自由烧结金刚石串珠冷压工艺研究

Research on Cold Pressing Process of Free Sintering Diamond Beads

采用同一种胎体配方结合剂,选择不同的冷压压力、不同的珠芯外径进行自由烧结,并做了串珠的剪切强度检测对比试验。根据检测结果得出:冷压金刚石串珠生坯压力需足够,压力足够不仅能使串珠自由烧结后其外形规整,还可确保串珠胎体与珠芯基体具有较高的抗剪强度;此外,根据胎体生坯的相对密度采用外径适合的珠芯,使串珠胎体在自由烧结时既能很好的"包住"珠芯,又能避免因珠芯外径过大而阻碍胎体的进一步收缩导致胎体有裂纹或微裂纹现象。

Free sintering has been conducted using the same matrix bond at different cold- pressing pressures with different bead core diameter. Contrast test of the shear strength of the beads has been done. Result shows that sufficient pressure should be put on the green of cold-pressing diamond beads in order to get beads of neat appearance after sinte- ring and to ensure high shear strength for bead matrix and bead core substrate. In addi- tion, adopting bead core of proper external diameter according to the relative density of the matrix green can ensure the bead core be well encased in bead matrix during sintering process and avoid matrix crack or microcrack caused by oversized bead core which hinders the further shrink of the matrix.