High volume fraction diamond particles reinforced Cu matrix composites are difficult to be machined due to high hardness. The net-shape forming has been successfully realized by combined process of diamond preforms by powder injection molding and then infiltrating the preforms with the copper. Critical processes involved in powder injection molding of diamond powder coated by Cr layer and Cu layer, including the choice of the binder, the injection molding process, the sintering process, were studied. The results show that feedstocks have excellent rheological properties and higher solid volume fraction using the binder composed of 70%paraffin, 25%high density polyethylene and 5% stearic acid as the carrier of diamond powder injection molding. Adopting the above binder, the best injection temperature is 165~175 ℃ and the injection pressure is 80~90 MPa. The best sintering conditions of injected diamond preforms by debinding is at 1 050 ℃ for 25 min at which the preforms strength can reach 10 MPa and open porosity is close to be 100%.% 高体积分数金刚石颗粒增强Cu基复合材料由于硬度高导致其难以加工成形。采用粉末注射成形制备多孔金刚石预成形坯和 Cu 熔渗相结合的工艺可以实现金刚石/Cu 的近净成形。本文对经过表面镀铬再镀铜的金刚石粉末注射成形涉及的关键工艺，包括粘结剂的选择、注射成形工艺过程、烧结工艺等进行研究。结果表明，采用成分为70%石蜡+25%高密度聚乙烯+5%硬脂酸的粘结剂作为金刚石粉末注射成形的载体时，喂料具备优异的综合流变性能，同时可以获得较高的固相体积分数。采用上述配方的粘结剂，最佳的注射温度为165~175℃，注射压力为80~90 MPa。脱脂金刚石预制坯最佳的烧结条件为：烧结温度1050℃，保温时间25 min，此时坯体的强度达到10 MPa，孔隙基本全部为开孔隙。
展开▼
