Effect Of Ceramic Particles On Corrosion Behavior Of Al-Zn-Sn-Ga Alloy

In order to solve the problems in conventional stage acidizing and fracturing operations,such as the failure of fracturing balls to flow back smoothly,the small production diameter,the need for drilling and plugging after pressure and other complicated processes and long construction time,a new technology was developed to apply soluble composite metal materials in oil and gas development engineering.At present,there are still some problems such as fast corrosion rate and insufficient alloy strength in the practical application of soluble aluminum alloy materials.It is found that the addition of ceramic particles can effectively enhance the mechanical strength of the soluble aluminum alloy and adjust the corrosion rate to a certain extent.In this paper,soluble aluminum alloys containing Ti B₂ and Si C with different contents（0.5wt%,1wt%）and different sizes（50nm,500nm,1～2μm）were prepared by stirring melting method,and various soluble aluminum matrix composites were obtained.The phase composition of the alloy was analyzed by means of metallographic observation,scanning electron microscope and X-ray diffraction.The corrosion properties,electrochemical properties and hardness were analyzed by immersion corrosion test,electrochemical workstation and microhardness tester.The influence of ceramic particles on corrosion properties of soluble aluminum alloy was summarized and the reasons were analyzed.It is found that when ceramic particles are added into Al-7Zn-3Sn-2.5Ga soluble aluminum alloy,the grain size of the alloy is refined,the grain size is reduced,and the hardness is effectively improved.The grain refinement effect of Ti B₂ is slightly better than that of Si C at the same size and content.The average grain size of both particles is the minimum when the content is 1wt%and the size is 500nm.When the particle size is lower than 50nm,the increase of grain content has no obvious effect on grain refinement.In addition,the microhardness of the two compounds is the highest when the size is 500nm,and further increases with the increase of content.The different content and particle size of Ti B₂ and Si C in the alloy will cause the change of the self-etching potential and the self-etching current density.The content and size of the two alloys are positively correlated with the self-corrosion tendency of the alloys,and the self-corrosion tendency is maximum when the content is 1wt%and the size is 1～2μm.The test and analysis of the solubility of two kinds of soluble aluminum-based ceramic composites in 3.5wt%Na Cl solution showed that during the process of dissolution,the pitting began at first,and then the pitting pit became deeper and gradually affected the surrounding area.When higher content of ceramic particles is added,the precipitated phase at grain boundary increases,and the intergranular corrosion becomes more serious,leading to faster dissolution rate of the alloy.Larger particle size will affect the integrity of the protective film on the surface of the alloy,making it more vulnerable to destruction.In addition,due to the accumulation of corrosion products in the corrosion pit,the dissolution rate of the alloy can not be maintained at a high level,and almost all alloy will gradually decrease after soaking for 90～120h.