低压烧结制备石墨烯增强WC-Co硬质合金

采用机械搅拌和静电吸附2种工艺制备氧化石墨烯增强WC-Co复合粉末,对复合粉末的微观形貌进行表征,并利用低压烧结工艺制备石墨烯增强WC-Co硬质合金,对硬质合金力学性能进行测试分析。静电吸附工艺和低压烧结相结合所制备的石墨烯增强WC-Co硬质合金抗弯强度和维氏硬度分别为3 250 MPa和1 846,比不添加石墨烯的WC-Co硬质合金抗弯强度和硬度分别提高了38.92%和7.93%;比机械搅拌工艺和低压烧结相结合所制备的石墨烯增强WC-Co硬质合金抗弯强度提高了8.33%,硬度略有提高。石墨烯通过静电吸附工艺均匀地分散在WC-Co基体中,高温烧结时通过阻碍晶界的扩散和位错的滑移来细化晶粒,有裂纹产生时会阻碍裂纹扩展,从而增强材料力学性能。     

HA/YSZ/Ti6Al4V生物复合材料的制备与界面特性

采用磁控溅射法制备出HA／YSZ／Ti6Al4V生物复合材料,利用X-射线衍射仪（XRD）、扫描电镜（SEM）和能谱分析（EDXA）研究复合涂层的相组成、表面微观形貌和界面微观形貌,并用划痕仪测定复合涂层与基体的界面结合力．结果表明：溅射的复合涂层中主要含有HA、ZrO2和Y2O3物相,此外还有少量的TCP和CaO相;该复合涂层表面凹凸不平,呈现网状微孔结构,其孔隙直径约为0．5～2μm,孔隙面积占薄膜表面积的30％～40％．划痕试验表明,复合涂层与Ti6Al4V基体结合力约为80N．复合涂层拉伸试样横断面分析显示,在涂层与基体界面处无裂纹,界面处存在Ti6Al4V基体成分Ti与复合涂层成分Ca、P问互扩散的扩散层,该扩散层厚度为0．5～1．5μm,复合涂层界面的结合机制为机械齿合和扩散结合．     

等离子喷涂WC-Co涂层的超声波评价

为了解决目前等离子喷涂涂层制备中的质量检测问题及为在役涂层质量评价提供无损评价技术,研究了一种新的涂层超声无损检测方法.该方法考虑超声波在涂层中传播时,不同界面的回波信号相互叠加并发生多重反射的传播特性,运用功率谱分析及互相关函数分析方法,提出了由涂层引起的群速度延迟时间及涂层密度的求解方法,建立了适于涂层材料评价的超声无损检测系统.对等离子喷涂铁基上的WC-Co涂层进行了密度测试,测试结果与质量差法测量结果误差3.7%.对不同厚度的涂层进行了测试,证明延迟时间与涂层厚度成比例,并与最小二乘法吻合.     

EB-PVD制备ZrO2涂层的微观组织结构研究

采用电子束物理气相沉积法在不锈钢基体上制备了氧化钇部分稳定氧化锆陶瓷涂层。利用XRD、XPS、SEM、AFM对涂层的相结构、化学成分、表面形貌进行了实验分析。结果表明,氧化锆涂层为四方相氧化锆,并不同程度存在织构现象。随着基体温度的升高,涂层中的晶粒尺寸在逐渐长大。涂层表面的小颗粒为柱状晶的上表面,涂层表面的粗糙度随着靶基距的升高而变小。涂层表面Zr-O结合态为Zr4+,而涂层内部存在少量的缺氧现象。     

微波辐射计用于隐身目标探测的性能分析

研究了微波辐射计用于隐身目标探测的若干基本问题。在分析现有主要隐身技术的基础上,针对隐身目标的特点和隐身材料的电磁热发射特性,提出了利用被动微波遥感器——微波辐射计探测隐身目标的方法。分析了微波辐射计用于隐身目标探测的主要性能指标,并对提高隐身目标被动微波探测性能的研究和发展方向进行了分析。     

等离子体喷涂ZrB2基复合涂层结构与性能

超高温陶瓷因其熔点高、热导率高和化学稳定性良好等特点而备受关注.ZrB_2是超高温陶瓷的典型代表.等离子体喷涂技术是制备超高温陶瓷涂层的有效方法.叙述了等离子体喷涂技术制备的ZrB_2基超高温复合涂层的近期研究成果,并简要展望了进一步改性该种涂层的方法.     

金属结构防腐蚀涂装的管理探讨

本文结合金属结构防腐蚀工作管理和质量控制的经验,探讨在防腐蚀施工过程中的管理工作及质量控制要点,希望对水电站建设的防腐蚀工作有所帮助。     

Effects of annealing temperature on the microstructure and hardness of TiAlSiN hard coatings

TiAlSiN hard coatings were synthesized on high-speed steel using an arc ion enhanced magnetic sputtering hybrid system.The microstructure and hardness of the coatings at different annealing temperatures were explored by means of XRD,TEM,EDAX and Vickers indentation.The as-deposited TiAlSiN coatings were confirmed to be amorphous due to high depositing rate and low deposition temperature during the film growth.The transformation from amorphous to nanocomposites of nano-crystallites and amorphousness were observed after the annealing treatment,the microstructure of TiAlSiN coatings annealed at 800°C and 1000°C were consisted of crystalline hcp-AlN,fcc-TiN and amorphous phase,however,the coatings were only consisted of fcc-TiN and amorphous phase when annealing at 1100°C and 1200°C.Meanwhile,the formation of Al2O3 was detected on the coating surface after annealing at 1200°C and it indicated the excellent oxidation resistance of the TiAlSiN coatings under the present experimental conditions.Furthermore,the average grain size of the TiAlSiN coatings after high temperature annealing even at 1200°C was less than 30 nm and the size increased with the increasing temperature.However,the hardness of the so-deposited coatings with HV0.2N=3300 dramatically decreased with the increase of temperature and reached nearly to the hardness of TiN coatings with HV0.2N=2300.     

Quality evaluation for air plasma spray thermal barrier coatings with pulsed thermography

Pulsed thermography (PT) as a non-contact non-destructiv e evaluation (NDE) technique was employed to examine as-sprayed air plasma spray (APS) thermal barrier coatings (TBCs) for quality eval uation. Thickness and micro-structural characteristics play a vital ro le in determining the quality. In this pape r, PT logarithmic peak second-derivative m ethod was adopted to measure the thickness of top coat. Time dependent ther mal images were used to characterize the microstructure which was confirmed by scanning electron microscope (SEM). The results showed that there was relationship between the temperature distribution of the surface and microstructu re change in TBCs. Temperature distribution in thermal images and measurement results of thickness were in fairly good agreement with the microstructure change. It can be concluded th at it was possible to employ these NDE methods as quality evaluation for as-sprayed TBCs.     

合成四甲氧甲基甘脲工艺条件的研究

四甲氧甲基甘脲是一种新型粉末涂料的交联剂。通过碱催化把甘脲和多聚甲醛缩合成四羟甲基甘脲中间体,然后再与过量的甲醇在酸性条件下合成四甲氧甲基甘脲。研究了反应物摩尔比、pH值、反应时间和温度,以及滴加速度等各因素对四羟甲基甘脲中间体和四甲氧甲基甘脲收率的影响,并通过正交实验得到最佳工艺条件。产物采用红外色谱仪(FT-IR)进行了表征;使用了高效液相色谱仪和紫外色谱仪检测了产品的纯度和产率。据上述红外、液相色谱分析可知,本方法合成的四甲氧甲基甘脲产率高,能达到80%(质量分数),纯度也高达到92%。