Study On Preparation Technology And Properties Of Al₂O₃-TiB₂ Solid-state Reaction Multiphase Ceramic Coating On AZ31B Alloy

The Al₂O₃-TiB₂ multiphase ceramic coating is in-situ synthesized through Al-TiO₂-B₂O₃ reaction system on AZ31B alloy surface. Study on the influence of the different ball grinding process on powder particle distribution, surface morphology and the activation effect of additives Zn powder and Bi₂O₃ to Al-TiO₂-B₂O₃ reaction system. The coatings′properties such as bond strength, wear resistance, corrosion resistance etc…are evaluated. Research results are obtained as follows:Results indicate that there are activation effects after adding Zn powder and Bi₂O₃ to Al-TiO₂-B₂O₃ primitive reaction system. Different complex reaction system respectively at 400℃and 500℃have reacted, but it is more apparent activation effect adding Bi₂O₃. Accordingly, adding Bi₂O₃ complex reaction system is used and the coating formed at 500℃is composed of Al₂O₃, TiB₂ and a few of Al, TiO₂ and Cr₂O₃. When the ratio of Al to TiO₂ and to B₂O₃ is 10:3:3 and adding 10% Bi₂O₃ in amount of substance and of the aggregate to adhesive is 1.35:1 in weight, the coating is the best. Its bonding strength can reach 14.78MPa, thermal shock times can reach 45, abrasive wear resistance improves 3.56 times than the base AZ31B, adhesive wear resistance improves 3.63 times than the base AZ31B, acid resistance performance improves 8.17 times and salt resistance performance improves 6.61 times. It is improved more times after sealing hole.