随着科学技术的飞速发展,用于机械加工、矿山采掘的硬质合金刀具在不断的更新,刀具涂层技术也在日趋多样化和复杂化,对生产工艺的要求也随之提高.文中介绍了硬质合金刀具涂层的2种主要制备方法即化学气相沉积法（CVD）和物理气相沉积法（PVD）,简述了刀具涂层即单组分涂层、多组分涂层、多层涂层和梯度涂层的发展,概括了几种新型涂层即金刚石涂层、类金刚石涂层、立方氮化硼涂层和氮化碳涂层,对未来硬质合金刀具涂层的发展方向进行了展望.

以钨粉、钴粉、碳黑、有机碳为原料,研究了W、Co和C混合粉末在放电等离子烧结系统中碳化反应快速烧结制备WC-6 wt.%Co硬质合金的原位碳化烧结工艺。系统研究了配碳量、烧结温度和加压方式对硬质合金的显微组织结构和性能的影响。结果表明:碳含量为理论值1.2倍时合金物相为纯WC和Co相,无脱碳相,也未发现游离碳;烧结温度在1 250℃时,WC晶粒均匀且无异常长大;在W、Co和C混合粉末烧结初期施加30 Mpa压强,待温度升到800℃时再将压强加到50 MPa制备的合金孔隙较少,致密化程度高。本工艺较传统制备工艺具有流程短,成本低的特点,可为硬质合金工业生产提供参考。

随着石油化工行业的发展,废钨催化剂日益增多.为了充分回收利用钨,设计了预处理-钠化焙烧-浸出-离子交换工艺利用废钨催化剂制备高纯仲钨酸铵.结果表明:制备高纯仲钨酸铵工艺流程可行,实现了有价金属的综合回收.通过对比实验优化关键工艺参数,确定了钠化焙烧温度为650℃、研磨粒度为0.1 mm、Na2CO3与WO3的摩尔比为0.8、结晶温度为100℃.通过对材料进行X射线衍射以及分析其衍射图谱、扫描电镜观察其形貌,使钨的回收率达到95%以上、制备出优于均国家质量标准（GB/T10116-2007）仲钨酸铵的产品.

Tungsten powder, cobalt powder and carbon black were invoked as raw materials.WC-6Co cemented carbides were prepared by ball-milling, compression moulding and microwave reaction sintering. The effects of sintering factors (Sintering temperature, heating rate and holding time) and the average particle size of W powders on the microstructure and properties of cemented carbides were investigated by XRD, SEM, Vickers hardness tester, et al. The results show that W powders with an average size of 1.3 μm can be carbonized to WC by C when the temperature is greater than 1100 ℃. The high densification of cemented carbide can be achieved when the temperature is 1300℃. The Vickers hardness (HV30) and fracture toughness (Wk) are 1999 N/mm2 and 8.51 MPa∙m1/2, respectively. No obvious property changes occur when sintering temperature increases to 1400℃. The residual pores in the alloy increase with reducing the sintering temperature, increasing the heating rate and reducing the holding time, which would result in the decrease of HV30 and Wk. It is considered that the microstructure is uniform and the comprehensive properties is the best when the microwave reaction sintering temperature is 1300℃, the heating rate is 100℃/min, and the holding time is 10 min. Subsequently, coarse grained WC-6Co cemented carbides are prepared from W powders with an average size of 27.0 μm and compared with fine grained WC-6Co cemented carbides. The results show that W2C exists in the alloy prepared from coarse W powders. The parameters of microwave reaction sintering are also affected by the average size of W powders. © 2020, Science Press. All right reserved.

以W粉、Co粉和碳黑为原料,通过球磨、压制成形及微波反应烧结制备WC-6Co硬质合金。采用XRD、SEM、密度计和维氏硬度计等研究微波反应烧结温度、升温速率、保温时间和W粉粒度4个因素对硬质合金组织与性能的影响。结果表明:选用粒度为1.3μm的W粉为原料,当温度大于1100℃时,W即可被C完全碳化生成WC;当温度为1300℃时合金致密性较好,维氏硬度(HV30)与断裂韧性（Wk）分别为1999N/mm~2和8.51MPa/m1/2,继续提高温度至1400℃时合金性能无明显变化。烧结温度越低、升温速率越大、保温时间越短,合金残留孔隙越多,导致维氏硬度与断裂韧性性能下降。当微波反应烧结温度为1300℃、升温速率100℃/min和保温时间10 min时制备的WC-6Co硬质合金微观组织均匀和综合性能最佳。选用粒度为27.0μm的W粉为原料按照最佳工艺烧结制备出WC-6Co硬质合金,并与平均粒度1.3μm的W粉制备的合金进行对比发现粗W粉颗粒制备的合金中存在W2C,微波反应烧结工艺参数与W粉平均粒度相关。

通过选区激光熔化（SLM）技术激光单道扫描成型了纯钨薄壁件,采用二维影像仪和光学显微镜分别测量了成型薄壁件壁厚和熔化道宽度,研究了激光功率和扫描速率对成型纯钨薄壁件壁厚和熔化道宽度的影响。利用光学显微镜观察了成型薄壁件表面2D和3D形貌。使用扫描电镜观察了成型薄壁件侧面粘粉情况,并分析了粘粉的原因。研究结果表明,成型薄壁件壁厚要大于熔化道宽度;随着激光功率的增大,薄壁件壁厚和熔化道宽度逐渐增大,薄壁件表面逐渐变得平坦;随着扫描速率的增大,薄壁件壁厚和熔化道宽度逐渐减小,熔化道由扭曲变得平直再变得扭曲,熔化道高度方向上的高度差先减小后增大;纯钨薄壁件由完全熔化区、球化区、半熔化区和未熔化区4部分组成。

稀土金属及化合物具有诸多的优异性能,将稀土元素以一定的方式加入到普通硬质合金中不仅能提高合金的硬度、抗弯强度和断裂韧性同时能够净化界面和改善硬质相与黏结相的湿润性.并且添加了稀土的硬质合金能够在现代科学技术的各领域发挥出独特的作用,故对稀土硬质合金做更加全面和系统的研究也成为必要.文中综述了稀土硬质合金的发展现状、介绍了稀土的添加形态和方法、稀土元素对硬质合金组织影响,最后对硬质合金的研究方向和趋势做了一定程度的介绍.