Study On The Coating Preparation And Corrosion Resistance Of Zn-Ti-Al Ternary Alloy

To improve the corrosion resistance of steel, hot-dip with a simple operation, low cost of production, strong adaptability and good protective effects can be one of the most important ways. Hover, people's needs of antiseptic engineering is higher and higher, the traditional zinc coating is no longer satisfy the needs of people's production and daily life.Current research topics which the domestic and foreign academicians study, have changed from a single coating to a multi-zinc-based alloy. With the excellent corrosion resistance, Al and Ti are often used in various corrosive media, and Al is the most widely used alloying elements in hot-dip areas, Ti is less. On the basis of hot-dip basic theory and traditional craft, this paper will optimize and determine the Ti and Al content and additional way, prepare Zn-Ti-Al alloy coating, study on the corrosion resistance of the Zn-Ti-Al ternary alloy coating, and explore the corrosion mechanism further.Firstly, according to the analysis of phase diagram and theoretical calculation, and made the Zn-Ti binary alloy, and then prepared the Zn-Ti alloy coatings in different levels of Ti. Using the assessment of appearance quality, the surface hardness test, electrochemical test, neutral salt spray test and other analytical test methods, and found that the number of 4*,6 #,7# Zn-Ti binary alloy coating re nearly the same as pure zinc coating, while the corrosion resistance is better than the pure zinc coating, which met the follow-up tests.Secondly, added Al into the number of 4#,6#,7# binary alloy liquid, to get a Zn-Ti-Al ternary alloy plating in different levels of Al. Using the assessment of appearance quality, the surface hardness test, electrochemical test, neutral salt spray test and other analytical test methods, and found that added Al can improve the quality and smoothness of the surface coating. But the impact of coating corrosion resistance was more complex. Among the ternary alloy coatings, the number of 6-4# has the most excellent corrosion resistance.Finally, through the way of SEM, EDS, XPS and other methods, tested the coating microstructure, coating the surface material morphology of Zn-Ti and Zn-Ti-Al alloy to determine the way which Ti and Al alloy coating to improve corrosion resistance. Test results shod that Ti not only changed the internal organizational structure of Zn-Ti alloy coating, facilitatingζphase layer thinner or disappear, making the entire coating become more dense, but also caused changes in material form of the surface coating, which covered by a layer of dense TiO2 layer in surface of the alloy plating. Thereby, it increased the corrosion resistance of Zn-Ti binary alloy coating. Al also influenced on the structure of Zn-Ti-Al alloy coating, it caused the internal organization layered not obviously, the traditional shape of theδ-phase layer andζ-phase layer replaced by a new granular layer of theδ-phase, and Ti or Al oxides in the surface coating re not find.This shows that added Ti and Al have changed the internal organization structure and the material form in the surface coating, thus their corrosion resistance was improved.