Research On Thermal Storage Properties Of Phase-change Materials Based On Mg-Cu-Zn-Al-Si Alloy

With the coming of21stcentury, economic internationalization have bringvirous opportunities as well as obvious environmental problems. The national fog hasmade it even worse and give birth a nervous concern about ecological balance as aresult of environmental pollution. Solar energy as a clean resource, characterized byan inexhaustible supply.The problem of environmental pollution will controlefficiently with the solar energy fully exploited. Latent heat storage materials are,however, the key ingredients for powering in that composite heat storage materialwith metal and molten have some advantages in the function of higher temperatureand stronger capacity of heat storaging.This paper has developed four kinds of Mg-Cu-Zn alloy and Mg-Cu-Zn-Al-Sialloy on the basis of Mg-25Cu-15Zn eutectic alloy by adding Al element and Sielement. It analyses microstructure through the metallurgical microscope and X-raydiffraction, measures phase inversion temperature and latent heat with differentialscanning calorimetric. At the same time, it employs respectively two principles ofNeumann-kopp and Archimedes to measure heat capacity of alloy and material denseunder the condition of draining. The result is as follows. Both the sensible heat andlatent heat has served as important factors for heat storage because Mg-25Cu-15Znalloy has a strongest capacity of latent heat storage and a largest number of total heatstorage with the value of238.6Joule per gram and1033.0Joule per cubic centimeterrespectively. More quantities of the elements of Al and Si added, higher values oflatent heat and the whole heat storage per volume, even Mg-17.9Cu-10.8Zn-21.3Al-7.1Si alloy can reach values of265.9Joule per gram and1358.7Joule per cubiccentimeter respectively.This paper studies the corrosion property of liquid Mg-17.9Cu-10.8Zn-21.3Al-7.1Sia latent heat sample of virous steels such as20steel, A3steel,18Cr9Nistainless and0Cr25Ni20stainless under the temperature of500centigrade. It analyseserosive microstructure through microscopes and XRD diffraction, study theconsistency of alloy and container by measuring erosive layer with scanningelectronic, measuring the thickness of microprobe erosive layer with photometric analyzer.The result indicated that the erosive layer of iron steel is a loose and joggedstructure, while the erosive layer of stainless is a dense and even structure. Althoughit includes two elements of Fe and Mg and decrease in the thickness, stainless haslittle thickness of erosive layer than iron steel. The delicate erosion of liquidMg-17.9Cu-10.8Zn-21.3Al-7.1Si alloy is as follows though tests. As a start, twokinds of atomics of Mg and Al touch with the erosive layer parameters under the hotconditions, subsequently bring continuous erosive layers, finally the atomics of Mgwill spread from the dense regions to sparse regions. What’s more, BoundarySegregation of alloy elements of stainless occurs on crystal interface, forming aprotective layer in order to hider diffusion of Mg atomics. Since the perversion isstronger than C atomics, it makes the speed of forming erosive layers more slowly.Collusively, stainless has a prior to iron steel bearing corrosion.Through the field monitoring, studies have find Mg-Cu-Zn-Al-Si alloy havesome incomparable advantages than pure Al element such as well heat naturalproperties, better compatibility and better potation as a latent heat material.