It is always challenging to synthesize corundum abrasives with high strength and toughness. In this study, pure α-Al₂O₃/LaAl₁₁O₁₈ dual-phase corundum abrasives were synthesized by the sol-gel method using pseudo-boehmite as the raw material and CoO–NiO binary additives as a sintering aid. By regulating the molar ratio of CoO and NiO in the sintering additives, dense and fine corundum abrasives were prepared at a low temperature of 1400 °C. We show that the addition of CoO–NiO additives can effectively prevent the abnormal growth of α-Al₂O₃ grains and facilitate the formation of LaAl₁₁O₁₈ s-particles between α-Al₂O₃ grain boundaries, resulting in final corundum abrasives consisting of equiaxed α-Al₂O₃ and needle-shaped LaAl₁₁O₁₈ grains. Moreover, the presence of the needle-shaped LaAl₁₁O₁₈ phase promotes the fracture toughness of corundum abrasives, and the high density of corundum abrasives also makes them retain a relatively higher hardness and strength. When the molar ratio of sintering additive (n(CoO)/n(NiO)) reaches 1: 1, the single-particle strength, Vickers hardness, fracture toughness, and maximum density of our synthetic corundum abrasives are 53.4 N, 18.9 GPa, 4.53 MPa·m^1/2 and 3.94 g·cm⁻³, respectively. The process route suggested in this study is expected to guide the low-temperature synthesis of corundum abrasives with well-rounded mechanical properties.

合成具有高强度和韧性的刚玉磨料始终具有挑战性。本研究以假勃姆石为原料，CoO-NiO二元添加剂为烧结助剂，采用溶胶-凝胶法合成了纯α-Al ₂ O ₃ /LaAl ₁₁ O _{18双相刚玉磨料。}通过调节烧结助剂中CoO和NiO的摩尔比，在1400℃的低温下制备致密、细小的刚玉磨料。我们表明，添加CoO-NiO添加剂可以有效防止α-Al ₂ O _{3晶粒的异常生长，促进α-Al 2}之间形成LaAl ₁₁ O ₁₈  s-粒子。O _{3晶界，产生由等轴}α - Al ₂ O ₃和针状LaAl ₁₁ O ₁₈晶粒组成的最终刚玉磨料。此外，针状LaAl ₁₁ O ₁₈相的存在促进了刚玉磨料的断裂韧性，而刚玉磨料的高密度也使其保持了较高的硬度和强度。当烧结助剂摩尔比(n(CoO)/n(NiO))达到1:1时，我们合成刚玉磨料的单颗粒强度、维氏硬度、断裂韧性和最大密度为53.4 N，18.9 GPa， 4.53 MPa·m ^1/2和 3.94 g·cm ^-3， 分别。本研究提出的工艺路线有望指导具有全面机械性能的刚玉磨料的低温合成。