Study Of Al-TiO₂-B₂O₃ Mechanical Alloying Mechanism

In order to preparation of ideal composite coatings on aluminum alloy surface with good hardness and wear resistance and other important performance index. This paper have been in detail analyzed Al-TiO2-B2O3 powders to product Al2O3-TiB2 composite phase ceramics by mechanical alloying reaction mechanism regularity as provides the theory basis for as many relevant applications in situ reaction and plasma spraying technology; At the same time, in order to further explore and research to improve the surface coatings of aluminum alloy density, this paper deeper discussed the attached Al binder in Al-TiO2-B2O3 ternary reaction system of powders preparation of good comprehensive performance of Al-Al2O3-TiB2 composite reaction conditions, and analysis of binder Al at inspraying effect in the reaction and synthetic good density Al-Al2O3-TiB2 composite material reaction mechanism.This papers’ topic is based on Al-TiO2-B2O3 ternary reaction powders as raw material, around the critical grain mechanism, the critical strain mechanism, the critical ignition temperature reducing mechanism in detail to discussed the thermodynamic feasibility analysis of series powder reaction, and produce by-products in turn. To detected particles performance by SEM, XRD analysis and TG and DSC analysis during ball-mill time, and the experimental results show that when ball-milled time at 12 hours have obtained small complex composite particles, and at 16 hours ignited self-propagating combustion reaction to generate the required Al2O3-TiB2 composites; and TG-DSC experiment curve analysis ball milled 12-hours of Al-TiO2-B2O3 ternary reaction powders, its combustion reaction method has been developed from the original 670～960 ℃ heating to keep continuous exothermic reaction change into sharp exothermic reaction at 560 ℃; by starink method can calculated activation energy values, witch the vales at 12-hours ball-mill time only a quarter of raw materials, and in the line with Forrester put forwarded the critical ignition temperature conclusion.On the analysis of the binder Al effect in the reactive spraying and synthetic Al-Al2O3-TiB2 composite reaction mechanism, and further discusses the 5-25 wt.% Al binder in Al-TiO2-B2O3 performance during mechanical alloying and TG-DSC experiment. The results show that the adhesive Al powder can effectively refine the grain size, effectively reduce the contact with elements diffusion, while reducing partial melting ignited reaction probability to inhibit combustion reaction degree so that can get nearly nanoscale Al-TiO2-B2O3 complex reactive particles; High-energy compound reaction particles under the condition of 560 ℃ heating can be violent reaction to generate tiny Al2O3, TiB2, with internal system exothermal lead Al melt, the molten Al fluid can spread on Al2O3 and TiB2 particles surface and in pore of diffusion capillary so...