Physicochemical aspects of technology of the Al₂O₃-Al layered cermet obtained using reaction sintering

Abstract

Certain features of the technology of the Al₂O₃-Al layered cermet obtained by the reaction sintering (RS) in air of powdered billets that were fabricated by pressing the charge from the PAP-2 plateletshaped aluminum powder. The RS process was activated by the introduction of a dry residue of liquid glass (DRLG) into the charge (C = 3–28%). According to the data of the X-ray phase analysis, the sintered material contains (vol %): Al (61–82), γ-Al₂O₃ (8–25), Na₂Si₂O₅ (2–15), and Si (1–14). Oxide phases and silicon are nanodimensional morphological objects (13–100 μm) in the layered aluminum host. The cermet density is 2.1–2.45 g/cm³, tensile strength is 45–90 MPa, and the ultimate bending strength is 320 MPa. The activation of RS by a small DRGL additive (3%) retains the layered cermet structure. It is leveled at a considerable increase in the RS time (up to 600 min) or C (up to 28%) because of recrystallization and involves plateletshaped aluminum particles in the chemical interaction.