Study On Formation Mechanism And Mechanical Properties Of Al₂o₃ -tib₂ Solid-state Reaction Multiphase Ceramic Coating

The Al-TiO2-B2O3 reaction system superfine powder made by mechanical ball milling is mixed with a proportional aluminum phosphate adhesive and deposited on the surface of Q235 and then undergo thermocuring, through the solid-state reaction of which, Al₂O₃-TiB₂ multiphase ceramic coating is in situ synthesized at 700℃.The mechano-chemical and thermo-chemical characteristics including micro-morphology, particle distribution, phase composition, grain size changes etc. of the Al-TiO₂-B₂O₃ composite powder are studied with SEM, laser fineness gage, XRD, DTA etc..The formation mechanism of coating is investigated with thermodynamics and dynamic method. The mechanical properties such as bond strength, wear resistance etc. is tested.Results indicate that the mechanochemical force can make the Al-TiO₂-B₂O₃ system react at 670℃. Accordingly, the coating formed at 700℃is composed of Al₂O₃, TiB₂ and a few of Al,TiO₂, Cr₂O₃ and MgAl₂O₄. When the ratio of Al to TiO2 to B₂O₃ is 10:3:3 in amount of substance and of the aggregate to adhesive is 1.5:1 in weight, the coating is the best. Its bonding strength can reach 13.4MP, thermal shock times can reach 45, and wear resistance improves 3.21 times than the base Q235.