Cr镀层对金刚石/铝硼硅玻璃复合材料中金刚石氧化反应的抑制研究

为研究在镀铬金刚石/铝硼硅玻璃复合材料中Cr镀层对金刚石氧化反应的抑制作用，将不同镀层厚度的镀铬金刚石和铝硼硅玻璃在相同工艺下烧制成试样，检测试样的体积膨胀率和抗折强度，观察其断面形貌；同时分析烧结后金刚石单颗粒抗压强度和金刚石-结合剂界面的成分。结果表明:Cr镀层具有消耗和隔绝氧元素的双重保护作用，能有效抑制金刚石的氧化。同时，镀层厚度对金刚石氧化反应影响显著:镀层太薄，不能在高温烧结过程中持续保护金刚石；镀层太厚，会由于应力匹配问题产生裂纹或成片剥落，使金刚石暴露在有氧环境中，反而失去保护作用。对于粒度号为140/170的金刚石，最佳镀层厚度为1.58 μm。 

Research on Cr coating layer inhibiting oxidation of diamond in diamond/Al-borosilicate glass composites

The inhibiting effect of Cr coating on diamond oxidation in diamond/Al-borosilicate glass composites was studied. Coated diamonds with different Cr layer thickness was sintered with Al-borosilicate glass at the same process. The samples were tested and observed for volume expansion rate, bending strength and section morphology. The single particle compressive strength of sintered diamonds and the composition at the interface were analyzed. Results show that Cr coatings could protect the diamond through both isolation and consumption of oxygen, which effectively inhibits the oxidation of diamonds. Meanwhile, the thickness of coating layer has significant influence on diamond oxidation. If the coating is too thin, it could not continuously protect the diamond during high temperature sintering. If the coating is too thick, there would be cracks and flake spalling on it due to the thermal stress mismatch, exposing the diamond to oxygen environment and failing to protect. For 140/170 diamond, the optimum coating thickness is 1.58 μm.