(1. 中南大学材料科学与工程学院，长沙 410083；
2. 中南大学粉末冶金国家重点实验室，长沙 410083；
3. 自贡硬质合金有限责任公司研发中心，自贡 643011；
4. 希伯来大学卡萨利应用化学中心，耶路撒冷91904)
摘 要: 为了实现3D打印硬质合金的目的，论文提出了一种基于光固化3D打印硬质合金的方法，即以钨盐和钴盐为原料，并借助光辐照聚合，光固化打印硬质合金前驱体坯体，再通过后处理——高温还原/碳化并烧结致密化为硬质合金。论文采用流变仪、紫外分光光度计、同步热分析仪和XRD衍射仪等研究了墨水的紫外流变性能和稳定性，分析了前驱体的转变过程，探究了钨盐/有机物比例对高温后处理产物的影响规律，最终获得了蜂窝结构的3D打印硬质合金部件。研究表明：优化的墨水配方中，水/丙烯酸比值为2.5，偏钨酸铵溶解度为100%以下，TPO和PEGDA的加入量为溶剂质量的2%。在高温后处理过程中，3D打印硬质合金前驱体内的盐和有机物发生分解、还原和碳化等一系列反应。偏钨酸铵首先分解为氧化钨，再在氢气气氛下被还原为纯钨，然后与有机物分解产生的碳源依次发生碳化为W2C和WC。当钨盐/有机物比例低于0.85时，高温后处理产物为纯WC相。最终获得的3D打印蜂窝结构硬质合金，结构完整、表面光滑，主要物相为WC和Co。
关键字: 3D打印；硬质合金；光固化；碳化钨；水基墨水
（1. School of Materials Science and Engineering, Central South University,Changsha 410083, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
3.Zigong Cemented Carbide Corp. R&D Centre, Zigong 643011, China;
4.Casali Center of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel）
Abstract:In order to obtain 3D printed cemented carbide, this paper proposed a method based on photocuring 3D printing technology. Tungsten salt and cobalt salt were used as raw materials to print precursors by light irradiation polymerization. The precursors were sintered and densified into cemented carbide after high temperature reduction/carbonization. In this paper, apparatuses such as rheometer, UV spectrophotometer, synchronous thermal analyzer and X-ray diffractometer were used to study the UV rheological properties and stability of inks, the phase transformation process of precursors, and the effect of the ratio of tungsten salt to organic matter on the final product. Finally, 3D printed carbide parts with honeycomb structure were obtained. The results are as follows: in optimized ink, the ratio of water to acrylic acid is 2.5, the solubility of ammonium metatungstate is less than 100%, and the amount of TPO and PEGDA is 2% of the solvent mass. In post-treatment processing, a series of reactions including decomposition, reduction and carbonization occur. Ammonium metatungstate is subsequently decomposed to tungsten oxide, reduced to pure tungsten in hydrogen atmosphere, and carbonized to W2C and WC. As the ratio of tungsten salt to organic matter is lower than 0.85, the product is pure WC. Finally, the 3D printed honeycomb cemented carbide possesses complete structure and smooth surface, whose main phases are WC and Co.
Key words: 3D printing; Cemented carbide; Light curing; Tungsten carbide; Water-based ink
