陶瓷.对热压烧结的纯Al2O3以及Al2O3-SiC复相陶瓷进行了摩擦磨损实验,研究了SiC添加量对复 相陶瓷摩擦磨损性能的影响.结果表明:在压力为25 MPa,1635℃热压烧结1h,当SiC的质量含量为5%时,Al2O3-SiC复相陶瓷的耐磨性最佳,虽摩擦系数最大(0.61,Al2O3则为0.46),但磨损率(WR)仪为5×10-4mm3/(N·m).Al2O3-SiC复合材料的磨损机理为脆性断裂引起的磨粒磨损,材料的 WR与断裂韧性(KIc)和Vickers硬度(Hv)的乘积(KIc1/2HV5/8)成反比.     

Al2O3/TiC复合陶瓷拉丝模材料的摩擦磨损性能

采用热压法制备出Al2O3/TiC复合陶瓷材料,该材料具有良好的综合力学性能,抗弯强度为850MPa,断裂韧性为4.9MPa·mi/2.由高速环块磨损试验机对其摩擦磨损行为及其磨损机理作了试验研究.用扫描电镜观察了磨损表面形貌.结果表明Al2O3/TiC复合陶瓷拉丝模材料磨损率随试验转速升高而下降,但压力变化对磨损率的影响不大.Al2O3/TiC复合陶瓷拉丝模材料磨损机理主要是脆性脱落和犁沟,具有良好的耐磨性.是制备拉丝模的优良材料.     

自增韧陶瓷复合材料的研究

本文叙述了Si3N4、Sialon、Al—Zr—C、Ti—B—C、SiC、Al2O3和玻璃陶瓷等自增韧陶瓷复合材料的研究，并简要介绍了自增韧陶瓷复合材料的制备工艺、微观结构、增韧机理，及材料形成的热力学和动力学条件。     

自蔓延离心熔铸TiB2-(Ti,W)C-TiC陶瓷研究

基于离心热爆反应、难熔液相分离与快速凝固原理,选取(WO3+Al+C)体系辅助(B4C+Ti)反应体系,采用自蔓延离心熔铸工艺可以成功制备出TiB2微纳米晶补强TiC-(Ti,W)C陶瓷基复合材料.将(B4C+Ti)、(WO3+Al+C)两种反应体系依次装填入坩埚中进行SHS离心熔铸实验,发现因W-Ti-C液相动力学粘度的降低、Al2O3液滴迁移路程减小,极大促进Al2O3液滴的Stokes上浮过程,故而显著减小残存于陶瓷基体上的氧化物夹杂含量与尺寸,进而TiB2微纳米片晶诱发的强烈自增韧机制与Al2O3微纳米晶产生的残余应力增韧效应,使得TiB2-(Ti,W)C-TiC陶瓷的弯曲强度、断裂韧性与维氏硬度分别达到(952±25)MPa、(12.6±2.5)MPa·m1/2与(28.6±1.2)GPa.     

制备工艺对Al2O3陶瓷的组织和冲蚀性能影响

论文采用二种工艺制备了Al2O3陶瓷材料，在相同条件下对所制备的陶瓷材料进行了冲蚀磨损实验；通过对冲蚀磨损前后材料的形貌和断口的扫描电镜观察，详细讨论、分析了实验结果。结果表明：采用搅拌磨混料和冷等静压处理工艺制备的试样具有优良的冲蚀磨损性能；与干混料干压成型制备的试样相比，冲蚀磨损率可以降低约50％；而且发现磨粒的形貌对材料的冲蚀磨损性能有一定的影响。     

液体橡胶／环氧树脂复合材料的制备与性能研究

用端异氰酸酯基聚丁二烯液体橡胶与环氧树脂制得端异氰酸酯基聚丁二烯液体橡胶与环氧树脂反应物（ETPB）。在ETPB中加入纳米Al2O3,并选择适宜的固化剂固化,制得ETPB／Al2O3复合材料。测试了ETPB和ETPB／Al2O3复合材料于石英砂-水介质中的冲蚀磨损性能,并用扫描电子显微镜（SEM）对材料磨损表面进行了观察。结果表明,ETPB和ETPB／Al2O3复合材料在不同线速度下,随着线速度的增加冲蚀磨损率也随着增加。     

Al2O3-瓷釉复合陶瓷涂层冲蚀磨损性能研究

利用搪瓷涂层的制备工艺在Q235A钢表面制备Al2O3-瓷釉复合陶瓷涂层,研究了瓷釉粒度、Al2O3陶瓷颗粒的粒度和体积分数对复合涂层耐冲蚀磨损性能的影响。结果表明:过渡层原料瓷釉粒度为16μm时获得涂搪性较好;硬质耐磨相的加入可显著提高复合涂层的耐冲蚀性能;本实验中在45°冲蚀角、15 MPa冲蚀气压、2.2 kg冲砂量的冲蚀实验条件下Al2O3粒度为50μm、体积分数为30%时涂层具有很好的耐冲蚀性,是无硬质相搪瓷层的4倍。     

Wear behavior of ceramic nozzles in sand blasting treatments

Sand blasting nozzle is the most critical part in the sand blasting equipment. Ceramics being with high wear resistance have great potentials as the sand blasting nozzle materials. In this paper, monolithic B₄C and Al₂O₃/(W,Ti)C ceramic composite were developed to be used as nozzle materials. The wear behavior of nozzles made from these ceramic materials was compared by determining the cumulative mass loss and the erosion rates. Effect of the factors that influence the nozzle wear was investigated. Results showed that the hardness of the nozzles plays an important role with respect to its erosion wear in sand blasting processes. The monolithic B₄C nozzles being with high hardness exhibited lower erosion rates, while the Al₂O₃/(W,Ti)C nozzles with relative low hardness showed higher erosion rates under the same test conditions. Studies of the worn surface of the ceramic nozzles demonstrated that monolithic B₄C nozzles exhibited a brittle fracture induced removal process, while Al₂O₃/(W,Ti)C nozzles showed mainly a plowing type of material removal mode.     

Microstructure and mechanical properties of hot-pressed SiC/(W,Ti)C ceramic composites

SiC/(W, Ti)C ceramic composites with different content of (W, Ti)C solid-solution were produced by hot pressing. The effect of (W, Ti)C content on the microstructure and mechanical properties of SiC/(W, Ti)C ceramic composites has been studied. Densification rates of the SiC/(W, Ti)C ceramic composites were found to be affected by addition of (W, Ti)C. Increasing (W, Ti)C content led to increase the densification rates of the composites. The sintering temperature was lowered from 2100 °C for monolithic SiC to 1900 °C for the SiC/(W, Ti)C composites. Results show that additions of (W, Ti)C to SiC matrix resulted in improved mechanical properties compared to pure SiC ceramic. The fracture toughness and flexural strength continuously increased with increasing (W, Ti)C content up to 60 vol.%, while the hardness decreased with increasing (W, Ti)C content.     

基于反向神经网络的陶瓷材料Vickers硬度预测

误差反向传播神经网络(BP网络)具有能够正确逼近非线性映射关系的优点。将其运用到复相结构陶瓷材料Vickers硬度预测当中，克服了陶瓷材料研究中单因素实验法不能正确反映Vickers硬度与添加组分多因素之间复杂非线性关系的弱点，通过硬度预测和试验验证表明，该方法可行有效，为快捷、经济地开发研制新的陶瓷材料提供了新的思路和有效手段。     

Layered structures in ceramic nozzles for improved erosion wear resistance in industrial coal-water-slurry boilers

The nozzle is the most critical part in the coal-water-slurry (CWS) boilers. Ceramics being highly wear resistant have great potential as CWS nozzle materials. In this paper, Al₂O₃/(W,Ti)C + Al₂O₃/TiC layered ceramics (LN1, LN2, and LN3) with different thickness ratios among constituent layers were developed to be used as nozzles in CWS boilers. CWS burning tests in a boiler with these nozzles were carried out. The erosion wear behavior of the layered nozzles was investigated and compared with an unstressed reference nozzle (N5). Results showed that the layered ceramic nozzles exhibited an apparent increase in erosion wear resistance over the unstressed reference one. The mechanisms responsible were found to be that layered structure in the CWS nozzles can improve the hardness and fracture toughness of the external layer, and reduce the temperature gradients and the thermal stresses at the exit of the nozzle during CWS burning processes. It is suggested that layered structures in ceramic nozzles is an effective way to improve the erosion wear resistance over the stress-free ceramic nozzles in industrial CWS boilers.     

陶瓷-硬质合金复合刀片材料的力学性能与界面结构

采用热压烧结工艺制备了刀具用陶瓷－硬质合金复合片．复合片上层为具有一定厚度的Ａｌ２Ｏ３／ＴｉＢ２陶瓷材料,下层为ＷＣ／Ｃｏ硬质合金．结果表明：复合片综合了陶瓷材料的高硬度和硬质合金的高强度,其性能介于陶瓷材料和硬质合金之间．Ｘ射线衍射、电子探针和扫描电子显微镜分析表明：烧结过程中硬质合金和陶瓷材料中的元素在界面相互扩散,并有新相形成,增加了界面结合强度,其界面为化合物型和扩散型的混合．     

Erosion behavior of B4C based ceramic nozzles by abrasive air-jet

TiC and Mo were introduced into B₄C-based ceramic nozzles, which were obtained by hot-press sintering. The effect of TiC content on mechanical properties and erosion behavior of B₄C-based ceramic nozzles were analyzed. XRD analysis showed that chemical reactions took place during the sintering process, which resulted in B₄C/Mo/TiB₂ ceramic nozzle with high density and improved mechanical properties compared with B₄C/Mo ceramic nozzle. The sintering temperature was decreased from 2150 °C for B₄C/Mo ceramic nozzle to 1950 °C for B₄C/Mo/TiB₂ ceramic nozzle. Results of erosion wear tests indicated that the hardness and toughness were the key factors influencing the erosion rate of B₄C/Mo/TiB₂ ceramic nozzle. Analysis of the eroded bore surfaces of B₄C/Mo/TiB₂ ceramic nozzle showed that the entry bore section exhibited a brittle fracture induced material removal process, and the center bore section showed plowing and polishing of material removal. Fracture and plowing of material removal occurred at the exit bore section.     

Al2O3-CoCrAlY 复合陶瓷激光熔覆层的组织与性能

研究了Ａｌ２Ｏ３－ＣｏＣｒＡｌＹ复合陶瓷涂层的组织结构、成分分布及其耐磨性能。结果表明：等离子喷涂层的组织呈层片状,面层由α－Ａｌ２Ｏ３和少量的γ－Ａｌ２Ｏ３组成,层间为机械结合界面,涂层平均硬度为８９７ＨＶ０．２。经激光重熔后的组织为单一的α－Ａｌ２Ｏ３柱状晶,在ＣｏＣｒＡｌＹ与基体间有界面相形成,其界面为冶金结合,层间存在着平缓的成分过渡;Ａｌ２Ｏ３与ＣｏＣｒＡｌＹ间的界面结合状况得到了明显的     

钇补强颗粒弥散陶瓷复合材料增韧机制的微观结构表征

在Al2O3/（W,Ti）C陶瓷复合材料中适量添加稀土元素钇能显著提高其断裂韧性。本文运用SEM与TEM技术,从微观结构的角度探讨了其增韧机制。表明,由于稀土钇的添加,使材料内部形成不同程度的强弱界面,它们与扩展中的裂纹相互作用,使得裂纹桥联、裂纹分支、裂纹偏转以及微裂纹增韧机制得到明显增加和加强,从而以多种增韧机制及其协同作用共同提高稀土补强Al2O3/（W,Ti）C陶瓷复合材料的断裂韧性。